Applied Science, Faculty of
Engineering, School of (Okanagan)
DSpace
UBCO
Haibo, Feng
Doctor of Philosophy - PhD
University of British Columbia
The environmental impacts of building stock have received significant attention in recent years, as buildings consume more than 40% of the world’s energy and release one third of total greenhouse gas emissions. In the past, most efforts were focused on mitigating environmental impacts during the operational stage of buildings, while the environmental performance of the other life cycle stages received limited attention. In an attempt to address this limitation, whole-building life cycle assessment (WBLCA) has become a trend in order to ensure the best environmental performance of a building in holistic terms. However, research studies usually face challenges to systematically evaluating WBLCA performance at the design stage due to the complexity of assessments at the building level. On the other hand, there are very few studies that consider environmental and economic impacts simultaneously at the building level. Furthermore, the current WBLCA studies usually end after the LCA results are calculated and interpreted. There is no study that provides a building design improvement method based on the final LCA results. The main goal of this research is to develop a design improvement framework based on the proposed WBLCA method to evaluate and improve the environmental and economic performance at the building level. The Environmental Product Declaration (EPD) methods were adopted at the building level to ensure the WBLCA is comprehensive and reliable. Building Information Modelling (BIM) and life cycle cost (LCC) were used to ensure the building assemblies are accurate, and to provide dynamic material updates with associated costs for the design improvement framework. The fuzzy-based multiple criteria decision making (MCDM) approach was used to compare the comprehensive building-level LCA results, and select the most suitable building design by considering all the environmental and economic impacts at different life cycle stages. The deliverables of this research will aid in decision making for sustainable urban planning and environmental performances in the building sector. The developed design improvement framework will assist building designers in efficiently improving the WBLCA performance by highlighting the most critical life cycle stages and building assemblies while considering the economic performance. The BIM-based WBLCA approach will contribute to the development of a digital platform that can also support designers through dynamic WBLCA results in the design revision stages.
WHOLE BUILDING LIFE CYCLE ASSESSMENT FOR RESIDENTIAL BUILDINGS: A DESIGN IMPROVEMENT FRAMEWORK by Haibo Feng M.A.Sc., The University of British Columbia, 2013 B.Sc. (Eng.), Wuhan University of Science and Technology, 2008 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE COLLEGE OF GRADUATE STUDIES (Civil Engineering) THE UNIVERSITY OF BRITISH COLUMBIA (Okanagan) October 2020 © Haibo Feng, 2020 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the dissertation entitled: BIM-EPD based whole-building life cycle assessment for single family houses: A design optimization framework submitted by Haibo Feng in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Civil Engineering Examining Committee: Dr. Kasun Hewage, School of Engineering Supervisor Dr. Rehan Sadiq, School of Engineering Co-Supervisor Dr. Zheng Liu, School of Engineering Supervisory Committee Member Dr. Sumi Siddiqua, School of Engineering Supervisory Committee Member Dr. Nathan Pelletier, School of Management University Examiner Dr. Fuzhan Nasiri, Department of Building, Civil and Environmental Engineering, Concordia University External Examiner iii Abstract The environmental impacts of building stock have received significant attention in recent years, as buildings consume more than 40% of the world’s energy and release one third of total greenhouse gas emissions. In the past, most efforts were focused on mitigating environmental impacts during the operational stage of buildings, while the environmental performance of the other life cycle stages received limited attention. In an attempt to address this limitation, whole-building life cycle assessment (WBLCA) has become a trend in order to ensure the best environmental performance of a building in holistic terms. However, research studies usually face challenges to systematically evaluating WBLCA performance at the design stage due to the complexity of assessments at the building level. On the other hand, there are very few studies that consider environmental and economic impacts simultaneously at the building level. Furthermore, the current WBLCA studies usually end after the LCA results are calculated and interpreted. There is no study that provides a building design improvement method based on the final LCA results. The main goal of this research is to develop a design improvement framework based on the proposed WBLCA method to evaluate and improve the environmental and economic performance at the building level. The Environmental Product Declaration (EPD) methods were adopted at the building level to ensure the WBLCA is comprehensive and reliable. Building Information Modelling (BIM) and life cycle cost (LCC) were used to ensure the building assemblies are accurate, and to provide dynamic material updates with associated costs for the design improvement framework. The fuzzy-based multiple criteria decision making (MCDM) approach was used to compare the comprehensive building-level LCA results, and select the most suitable building design by considering all the environmental and economic impacts at different life cycle stages. The deliverables of this research will aid in decision making for sustainable urban planning and environmental performances in the building sector. The developed design improvement framework will assist building designers in efficiently improving the WBLCA performance by highlighting the most critical life cycle stages and building assemblies while considering the economic performance. The BIM-based WBLCA approach will contribute to the development of a digital platform that can also support designers through dynamic WBLCA results in the design revision stages. iv Lay Summary This study aimed to promote the evidence-based development of environmental-friendly and cost-effective single-family houses in British Columbia and across Canada. The main goal was to develop a design improvement framework based on whole-building life cycle assessment (WBLCA) by integrating with standard environmental and cost declaration methods, and the BIM platform. WBLCA is used to calculate environmental and economic impacts not only during the operational stage, but also during material manufacturing and transportation, and building construction and demolition. Environmental Product Declaration (EPD) is a method that reports the environmental impacts of building materials, using reliable data verified by a third party. This study integrates the EPD method into WBLCA, to develop more reliable and comprehensive impact results. This study also applies the BIM-based dynamic life cycle cost assessment technique to WBLCA, to evaluate the design options with more affordable costs. The results can be used to help building designers and municipalities to identify optimal choices, to improve the whole life cycle performance within the building sector by considering both environmental and economic impacts. v Preface I, Haibo Feng, intellectualized and developed the entire thesis under the supervision of Dr. Kasun Hewage and Dr. Rehan Sadiq. Five journal articles, two conference proceedings, and one poster presentation, which are currently published, accepted, or under review, have been prepared directly or indirectly from the research presented in this thesis. The first journal article was a literature review on the development of environmental product declaration (EPD) in the building sector globally. The second journal article was focused on the WBLCA for an existing building under different renovation and reconstruction strategies. The third journal article was focused on the development of a design optimization framework for designers to achieve the best WBLCA performance with the support of BIM and EPD. The fourth journal article was focused on the comparison of two typical single-family houses under different building standards, with the WBLCA method developed in the third journal article, and the MCDM approach to treat and compare the LCA results. The fifth journal article was an extended work based on the future work of the thesis. Two conference proceedings and one poster presentation were developed as extensions of the first and second articles. Journal Articles: 1. Feng, H., Hewage, K., and Sadiq, R., (2020). Environmental product declaration for a whole-building life cycle assessment: A review (2nd revision). Canadian Journal of Civil Engineering. CJCE-2020-0284. 2. Feng, H., Liyanage, D. R., Karunathilake, H., Sadiq, R., & Hewage, K. (2019). BIM-based life cycle environmental performance assessment of single-family houses: Renovation and reconstruction strategies for aging building stock in British Columbia. Journal of Cleaner Production. https://doi.org/10.1016/j.jclepro.2019.119543. 3. Feng, H., Hewage, K., and Sadiq, R., (2020). BIM-based whole building life cycle assessment with Environmental Product Declaration: A design optimization framework (submitted). Automation in Construction. AUTCON-D-20-00128. vi Journal Articles under preparation 4. Feng, H., Hewage, K., Sadiq, R. (2020). BIM-based whole-building life cycle assessments between a net-zero energy building and a code-specified building: A fuzzy MCDM approach. (Expected to be submitted to Building and Environment (Elsevier) in September 2020.) 5. Feng, H., Hewage, K., Sadiq, R. (2020). Uncertainties in Whole-building life cycle assessment: A review. (Expected to be submitted to International Journal of Life Cycle Assessment (Elsevier) in August 2020.) Conference Articles: 1. Feng, H., Hewage, K., and Sadiq, R. (2019), Life cycle environmental and cost analysis for single family houses with different renovation strategies. ISIE conference, July 7-11, 2019. Beijing, China. 2. Feng, H., Hewage, K., and Sadiq, R. (2019), Is it better to renovate an old house or rebuild it? International Symposium for sustainable systems and technology, June 25-28, 2019. Portland, Oregon. (Best poster presentation award) 3. Feng, H., Hewage, K., and Sadiq, R. (2018), Comparative Analysis of Environmental Product Declarations on Building softwoods under different Product Category Rules. NHICE 01 – 1st International Conference on New Horizons in Green Civil Engineering, April 25-27, 2018. Victoria, BC. vii Table of Contents Abstract ......................................................................................................................................... iii Lay Summary ............................................................................................................................... iv Preface .............................................................................................................................................v Table of Contents ........................................................................................................................ vii List of Tables ............................................................................................................................... xii List of Figures ............................................................................................................................. xiv List of Abbreviations ................................................................................................................. xvi Acknowledgements ................................................................................................................... xvii Dedication ................................................................................................................................... xix Chapter 1: Introduction ................................................................................................................1 Background and pressures .............................................................................................. 1 Research gap ................................................................................................................... 2 Research motivation........................................................................................................ 4 Research objectives ......................................................................................................... 5 Thesis organisation ......................................................................................................... 6 Chapter 2: Research Methodology ...............................................................................................8 Chapter 3: Literature Review .....................................................................................................11 The status of whole-building LCA ............................................................................... 11 Challenges of whole-building LCA .............................................................................. 12 EPD – the future of sustainability communication ....................................................... 17 3.3.1 EPD for building and construction materials ........................................................ 19 3.3.2 International trend in EPD development............................................................... 20 3.3.2.1 In Europe ........................................................................................................... 20 3.3.2.2 In Asia ............................................................................................................... 21 viii 3.3.2.3 In North America .............................................................................................. 21 3.3.3 EPD development processes for building materials ............................................. 24 3.3.3.1 Step one – Search or create relevant PCR ........................................................ 24 3.3.3.2 Step two – Conduct and verify LCA................................................................. 25 3.3.3.3 Step three – Compile EPD ................................................................................ 27 3.3.3.4 Step four – Verify EPD ..................................................................................... 27 3.3.3.5 Step five – Register EPD .................................................................................. 28 3.3.4 EPD use in building labelling and certification schemes ...................................... 28 Building life cycle costing analysis .............................................................................. 30 Integration of BIM with LCA and LCC ....................................................................... 32 Chapter 4: Whole Building Life Cycle Assessment (WBLCA): An Integrated Approach with BIM, EPD and LCC .....................................................................................................................34 Background ................................................................................................................... 34 Methods and Procedure................................................................................................. 35 4.2.1 WBLCA development with EPD rules ................................................................. 37 4.2.1.1 Goal and scope definition with EPD ................................................................. 37 4.2.1.1.1 Functional equivalent .................................................................................. 38 4.2.1.1.2 Reference study period (RSP) ..................................................................... 38 4.2.1.1.3 System boundary ......................................................................................... 38 4.2.1.2 Life cycle inventory (LCI) analysis .................................................................. 39 4.2.1.2.1 Manufacturing stage (A1-A3) ..................................................................... 40 4.2.1.2.2 Construction stage (A4-A5) ........................................................................ 41 4.2.1.2.3 Usage stage (B1-B5) ................................................................................... 41 4.2.1.2.4 End-of-life stage (C1-C4) ........................................................................... 42 4.2.1.3 LCIA for WBLCA ............................................................................................ 42 4.2.1.4 Life cycle results interpretation for WBLCA ................................................... 45 ix 4.2.2 Whole building LCC development ....................................................................... 45 4.2.3 BIM Integration method ....................................................................................... 47 4.2.4 WBLCA results comparison with MCDM ........................................................... 49 Discussions ................................................................................................................... 50 Summary ....................................................................................................................... 52 Chapter 5: WBLCA for New Residential Buildings .................................................................53 Background ................................................................................................................... 53 Methods and procedure ................................................................................................. 54 5.2.1 Data collection ...................................................................................................... 54 5.2.1.1 Manufacturing stage (A1-A3) ........................................................................... 54 5.2.1.2 Construction stage (A4-A5) .............................................................................. 56 5.2.1.3 Usage stage (B1-B5) ......................................................................................... 57 5.2.1.4 Disposal stage (C1-C4) ..................................................................................... 57 5.2.2 Life cycle impact assessment ................................................................................ 57 5.2.3 LCC assessment .................................................................................................... 58 WBLCA results ............................................................................................................. 59 Building design improvement based on WBLCA results ............................................. 65 Discussion ..................................................................................................................... 68 Summary ....................................................................................................................... 72 Chapter 6: WBLCA for Existing Residential Building Renovations and Reconstruction ...74 Background ................................................................................................................... 74 Methods and Procedure................................................................................................. 77 6.2.1 Typical house selection and BIM model development ......................................... 77 6.2.1.1 Existing house selection and BIM model ......................................................... 77 6.2.1.2 BIM model of a newly built house ................................................................... 79 6.2.2 Scenario development ........................................................................................... 81 x 6.2.3 WBLCA data collection ........................................................................................ 85 6.2.3.1 Manufacturing stage.......................................................................................... 85 6.2.3.2 Construction stage ............................................................................................. 88 6.2.3.3 Usage stage ....................................................................................................... 88 6.2.3.4 Demolition stage ............................................................................................... 90 6.2.4 Life Cycle Impact Assessments ............................................................................ 91 6.2.4.1 Manufacturing stage (A1-A3) ........................................................................... 91 6.2.4.2 Construction stage (A4-A5) .............................................................................. 94 6.2.4.3 Usage stage (B1-B5) ......................................................................................... 95 6.2.4.4 Disposal stage (C1-C4) ..................................................................................... 96 6.2.5 LCC assessment .................................................................................................... 97 WBLCA results ............................................................................................................. 97 Discussions ................................................................................................................. 101 Summary ..................................................................................................................... 107 Chapter 7: Uncertainty Analysis for WBLCA ........................................................................108 Background ................................................................................................................. 108 Method and procedure ................................................................................................ 109 7.2.1 Fuzzy-based MCDM method .............................................................................. 110 Case study ................................................................................................................... 113 7.3.1 WBLCA calculations .......................................................................................... 117 7.3.1.1 Manufacturing stage (A1-A3) ......................................................................... 118 7.3.1.2 Construction stage (A4-A5) ............................................................................ 118 7.3.1.3 Usage stage (A4-A5)....................................................................................... 119 7.3.1.4 Disposal stage (C1-C4) ................................................................................... 119 7.3.2 Life cycle impact assessment .............................................................................. 120 7.3.3 LCC assessment .................................................................................................. 120 xi 7.3.4 Fuzzy MCDM approach for WBLCA results comparison ................................. 120 Results ......................................................................................................................... 121 Discussion ................................................................................................................... 128 Summary ..................................................................................................................... 131 Chapter 8: Conclusions and Recommendations .....................................................................132 Summary and Conclusions ......................................................................................... 132 Originality and Contributions ..................................................................................... 135 Limitations .................................................................................................................. 137 Future Research .......................................................................................................... 139 References ...................................................................................................................................141 Appendices ..................................................................................................................................163 Appendix A : Data collection scenario tables for Chapter 5 .................................................. 163 Appendix B : WBLCA results of the case study for Chapter 5 .............................................. 173 Appendix C : Data collections of WBLCA results of different scenario analysis in Chapter 7................................................................................................................................................. 175 Appendix D : Data collections of WBLCA results of different scenario analysis in Chapter 6................................................................................................................................................. 192 xii List of Tables Table 3-1: WBLCA methods applied in green building certification schemes. ........................... 12 Table 3-2: The inconsistency of WBLCA methods in different case studies. .............................. 15 Table 3-3: Summary of EPD programs currently operating in the world..................................... 22 Table 3-4: The PCR development stage [61][91]. ........................................................................ 25 Table 4-1: Functional equivalent of the proposed method ........................................................... 38 Table 4-2: System boundary of a whole building LCA according to EN 15978. ......................... 39 Table 4-3: Building elements that are included in the proposed LCA method [138]. .................. 41 Table 4-4: Environmental indicators declared in LCIA, based on EN15978 standard [135] ....... 43 Table 5-1: Bill of quantities for the studied single-family house (summarized from BIM output)....................................................................................................................................................... 55 Table 5-2: Environmental indicators and the evaluation methods [135] ...................................... 58 Table 5-3: WBLCA results: environmental impact results from each building module in different category ......................................................................................................................................... 60 Table 5-4: BIM model optimization details for two design revisions. ......................................... 66 Table 6-1: Points of renovation under the existing house renovation pilot project in Vancouver [197]. ............................................................................................................................................. 81 Table 6-2: Most common renovation locations for the existing old houses in Vancouver [198]. 81 Table 6-3: Thermal character of the mechanical systems and building envelopes of each scenario........................................................................................................................................................ 84 Table 6-4: Material quantities of existing house renovation and waste disposal for Scenario 3 .. 86 Table 6-5: Material quantities of existing house renovation and waste disposal for Scenario 4 .. 86 Table 6-6: Material quantities of new house construction based on BC building code for Scenario 5 (Generated from BIM model). ................................................................................................... 87 Table 6-7: Material quantities of new house construction based on passive house standard for Scenario 6 (Generated from BIM model). .................................................................................... 87 xiii Table 6-8: Lifespan of different building materials for single house [208] .................................. 90 Table 6-9: Recycling materials and percentages from house demolition. .................................... 91 Table 6-10: Unit environmental impacts of the materials for newly built house construction and existing house renovation ............................................................................................................. 92 Table 6-11: Summary of environmental impacts at product manufacturing stage ....................... 94 Table 6-12: Summary of environmental impacts at construction stage ........................................ 95 Table 6-13: Summary of annual environmental impacts at operational stage .............................. 96 Table 6-14: Summary of annual environmental impacts during maintenance ............................. 96 Table 6-15: Summary of annual environmental impacts at disposal stage ................................... 97 Table 6-16: WBLCA results from all the life cycle stages ........................................................... 98 Table 6-17: WBLCA results rankings with TOPSIS method ..................................................... 100 Table 6-18: WBLCA results for scenarios 2-4 ........................................................................... 101 Table 6-19: WBLCA results rankings with TOPSIS method ..................................................... 101 Table 7-1: Weighting factors assigned based on different stakeholders. .................................... 111 Table 7-2: Design specifications of building evelope and HVAC system in scenario 1 ............ 116 Table 7-3: Design specifications of building evelope and HVAC system in scenario 2 ............ 116 Table 7-4: Design specifications of building evelope and HVAC system in scenario 4 ............ 117 Table 7-5: The differences of material list among five scenarios ............................................... 118 Table 7-6: Annual energy use of single-family building in different scenarios (Output from HOT2000 simulation) ................................................................................................................. 119 Table 7-7: Triangular fuzzy number of WBLCA results ............................................................ 124 Table 7-8: Normalized decision matrix after fuzzy-based normalization .................................. 126 Table 7-9: Final scenario rankings with maximizing and minimizing set method ..................... 128 xiv List of Figures Figure 1-1: Integration of objectives and thesis organization ........ Error! Bookmark not defined. Figure 2-1: Phases of the research .................................................................................................. 8 Figure 3-1: ISO 14000 Framework for Environmental Certification [66][67]. ............................ 18 Figure 3-2: Regulatory framework for EPD of building materials ............................................... 19 Figure 3-3: EPD development process ......................................................................................... 24 Figure 3-4: Two options for EPD development (Derived from ISO 14025) ................................ 26 Figure 3-5: Hierarchy of ISO 15686 -5 standard [107] ................................................................ 31 Figure 4-1: WBLCA with the integration of EPD, BIM, and LCC development framework ...... 36 Figure 4-2: WBLCA development with EPD method .................................................................. 37 Figure 4-3: Matrix calculation method for module i of the building environmental impacts and relevant data sources ..................................................................................................................... 44 Figure 4-4: BIM integration details with EPD and LCC calculations .......................................... 48 Figure 5-1: 3D and 2D plan of the studied single-family house (derived from BIM model) ....... 54 Figure 5-2: Information module contribution to the WBLCA results .......................................... 61 Figure 5-3: LCA results for material usage in different building elements .................................. 63 Figure 5-4: Material type contribution to material use LCA results ............................................. 64 Figure 5-5: WBLCA results with different BIM designs ............................................................. 67 Figure 6-1: Materials of the existing house for BIM model input. ............................................... 79 Figure 6-2: First (left) and second (right) floor plans of the Existing House from Revit. ............ 79 Figure 6-3: Materials of the newly-built house for BIM model input. ......................................... 80 Figure 6-4: Basement (left) and first (middle) and second (right) floor plans of the Newly-built House. ........................................................................................................................................... 81 Figure 6-5: Operational energy simulation details with HOT2000 model. .................................. 89 Figure 6-6: Annual operational energy consumptions in each scenario ....................................... 95 Figure 6-7: Details of total GHG emission from different life cycle stages ................................. 99 xv Figure 7-1. Fuzzy ranking based on maximising set and minimising set ................................... 113 Figure 7-2: 3D and 2D layouts for a typical single family building in Kelowna BC ................. 115 Figure 7-3: The overall WBLCA performance index after fuzzy-based calculations ................ 127 Figure 8-1: Proposed strategic map ............................................................................................ 135 xvi List of Abbreviations Acronyms AHP Analytical Hierarchy Process BC British Columbia BMP Best management practices CPT Conditional probability table DST Decision support tool GHG Greenhouse gas GSHP Ground source heat pumps LCA Life cycle assessment LCC Life cycle costing LCI Life cycle inventory LCIA Life cycle impact assessment LCOE Levelized cost of energy MADM Multi-attribute decision making MCDM Multi-criteria decision making MODM Multi-objective decision making MOO Multi-objective optimisation MURB Multi-unit residential building NZE Net-zero energy OTEC Ocean thermal energy conversion PV Photovoltaics RDF Refuse derived fuel RE Renewable energy RES Renewable energy sources RET Renewable energy technologies ST Solar thermal TBL Triple bottom line WtE Waste-to-energy Abbreviations and units CAD Canadian Dollars GJ Gigajoule kW Kilowatt kWh Kilowatt-hours MWh Megawatt hours O&M Operations and maintenance USD United States Dollars xvii Acknowledgements My deepest gratitude goes to Dr. Kasun Hewage for his support and guidance throughout my graduate studies as the best supervisor and friend. He gave me the opportunity to come to Canada and carry out my graduate studies in an area that truly interested me at the University of British Columbia. He also provided me the best research platform with the most flexibility that made me who I am today. The experience and exposure I gained under his supervision during my time in his research group has made me a stronger professional, and has given me the confidence to succeed in my graduate studies and my career. I am forever indebted to him for the immense support, kindness, inspiration, and motivation he gave me. I wish to thank Dr. Rehan Sadiq for his support and mentorship throughout my time at UBC. Despite his busy schedule and numerous responsibilities, he is always providing brilliant suggestions with his wisdom, and showing us what a great scholar should be. He always finds time for me to discuss my research and help me in learning and developing new concepts, and he also spared his time to guide me towards being a better professional and a person. I was inspired to become a better academic from his example. I would like to also thank Dr. Zheng Liu for the advice he provided either for my academic career or for my personal development. I am lucky to have had him as a mentor during my PhD studies. I also would like to express my deep appreciation to my committee member, Dr. Sumi Siddiqua, for her continuous support in my PhD studies. In addition, my thanks also goes to Dr. Eric Li and Dr. Yang Cao for their kindness and support all the way as instructors and friends. Moreover, I would like to acknowledge the School of Engineering administrative staff, including Ms. Shannon Hohl, Ms. Angela Perry, Ms. Karen Seddon, and Ms. Teija Wakeman for their support. My PhD journey was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) through the Canada Graduate Scholarships - Doctoral Program. I would not be able to make it without their support. I would like to express my appreciation to NSERC Michael Smith Foreign Study Supplements and Dr. Guillaume Habert so that I could have visiting studies in ETH Zurich. I would also like to acknowledge the support from Dr. John Venderley and Ms. Fernanda Silva for their professional support on life cycle assessment. My great appreciation to Dr. Dezhi Li in Southeast University that brought me into the Chinese academia community. My great appreciation to Jennifer O’Connor and Matt Bowick from Athena Sustainable Materials Institute xviii for providing me guides and research materials for my PhD analysis. My great appreciation to all the faculty members and stuff in the School of Engineering who together provide me the best place to conduct my PhD studies. I treat Kelowna as my second home since I spent 9 years of my life in this beautiful place. I would love to express my appreciation to my dear friends John and Wendy Burn, Jeremy and Bobbi Newell, Moris and Ellen DiGiovanni, as well as all the badminton friends, Dr. Yong Gao, Dr. Adam Wei, Mr. Bing He, Mr. Guo, Victor family, Nianxin, etc., that show up every Monday and Thursday at 8:30pm, even on Christmas Eve. My love to the committee members, Taylor Liu, Qiang Li, Yakang Xia, Grace Liu, Lucy, Yanjie Dong, and Hongzheng Zhu of the Kelowna Chinese Student and Scholar Association that gives me opportunity to meet new friends and serve the Kelowna community. Throughout these years, I have received tremendous support from my colleagues at the Life Cycle Management Laboratory. Dr. Rajeev Ruparathna and Dr. Hirushie Karunathilake in particular were always generous with their advice and guidance. They always encouraged me to push past my limits to achieve higher expectations. Without their support, both professional and personal, I could not have succeeded in this task, and I would like to offer my special thanks to them. My warm gratitude goes to Piyaruwan Perera, Tharindu Prabatha, Gyan Kumar Chippi-Shrestha, Tharaka, Rukmal, Ravi, Ishanka and Kavisha, with all the pleasant time in EME 3287. My gratitude to Sarin, Manjot, Sana, Syed, Guangji, and Haroon for all the great time we had in Sunshine Cafeteria and the Wings pub. My gratitude to my Chinese mates, Ray He, Shiyao Zhu, Guowu Tao, Haonan Zhang, Peng Zhang that always stand by my side. My gratitude also goes to all the other members for their incredible friendship and companionship throughout my PhD studies. Lastly, I would like to thank my amazing parents and sisters, who always believed in me. They always supported me in every endeavour I undertook, and had more faith in my success than I myself ever did. I am grateful for their love and patience during all these years. To my wife, Yu Cao, for her warm support during the past years. Without her support and patience, accomplishing any of my achievement would not have been possible. To my son, Lucas Feng, that provides me endless courage and strength to face any life uncertainty in the future. xix Dedication Dedicated to my beloved family, friends, and teachers, Who loved me, protected me, and made me who I am… 1 Chapter 1: Introduction Background and pressures Canadian governments at all levels highly encourage economic progress through sustainable development and maintaining environmental sustainability. However, recent trends show a somewhat contradictory picture in practice [1]. Canada has “poor” environmental performance when compared to many developed countries, since Canada ranked 24th on an environmental performance index developed by Yale University [2]. The David Suzuki Foundation advocated that Canada has room to improve its current environmental performance and has the ability to become a world leader in sustainability [3]. Canada has taken several steps to reinforce sustainable development. Reducing greenhouse gas (GHG) emissions and the environmental footprint are priority themes of the Federal Sustainable Development Strategy (FSDS) of Canada [4]. The Government of Canada has set an ambitious emissions reduction target: to cut greenhouse gas (GHG) emissions by 80% from the 2005 levels by 2050 [5]. However, recent reports reveal that Canada will miss its 2020 GHG emission reduction targets [6]. Consequently, Canada has to pursue an aggressive strategy to achieve the above targets [7]. The building sector has a significant impact on Canada’s total natural resource consumption and on released emissions. According to Industry Canada, buildings consume 50% of extracted natural resources and 33% of the country’s energy use. In addition, buildings produce 25% of the landfill waste, 10% of airborne particles, and 35% of greenhouse gas (GHG) emissions [8]. One reason for this magnitude is that Canadians spend about 90% of their time inside buildings, whether at homes, work, or play [9]. Due to the above concerns, the Canadian building sector will play a major role in enhancing Canada’s sustainability performance. More specifically, residential buildings account for a major portion of the building stock in Canada [10]. With the global demand for new residential buildings expected to grow steadily, there is a substantial push towards more sustainable and resilient buildings. Many strategies have been introduced to improve building performance, such as green buildings, zero-energy buildings, and building rating systems [11–13]. But only a few of these methods consider life cycle impacts [14]. 2 More importantly, popular rating systems fail to rank a building considering life cycle-based criteria, as they are primarily design tools that do not consider the overall performance of the buildings [15]. The current rating systems are not suited for monitoring the environmental performance of buildings throughout their entire life cycle. Hence, new methods and approaches are necessary to assess and monitor the environmental performance of buildings. Life cycle assessment (LCA) is one of the most popular tools to evaluate building performance, as it provides ways to access the resource and emission flows of a building throughout its service life [16,17]. The whole-building LCA (WBLCA) method has been proposed in different studies to provide a holistic picture of building performance using science-based, standardized metrics [18,19]. WBLCA covers the environmental performance of a building throughout its service life to avoid passing the environmental load from one life cycle phase to another in the process of decision making. Since environmental impacts during the operational stage are not the only ones considered, the manufacturing, maintenance, and disposal stages are also monitored in WBLCA. However, due to the complexity of building structures, the variability in building and material lifespans, and the design quality, current studies usually face challenges when applying the LCA for a whole building [20][21]. At the same time, life cycle cost should be considered simultaneously while improving environmental performance. A comprehensive method for performing an environmental and cost-based WBLCA is required to obtain LCA results that are easily understandable and comparable. Research gap A comprehensive literature review of environmental and economic performance assessments at the building level revealed several gaps in the current body of knowledge. Comprehensive method is lacking in whole-building life cycle assessment: Due to the flexibility of LCA development standards and the complexity of building structures, WBLCA studies usually have different assumptions and limitations, which make the LCA results unreliable and incomparable between buildings [20]. For example, there are differences in LCA scopes and data collection methods, deviations in building assemblies, and variances in life cycle stages and impact categories [19,21]. The published literature highlighted a lack of comprehensive methods to conduct whole-building life cycle assessment. 3 Life cycle assessment and economic analysis have rarely been studied together in WBLCA: Due to the development rules defined by international standards, it is already very complicated to conduct a WBLCA. Therefore, there are limited studies that consider the economic impacts while conducting WBLCA. However, the best environmental performance does not always make sense from a cost perspective. Building designers, contractors, and city planners usually make project cost a priority before finalizing a design option. Therefore, it is necessary to propose building-level LCA studies that can offer the best options to balance environmental and economic impacts. Existing building renovation strategy is limiting to achieve the best whole-building life cycle performance in terms of environment and cost: Literature shows that over 50% of residential buildings are more than 30 years old, and over 20% of residential buildings are more than 50 years old in Canada [22]. Two common options to improve the environmental performance of existing buildings are renovation and reconstruction. Renovations are expected to reduce the building energy consumption and emissions, while the embodied energy and material use during renovation might outweigh any potential environmental benefits gained through their use [23]. On the other hand, renovation is largely based on the intention of the building owners, and the costs of different renovation strategies should be evaluated with environmental performance to provide more reasonable building solutions. Therefore, it is necessary to have building renovation strategies to analyze different levels of renovation and ensure the best output of whole-building life cycle performance for existing buildings in terms of environment and cost, which is currently lacking in the literature. No design improvement framework to achieve the best whole-building life cycle performance: WBLCA studies usually end after the LCA results are interpreted, and there is rarely a study that provides guidance for building designers to further improve the building design based on the WBLCA results [24,25]. While the current focus of WBLCA studies is to assess building performance, the true values of WBLCA results should be further extended to improve the building performance with detailed procedures. Whole-building life cycle assessment results with multiple impact factors have not been properly analyzed: With commonly-used life cycle impact assessment methods, the WBLCA results come with a set of impact factors. In order to evaluate the environmental performance of two residential buildings with the same functional unit, the results are usually treated as a single unit for 4 comparison. One of the common paths is to go through results normalization. However, WBLCA results normalization is not the best way to compare the performance of two buildings, since the comprehensiveness of the WBLCA results are usually simplified with subjective weightings [26,27]. There is a lack of approach that uses multi-criteria decision making analysis to compare two sets of WBLCA results with different impact factors. Considering the above limitations in the existing body of knowledge, the following research questions arose in this study. i) How to develop a comprehensive WBLCA method with consideration of environmental and economic impacts at all life cycle stages to ensure reliable and comparable LCA results? ii) How to improve a new building design to achieve the best WBLCA performance? iii) How can existing buildings be renovated to achieve the best WBLCA performance? iv) How to analyze and compare WBLCA results under uncertainty? Research motivation It is often assumed that a building has more operational carbon emissions than embodied carbon emissions. Therefore, the building industry currently focuses on reducing operational carbon emissions [28][29]. While innovations and technological advances are applied during this phase to reduce operational carbon emissions in buildings, these actions often lead to emission increases in other life cycle phases, such as in the materials production phase or the demolition phase [30]. Other studies show that embodied carbon emissions from building materials also contribute significantly to their life cycle emissions. On the other hand, the traditional method to enhance building environmental performance is to focus on building elements that are easily managed by building designers, such as the energy reduction calculation in the operation stage, or waste production control in the construction stage [31,32]. However, this trend does not provide designers a complete understanding of the building’s environmental performance, which makes it difficult for designers to make the best decisions for overall building environmental performance. Moreover, improvements to building environmental performance usually lead to cost increase. It is necessary to monitor economic performance while reducing the overall environmental impacts. The motivation for the research stems from the evident need for a consolidated approach to developing a comprehensive WBLCA method, and conducting building design improvement using this method. Researchers and practitioners are applying WBLCA in their studies while they 5 pursue more sustainable building performance. However, WBLCA development methodologies are different among those studies. Although there are basic guidelines for WBLCA development, the flexibility of the current standards creates uncertainties in the results, and economic performance has rarely been evaluated together with WBLCA development. Leadership in Energy and Environmental Design (LEED), the most popular sustainable building rating system in North America, also granted credits for WBLCA reports [33]. However, there is little information from the rating system about how to conduct a WBLCA and how to specifically compare the original design with the upgraded design to measure improvement. Furthermore, the designer does not receive any practical guidelines from the LEED reports about how to improve the WBLCA performance. This research aims to develop a dynamic design improvement framework to enhance the overall environmental performance of residential buildings by developing a comprehensive WBLCA that provides systematic and reliable LCA results with the support of digital platforms and well-known assessment tools such as Building Information Modelling (BIM) and Environmental Product Declaration (EPD). This research would assist building designers to better capture and improve the overall environmental and economic performance of residential building design by providing the most comprehensive environmental and economic information in buildings throughout their life cycle. This research would contribute to implementing and managing city-level environmental performance improvement in the residential building sector to ensure environmental protection, reduce energy resource use and waste disposal, balance the overall cost, and improve the quality of life. The developed resources would help to minimize the knowledge gap in the practical use of LCA as a decision-making tool in the building sector. Research objectives The main goal of this research is to develop a life cycle thinking-based framework for assessing whole-building environmental and economic performance of residential buildings. The specific sub-objectives of the research are outlined below. i) Identify current developments, technical constraints, data requirements, and potential applications of WBLCA in residential construction. ii) Develop comprehensive guidelines for WBLCA by incorporating EPD/LCC and BIM for residential buildings. 6 iii) Propose a WBLCA-based design improvement framework to achieve enhanced environmental and economic performance of new buildings. iv) Apply the proposed WBLCA method to identify the most pragmatic renovation strategies for existing buildings. v) Develop a method to evaluate, compare, and interpret the WBLCA results in consideration of uncertainty. The deliverables of this research will act as an aid in decision making for community-level planning and improvement in the building sector, with a focus on ensuring the best performance in environmental impacts, resource use, and waste disposal. The outcomes are expected to bring the concept of WBLCA to community-level planning, specifically for residential communities. In addition to delivering optimum environmental and economic performance to existing buildings and new developments, it will also align with the climate action goals held by government bodies across Canada, such as the BC Energy Step Code. Building designers and developers will be guided through the design optimization framework without additional burdens being placed on them for in-depth technical expertise. Furthermore, this research will be a step towards ensuring the best management practices are followed at the planning stage of community development. The findings can be potentially further extended and adapted for different building types. Thesis organisation This thesis consists of eight chapters, which focus on the literature review, methods used, findings, and conclusions. Chapter 1: This chapter provides an overall introduction to the background and pressures, research gaps, motivation, objectives and deliverables, main concepts, and the overall design optimization framework proposed in the study. Chapter 2: This is a summary of the methodology followed in the thesis. The chapter provides an insight into the key research phases and methods followed in achieving the goals of each phase. Chapter 3: The third chapter provides a comprehensive literature review on the current state and needs for WBLCA, state-of-the-art building environmental performance evaluation technologies, and the methods used in developing the planning framework. Chapter 4: This chapter presents the detailed processes to develop the comprehensive WBLCA method for residential buildings based on technical viability and international standards. The EPD 7 method is integrated into the WBLCA development processes to ensure the reliability and comprehensiveness of the LCA results for building-level environmental performance evaluation. Dynamic Building Information Modelling (BIM) is used to ensure the comprehensiveness of the input data for the building assemblies, as well as the efficient reflection on design revisions and cost. Chapter 5: In this chapter, the proposed WBLCA method is applied to improve new building designs. A single-family detached house is selected for this case study by strictly following the WBLCA development method. The WBLCA results are calculated and arranged properly with key contributors in terms of building assemblies and life cycle stages, and the design revisions are proposed based on the performance of these contributors. A new building design improvement framework is established based on this case study to efficiently improve the environmental performance while balancing the cost. Chapter 6: In this chapter, the proposed WBLCA method is applied to develop existing building renovation strategies. The detailed renovation scenarios are developed based on data gathered from the existing building renovation program conducted in BC Canada. The proposed WBLCA development method is used to calculate the environmental and economic performance of each scenario. The WBLCA results are calculated, interpreted, and compared to select the best overall performance for different levels of existing building renovation strategies. The guideline for existing building renovations is proposed for community-level planning use. Chapter 7: In this chapter, a fuzzy-based MCDM approach is used to conduct uncertainty analysis for the proposed WBLCA method. Fuzzy logic is used to ensure the effectiveness and accuracy of results analysis. A detailed method for conducting the fuzzy-based MCMD is developed, and a case study is conducted to demonstrate the uncertainty analysis method. Building scenarios with different design requirements and energy performance are established in the case study. Chapter 8: This chapter is focused on the conclusions derived from the study, recommendations and future work, originality, and avenues for future research. Figure 1-1 depicts the connection between the research objectives and the chapters, and the content in each chapter. The activities carried out to achieve each objective, and the main outcome of the objective are displayed in the figure, under the relevant chapters. 8 Figure 1-1: Integration of objectives and thesis organization 9 Chapter 2: Research Methodology The focus of the research is to develop a building design improvement framework by integrating EPD, LCC, and BIM techniques. The objectives were achieved in several research phases. The details of the proposed framework and demonstration steps are explained in the body of this thesis. Figure 2-1 depicts the connections between various research phases. Figure 2-1: Phases of the research 10 The detailed methodology followed in each phase is presented in individual chapters. The following is a summary of the methodology followed in this research. Phase 1 – Literature review and data collection This phase involved a comprehensive literature review on sustainable building technologies and environmental product declarations. Moreover, the challenges of building-level LCA, and the developments of EPDs on the building sector were investigated to demonstrate the necessity for this study. The review was based on the articles published in the past 20 years in high impact-factor journals on building level LCA. Multiple sources were used to obtain data for the following phases, including reports and standards published globally by reputable organizations, case studies, feasibility studies, LCA databases, building energy code, existing building data sets, ISO/EN standards, and best management guidelines. Building design plans were collected for the detailed building assemblies, energy technologies, and emission performances. Regular communications were held with project partners for determining and refining the specific data requirements. The detailed findings of the literature review and data collection are presented in Chapter 3. Phase 2 – Comprehensive WBLCA method development Based on the literature review on Phase 1, a comprehensive whole-building LCA method with the integration of EPD/LCC and BIM was developed for the environmental and economic performance of single-family buildings with the aim of generating reliable and detailed LCA results. The international standards EN 15978 and ISO 21930 were studied to define the fundamental requirements for developing WBLCA with EPD, including goal and scope, scenario development and life cycle inventory analysis, life cycle impact assessment, and results interpretations. The international standard ISO 15686-5 was also analyzed to set up the rules for developing building level LCC analysis. The building assemblies that were included in the proposed WBLCA method were defined based on the Uniformat method. The BIM technique was integrated throughout the WBLCA development processes to improve the efficiency and accuracy of data collection and calculations. The detailed methodology of the proposed WBLCA method is provided in Chapter 4, section 4.2. Phase 3 – Design improvement framework for new building design with WBLCA method A design improvement framework was developed for new building designs based on the proposed WBLCA method. A typical new building plan was selected and the WBLCA results were 11 calculated based on the proposed WBLCA method in terms of LCA and LCC performance. The contribution analysis was conducted by arranging the comprehensive WBLCA results at the life cycle module level, building assembly level, and building material level. The building design revisions were proposed based on the most significant impacts from contribution analysis, and the comparable analysis was conducted of the revised building designs as well as the original design using the TOPSIS method. The design option with the best LCA and LCC performance through comparable analysis was selected as the design improvement strategy. The detailed methodology of the proposed design improvement framework is provided in Chapter 5, section 5.2 – 5.4. Phase 4 – Existing building renovation strategies with WBLCA method A scenario-based existing building renovation strategy was proposed in this phase based on the proposed WBLCA method developed in Phase 2. This model is capable of proposing the best renovation strategies based on the evaluation of the current environmental and economic performance of existing buildings. The BIM models for existing residential buildings were built for different renovation strategies based on a summary of municipality renovation pilot programs. The LCA/LCC performances of each existing building renovation scenario were evaluated based on the proposed WBLCA method introduced in Phase 2, and the LCA/LCC results were interpreted and compared using the TOPSIS method. The renovation strategy was developed to propose the most practical solutions based on the condition of any existing building. Phase 5 – Fuzzy-based MCDM approach to address uncertainties in WBLCA method A fuzzy-based MCDM approach was explored to define the ranges of LCA/LCC data inputs, interpret the WBLCA results, and address uncertainties in the WBLCA method. The detailed calculation process for the fuzzy MCDM method was presented to conduct a comprehensive analysis of buildings. The fuzzy MCDM method was applied to support decision making with a case study of five building designs: one code-specified building and four net-zero energy buildings. The relationships between the environmental and economic performance of the five building designs were studied. The strengths and weaknesses of the five building designs were explored based on the proposed WBLCA method and the fuzzy MCDM approach. The proposed fuzzy MCDM approach was evaluated as a solution for supporting further building design while considering the uncertainties of the WBLCA method. 12 Chapter 3: Literature Review Part of this chapter has been resubmitted to the Canadian Journal of Civil Engineering as an article titled “Environmental Product Declarations for A Whole-building Life Cycle Assessment: A Review” and in 1st International Conference on New Horizons in Green Civil Engineering (NHICE-01) 2018 as an article titled “Comparative Analysis of Environmental Product Declarations on Building softwoods under different Product Category Rules.” The status of whole-building LCA WBLCA is a method that measures building performance at all life cycle stages, from material extraction and production, through construction to demolition and recycling, which allows the designers to work out the optimal solution for improving building performance [19,34]. WBLCAs are becoming increasingly popular in building construction-related decision making due to the comprehensive and systematic approach of LCA to environmental evaluation [35][36]. Researchers have already begun applying the WBLCA concept into studies. Kylili et al. [19] conducted a WBLCA for a passive house located in Cyprus to assess its environmental performance, and a parametric analysis was performed to optimize the passive house design without increasing the total environmental emissions. Kristjansdottir et al. [37] also conducted a LCA for eight different single-family houses in Norway, and the results demonstrated the relationships between the operational and embodied environmental impacts. Atmaca and Atmaca [38] analyzed the life cycle carbon and energy emissions of two residential buildings from the construction phase to the demolition phase. The results show that emissions in the operation phase are much higher than the embodied emissions. Evangelista et al. [39] presented a “cradle to grave” LCA analysis for four typical Brazilian residential buildings in eight impact categories. The building operational phase and material production phase contribute the largest portion to the total environmental impacts, and the foundation creates the greatest fraction of environmental impacts in terms of materials. Wang et al. [40] also studied the life cycle energy performance of ten high-rise office buildings in Hong Kong. The results show that around 80% of the life cycle energy was consumed during the operational phase. The studies listed above show that WBLCA methods are widely used in the analysis of different type of buildings worldwide. The building performance in 13 each life cycle stage was calculated and compared with different impact factors and building components. WBLCA is also part of the overall assessment process in existing green building certification schemes. Table 3-1 lists a few popular building rating schemes around the world that adopt WBLCA into their assessment criteria. Most of these rating schemes analyze all the materials that form the building structure and enclosure, and a whole-building life cycle is included from material production and building construction, to building operation and demolition. Table 3-1: WBLCA methods applied in green building certification schemes. The adoption of WBLCA in academic research and in the green building rating schemes helps the public understand carbon emissions and other environmental impacts, while also helping the government to fulfill legislative requirements and achieve environmental targets. However, the current development of WBLCA encounters many challenges due to the variety of LCA methods and the complexities of building structures. Challenges of whole-building LCA The LCA methods developed for buildings in research and industrial analysis usually have different assumptions, cut-off rules, and limitations. Therefore, WBLCA results from different Certification Boundary Details BREEAM Cradle to grave All building materials used in construction included in the LCA, BREEAM LCA tools and benchmark established for credit calculation, and EcoPoints indicator introduced. DGNB Cradle to grave Building elements clearly described with exclusions, environmental values of the reference building established for credit calculation, and five impact factors included. LEED v4 Cradle to grave Materials of building’s structure and enclosure included in LCA, design building should achieve min. 10% reduction from reference building, and six impact factors included. Green Globes Cradle to grave Building elements clearly described with exclusions, building final design achieves 10-20% reductions for different indicators in comparison with the reference buildings, and six impact indicators included. CASBEE Cradle to grave Building elements defined, building final design reaches different level based on the reference building which is developed from historical data, life cycle CO2 calculated. Green Star Cradle to grave Building elements clearly defined, building final design achieves points by comparing with reference building (two options), and seven impact indicators included. 14 studies are not comparable. For example, due to data availability, the system boundary could be different between case studies, which leads to differences in calculation results and sensitivity increase [41,42]. Citherlet and Defaux conducted a WBLCA for three home designs in Switzerland; however, the system boundary of this study was not complete and additional material losses were considered in the LCA [43]. On the other hand, the reference service life of the building could also result in a variation of LCA results. One study states that the annual energy demand could decrease approximately 14% when the building service life changes from 50 years to 75 years [44]. The variances in building structures between different case studies also create uncertainty in the LCA results. It was stated that a concrete structure has a higher impact than a wood structure in residential buildings [45]. It is possible there are more than 60 materials and 1000 products in a single building. The variances in materials and cut-off rules in different case studies make the LCA results difficult to compare [46]. In terms of LCA methods and database, there are many methods, such as CML, Impact 2002+, TRACI, Athena, etc., and the use of different databases could provide a variation in LCA results. One study indicates that embodied CO2 emission results could have a difference of over 50% between the Ecoinvent database and ICE database for different building designs [47]. Table 3-2 lists the detailed LCA information of a few WBLCA case studies that have various LCA structures. The results show that the WBLCA development methods are inconsistent at the current stage, and results comparisons between case studies are not very applicable. The green building rating schemes that conduct WBLCA also adopt different LCA methods, and these LCA results cannot be compared to or referenced with each other. As shown in Table 3-1, all the rating schemes have the system boundary from cradle to grave. However, they are aligned with different standards. ISO 14044 was referenced in Green Globes and LEED v4, while EN 15978 was referenced in Green Star, and EN 15804 was referenced in DGNB. Internal rules were also developed for the system boundaries of BREEAM and CASBEE. Although these rating schemes in Table 3-1 all have similar system boundaries, and ISO 14040, EN 15804, and EN 15978 standards are related to each other, the details in each rating scheme could be much different when applied by different designers. On the other hand, the building elements that are included in LCA are defined in a diverse way by different rating schemes. For example, in Green Globes, the whole building structure including envelope, foundation and footings below grade, or an attached parking garage are considered in the assessment. In LEED V4, the building elements are not 15 described in the rating guide, which only requires the data set to be compliant with ISO 14040. In Green Star, EN 15978 section 7.5, “The building model,” is clearly cited to guide development of the building elements. DGNB, BREEAM, and CASBEE all developed a detailed list of building elements that must be included in WBLCA. Thirdly, the impact factors that are adopted by each rating scheme in Table 3-1 are also not the same. Most of these rating schemes have six impact factors, such as Green Globes, LEED, and Green Star. DGNB has five impact factors and CASBEE only has CO2 as its impact factor. BREEAM is unique as it developed its own impact factor, called EcoPoints. 16 Table 3-2: The inconsistency of WBLCA methods in different case studies. Reference Type Goal and scope LCI LCIA Boundary Building elements Life (yr) Scenario development Database/Method [19] Passive house Cradle to site Ground and first floor bill of quantity (BoQ) 50 External drainage, sewage, excavation not included EcoHestia/ CML2001 [48] Net-zero energy building Product stage Major components from structure to interior as well as ductwork, Photovoltaic (PV) panel 50 Landscaping, interior finishes not included Franklin USA98/ CED [38] Resident building Cradle to gate Major building structures, material replacement factor considered 50 Energy consumption and CO2 emission in different stages accumulated ICE database [49] Resident houses Cradle to grave BoQ from construction guides and material specifications 50 Energy and water in usage stage assumed Econinvent/Gabi V4.3 [50] Three types of buildings Cradle to grave Envelope and equipment system classified based on UNI 8290 50 Transport distance assumed, MC4 software for usage stage Ecoindicator 99, IPCC 2007, CED [51] Passive house Cradle to grave Ground and first floor, entrance ramp and two exterior stairs, detailed end-of-life recycling stage 70 Life cycle improvement stage included, construction waste considered Ecoinvent/ EPD 2007 Ecoindicator 99 [52] Three hypothetical buildings Cradle to gate Building components built in Revit, VIP insulation material studied 50 Material transport not included International, German and Norwegian EPD system [53] Three residential buildings No end-of-life stage Seven building elements info obtained from original drawings. 75 Retrofit phase included, only energy and GHG impact considered ICE 2.0 [54] 10 case studies Product stage Material quantities from standard BoQ in public works department n/a Only embodied energy and carbon calculated ICE 2.0/I-O LCA [55] 26 buildings Cradle to grave BoQ not clearly presented, building floor area included 50 Life cycle CO2 calculated only, retrofit phase not included BELES database [56] Heritage theatre Cradle to grave Five main materials analyzed n/a Usage stage excluded, only GWP and CED calculated Ecoinvent 2.0 17 [57] Industrial building Cradle to grave Equipment not analyzed, electrical & mechanical components included 20 Designer builder applied in usage stage, retrofit not studied Ecoinvent 3.0 & ESUCO [58] Apartment building Cradle to grave Major renovation materials, exterior walls, doors, windows, balcony 30 Retrofit not considered Ecoinvent 3.1/ReCiPe [39] Four Brazilian dwellings Cradle to grave BoQ of main construction materials listed 50 water, energy use, waste during construction considered Ecoinvent 3.01/CED 1.08 & ILCD 2011 18 EPD – the future of sustainability communication As part of the ISO 14000 series of environmental standards, the International Standards Organisation has set up a collection of standards on environmental labeling which covers three types: Type I Environmental labels describe the product’s or service’s impacts on the environment, and its acquisition is based on voluntary action [59]; Type II Environmental labels consist of companies’ and organisations’ self-declared environmental claims without verification by any third party [60]; and Type III Environmental labels are also called EPDs. EPD provides quantified environmental information which is independently verified by a third party over the life cycle of a specific product [61][62]. The international EPD system, launched in 1999, was the first EPD program developed on a worldwide scale and the most commonly implemented system in Europe [63]. In 2000, Earthsure was founded by the Institute for Environmental Research and Education in the US, which became the first EPD program in North America [64]. As more EPD programs are established, systems for Type III EPDs are gradually becoming more popular and practical in the industry due to their ability to communicate objective, comparable, and credible information relating to the environmental performance of products and services [65]. The quantified environmental information and impact categories of EPDs are based on a life cycle assessment (LCA) per the ISO 14040 (2006) series of standards. In the international standard, EPDs are primarily designed to be used in business-to-business communication, though EPDs might also be used to provide quantitative and detailed data in business-to-customer communication [61]. The regulatory framework regarding the relationships between EPDs and the ISO 14000 series is shown in Figure 3-1. 19 Figure 3-1: ISO 14000 Framework for Environmental Certification [66][67]. The overall goal of EPDs is to promote the supply of building products that are more environmentally friendly by communicating verifiable and accurate information, and to increase the potential of continuous environmental improvement [68]. Based on ISO 14025, the detailed objectives of EPDs are as follows: 1) To provide LCA-based information and additional information on the environmental performance of products; 2) To help users and purchasers making informed comparisons between products; 3) To encourage improvement of environmental performance; 4) To provide information for evaluating the environmental impacts of products over their life cycle [61]. EPD is an important tool to help professionals productively lower carbon emissions and other negative impacts of building design and construction. Stakeholders involved in the construction chain can use EPDs in different ways to compare the environmental impact of building products under certain conditions. An EPD is a verified data source for a designer to select building materials, and for end-users to purchase building materials. EPD is also a credible and transparent ISO 14000Environmental ManagementISO 14020 (2000)Environmental Labels and DeclarationsGeneral PrinciplesISO 14024 (1999)Type I Environmental Labeling: Principles and proceduresISO 14021 (1999)Type II Environmental Labeling: Self-declared environmental claimsISO 14025 (2006)Type III Environmental Labeling: Environmental product declarationISO 14040 (2006)Life Cycle AssessmentPrinciples and FrameworkISO 14044 (2006)Life Cycle AssessmentRequirements and guidelines20 way to communicate the environmental performance of building materials for different manufacturers [69]. 3.3.1 EPD for building and construction materials In the building and construction field, the ISO 21930 (2007) standard complements ISO 14025 (2006) to define more specific requirements for the EPD of building products. Moreover, ISO 21930 (2007) developed a framework and the basic requirements for product category rules (PCRs) of building products as defined in ISO 14025 (2006), and it focuses on environmental impacts when developing declarations [68]. Another approach developed by the technical committee of the European Committee for Standardization (CEN) for the sustainability of construction works is EN 15804 – Sustainability of Construction works – Environmental Product Declarations. EN 15804 is the core PCR for the environmental assessment of building products within the framework of EPD, according to ISO 14025 [70][71]. Based on the EN 15804 standard, the ECO Platform is developed by various national EPD program operators to create a European Core EPD system. EPDs from the ECO Platform are the best way to provide proven and quantitative information about the environmental performance of construction products from a comprehensive life cycle perspective [72][73]. The relation between the LCA in EPDs and sustainability in the building and construction materials sector is shown in Figure 3-2. ISO 14044 (2006)LCA: Requirements and guidelinesISO 14040 (2006)Life cycle assessmentISO 14044 (2006)LCA: Requirements and guidelinesISO 14020 (2000)Ecological labels and environmental declarationsISO 21930 (2007)Environmental declaration of building productsEN 15804 (2012)Sustainability of construction works - EPD – core rules for the product category of construction materials Figure 3-2: Regulatory framework for EPD of building materials EN 15804 is one of the most significant PCR publications for EPDs in the construction and building material field. The standard defines the general rules and principles for drawing up EPDs for building products and services, including the rules to draw up scenarios, the life cycle stages to report, and the processes and limitations of concern. EN 15804 also specifies a consistent method for supplying environmental information of building products, which can be combined 21 with data from other products to evaluate buildings [67]. EN 15804 sets a convention for several issues where ISO 14040/44 leave space for adjustment, in which the LCA of building products needs to be subdivided into different life cycle stages—product stage, construction stage, usage stage, and end-of-life stage—and the results for each stage need to be displayed separately [70]. EPDs can be divided into three types based on system boundaries: cradle-to-gate, cradle-to-gate with options, and cradle-to-grave. A cradle-to-gate type EPD only covers minimum information from the product stage. Cradle-to-gate with options type EPD covers the information from the product stage, plus additional information from other stages. A cradle-to-grave type EPD covers all the life cycle stages as a minimum, and some benefits or loads beyond the system boundary might be included as well. Only a cradle-to-grave type EPD can be used for comparison if the functional unit is equivalent [70]. 3.3.2 International trend in EPD development Since the launch of the first scheme in 1998, EPDs have continued to be developed worldwide either by independent organizations or within highly organized frameworks [74][75]. New EPD publications reached their highest rates of growth in the years 2009 and 2011, and the categories of “food & agriculture product” and “construction products” had the highest growth rate [76]. As of May 2013, 556 PCR and 3614 EPD documents were published worldwide [77]. Italy and Sweden have the highest number of products with EPDs, followed by Spain and Switzerland [76]. 3.3.2.1 In Europe A number of European countries currently have a mature EPD system, especially Sweden, France, Germany, Italy, and the United Kingdom (UK). Sweden was the first country to have a registered EPD and has been a leader in developing the international EPD network [78]. In Germany, the use of EPD is encouraged by major building certification systems as a feasible communication format. “Institut Bauen und Umwelt e.V.” (IBU), the initial and most relevant EPD program operator in Germany, has already held more than 700 EPDs as of 2015 [79]. In France, the environmental and health reference data for building (INIES) was developed in 2001 for the environmental assessment of buildings. More than 1500 EPDs covering more than 27,000 commercial references are available in the INIES database [80]. As of January 2014, EPD has to be registered in the national database if a manufacturer in France wants to make a claim or statement about a product’s environmental aspects, making France the first EU nation to move towards mandatory EPDs [81]. 22 In 2014, ECO Platform was established as an umbrella organization of various national EPD program holders in Europe to generate cross-border recognition of European Core EPDs based on the EN 15804 standard and their implementation. The new EPD label “ECO EPDs” was announced at the first conference of the ECO Platform. ECO EPDs are common minimum standards of verification procedures and quality management by the ECO Platform according to EN 15804. There are 22 founding members and 15 regular members so far in the ECO Platform across Europe [72]. 3.3.2.2 In Asia Japan, Korea, China, Taiwan, and Australia have some or all of the EPD infrastructures in place. Japan created a national database called “EcoLeaf” for its EPD program in 2002, which is aligned with ISO 14025: Type III environmental declaration. The program was operated and administered by the Japan Environmental Management Association for Industry [82]. Korea also developed an EPD program in 2002, managed by Korea Environmental Industry & Technology Institute [83]. In 2014, the Australasian EPD Program was launched at a New Zealand LCA conference, and it is the first program in Australasia [84]. 3.3.2.3 In North America In the US, there are a number of EPD programs in both the public and private sectors, such as the International Green Construction Code (IgCC) for commercial buildings, and the National Green Building Standard (NGBC) for residential and multifamily construction [85]. In Canada, FP Innovations became the first program operator to develop PCRs and EPDs for wood products in North America [86]. In terms of the international harmonization of the EPD process in North America, ASTM International is working towards a standard practice for the development of PCRs, which includes definition of functions of the program operators and creation of EPDs from LCA [78]. Table 3-3 shows a summary of the main EPD programs from across the globe based on the information reviewed online. It is observed that not all the programs are necessarily compliant with the requirements in ISO 14025 [87][79]. 23 Table 3-3: Summary of EPD programs currently operating in the world. Continent Program Name Program Operator Country of Origin Year of Foundation Program Webpage Europe International EPD system The International EPD Cooperation Sweden 1998 http://www.environdec.com/ MRPI The Association for Environmental Relevant Product Information Netherlands 2002 http://www.mrpi.nl/mrpi EPD Norge The Norwegian EPD Foundation Norway 2002 http://epd-norge.no/ IBU EPD Institut Bauen und Umwelt e.V. Germany 2004 http://ibu-epd.com/en/epd-program/ ITB-EPD Instytut Techniki Budowlanej Poland 2004 http://www.itb.pl/ European Aluminum EPD European Aluminium Association EU 2005 http://www.aluminum.org/sustainability/ environmental-product-declarations EPD Danmark Danish Technological Institute Danmark 2013 http://www.epddanmark.dk/ site/index_eng.html Fiches de déclarations environnementales et sanitaires (FDES) Environmental and health reference data for building (INIES) France 2006 http://www.inies.fr/produits-de-construction/ Environmental Declaration Programme PlasticsEurope EU 2007 http://www.plasticseurope.org/home.aspx PEP ecopassport P.E.P Association France 2007 http://www.pep-ecopassport.org/ EN 15804 EPD Scheme BRE Global UK 2008 http://www.bre.co.uk/page.jsp?id=3737 DAPc® – Declaración Ambiental de Productos de Construcción Agenda de la Construcción Sostenible Spain 2008 http://www.csostenible.net/index. php/es/sistema_dapc ift Muster EPD ift Rosenheim Germany 2011 https://www.ift-rosenheim.de/ift-muster-epd Global EPD The Spanish Association for Standardisation and Certification (AENOR) Spain 2011 http://www.en.aenor.es/aenor/ inicio/home/home.asp EPDs - CENDEC Centrum environmentálních prohlášení Czech 2012 http://cendec.cz/cs/cendec/ EPD-DAP® cons Declaración Ambiental de Productos de Construcción (DAPcons) Spain 2012 http://www.csostenible.net/index.php /es/sistema_dapc/epd ZAG EPD Slovenian National Building and Civil Engineering Institute Slovenia 2013 http://www.zag.si/en Austrian EPD Platform Bau - EPD Austria 2013 http://www.bau-epd.at/en/building- materials-with-transparency/ EPDs The DAPHabitat system Portugal 2013 http://daphabitat.pt/?page_id=461 The International EPD® System Türkiye The International EPD Cooperation Turkey 2013 http://environdec.com/tr/ EPDItaly - ICMQ Istituto di certificazione e marchio qualità Italy 2015 http://www.epditaly.it/en/epditaly-program/ Environmental Declaration of Building Products Danish Building Research Institute Denmark 2006 http://sbi.dk/en 24 North America Earthsure Institute for Environmental Research and Education (IERE) US 2000 http://iere.org/programs/earthsure/ SCSglobal SCS US 2000 https://www.scsglobalservices.com/ environmental-product-declarations Environmental Product Declaration (EPD) NSF International US 2011 http://www.nsf.org/ EPDs UL Environment US 2011 http://www.ul.com/ SM Transparency ReportTM Program Sustainable Minds US 2013 http://www.sustainableminds.com/ transparency-report-program EPD Mark ICC Evaluation Service US 2012 http://www.icc-es.org/ep/epd-mark.shtml EPDs ASTM International US 2013 https://www.astm.org/ NRMCA EPD Program National Ready Mixed Concrete Association US 2013 https://www.nrmca.org/ EPDs Canadian Standard Association Group Canada 2012 http://www.csagroup.org/ EPD Program FP Innovations Canada 2011 https://fpinnovations.ca/Pages/index.aspx Asia EPD China The International EPD Cooperation China 2015 http://www.environdec.com/en/ ECO-LEAF Japan Environmental Management Association for Industry (JEMAI) Japan 2002 http://www.ecoleaf-jemai.jp/eng/ Environmental Declaration of Products (EDP) Korean Environmental Industry & Technology Institute (KEITI) Korean 2002 http://www.epd.or.kr/edp/english/ process/process_list.asp Taiwan EPDs Environment and Development Foundation Taiwan 1998 http://www.edf.org.tw/english/greenmark/3rd.asp EPD Program Global GreenTag (old name: ecospecifier) Australia 2012 http://www.globalgreentag.com/epd-program/ Australian and New Zealand EPD System The International EPD Cooperation Australia 2014 http://www.epd-australasia.com/ Latin America EPD Latin America Hub Latin America International EPD System Mexico/Chile 2015 http://www.epd-americalatina.com/ 25 3.3.3 EPD development processes for building materials As shown in Figure 3-3, based on the ISO 14025 standard, there are five steps involved in the EPD development process: select or develop the appropriate product category rule, conduct and verify the product LCA, develop the environmental information and compile it into the EPD reporting format, verify the EPD by submitting the documents to an independent third party for a thorough review, and register the EPD by submitting the final document to an EPD program operator [61]. Figure 3-3: EPD development process 3.3.3.1 Step one – Search or create relevant PCR To facilitate environmental comparison between products that perform the same function, EPD must be conducted under specific standardized guidelines for each product category, known as PCRs [88]. PCRs identify the scope and goal of the LCA-based information for the product category, and the guidelines for creating additional environmental information for the product category. PCRs also specify the covered parameters, the included life cycle stages, and information that must be collated and reported in the EPD. Program operators oversee PCR development and provide detailed guidelines for developing PRCs and EPDs. [61]. PCRs are created by single companies, companies in partnership with others, or companies in partnerships with LCA experts in an open consultation process, and they are reviewed by an independent panel prior to publishing [89]. If a suitable PCR is available for specific material, it can be used to start the EPD creation. If an appropriate PCR does not exist, a new PCR must be developed and approved for use by a credible EPD program operator [90]. The program operator shall produce the PCR document using the established consultation process, including the involvement of interested parties. In accordance with ISO 14025, Table 3-4 shows the detailed stages that make up the development of a PCR. Search/Create relevant PCRConduct and Verify LCACompile information in EPD Verify EPDRegister EPD26 Table 3-4: The PCR development stage [61][91]. (1) PCR Initiation Determine the need for PCRs Identify a program operator Determine the product category Perform PCR search Announce intention to develop PCRs Involve appropriate stakeholders Create PCR committee Determine the need for (1) revised PCR, (2) new PCR, (3) adapted PCR, or (4) unified PCR (2) PCR Development Create PCR (3) PCR Review Create PCR review panel Perform PCR review Public consultation Addressing reviewer comments (4) PCR Publication & Maintenance PCR Publication & Maintenance (5) PCR Use PCR Use 3.3.3.2 Step two – Conduct and verify LCA According to ISO 14025, quantified environmental information of the product/services shall be based on results from one or more life cycle assessments within the ISO 14040 series of standards. As shown in Figure 3-4, two methodological options are defined for EPD development: Option A: LCA study, including goal and scope definition, life cycle inventory (LCI), life cycle impact assessment (LCIA), and interpretation; Option B: LCA study, including goal and scope definition, life cycle inventory analysis, and interpretation [61]. 27 Type III environmental declarationAdditional environmental informatione.g. Hazard and risk assessment, information on the absence of substancesEnvironmental Impactse.g. Global warming, ozone depletion, eutrophication, acidification (LCIA)Material Flowse.g. Emission data, Consumption of energy, and resources and materials (LCI)InterpretationOption A Option BISO 14040 LCA SeriesISO 14020 Figure 3-4: Two options for EPD development (Derived from ISO 14025) The additional environmental information shown in Figure 3-4 is used to ensure that all relevant environmental aspects of the product are covered. The additional environmental information may or may not be derived from an LCA, or it may be related to other issues associated with the product’s overall environmental performance [61]. LCA data collection is a core activity for EPD development. It must follow the general purpose of EPDs, as well as the methods and assumptions used in ISO 14025 and described in the general program instructions. It also must be in line with the PCRs [90]. In some cases, specific LCA data does not exist when the EPD covers the entire life cycle of a product or service. A special rule described in the PCR from the International EPD system allows companies and organizations to use a defined proportion of selected generic data and other generic data in their LCA calculation [90]. 28 3.3.3.3 Step three – Compile EPD Once the applicable PCR has been identified or developed and an LCA is completed and verified, the EPD document can be prepared. An EPD document contains the required information as per the general program instructions and the relevant PCRs. Aside from LCA results, the EPD is able to cover a much wider aspect of relevant environmental information with specific value for an organization. Based on the requirements from EN 15804, EPDs of building materials shall include certain general information, such as a description of the manufacturer, a description of the product components, and a description of program operation and PCR reference [70]. The environmental impacts from a LCIA should also be reported in EPD documents with the defined impact categories, such as global warming potential, ozone depletion potential, and acidification potential. The resource use, water, and other output flows derived from the results of the life cycle inventory (LCI) should also be included in the EPD document [92]. When horizontal measurement standards are published by CEN TC 351: Construction Products – Assessment of Release of Dangerous Substances, additional information on emissions to indoor air, soil, and water during the use stage, or construction products exposed to interior spaces of the building shall be listed in an EPD [70]. EPD documents shall have a mandatory statement or interpretation section, which includes information about means of obtaining explanatory materials, any omissions of life cycle stages or a statement indicating that EPDs from different programs may not be comparable, and a section describing the verification procedure [90]. 3.3.3.4 Step four – Verify EPD To ensure that data and other environmental information provided in an EPD are reliable and trustworthy, an EPD must be subject to independent verification. Four procedures were developed in ISO 14025 for the independent review and verification of an EPD. First of all, the general rules for verification shall be set up in accordance with the ISO 14020 and ISO 14040 series [90]. Secondly, a third-party panel with a minimum of a chair and two members will conduct the PCR review. The purpose of the PCR review is to ensure that the PCR has been developed with the ISO 14040 series of standards and the general program instructions. Thirdly, independent verification will be conducted for data from LCA, LCI and information modules, and additional environmental information. These data should be in conformance with the PCR, ISO 14040 series of standards, and general program instructions. The quality and accuracy of LCA-29 based data, additional environmental information, and the supporting information shall be verified in this stage. Lastly, the independent verification should be verified to confirm that the Type III EPD is in conformance with ISO 14020 and the relevant requirements of this international standard, general program instructions, and the current PCR. The verification procedure shall be transparent, and the EPD data should be valid and scientifically correct [61]. 3.3.3.5 Step five – Register EPD Once the EPD has passed the verification process, the final step is to send the document for publication in the corresponding EPD program. Regardless of the program, the EPD has to include a description of the product and the manufacturer, the environmental performance, and the information from related organizations and certification bodies. For building materials, it is stated in EN 15804 that EPDs are valid for five years from the date of issue. An EPD does not have to be recalculated after five years if there are no significant changes in the product’s composition or product process that result in a change of greater than +/- 10% of any one of the declared parameters of the EPD [92]. When updating an EPD, the same requirements shall be fulfilled as in the development of the original declaration. The organization developing the EPD should notify the program operator of the requested changes and provide the program operator with a document from the verifier confirming conformance with relevant requirements [70]. 3.3.4 EPD use in building labelling and certification schemes Due to the newly-introduced requirements or encouragement by green building certifications or organizations, EPDs have become a more useful guideline in the building and construction sector [93][87]. The following paragraphs introduce current EPD applications in different building labelling and certification schemes. a) 2030 Challenge for products: Architecture 2030 initiated the “2030 Challenge” program, asking the global architecture and building community to achieve carbon-neutral by 2030. The 2030 Challenge for Products target is to reduce embodied carbon in building products by 50% over the same time period [94]. The plan asks third parties to display the embodied carbon-equivalent footprint of a product while developing verified LCA results and/or EPDs from product manufacturers and suppliers. The plan 30 also calls for industry groups to standardize data across product categories and to track progress toward embodied energy goals by developing PCRs and ultimately EPDs [95][96]. b) Leadership in Energy and Environmental Design (LEED) v4: LEED, developed by the US Green Building Council (USGBC), is one of the most thorough building assessment schemes to encourage the use of products with available EPD information. LEED v4 provides architects opportunities to immediately gain one LEED credit by using 20 different, permanently installed products sourced from at least five different manufacturers that meet one of the disclosure criteria below: i. Product-specific life cycle assessment (valued at ¼ product) ii. Industry-wide generic third-party certified Type III EPDs (valued at ½ product) iii. For the highest contribution, product-specific third-party certified Type III EPDs (valued at 1 product) [97]. c) Green Globes Green Globes is an online green building certification tool developed in 2000 by ECD Energy and Environment Canada. Green Globes is primarily used in Canada and the USA. Green Globes grants points for the use of products that have EPDs, third-party certifications, or third-party-verified LCAs, based on a percentage of total products used in assembly that meet these criteria [98]. d) Building Research Establishment Environmental Assessment Method (BREEAM) As one of the most popular environmental assessment methods in the world, BREEAM was launched in 1990 to address key environmental, social, and economic sustainability objectives and planning policy requirements [99]. In the criteria section, 9.0 Materials - Mat 01 Life Cycle Impacts, an EPD can potentially be used to gain BREEAM credits when a third-party verified EPD is available for a product that forms part of an assessed element [100]. e) Other building assessment schemes The French green certification system, HQE (High Environmental Quality) certification, was launched in 1996 and requires EPDs for both residential and non-residential buildings [101]. Miljöbyggnad is the most commonly used building assessment scheme in Sweden. Version 3.0 of Miljöbyggnad proposed that EPDs be used to fulfill the silver or bronze level of the criteria related to life cycle emissions of greenhouse gases [102]. GreenStar is a scheme originating from Australia 31 that allows EPDs to be used in the rating system to obtain the life cycle impact credits [103]. The ÖGNB rating system from the Austrian Sustainable Building Council and the DGNB certification system from the German Sustainable Building Council both apply EPDs in their systems to encourage the use of products with life cycle information [79]. Building life cycle costing analysis Life cycle costing (LCC) analysis method is used to evaluate the overall economic performance of a building throughout its life cycle. The LCC calculation considers the same life cycle stages as the LCA studies. It considers the activities, processes, and assumptions of all building costs and time of occurrences, discounting future costs in the lifespan from the present value [104,105]. LCC, including its core principles and restrictions on how it can be used, is very important in scoping, designing, and delivering a project. In the public sector, there are policies from the government that ask any procumbent to consider the best value other than the initial cost, which is the essence of LCC. UK construction strategy documents even mention a 33% reduction in the life cycle cost of government assets in 2025 [106]. The LCC analysis can be applied to building design solutions in two different ways. Firstly, LCC can be used to assess and predict the cost performance of constructed assets. Secondly, LCC can be used as a comparison tool to work out the life cycle costs of each design, and to select the best alternative when a list of possible designs are being considered [107]. The LCC results of sustainable buildings usually have higher initial capital cost than conventional ones [108]. However, when the life cycle cost of the project is considered, the additional capital cost spent on sustainable building can easily be recovered in a few years due to different factors, such as energy consumption drop during the operational stage [108]. Furthermore, there is a strong correlation between energy consumption and the LCC, as choosing different construction materials has a significant impact on LCC. On the other hand, when it comes to improving building environmental performance, it is always challenging to find a balance between environmental performance and LCC [109]. International code ISO 15686-5 describes the LCC method for the built environment. This code is part of a series of standards that covers service life planning, the long-term understanding of building elements, components, and equipment, and there is a difference between LCC and whole life costing, which is clearly explained by the ISO standard and shown in Figure 3-5. According 32 to the definition in ISO 15686-5, LCC includes initial construction cost, operation and maintenance cost, and end-of-life cost, while whole life costing also includes non-construction activities and income generation, such as receiving rent from tenants [107]. The LCC application is more relevant to contractors, designers, and asset managers; whole life costing is more suitable to owner-occupiers, developers, and landlords. Figure 3-5: Hierarchy of ISO 15686 -5 standard [107] Despite the significant contribution of research to building environmental performance improvement, there are limited studies that focus on the environmental and economic impacts of a building throughout its life cycle [109]. Luerssen et al. conducted LCC studies on PV-powered cooling systems of three off-grid applications, and results show that LCC is especially influenced by financial parameters, such as fuel price and discount rate [110]. Islam et al. conducted LCA and LCC studies to evaluate alternative wall assemblies, and the optimum assembly design was reported using an optimization algorithm [111]. Kneifel conducted a life cycle energy, carbon, and cost analysis for new commercial buildings using an integrated design approach, and the results show that conventional energy efficiency technologies can lead to decreased energy use with negative life cycle costs [112]. Ristimaki et al. analyzed the LCA and LCC of a new residential district energy system Whole Life CostExternalitiesNon-construction costLife cycle cost (LCC)Construction costsOperation costsMaintenance costsEnd-of-life costsIncome33 design in Finland, and the results show that balanced economic and environmental design can be identified if implementing LCA and LCC analysis at an early design phase [113]. Marzouk et al. proposed a BIM-based framework to implement a stochastic LCC model for buildings, to select the optimum building material alternatives [114]. LCA and LCC integrated studies usually do not consider all life cycle stages or the full list of building assemblies. On the other hand, the large amount of data created from LCA and LCC analysis makes it difficult to determine the best solutions. Therefore, the integration of LCA and LCC with digitalized tools such as BIM is becoming a new trend in developing sustainable building designs. Integration of BIM with LCA and LCC Evaluating the environmental emissions and total costs of a building using simulation is becoming a popular technique. Several studies have been published with sustainability in the construction industry [115]. BIM tools, such as Revit, have the potential to connect with the environment emissions analysis and total cost applications based on add-ins [109]. In particular, BIM has become the foundation for digitalisation of the construction industry. As a result, the integration of BIM with LCA and LCC has been explored in recent publications, since BIM tools can greatly mitigate some of the limitations of LCA and LCC analysis [116,117]. Currently, there are three main approaches to BIM integration with LCA and LCC. The first approach uses a range of tools for project modelling to conduct LCA and LCC analysis. The second approach generates a quantity take-off from a BIM model with LCA/LCC databases to obtain total environmental impacts and costs of a project. The third approach incorporates sustainability-related information from BIM models to promote automatic simulations and improve information exchanges [115,118]. The first approach was started a while ago. Wang et al. explored the BIM-LCA potential to assess building environmental impacts, and the most sustainable solutions were identified using Ecotect [119]. Basbagil et al. presented a method to apply LCA to the early stage of a project, to inform building designers of the relevant environmental impact importance of building component materiasl and dimensioning choices [120]. Jalaei and Jrade proposed an automated model link green building certification system with BIM, LCA, energy analysis, and lighting simulations, which will provide a new way for designers to identify potential energy changes at the building level [121]. Jrade and Abdulla also developed a prototype to link the Athena EcoCalculator with a BIM model to perform an LCA on a simple 3D object-oriented model using Industry Foundation Classes (IFC) as the data exchange standard [122]. 34 The second approach is more recent due to advances in BIM technology and market demand for more automatic analysis. Jrade and Jalaei developed an integrated framework to assess the environmental performance of buildings. BIM was used to generate a quantity take-off, which is linked with external environmental and cost data for building components [123]. Oti and Tizani also created a tool that extracts the materials’ bill of quantity from the BIM model, and connected it with an external database to perform LCC, CO2 emissions, and ecological footprint analysis [124]. Shin and Cho proposed a framework that integrates LCA and LCC analysis with BIM tools. The building quantity information was exported from BIM and fed into an Excel spreadsheet that conducts LCA and LCC analysis [125]. Similar research conducted by Kreiner et al. used the bill of quantities from the BIM model to optimize building sustainability performance [126]. Liu et al. used the particle swarm optimization algorithm to identify the trade-offs between life cycle CO2 emission and LCC [127]. Yung and Wang also used BIM to evaluate building sustainability with an external database. The BIM 4th dimension was used for schedule management and employee arrangement [128]. The third approach has rarely been explored. Anton and Diaz conducted a study using the third approach and stated that incorporating sustainability-related information within BIM models can improve information exchange [129][130]. Santos et al. also proposed a BIM-based LCA and LCC prototype tool to improve the integration and tested it with a pilot case study. This work is expected to contribute to the development of automatic sustainability simulations [115][118]. The main advantage of the third approach is that BIM is treated as a data exchange platform between users and tools, which allows the information stored in BIM to be easily edited and quickly updated by other users for LCA and LCC studies. Despite their originality, the first two approaches still have limitations: human-made errors, database flexibilities, and interoperability issues between tools. Building on the third approach, recent studies focus on the inclusion of environmental information in the BIM model to overcome these limitations. However, additional information in objects is limited to the building-elements level without considering materials, and it is still difficult to performance a comprehensive BIM-based LCA analysis. Furthermore, the integration of BIM with LCA and LCC still remains unexplored, which has already been identified by other authors and professionals as a limitation [115][118]. Therefore, further studies are required to strengthen the knowledge of BIM integration with LCA and LCC. 35 Chapter 4: Whole Building Life Cycle Assessment (WBLCA): An Integrated Approach with BIM, EPD and LCC Parts of this chapter has been submitted to the Journal of Automation in Construction (Elsevier), as an article titled “BIM-based whole building life cycle assessment with Environmental Product Declaration: A design optimization framework”. Background Environmental Product Declaration (EPD) is one of the most recommended methods to report the life cycle performance of building materials, since EPDs provide uniform and independently verified environmental information based on ISO 14040 and ISO 14025 standards [87,131]. Developing WBLCA through the EPD method could help address current research limitations and provide comparable and transparent LCA results for a whole building. However, it is challenging to present the comprehensive WBLCA processes, especially when the EPD method is integrated to conduct the LCA. In this situation, BIM would be a helpful tool to be integrated with WBLCA. Building information modeling (BIM) is a rising technology that uses a digital platform to store and exchange building-related data. BIM can substantially minimize the time and effort in managing the material data of a building [132]. A BIM model includes graphical information about building assemblies and materials. BIM can be used to improve a project’s flow of information and allows users to obtain material information efficiently and systematically [133,134]. In order to make sure the suggestions provided by the BIM and EPD based WBLCA results are reasonable to the building owners and developers, the LCC should be involved as an additional impact category besides the environmental impact categories. Therefore, a systematic methodology is required to integrate these techniques to provide reliable and comprehensive WBLCA results. As discovered in the literature review, the following processes need to be developed to create a reliable and comprehensive WBLCA method. a) Detailed processes to integrate EPD development rules into the WBLCA method, based on the EN 15978 standard. b) Detailed processes for implementing the BIM technique in the WBLCA method to improve the efficiency and accuracy of data collection and design improvements. c) Detailed processes for conducting LCC for a whole building using the BIM platform. 36 d) Due to the complexity of LCA and LCC results for a whole building, the detailed WBLCA results interpretation and comparison method is required to ensure the WBLCA results are easily understood. A harmonized methodology is required to solve all the above challenges and ensure that WBLCA results are following the standard LCA procedures mentioned in ISO 14040 and EN 15978. Therefore, this chapter introduces the detailed processes for developing WBLCA with the integration of EPD, BIM, and LCC. Methods and Procedure In this section, the detailed processes for integrating EPD into WBLCA were developed for residential buildings based on EN 15978 standards, and the LCC development rules were also established to evaluate building performance with the EPD results. The application of BIM into WBLCA was demonstrated to support data collection throughout the building level LCA/LCC development. Figure 4-2 presents the WBLCA development framework with the integration of EPD, BIM, and LCC. The framework was further explained in four sections as follows. 37 Figure 4-1: WBLCA with the integration of EPD, BIM, and LCC development framework 38 4.2.1 WBLCA development with EPD rules Based on EN 15978 and EPD development rules described in ISO 21930, the EPD-based building level LCA development method, which assesses the environmental performance of a building with a clear standard for goal and scope definition, as well as a complete LCI analysis and a specified LCIA method were developed. The systematic results interpretation was also developed at the end to help users have a better understanding of the results. Figure 4-2 presents the detailed steps to conduct WBLCA by following the EPD development method. Search/Create relevant PCR for all building materialsConduct and verify LCA for all building materialsCalculate and compile LCA results into EPDVerify EPD for a WBLCAThe goal and scope definitionLife cycle inventory analysisLife cycle impact assessmentLife cycle interpretation Define building assessment scope Function unit and building lifespan Develop system boundary Product stage, construction stage Usage stage, end-of-life stage  Interpret LCA results Contribution analysis Sensitivity analysis Define assessment scenarios Energy and material use in construction Operation and demolition water and energy use Cut-off rules Identify assessment indicator Environmental impacts, resource use waste categories, output flow LCA database and methods Figure 4-2: WBLCA development with EPD method 4.2.1.1 Goal and scope definition with EPD One of the major issues among WBLCA results is the variances in LCA goal and scope definition. Due to project differences and data availabilities, LCA results among studies are usually full of uncertainties. The goal of this assessment was to calculate the sustainability performance of single-family residential buildings. The functional equivalent, reference study period, and system 39 boundary were defined in this section to ensure the assessment results are reliable and comprehensive. 4.2.1.1.1 Functional equivalent Functional equivalent is a parameter to define the functionalities and characteristics of buildings to ensure fundamental building information is clearly presented for fair comparison, if needed [135]. Table 4-1defines the functional equivalent of the proposed method. With a clear definition of functional equivalent, the whole-building LCA results for different buildings conducted with the proposed method can be easily classified and compared. Table 4-1: Functional equivalent of the proposed method 4.2.1.1.2 Reference study period (RSP) The RSP is the period over which the time dependant characteristics of the building are analyzed [135]. Impacts during building usage, building material maintenance and replacement activities, and water use and operational energy are deeply responsive to the definition of RSP. In this proposed framework, the reference study period was assumed to be the same as the required service life. 4.2.1.1.3 System boundary The system boundary of LCA defines which life cycle activities are to be included in the analysis. Based on the EPD development setup from EN 15978 shown in Table 4-2, the system boundary in this framework was defined as cradle to grave, from product stage (A1-A3) to end-of-life stage (C1-C4), which provided a consistent and transparent reporting format for WBLCA. The product stage (A1-A3) includes the primary resource mining for raw materials, transportation of raw materials to factories, and manufacture of raw materials to products. The construction stage (A4-A5) includes material transportation from factory to construction site, and on-site energy use and material waste during construction. The operation stage (B1-B5) includes building maintenance, Building Type Residential buildings Technical and functional requirements Minimum BC Building code specified Pattern of use Required Unit of final results Value / (m2 • occupant) Required service life Required 40 repair and replacement, and operational water and energy use. The disposal stage (C1-C4) includes building demolition, demolition waste transportation, and waste processing in different facilities. Table 4-2: System boundary of a whole building LCA according to EN 15978. Stage Information Module Name Product Stage A1 Raw material supply A2 Transport A3 Manufacturing Construction Stage A4 Transport A5 Construction Use Stage B1 Maintenance B2 Repair B3 Replacement B4 Operational energy use B5 Operational water use End of Life Stage C1 Demolition C2 Transport C3 Waste processing C4 Disposal Benefits and loads beyond the building life cycle D Reuse Recovery Recycling Exported Energy 4.2.1.2 Life cycle inventory (LCI) analysis In the life cycle inventory analysis, data collection methods, scenarios development, and cut-off rules all have significant impacts on LCA results. Therefore, a clear definition of each factor could help develop a complete LCI and reliable LCA results. However, the current research on WBLCAs does not pay attention to the development of these factors, which leads to inconsistency of LCA methods and assumptions at a building level. In EPD development for a whole building, these factors were clearly described to ensure consistency and accuracy, and to maintain the comparability for EPD results at the building level. In terms of data collection, EPD for a WBLCA collected qualitative and quantitative data—either measured, calculated, or estimated—for each unit process within the system boundary. When data were significant for the LCA results, the details of the data collection process were recorded [92,136]. The data collection requirement from EPD development ensured that the LCI analysis is complete and the LCA results are reliable. 41 In terms of the cut-off rules, EPD for a WBLCA ensured that the total neglected input flows per module did not exceed 5% of energy usage and mass. The input flows that have significant effects in their extraction, use, or disposal, or any flows that have been classified as hazardous waste were neglected in the calculation [92]. EPD for a WBLCA also conducted a mass balance check to ensure there are enough stated inputs to produce all the outputs, including waste arising. With such a detailed cut-off rule, the data adequacy was guaranteed in EPD for a WBLCA. In terms of scenario development, the scenario for each module was developed within the system boundary and aligned with the general scenarios defined at the building level. The scenario development clearly stated whether the information/data collected for each scenario was calculated, assumed, or estimated, or based on actual measurements. With specific requests for each module, the scenario developments of EPDs among different buildings were uniformed, and the WBLCA results were consistent and comparable. Scenarios developed should be consistent with the boundaries defined in Table 4-1 and general scenarios defined at the building level. Scenarios in this framework included the information collection method at all life cycle stages. The scenario development rules employed in the assessment were clearly documented to show whether the data was collected through assumption, estimation, or calculation, or was based on actual measurement. 4.2.1.2.1 Manufacturing stage (A1-A3) The manufacturing stage covers the impacts from the material factories, which includes primary resource mining, raw material transportation to the factory, and manufacture of raw materials to products. The detailed material type and quantity for a building are based on the building design layout, which can be modeled and calculated by the BIM model. The material coverage of a building starts from the basement foundation to the roof coverings. Based on the UniFormat system, a uniform definition of construction assemblies and systems developed by Construction Specification Canada was used to promote the BIM application. The detailed building elements included in the proposed method are listed in Table 4-3 [137]. 42 Table 4-3: Building elements that are included in the proposed LCA method [138]. A: Substructure A1010 Standard foundation A1020 Special foundation A1030 Slab on grade A2020 Basement walls B: Shell B1010 Floor construction B1020 Roof construction B2010 Exterior walls B2020 Exterior windows B2030 Exterior doors B3010 Roofing B3020 Roof openings C: Interior C1010 Interior partitions C1020 Interior doors C2010 Stair construction C2020 Stair finishes C3010 Wall finishes C3020 Floor finishes C3030 Ceiling finishes 4.2.1.2.2 Construction stage (A4-A5) Scenarios for the construction stage covered the period from the manufacture centre to the end of site construction work. The impacts in this stage are coming from materials transport to site, construction energy use, and construction material waste. The impacts of transportation were calculated based on the distances between the material factories and the construction site. The impacts from construction energy use were calculated based on fuel consumption by on-site equipment. The on-site construction waste was assessed based on the materials quantity list from building design layouts generated by BIM. and the waste percentage during construction using Equation 1: Qy = My×Py Equation 1 Where Qy is the total waste quantity of material y, My is the material quantity from building design layout, and Py is the construction waste factor. 4.2.1.2.3 Usage stage (B1-B5) During the usage stage, the maintenance, repair, and replacement activities occur to make sure the building is functioning properly. In this framework, the task occurrence in the building lifetime was calculated using Equation 2: 43 Nx = (RSP-Fx)/Fx Equation 2 Where Nx is occurrence time; RSP is the building referenced study period (years); and Fx is the life span of each material in years. Therefore, the total quantity of material replacements in the usage stage was calculated by using Equation 2 times the quantity of each material that is replaced at each task. The energy use during building operation includes energy consumed from domestic hot water, cooling, heating and ventilation, lighting, and control. The assessment of energy use shall come from the actual expenses. However, in the design stage, the energy use shall be estimated based on the accurate energy modelling results from simulation software, such as HOT2000, DesignBuilder, eQUEST, and EnergyPlus. The building-related energy production, such as solar and geothermal energy, was clearly quantified. The operational water use included (but was not limited to) the consumption of potable water from water closet, urinals, showers, lavatory taps, kitchen taps, and landscaping. The potable water reduction due to the use of rainwater harvesting, water recycling, and/or other sources was clearly reported. 4.2.1.2.4 End-of-life stage (C1-C4) Scenarios for the end-of-life stage should describe the processes included in the system boundary in Table 4-1. In building demolition, the diesel-fueled equipment was used to demolish building assemblies, and the demolition impacts were based on the consumption of diesel, which was further evaluated by the builders. The impacts of waste transport were calculated based on the distance between the building location and the nearest treatment facilities. The unit transport impact values (per ton kilometer) were derived from the LCA database. In demolition waste processing, the percentage of waste materials that are sorted to different facilities for reuse, recycling, landfill, and incineration were defined by the database. The unit processing impacts for each facility were also derived from the LCA database. 4.2.1.3 LCIA for WBLCA The current research on WBLCA does not have uniform impact indicators, LCA methods, or a database for different building’s analysis, which makes the LCIA results uncertain. EPD for a WBLCA could address this issue by choosing a complete list of impact indicators and defining accurate LCA methods and databases. There are different types of data sources, such as the USLCI and Ecoinvent LCI databases. EPDs for a WBLCA were developed with the specific EPD for 44 individual materials or services based on the local market, which created the most accurate environmental information for the specific projects. For building materials or services that do not have existing EPD reports, the EPD results from Ecoinvent v3 database were used instead. Indicators were used to measure the environmental impacts caused by the building during its whole life cycle. EPD-based life cycle assessment followed the EN 15978 standard, and the indicators for this assessment are listed in Table 4-4. Table 4-4: Environmental indicators declared in LCIA, based on EN15978 standard [135] Environmental Indicators Units Environment Global warming potential (GWP) Kg CO2 eq. Acidification potential of land and water (AP) Kg SO2 eq. Depletion of the stratospheric ozone layer (ODP) Kg CFC-11 eq. Eutrophication potential (EP) Kg N eq. Photochemical oxidation potential (POCP) Kg O3 eq. Abiotic resource depletion potential of fossil fuels (ADP) MJ surplus Resource use Renewable primary energy resources used (RPE) MJ Non-renewable primary energy resources used (NRPE) MJ Secondary material (SM) Kg Net use of fresh water (FW) m3 Waste flow Waste disposed (WD) Kg Materials for recycling (MR) Kg Components for re-use (CRU) Kg Based on a matrix calculation routine, the values for each of the above-mentioned indicators were calculated for each module (A1-C4) in the life cycle stages, as illustrated in Figure 4-3. 45 a1 a2 a3 a.. anGWPa1,iAPa1,iEPa1,iODPa1,i….GWPa2,iAPa2,iEPa2,iODPa2,i….GWPa3,iAPa3,iEPa3,iODPa3,i….GWPa..,iAPa..,iEPa..,iODPa..,i….GWPan,iAPan,iEPan,iODPan,i….a1,ia2,ia3,ia..,ian,iGWPiAPiEPiODPi….=Environmental impact per unit of product/processAmount of products/processes used in stage iEnvironmental impact of stage iSources: BIM model Scenarios developedSources: EPDs Generic databases LCA studiesi = [A1-A3, A4, A5, B1, B2, B3, B4, B5, C1, C2, C3, C4] Figure 4-3: Matrix calculation method for module i of the building environmental impacts and relevant data sources The basic principle of this matrix calculation routine is to multiply each product and service calculated in a module of the life cycle of the building with its perspective value for each environmental indicator as described in Equations 3 and 4. 𝑬𝑷𝒊 = 𝒂𝒋⃑⃑ ⃑ × 𝑴 Equation 3 Where EPi is the total indicator value of the module i of the building; 𝑎𝑗⃑⃑ ⃑ is the vector containing the gross amounts of all products and services used in the module j of the building; M is the matrix containing in its columns the environmental indicator values per unit of all products and services used in the module i of the building. Equation 4 shows the calculation for the quantification of the GWP of stage i: 𝑮𝑾𝑷𝒊 = 𝒂𝟏,𝒊 × 𝑮𝑾𝑷𝒂𝟏,𝒊 + 𝒂𝟐,𝒊 × 𝑮𝑾𝑷𝒂𝟐,𝒊 + ….. + 𝒂𝑵,𝒊 × 𝑮𝑾𝑷𝒂𝑵,𝒊 Equation 4 Where 46 GWPi is the global warming potential quantified for the module i of the building; 𝑎𝑛,𝑖 is the gross amount of product or service ‘n’ used in the module i of the building (n=1, 2, 3, .... N). The calculation method above applies to all environmental indicators presented in Table 4-4. 4.2.1.4 Life cycle results interpretation for WBLCA In the life cycle interpretation stage, the significant issues that led to the most life cycle impacts were identified based on the LCA results. However, the results interpretations are different in each LCA study since the intent of LCA varies [139]. Furthermore, the complexity of the building system and the number of indicators declared in the LCA created a large amount of LCA results, which makes it harder to fully understand without a systematic and complete results interpretation. However, the WBLCA method with EPD ensures an adequate result interpretation strategy, since the principles of result reporting and interpretation are clearly defined in the EPD development method [135]. LCA results from the EPD were simplified based on different targets before communicating with other EPD results. Based on the intent of the LCA studies, LCA results in the EPD were arranged at a building part level, element level, component level, or product level. The LCA results can also be limited to a selection of indicators and presented in different information modules. For example, the results can be presented as total LCA results, resource type contribution results, construction element contribution results, and fuel type contribution results. The LCA results can also be normalized to functional units, such as per-m2, per-occupant, per-year, per-m2-year, and per-occupant-year. No matter how the LCA results are interpreted and presented, EPD for a WBLCA requires that the findings of all results shall be traceable and transparent, and the results are presented in sufficient details to allow for further verification by a third party. With a transparent and systematic EPD interpretation rule, the LCA results for a whole building would be more reliable and comparable. 4.2.2 Whole building LCC development Beside the detailed environmental assessment for building sustainability, it is necessary to have the life cycle costs as an additional parameter to identity building solutions that are economically friendly while improving environmental performance. According to ISO 15686-5:2008 and the European Commission’s report, one of the most common LCC methods in the building 47 construction sector is net present value (NPV) [107][140]. The NPV is the sum of the discounted future cash flows, considering both costs and profits, and can be determined using Equation 5. 𝑪𝑵𝑷𝑽 = ∑𝑪𝒏(𝟏+𝒇)𝒏𝒑𝒏=𝟏 Equation 5 Where: 𝐶𝑛 is the cost in year n; f is the expected discount rate per year; and p is the research study period. Similar to the environmental LCA studies, LCC for WBLCA studies the life cycle of a building to evaluate the economic performance. In this study, the building level LCC estimated all the relevant costs from material manufacturing (𝐶𝑚) and construction 𝐶𝑐, to building usage 𝐶𝑜 and disposal 𝐶𝑑. The manufacturing and construction costs are present value, and the building usage and disposal costs are future values, using Equation 5 to get the net present value. The total building-level LCC (𝐶𝑡𝑜𝑡𝑎𝑙) was calculated using Equation 6. The detailed processes considered in the building-level LCC were in line with the system boundary modules defined for WBLCA by EN 15978, shown in Table 4-2, which is from A1 to C4. 𝑪𝒕𝒐𝒕𝒂𝒍 = 𝑪𝒎 + 𝑪𝒄 + 𝑪𝒐 + 𝑪𝒅 Equation 6 In material manufacturing stage, the costs of purchasing each material 𝐶𝑚 included in the building design plan were included, which can be calculated using Equation 7. 𝑪𝒎= ∑ (𝑸𝒂𝒊𝒂=𝟏 × 𝑪𝒂) Equation 7 Where 𝑄𝑎 represents the quantity of material ‘a’ used in construction; 𝐶𝑎 represents the purchasing cost of material ‘a’. In the construction stage, the costs include the cost to transport each type of material to the construction site, the cost to assemble construction elements, the cost of energy used during construction, and the cost of material waste during the construction phase, which can be summarized using Equation 8. 𝑪𝒄= ∑ (𝑸𝒂𝒊𝒂=𝟏 × 𝑪𝒂) + ∑ (𝑸𝒂𝒊𝒃=𝟏 × 𝑪𝒃) + ∑ (𝑸𝒄𝒆𝒏𝒊𝒄=𝟏 × 𝑪𝒄𝒆𝒏) + L × ∑ (𝑸𝒅𝒊𝒅=𝟏 × 𝑪𝒅) Equation 8 Where 𝑄𝑑 represents the quantity of material ‘d’ used in construction; 48 𝐶𝑎 represents the cost of transport material ‘a’ to site; 𝐶𝑑 represents the cost of transport material ‘d’ to site; 𝐶𝑏 represents the cost of assemble material ‘b’; 𝑄𝑐𝑒𝑛 represents the quantity of energy spent during construction; 𝐶𝑐𝑒𝑛 represents the unit cost of the energy spent during construction; L represents the percentage of waste materials produced during the construction phase. In the usage stage, the costs include utilities spent during building operations, and the material costs due to the repairs, which can summarized using Equation 9. 𝑪𝒐 = ∑ (∑ (𝑸𝒂,𝒏𝒐𝒑𝒎𝒏=𝟏 × 𝑪𝒂𝒐𝒑×𝟏(𝟏+𝒇)𝒏))𝒍𝒂=𝟏 + ∑ (∑ (𝑸𝒃,𝒏 𝒎𝒏=𝟏 × 𝑪𝒃 ×𝟏(𝟏+𝒇)𝒏))𝒐𝒃=𝟏 Equation 9 Where 𝑄𝑎,𝑛𝑜𝑝 represents the consumption of utility ‘a’ in year ‘n’ in usage stage; 𝐶𝑎𝑜𝑝 represents the cost of utility ‘a’; 𝑄𝑏,𝑛 represents the quantity of material ‘b’ to be replaced in year ‘n’; m, n, o represent the number of materials replaced during the building usage stage. In the disposal stage, the costs include the transport of building material waste to the recycling or landfill facilities. The life cycle inventories of LCA and LCC were assumed to be the same, and the total LCC of a building was treated as an additional impact category for WBLCA, which will provide more reasonable and affordable solutions to improve the building-level environmental performance. 4.2.3 BIM Integration method The purpose of integrating BIM is to efficiently quantify energy and mass flows. This quantification should be organized in a structured way. BIM software is able to be used in building model development to hold material property information. Integrating BIM into WBLCA is an ideal solution for addressing the challenges associated with EPD applications. The application of BIM through Revit software was conducted throughout the LCA processes. BIM provides material information to different life cycle stages in LCI analysis. At the same time, BIM also embeds 49 material cost information within the model. The detailed BIM integration method is presented in Figure 4-4. Figure 4-4: BIM integration details with EPD and LCC calculations In WBLCA for building environmental performance, the BIM model was developed to provide material quantity information for the calculation of environmental impacts in the manufacturing and construction stages. In the usage stage, BIM provided material information as inputs for building energy simulations, and material repair and replacement calculations. In the disposal stage, the quantities of building material waste were also based on BIM quantity takeoffs. Therefore, BIM model integrations are significant for WBLCA calculations. In WBLCC for building economic performance, the BIM platform would be more involved since the cost information of 50 each type of building material could be recorded in the model, and the total cost of a building would be always accurately presented as output and linked with the design changes. 4.2.4 WBLCA results comparison with MCDM The WBLCA with LCC studies will generate a large amount of LCA and LCC results. It is necessary that the findings of LCA and LCC are summarized systematically and analyzed separately to allow designers to access the research output from different perspectives. The contribution analysis was conducted in this method to interpret all the results from different perspectives. Information module contribution was analyzed to highlight the most significant modules, construction element contribution was analyzed to show the most important building elements, and the material type contribution was analyzed to point out the most critical building materials to LCA or LCC results. Based on the contribution analysis, the most critical contribution factors were targeted to further improve the WBLCA performance through BIM design revisions. In order to achieve the balance between environmental and economic performance, the integration analysis of LCA and LCC results is necessary. In this approach, the LCC results were treated as another impact category in addition to the 13 impact categories listed in Table 4-4. To conduct comparisons between different buildings, the results have to be converted to a comparable scale. There are different ways to treat the WBLCA results, such as Multi-Criteria Decision Making (MCDM) and results normalization [141,142]. In the proposed method, the TOPSIS-based MCDM method was adopted to compare results. TOPSIS is a relatively simple and straightforward process that can represent the rationale in individual human choices and can be used in spreadsheet form [143,144]. In the TOPSIS method, the worst and best scenarios could be presented at the same time, allowing the best option to be selected under each criterion [145]. These factors are all important in this study, and it is necessary to develop user-friendly tools whose computational logic can be easily explained. The weights were taken as crisp values in the decision making as they were defined according to weighting schemes under decision makers' priorities, hence not being subject to data uncertainty [146]. There are usually seven steps required to conduct a TOPSIS analysis, the details of which are described in the article written by Roszkowska [144]. Since environmental emissions and cost are in two sectors, the weighting rules during the MCDM process should be clearly defined based on the involved stakeholders. Based on the expert 51 information from municipalities, energy firms, and strata managers, three sets of weighting schemes were proposed in the results comparisons from the perspectives of building owners, city planners, and environmentalists. Discussions WBLCA studies have been conducted over the past two decades and have become the mainstream method for improving environmental impacts of the building sector. However, current studies have faced challenges in presenting comprehensive LCA results due to the complexity of assessments at the building level. Limited methods are available to systematically evaluate and improve the WBLCA performance of buildings at the design stage. The literature shows that the current building-level LCA studies either do not consider the full set of impact categories when conducting impact assessment, or do not include a cradle-to-grave analysis by neglecting some life cycle stages. On the other hand, some of these building level LCA studies do not cover the full building assemblies, and the current WBLCA studies usually end after the LCA results are calculated and interpreted. There is rarely a building-level LCA study that provides building design comparison and improvement strategies based on the final LCA results. The proposed WBLCA method in this study addressed all these challenges with a comprehensive assessment method. Furthermore, the EPD method and BIM technique were included in the LCA studies to provide an accurate and efficient data collection method, and the economic perspective was considered as an additional impact category to assist building designers in improving building sustainability in a more affordable way. The proposed EPD method for a whole building was developed strictly following the ISO 21930 series and EN 15978 standards. With clear and uniform requirements for all LCA processes, the EPD results for a whole building will be easy to understand and possible to compare with other EPD results with defined interpretation methods. WBLCA with the EPD method can help reduce the construction sector’s climate impact by encouraging planners and designers to use LCA in the building planning and design stages. EPDs can be used as a management tool to improve product environmental performance by monitoring product environmental data, and can also be used as an action tool to identify concerning areas requiring improvement for a product’s environmental sustainability [147]. By promoting EPD development for a whole building, the LCA results between different buildings, building components, and elements will be more comparable, which will improve a building’s environmental performance. 52 The development of EPD for the proposed WBLCA method raises awareness about the value of LCA in bringing a data-driven perspective to sustainable design, and advocates for consistent and transparent reporting of WBLCA results. In addition, conducting EPD for a WBLCA can help motivate the use of LCA in design practice, which will advance sustainable design by providing data to guide decisions with measurably better environmental impact outcomes. EPD for a WBLCA can be used an assessment tool to evaluate the environmental performance of building materials and to select the most appropriate construction methods. EPD for a WBLCA can also be a comprehensive procurement tool for government, corporations, and institutions to achieve environmental targets. With a detailed analysis of building environmental performance, it is certain that the best solutions to improve building performance could be proposed according to the WBLCA results. However, the solution that creates the best building environmental performance is not always the most welcomed one in the real world. In the construction industry, stakeholders such as building owners, contractors, or architects are always concerned about project budget first. Without considering the economic feasibility, a proposed solution to reducing environmental emissions is not comprehensive. In the current building-level LCA, LCA/LCC-based studies are limited. The proposed WBLCA in this study included the LCC as an additional impact category to provide economic impacts of each building improvement strategy, which makes solutions for building sustainability improvement more comprehensive. A building is a complicated system that needs to satisfy multiple functional requirements. As a result, there are numerous materials involved and it is complicated to track all of them and their quantities. Another strength of the proposed WBLCA method is having BIM involved in the analysis as a data exchange platform. Once the BIM model is established, the material quantities can be automatically generated. Since the cost data was inserted while developing the model, the total material cost information could also be generated along with material quantities. On the other hand, when design revisions happen, the material quantities and costs of the revised portion could be exported simultaneously. There is a BIM-based LCA tool called Tally that can directly generate the building LCA results without taking the material quantities to the external LCA data, but Tally is limited in that it can only calculate the building LCA a the building assembly level, which makes the LCA results unreliable. As well, the building materials have to match the database that Tally 53 LCA pulls from. The BIM-based approach applied in this study can not only guarantee the accuracy of the WBLCA results, but also provides dynamic LCC information. Summary The literature shows that the development of WBLCA is experiencing a bottleneck due to the variety of LCA methods and the complexity of building structures. Therefore, studies are required to work on LCA development methods and the complexity of a building structure while implementing WBLCA, in particular the system boundary, scenario development, building elements, database selection, and associated life span. Applying the EPD method to a building can help address the current research gap on WBLCA, since EPD has a uniform process for LCA development with clearer goal and scope definition, more comprehensive LCI analysis, more accurate LCIA development, and more systematic results interpretation than the existing WBLCA. In this proposed method, EPD method was applied to present a detailed building-level LCA method while following the EN 15978 standard. The detailed LCC calculation process was also presented clearly to provide an additional impact category to support the environmental analysis. At the same time, the BIM technique was integrated to provide a data store and exchange platform to guarantee the accuracy and efficiency of the LCA data collection process. The detailed BIM integration processes with LCA/LCC were illustrated and explained here in this proposed method. Furthermore, the specific interpretation requirements and comparison strategies for final LCA/LCC results were proposed. In the next step, it is necessary to validate the performance of the proposed WBLCA method in terms of new building designs and existing building renovations, which are to be conducted in the following chapters. 54 Chapter 5: WBLCA for New Residential Buildings Parts of this chapter have been submitted to the Journal of Sustainable Cities and Societies (Elsevier), as an article titled “BIM-based whole building life cycle assessment with Environmental Product Declaration: A design optimization framework”, and in International Symposium for Sustainable Systems and Technology 2019 as an article titled “Is it better to renovate an old house or rebuild it?”. Background This chapter focuses on demonstrating the application of the proposed WBLCA method presented in Chapter 4 on new residential buildings through case studies, to identify environmentally and economically feasible design improvement strategies. Through the WBLCA results interpretation, the major contributions to overall impacts are highlighted, and the alternative design solutions are proposed in the case study to compare with the original design. Finally, the building design improvement strategies are proposed based on the comparison results. A typical newly built single-family house located in the City of Kelowna, British Columbia was selected for this case study. The building complies with the BC building code. The functional equivalent is a single-family house with one level and a walkout basement, and the total floor area is 2940 ft2. The house consists of 4 bedrooms and 3 bathrooms. Based on the as-built drawing from the designer, the 3D and 2D plans of the studied single-family house are presented in Figure 5-1. The life span of the house is assumed to be 60 years. The system boundary of this WBLCA is from the material manufacturing stage to the end-of-life stage. 55 Figure 5-1: 3D and 2D plan of the studied single-family house (derived from BIM model) Methods and procedure The detailed processes described in Chapter 4 were strictly followed in this case study to ensure the accuracy of the WBLCA results. 5.2.1 Data collection In order to complete a WBLCA, the impact data for each life cycle stage needs to be clearly calculated from the manufacturing stage (A1-A3) and construction stage (A4-A5), to the usage stage (B1-B5) and disposal stage (C1-C4). 5.2.1.1 Manufacturing stage (A1-A3) Based on the building layout of the single-family house, the Autodesk Revit 2018 version was used to generate the accurate material BoQ. Table 5-1 lists the detailed layers and materials used in the building assemblies. The quantity of materials that needs to be produced in the manufacturing stage was summarized from Table 5-1. Table 5-1 also has a direct connection with the construction stage, usage stage, and disposal stage. 56 Table 5-1: Bill of quantities for the studied single-family house (summarized from BIM output) Assembly Code Assembly Description Family and Type Area (m2) Detailed Layers A1010 Standard Foundations Basic Wall: Foundation - Concrete footing 26 Concrete wall 26 2.4'' rigid XPS insulation 23 Concrete footing A1030 Slab on Grades Floor: Floor - Basement level 135 4'' reinforced concrete slab 135 6 mil poly vapour barrier 135 6'' compacted granular fill Floor: Patio floor - Basement level 20 4'' concrete footing Floor: Floor - main entrance 4 4'' concrete footing A2020 Basement Walls Foundation - 300mm Concrete wall 143 concrete wall Exterior Wall - basement (at garage) 76 2x6 back framing at 16'' O.C. 76 R24 batt insulation 76 6 mil poly vapour barrier 76 1/2'' standard gypsum wall board 76 Paint finish Basic Wall: Exterior Wall - basement 79 Hardie board siding 79 Building paper (air barrier) 79 7/16'' plywood sheathing 79 2x6 S.P.F. #1/2 studs @ 16'' O.C. 79 R24 batt insulation 79 6 mil poly vapour barrier 79 1/2'' standard gypsum wall board 79 Paint finish B1010 Floor Construction Floor: Floor - main level 138 Finished flooring 138 3/4'' T&G spruce plywood sheathing 138 11 7/8'' engineered I-joists @ 16'' O.C. 138 Spray foam to 3 3/8'' depth in I-joists 138 1/2'' C.D board to finish area 138 Painted - lightly textured finish Floor: Garage floor - Main level 47 4'' reinforced concrete slab 47 6 mil poly vapour barrier 47 6'' compacted granular fill Patio floor - main level 20 vinyl decking 20 torch-on waterproof membrane 20 3/4'' T&G spruce plywood sheathing 20 7 1/2'' LSL'S AT 12'' O.C. 20 Perforated soffit B1020 Roof Construction Basic roof: Generic roof - 300 mm 271 Shingles 271 building papers 271 engineered trusses c/w H-clips 271 ½’’ plywood sheathing 182 R50 loose fill spray over living spaces 182 6 mil poly. Vapour barrier 57 B1020 Basic roof: Generic roof - 300 mm 182 1/2'' C.D. gypsum board 182 painted B2010 Exterior Walls Basic wall: Exterior Wall - Main 210 Hardie board siding 210 Building paper (air barrier) 210 7/16'' plywood sheathing 210 2x6 S.P.F. #1/2 studs @ 16'' O.C. 210 R24 batt insulation 210 6 mil poly vapour barrier 210 1/2'' standard gypsum wall board 210 Paint finish B2020 Exterior Windows fixed windows 2' x 4' (3 pieces) 2.2 Double-pane glazing + Aluminum frame double windows 5' x 5' (2 pieces) 4.6 Double-pane glazing + Aluminum frame fixed windows 2' x 4' (7 pieces) 5.2 Double-pane glazing + Aluminum frame fixed windows 6' x 2' (2 pieces) 2.2 Double-pane glazing + Aluminum frame double windows 6' x 6' (3 pieces) 10 Double-pane glazing + Aluminum frame B2030 Exterior Doors glass sliding door 8' x 6'8'' 5 Glass door glass sliding door 8' x 8' 6 Glass door main entrance door 3' x 8' 2 Wood door Garage door 16' x 8' 12 Garage door C1010 Partitions Basic Wall: Interior - Basement + main level 343 Paint 343 1/2'' standard gypsum board 343 2x6 studs at 16'' O.C. 343 1/2'' standard gypsum board 343 Paint C1020 Interior Doors wood sliding door 5' x 6'8'' (2 pieces) 6 Wood door standard door 2'8'' x 6'8'' (5 pieces) 8 Wood door standard door 2'8'' x 6'8'' (6 pieces) 10 Wood door wood sliding door 2'10'' x 6'8'' (1 piece) 2 Wood door wood sliding door 5' x 6'8'' (1 piece) 3 Wood door C2010 Stair Construction 9 3/4'' T&G spruce plywood sheathing 9 laminated flooring (stair tread) 5.2.1.2 Construction stage (A4-A5) In the construction stage, the impacts come from material transport, equipment energy use, and construction waste. The transport distances of each material were estimated based on the distances between the nearest manufacturing factories and the construction site. Detailed information is provided in Table A1 of Appendix A. The energy consumed by the construction equipment was estimated based on the Athena Construction Energy Database and calculated by the height of the building and the total mass of the materials. The construction waste factors for each type of material were also based on the Athena Construction Energy Database [148] (listed in Table A2 of Appendix A). 58 5.2.1.3 Usage stage (B1-B5) Since the lifespan of the house was defined as 60 years, the maintenance, repair, and replacement activities were assumed to happen at different frequencies. Based on the calculation method described in the methodology section, the quantity of new materials needed for maintenance (B1), repair (B2), and replacement (B3) can be calculated based on the task frequency and the material use percentage. Table A3 of Appendix A presents the task frequency and the material use percentage of each material in each activity. In terms of the operational energy use, the energy simulation software HOT2000, one of the most popular energy simulation tools for single-family houses in Canada, was adopted to estimate the annual energy consumption [149]. The configurations of building assemblies were based on the details listed in Table 5-1. The operational water use was calculated based on the average daily water use statistics from the Government of Canada [150], which includes all potable water consumption from faucets inside the house, as well as the landscaping outside. Table A5 of Appendix A presents the annual energy and water consumption of the single-family house. 5.2.1.4 Disposal stage (C1-C4) In the disposal stage, the existing building is assumed to be torn down and the construction waste materials need to be sorted for reuse, recycling, or landfilling. Energy used by the demolition equipment (C1) was assumed based on the data from citations and evaluated by industrial professionals. Considering material recycling and reuse, equipment with fuel consumption of 35 L/h needs 40 hours to demolish a single-family house [151]. Based on the availability of recycling and landfill facilities closest to the site, the transport distance of waste materials (C2) to different facilities was estimated and is listed in Table A4 of Appendix A. The processing facility equipment energy use can be calculated based on the quantity of waste materials that are treated as reuse and recycle materials (C3). The percentages of waste materials for reuse and recycling are listed in Table A5 of Appendix A. The impacts from landfilling (C4) were estimated based on the quantity of materials that were sent to landfill centre. The percentage of waste materials for landfilling are also listed in Table A5. 5.2.2 Life cycle impact assessment After the data collection for each module from A1-C4, the whole building LCIA can be conducted from three aspects based on the reported environmental indicators listed in EN 15978, which are 59 presented in Table 5-2. The environmental impacts considered in this case study were evaluated according to EPD 2013 v1.03 method that was specifically developed in SimaPro 8.5.2.0 version to create EPD [152]. Cumulative Energy Demand (CED) v1.09 method was used to calculate the energy resource use for each material and service. Secondary material use was calculated by adding all the recycled and reused materials in product manufacturing. The net use of fresh water was calculated by adding up all the water consumption in product manufacturing and building operations. Waste flows were calculated by adding up the elementary or intermediate LCI flows during the building life cycle. Table 5-2: Environmental indicators and the evaluation methods [135] Environmental Indicators Methodology Unit Environmental Impacts Global warming potential (GWP) EPD 2013 V1.03 Kg CO2 eq. Depletion of the stratospheric ozone layer (ODP) EPD 2013 V1.03 Kg CFC-11 eq. Acidification potential of land and water (AP) EPD 2013 V1.03 Kg SO2 eq. Eutrophication potential (EP) EPD 2013 V1.03 Kg N eq. Photochemical oxidation potential (POCP) EPD 2013 V1.03 Kg O3 eq. Abiotic resource depletion potential of fossil fuels (ADP) EPD 2013 V1.03 MJ surplus Resource Use Renewable primary energy resources used (RPE) CED (v1.09) MJ Non-renewable primary energy resources used (NRPE) CED (v1.09) MJ Secondary material (SM) LCI flows assembly Kg Net use of fresh water (FW) LCI flows assembly m3 Waste Flow Waste disposed (WD) LCI flows assembly Kg Materials for recycling (MR) LCI flows assembly Kg Components for re-use (CRU) LCI flows assembly Kg 5.2.3 LCC assessment The unit processes and flows involved in each module (A1-A4) during the data collection stage were used to conduct the LCC assessment. The detailed calculation processes were presented in Chapter 4. The discount rate for this study was set at 4.65% per year based on the 2020 Bank of Canada information [153]. The fluctuations on discount rate have a huge impact on the final LCC results. However, it is hard to predict the economic performance in the future. Therefore, in this study, the discount rate was set to be the same as 2020 in the future building life span. 60 The material costs and construction costs were based on the RSMeans cost database 2019 version [154]. Table A7 lists all the initial costs collected from RSMeans based on the building materials derived from the BIM model. Transportation costs were also cited from the Canadian Trucking Alliance [155]. Utility costs were based on the unit prices from FortisBC and BC Hydro [156,157]. Construction waste disposal costs were based on the information from the City of Kelowna website [158]. The material quantities listed in Table 5-1 were used to calculate the manufacturing and construction costs. The data collected and listed in Table A1-A7 in Appendix A were also used to conduct the LCC calculation for the other life cycle stages. WBLCA results Table 5-3 shows the WBLCA results including LCA and LCC results of a single-family house for a 60-year lifetime. The contributions from different modules are presented, and the LCA results in terms of different impact factors and LCC results are listed in the table below. The results interpretation is challenging since it is summarized from different modules, life cycle stages, material types, and building assemblies. However, the proposed WBLCA method clearly presents and illustrates the performance of the building throughout its lifecycle, from different perspectives and with proper interpretation. 61 Table 5-3: WBLCA results: environmental impact results from each building module in different category Information module Module Name Environmental impacts Resource use Waste Economic impacts GWP ODP AP EP POC ADP RPE NRPE SM FW WD CRU MR LCC kg CO2 eq. kg CFC11 eq. kg SO2 eq. kg N eq. kg O3 eq. MJ surplus MJ MJ KG M3 KG KG KG C$ A1-A3 Raw material supply, transport, manufacture 5.10E+04 1.29E-02 2.42E+02 9.69E+01 3.82E+03 5.03E+04 1.11E+06 5.23E+05 2.34E+04 8.59E+02 7.17E+03 0.00E+00 0.00E+00 148,800 A4 Transport 1.26E+03 3.23E-04 3.30E+00 1.24E+00 4.77E+01 2.86E+03 2.82E+02 2.13E+04 0.00E+00 3.93E+00 1.33E+03 0.00E+00 0.00E+00 10,300 A5 Construction 4.46E+03 1.24E-03 3.42E+01 5.71E+00 9.33E+02 7.39E+03 4.99E+04 5.93E+04 1.12E+03 3.01E+01 3.05E+02 1.26E+02 5.47E+03 122,000 B1 Maintenance 1.63E+04 1.56E-03 9.07E+01 9.96E+01 8.36E+02 1.69E+04 4.55E+04 1.95E+05 0.00E+00 1.85E+02 4.34E+03 0.00E+00 0.00E+00 13,800 B2 Repair 1.42E+04 4.85E-03 8.51E+01 4.16E+01 9.08E+02 1.19E+04 8.99E+04 1.90E+05 1.68E+03 2.26E+02 1.95E+03 3.87E+02 7.13E+03 8,500 B3 Replacement 1.72E+04 1.43E-03 1.18E+02 5.74E+01 1.24E+03 1.56E+04 8.02E+04 2.92E+05 8.81E+02 3.47E+02 2.16E+03 5.51E+02 6.33E+03 27,800 B4 Operational energy use 2.89E+05 4.38E-02 4.31E+02 1.54E+02 3.77E+03 6.83E+05 3.94E+04 4.81E+06 0.00E+00 3.82E+02 2.78E+03 0.00E+00 0.00E+00 43,100 B5 Operational water use 2.10E+03 2.96E-04 1.25E+01 7.27E+00 1.22E+02 2.32E+03 2.98E+04 2.82E+04 0.00E+00 1.67E+04 5.02E+02 0.00E+00 0.00E+00 2,600 C1 Demolition 4.99E+03 1.22E-03 4.85E+01 5.86E+00 1.45E+03 1.08E+04 4.32E+02 7.75E+04 0.00E+00 9.99E+00 7.62E+01 0.00E+00 0.00E+00 1,000 C2 Transport 7.59E+02 1.92E-04 1.89E+00 7.21E-01 2.67E+01 1.70E+03 1.69E+02 1.26E+04 0.00E+00 2.28E+00 6.56E+02 0.00E+00 0.00E+00 800 C3 Waste processing -1.10E+04 -1.16E-03 -6.22E+01 -1.99E+01 -1.06E+03 -2.63E+04 -6.20E+05 -2.28E+05 0.00E+00 -2.55E+02 -1.22E+03 2.95E+04 1.07E+05 1800 C4 Disposal 5.02E+02 1.95E-04 4.95E+00 1.99E+01 1.19E+02 1.75E+03 -1.83E+02 1.11E+04 0.00E+00 7.70E+00 5.16E+04 0.00E+00 0.00E+00 400 Total A1–C4 3.91E+05 6.68E-02 1.01E+03 4.70E+02 1.22E+04 7.78E+05 1.45E+06 5.99E+06 2.71E+04 1.85E+04 7.16E+04 3.06E+04 1.26E+05 381,500 62 As shown in Figure 5-2, the contributions from different life cycle stages were summarized and illustrated based on the WBLCA results. Modules A1-A3 and B4 are the top two contributors to resource use and environmental impacts. Over 80% of the GWP, ODP, and ADP emissions, and over 50% of the AP, EP, and POCP emissions are coming from A1-A3 and B4 modules combined. In terms of resource use, modules B5 and C3 should be monitored beside the modules A1-A3 and B4. More than 90% of FW is consumed by the B5 module, and over 40% of RPE use was reduced at the C3 module. In C3, most of the results are negative as the material reuse and recycling reduce the quantity of raw materials needed in the manufacturing stage. In terms of waste flow, C3 and C4 are the key factors. Ninety-five percent (95%) of CRU and 84% of MR are contributed by C3, and 70% of the WD are contributed by C4. Figure 5-2: Information module contribution to the WBLCA results In terms of LCC, the product stage (A1-A3), construction stage (A5), and operational stage (B4) are the top three contributors. As listed in Table 5-3, the product stage cost $148,800, the construction stage cost $122,000, and the operational stage cost $43,100. These three stages spend 0% 20% 40% 60% 80% 100%GWPODPAPEPPOCPADPRPENRPESMFWWDCRUMRLCCA1-A3A4A5B1B2B3B4B5C1C2C3C463 over 80% of the total cost. Besides the material manufacturing stage and operational stage, the construction stage is also a key factor in term of LCC. In the LCA results, the construction stage always contributes a small portion of emissions. Therefore, it is hard to predict contributions are most important when considering LCA and LCC results together. Further exploration is needed to interpret the WBLCA results to find the balance between environment and cost. As shown in Figure 5-2, material embodied impacts and operational energy use impacts are the top two contributors for almost every impact factor. Therefore, the design should focus on these two modules to efficiently improve the overall building performance. This information will also help the designer quickly address the most important impact contributors on the design. Figure 5-2 also shows that transportation, including material transport from factory to site (A4) and waste material transport from cite to sorting facilities (C2), is a less important factor in this case study as it contributes less than 1% in each impact category. One of the main reasons is that most of the wood materials are manufactured locally, and the other materials are from either British Columbia or the neighbouring province. Figure 5-2 shows that material use is one of the most important contributors to WBLCA results. In order to optimize material usage during the building design, it is necessary to analyze the detailed allocations of material usage in different building assemblies. Figure 5-3 illustrates that the building assemblies have more or less similar allocations to the total results. The standard foundations, basement walls, and floor construction are the top three building assemblies that individually contribute an average of 14% of the WBLCA results in each impact factor. These three building assemblies should be focused on first to reduce the impacts of material use. The slab on grades, roof construction, exterior walls, and exterior windows are the second group that needs to be focused on, as each of them also contributes an average of 8% of the WBLCA results in each impact factor. The exterior windows need special attention, as the percentage of material weight is much less than the percentage of impact contribution. The interior and exterior doors, stairs, and partitions are the group that contributes the least to the total results, mainly due to having the least material usage in these assemblies. Table 5-1 lists the detailed configurations for each building assembly. As there are different types of materials forming each building assembly, it is necessary to understand the contributions from each material type. 64 In terms of the LCC information shown in Figure 5-3, the assemblies of basement walls, floor construction, roof construction, and exterior walls are the top four contributors to the total material costs, since a lot of materials are involved in each assembly. Basement walls have the highest costs mainly due to materials such as cast in concrete, concrete forming, exterior siding materials, etc. In terms of floor construction, the finished layer, joist, and plywood sheathing are the three materials that contribute the most. For the exterior walls on the main floor, the siding materials, plywood sheathing materials, framing studs, and gypsum boards are the major costs. In roof construction, the costs are almost equally contributed by each material layer. Asphalt shingles, roof framing, and sheathing cost a little more than the other materials in the roof assembly. Figure 5-3: LCA results for material usage in different building elements Figure 5-4 illustrates the WBLCA results in terms of material types. Concrete and wood materials are the top two contributors to the WBLCA results, adding a total of 60-90% to the WBLCA results, except for the MR, CRU, and ODP impact factors. The MR and CRU impacts usually happen when the materials are in the waste processing stage, and insulation materials are the major contributor to the ODP impact factor. Concrete is one of the biggest impact contributors, as well as the number one quantity that was consumed for the house construction. Concrete that consumes 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%GWPODPAPEPSPADPRPENRPESMFWWDCRUMRLCCStandard Foundations Slab on Grades Basement Walls Floor ConstructionRoof Construction Exterior Walls Exterior Windows Exterior DoorsPartitions Interior Doors Stair Construction65 less cement and uses waste aggregates, called green concrete, should be encouraged in building construction, although access to environmentally-friendly concrete is limited in the market [159][160]. The wood materials include the combination of wood strip, plywood sheathing, laminated flooring, engineered I-joist, engineered trusses, and wood doors. The total weight of the wood materials constitutes 12.5% of the building weight, while the total LCA impact contribution from wood materials is in the 20-45% range for different impact factors. Therefore, the life cycle performance of wood materials is significant for wood-structured single-family houses. Besides concrete and wood materials, the aluminum window frames should be investigated. The weight of the aluminum window frames is less than 0.2% of the total weight, and the LCA impact contribution is between 5-15% for different impact factors. These findings can be used as parameters to further conduct the building design optimization analysis described in the following section. Figure 5-4: Material type contribution to material use LCA results 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%GWPODPAPEPSPADPRPENRPESMFWWDCRUMRConcrete Steel Gypsum GlassWood Granular fill Plastic InsulationPaint Hardie board siding Asphalt shingles Aluminum66 Building design improvement based on WBLCA results Based on the WBLCA results shown in Figure 5-2, material use and operational energy use are the two major contributors to the WBLCA results. Therefore, the most efficient way to improve WBLCA performance is to reduce the LCA impacts from materials or operational energy use. In order to evaluate the proposed design optimization framework, two building design revision scenarios were proposed in this section to improve the performance of material and operational energy use separately, while monitoring the changes on the other information modules. In terms of material use impact, it is not easy to reduce the material quantity as the building layout is designed to satisfy functional requirements and the owner’s needs. Alternatively, materials with less LCA impact should be selected. Based on the WBLCA results shown in Figure 5-3, the standard foundations, basement walls, and floor construction are the top three building assemblies that should be focused on first. Based on the WBLCA results shown in Figure 5-4, the most efficient way to reduce material use impacts is to study the concrete, wood, and aluminum materials. Based on the detailed WBLCA results from the material manufacturing stage (A1-A3) listed in Table B1 of Appendix B, the total impacts of concrete, plywood sheathing, and aluminum window frames are the top contributors to the WBLCA results in most of the impact categories. Therefore, alternative materials with less LCA impacts but similar functionality were selected in Scenario 1 to recalculate the WBLCA results for building design optimization. In terms of building operational energy performance, there are quite a few options to mitigate the impacts. Based on the results from the HOT2000 energy simulation software, space heating and cooling and domestic hot water heating contribute the majority of energy consumption. Hot water demand is based on occupant behaviour, which is difficult for the designer to manipulate. However, a higher efficiency hot water tank can be selected to improve efficiency. In the original design, the hot water tank with the highest efficiency was already selected for building energy simulation. Based on the WBLCA results, Scenario 2 of the building design optimization focused on space heating and cooling performance, which can be improved through insulation, glazing, and improved airtightness [161][25]. Based on the analysis in the existing design, three parts were upgraded with the fewest changes to the original design. Basement slab insulation was added, the double-glazed windows were upgraded to triple-glazed windows, and the airtightness was set from 1.5 ACH to 1.0 ACH. The details of Scenarios 1 and 2 for building design revisions are listed in 67 Table 5-4. There are alternative options to improve building energy performance or reduce material use impacts. The optimization strategies listed in Table 5-4 are the most efficient, since they are specifically based on the WBLCA results. Table 5-4: BIM model optimization details for two design revisions. Original Design Scenario 1 Scenario 2 Material use upgrade Concrete - Quebec Concrete – North America Concrete - Quebec Plywood sheathing S.O.B Sheathing Plywood Sheathing Aluminum window frame Vinyl window frame Aluminum window frame Operation energy use upgrade No insulation on basement floor No insulation on basement floor 2.4'' XPS board insulation on basement floor Double pane windows Double pane windows Triple pane windows Airtightness 1.5 ACH Airtightness 1.5 ACH Airtightness 1.0 ACH Based on the changes added to the BIM models to reduce material use and operational energy use, the WBLCA results for the two scenarios were calculated and compared with the original WBLCA results; this is illustrated in Figure 5-5. Figure 5-5 shows that the WBLCA results in Scenario 1 are generally lower than the original design for each impact factor by an average of 5%, which means the design optimization in revision 1 is successful. The values of environmental impacts (GWP, ODP, AP, EP, POCP, and ADP) and resource use (RPE, NRPE, and SW) have reductions that are more obvious in Scenario 1. The reason is that the upgraded materials in Scenario 1 have lower resource use and environmental impacts than the original materials. The values of waste flow (WD, CRU, and MR) in the two designs are more or less the same because the material quantity does not change. In Scenario 2, the performance is similar to Scenario 1 except for the ODP values. As shown in Figure 5-4, insulation materials are the number one contributor to the ODP values. In order to improve operational energy use performance, more insulation was added into the basement slab, which led to a dramatic increase in ODP value. Since more insulation and glazing materials were added into the BIM design in Scenario 2, the total building material impacts (A1-A3) were increased from the original design by an average of 5% for each impact factor. On the other hand, the building thermal performance improved due to the additional materials added, and the impacts from operational energy use (B4) decreased by 8.5% instead. In terms of the LCC, Scenario 1 has lower total cost than the original design due to changes to materials and installation costs. The O.S.B boards used in the walls and roofs cost slightly less 68 than the plywood used in the original design. Furthermore, vinyl window frames are much cheaper than aluminum window frames based on the cost information from RSMeans. On the other hand, the additional materials added to increase the thermal insulation properties of the envelope also create a cost increase, which is almost 5% more than the original design. The main reason is the use of triple-pane windows, which are not commonly used in Canada. The price of one triple-pane window is around $850 more expensive than a double-pane window, on average [162]. Therefore, the designer should pay attention to materials that are not commonly used in the construction industry in order to maintain a balanced cost. Figure 5-5: WBLCA results with different BIM designs In order to evaluate which design is better with consideration of all these impact categories from the environmental and cost perspectives, the TOPSIS-based MCDM method was used to conduct the calculation. The results show that Scenario 1 is the best option among the three in terms of environmental and economic performance, as it has the best performance among the 13 environmental indicators and the one economic indicator. In terms of Scenario 2, in order to reduce the operational emissions, additional insulation was added and unique window materials were selected in the design, which makes the cost a bit higher than the original design. As shown in Figure 5-4, insulation materials are the number one contributor to the ODP values. With the additional insulation materials added in Scenario 2, the ODP values are also much higher than the original design. Even though there are a few environmental impact categories that have lower impacts than the original design, the increment impacts on costs are still much higher, no matter 0%20%40%60%80%100%120%140%160%180%200%GWP ODP AP EP POCP ADP RPE NRPE SW FW WD CRU MR LCCOriginal Revision 1 Revision 269 how much more weighting was assigned to the environmental impact factors. Therefore, improving the building operational energy use performance by adding more materials to the building design is not always a sustainable solution in terms of environmental and economic impacts. The impact reduction in operational energy use (B4) due to the increased insulation might not be enough to balance the increase in building material impacts (A1-A3) and costs. Therefore, the WBLCA results with LCC should be calculated to monitor the overall performance of a building including all the life cycle stages and all the impact factors, especially when the client imposes heavy LCC cost constraints on the designer. Discussion There are many studies conducted on WBLCA. However, most of these studies end when the WBLCA results are calculated and interpreted [25,163–167]. There is rarely a study that further analyzes the results and provides suggestions on building design optimization. The design improvement strategy proposed in this study fills this gap by providing detailed solutions to improve the building design, based on the WBLCA results acquired with consideration of environmental and economic impacts. The WBLCA with EPD, LCC, and BIM method proposed in Chapter 4 provides a holistic overview of the life cycle performance in different life cycle stages and highlights the most critical contributors in any circumstances. The case study in this chapter clearly presented the application of the proposed method in new building design, and demonstrated the advantages of applying the proposed method to improve building design performance. The case study results show that there are inter-connections between different information modules. When the building design changes to reduce the LCA impact of one module, the impacts of the other module might increase simultaneously. In this proposed framework, the relationships between each information module (A1-C4) are always monitored, and the designer has a full picture while optimizing the building design, including environmental emissions and costs. It is still challenging to figure out how to reduce the material embodied impacts after realizing their importance. The WBLCA method proposed in this study addressed this issue by calculating the building material quantities accurately with BIM. With the dynamic function of BIM, the materials can be categorized under different building assemblies. Therefore, the contributions from each building assembly can be calculated and the critical assemblies can be highlighted. This will help the designer narrow down the boundaries to improve the material embodied impacts. The 70 integration of BIM into WBLCA could also reduce the uncertainty of WBLCA results since all the building material details are stored in the 3D windows. With the dynamic function of BIM, the material BoQ list can be automatically generated and translated into the designed Excel file. The integration of BIM provides a platform for the designer to receive material BoQ changes efficiently while optimizing the building design. With further code development through the Revit API platform, it is possible to build an add-in tool to link the material BoQ from BIM with the LCA database to automatically calculate the LCA impacts from the materials [168,169], which should also be more accurate than the current Tally add-in in Revit. While the integration of BIM into building LCA analysis is popular in research and industrial practice, there is still a lack of studies that integrate BIM with a WBLCA that strictly follows the EN 15978 standard. A review study conducted by Soust-verdaguer et al. shows that most of the BIM-based LCA papers focused only on CO2 emission calculation instead of a complete set of assessment indicators [117]. Furthermore, the current BIM-based LCA either did not consider all the life cycle stages, or did not analyze the complete building assemblies [170–172]. The BIM and LCA integration in this paper fills this gap by providing a systematic framework for the designer to conduct the WBLCA with the EN 15978 standard to receive reliable and comprehensive results. The integration of BIM into WBLCA in this study ensures the data accuracy of building assemblies and materials. At the same time, the BIM-based WBLCA method can be used by designers or researchers to optimize the building plan according to the LCA results. The impacts of secondary materials, components for reuse, and material recycle (SM, CRU, and MR) were also monitored by the proposed method in this study. It is obvious from the WBLCA results that material embodied impacts (A1-A3) are one of the most significant contributors. The use of secondary materials in new material manufacturing can dramatically reduce the environmental impacts of embodied emissions. Waste material reuse and recycling reduce the use of raw materials in building construction, as well as the environmental impacts on waste treatment. The WBLCA with EPD, LCC, and BIM method proposed in this study monitors the performance of SM, CRU, and MR, which helps decision-makers to track down the percentage of these types of materials as well as to promote the materials that use secondary materials during manufacturing or can be reused or recycled at the end of the building life span. At the same time, the LCCs of building materials that use secondary materials are also monitored, since the usage of recycled/reused materials is not a common building material option. The recycling and reuse of 71 construction materials should be promoted by the government and related associations to break down LCC costs, which can be more affordable to select. The LCC allocations among different modules show that the initial cost to build a house is still a critical portion of the LCC. The annual operational cost, including electricity and natural gas costs, is over $2200. It would be quite a large number in 60 years. However, the discount rate assumed in this study is around 4.65% based on 2020 Bank of Canada information. The present value of lifetime utility costs is around $43,100. At the end of life of the building, the waste treatment stages (C1-C4) spend less than 1% of the total cost. The reason is that these activities happen in the future year 60, which has a great discount when transferred to present value. On the other hand, the city landfill does not charge a high rate for construction waste recycling or disposal. In order to push the construction industry into more sustainable construction, one option is to raise the waste disposal rate and encourage more recycling rules. It is also shown that the lifetime waste usage cost is less than 1% of the total cost. Since drinking water is a precious and limited resource, it is necessary to raise the water unit price to reduce average household water consumption. When considering the building level LCA results alone, the most important contributors could be summarized. On the other hand, the most important contributors in terms of LCC could also be pointed out if considering LCC alone. Nowadays, most studies analyze building-level performance individually, which makes the findings not very applicable to the industry. In the proposed WBLCA method, the LCA and LCC results are both calculated and analyzed together. The suggestions on building environmental performance are proposed with a consideration of budgets. This could be a new trend for any future studies on building level sustainability performance. Integration of WBLCA and the EPD method can further present impacts based on building material types, which will make the targets more specific for the designer. For example, FSC-certified wood materials are encouraged to be used in building construction as they are more environmentally friendly than non-certified wood materials [173]. Between wood materials, the processing techniques and LCA impacts can differ. For example, hardwood flooring and laminated flooring both work for the floor surface. However, laminated flooring has chemicals used in the manufacturing process, while hardwood flooring does not. Hardwood flooring has a longer lifespan than laminated flooring. The same is true with different types of sheathing wood materials. In order to find materials with better performance to replace the existing design, the LCA data for 72 each specific material should be presented and compared, instead of using background data from the LCA database. Therefore, the development of EPD for construction materials becomes very important, as the real data of each material in the same category will be presented precisely with the same Produce Declaration Rules (PCRs) [30,131]. The application of EPD into WBLCA can significantly increase the accuracy of material information and reduce the uncertainty of final WBLCA results. The designer can read the performance of each material on the third-party-verified EPD reports and choose the one with best LCA performance. The completeness of the EPD database in one industry can help promote environmentally-friendly and resource-friendly materials, and encourage the industry to innovate and move towards sustainable construction. The WBLCA results presented in this study are complex with over 14 indicators from environmental and economic perspectives. It is necessary to conduct results normalization when the building-level comparison process is conducted, in order to estimate which design option is the best. As part of the design improvement strategy, this case study included the LCA results normalization process after design revisions, which was rarely mentioned by peer researchers on WBLCA. In this case study, the results of Scenario 2 are the same or less than the original design, except for the ODP indicator, which is almost double the value of the original design and LCC costs. As a result, it is very hard to tell if Scenario 2 is better than the original design. Therefore, the simple TOPSIS-based MCDM method was adopted in this case study to conduct the comparison, and the total normalized WBLCA results show that Scenario 2 design is not as good as the original design. It would be interesting to investigate if the results vary when the other normalization methods are used. A few limitations need future research based on the case study. The LCA results of building materials were calculated based on the existing LCA databases. In reality, it would be more accurate to find the foreground data of different building materials, such as the material EPD reports, especially when the decision maker tries to reduce the embodied emissions from building materials. However, the full EPD database is not well developed yet in North America, which should be a future focus for sustainable construction. The operational energy use impacts for WBLCA are conducted through software simulation by assuming that the performance of the house stays the same in 60 years. However, building performance deteriorates every year along with material aging. It would be an interesting research topic to compare the performance of a building between the simulation results and the actual consumption results in different years. The 73 proposed method is targeting a single-family residential building in order to ensure an apples-to-apples comparisons, while the same framework can be further applied to other types of buildings with the associated LCA development setups. The other limitation is that the building material list only considers the architectural and structural domains, and the other domains, such as Mechanical, Electrical, and Plumbing (MEP), need to be further investigated. Therefore, future research should extend the application of the proposed WBLCA method to these areas to achieve optimal building performance. Summary This case study verified the WBLCA method proposed in Chapter 4 with a single-family house. The environmental and economic performance of the house was fully evaluated, and the design improvement strategy was proposed based on WBLCA results. With the proposed method, the LCA and LCC developments strictly followed EN15978 and ISO 15686 standards, which ensure the results are reliable. BIM integration ensures the building-level performance was accurately measured at the material level and the assembly level, and the material BoQ can be tracked dramatically with the design changes. The final WBLCA results in this framework were clearly interpreted so that the critical contribution factors that dominate the WBLCA results were highlighted. At the end, building design improvement scenarios were developed to reduce the impacts from the critical factors, and a WBLCA results comparison among these scenarios was conducted to select the best design with the best LCA performance. The proposed framework is a step further than the current WBLCA studies, providing a solution for the designer to improve the building design efficiently with the consideration of all life cycle environmental and economic impacts. The case study demonstrated that this WBLCA method with EPD, BIM, and LCC integration could help the decision maker easily improve the WBLCA performance. The case study results for a single-family house in BC, Canada indicate that the material embodied impacts (A1-A3) and the operational energy use impacts (B4) are the two critical factors that contribute 60-90% of the total impacts for most impact factors. The concrete and wood materials are the main material types that account for an average of 65% of the material embodied impacts. Air and water heating for the house are the main factors, which account for over 80% of the operational energy use impacts. The design improvement strategy shows that upgrading the materials with lower LCA impacts 74 reduces the WBLCA results by an average of 5%, while improving the thermal performance of the house with more insulation materials does not always reduce the WBLCA results, especially when the LCC is considered as an impact factor. However, due to the lack of an EPD database for building materials in North America, the calculations of some of the material embodied impacts still use background data from the database. In future, the development of an EPD database for building materials would be a significant contribution to sustainable construction. On the other hand, the developments on dynamic BIM-LCA could be further explored to link the material BoQ with the LCA database automatically, so the designer can review the building design performance simultaneously while updating the design without too much knowledge of LCA. 75 Chapter 6: WBLCA for Existing Residential Building Renovations and Reconstruction Parts of this chapter have been published in the Journal of Cleaner Production (Elsevier), as an article titled “BIM-based life cycle environmental performance assessment of single-family houses: Renovation and reconstruction strategies for aging building stock in British Columbia” [25]. Background Chapter 4 proposed a comprehensive WBLCA method to conduct environmental and economic analysis at the building level. Chapter 5 conducted a case study for the proposed WBLCA method on new building designs and developed a new building design improvement strategy to help designers efficiently improve environmental performance while considering the economic impacts. This chapter focuses on the application of the proposed WBLCA method on existing building renovation strategies, since there is a huge potential to improve the environmental performance of existing buildings with minimum effort. The degradation of building components and lack of compliance with the latest building codes are two of the major reasons that lead to this observed discrepancy between older and new constructions [174,175]. In order to meet emission reduction targets in time, immediate action needs to be taken to reduce the environmental impacts of old houses [176]. There are two common options to improve the environmental performance of old houses: renovation and reconstruction. Renovation means upgrading different parts of building components to make an old house closer to the current standard [177]. Reconstruction means demolishing the old house and building a new one that complies with the current building code [178]. Renovations are expected to reduce the building energy consumption, while the embodied energy and material use during renovation might outweigh any potential environmental benefits gained through their use [23]. Therefore, it is important to analyse different levels of renovation to ensure the best output in life cycle emissions. On the other hand, reconstruction can significantly improve environmental performance due to newer materials and higher building standards than the existing condition, while it also carries a significant amount of embodied energy use and emissions [179]. From an economic impact perspective, renovations improve the energy efficiency and reduce utility costs during operation, while the renovation cost is a constraint to the level of renovation. Furthermore, reconstruction cost is always significant to the building owners, and the energy 76 savings might not be the biggest motivation for the building owner to choose reconstruction. Therefore, building-level environmental and economic performance between different renovation options needs to be further analyzed to come up with an efficient and realistic renovation strategy for existing buildings. Studies have been conducted by different researchers to evaluate the strengths and weaknesses of renovation and reconstruction strategies. Semprini et al. [180] conducted an energy-economic analysis for a specific building in Bologna with different renovation strategies, and the results show that deep renovation of existing buildings is one of the best options to decrease energy consumption, although the initial capital cost represents high-factor risks. Alba-Rodriguez et al. [181] also conducted a study for a multi-family building in Spain by comparing renovation and reconstruction strategies, and the results illustrate that the renovation option has a lower economic and environmental impact than the total reconstruction option. Hasik et al. [167] conducted a whole-building life cycle assessment for an old warehouse in Philadelphia, and the findings show that the renovation approach reduces 53%-75% of the six different environmental impacts when compared to a reconstruction approach. Marique and Rossi [178] compared the GHG emissions and energy consumptions of office buildings in Belgium under renovation and reconstruction scenarios, and stated that renovating a building has lower life cycle emissions than reconstructing a building, due to the high embodied emission from construction and material manufacture. Weiler et al. [182] also compared the life cycle energy and emission performance of a multi-family building between renovation and reconstruction under four different building standards, and the results show that the highest level of renovation standard leads to the best life cycle energy and emission performance. Gaspar and Santos [183] assessed the renovation and reconstruction strategies for a 40-year-old single-family house in Portugal in terms of the embodied energy consumption, and concluded that renovation is a more sustainable strategy than reconstruction. Due to the unique nature of the operational and embodied energy use scenarios as well as the building codes and regulations applicable for various geographic and administrative regions, it is evident that a comprehensive study needs to be conducted to quantify the actual benefits of the retrofitting decisions. This need has been recently highlighted in British Columbia, Canada, with the advent of the BC Energy STEP Code, which mandates that provincial buildings be net-zero ready by 2032 [184]. While there are a few studies conducted on economic evaluation of retrofits [176], sustainability integration through retrofits [185], and residential energy-efficiency retrofit 77 behaviour [186] in the Canadian context, a comprehensive database review in the Compendex Engineering Village revealed that no studies have been conducted since 2009 on integrating life cycle thinking in the renovation vs. reconstruction decision for older building stock in the Canadian context, after the advent of the current building codes. While a study conducted in 2005 indicates that renovating existing buildings rather than completely rebuilding them reduces the generation of waste and pollutants [187], this knowledge needs to be reassessed in light of current conditions and practices. The need for comprehensive sustainability decision making support for existing building renovation has also been highlighted in the current literature [188]. A 2019 statement by the Canada Green Building Council indicates that retrofitting and improving the performance of the existing building stock is especially important in reducing the carbon footprint of the building sector as per government targets [189]. Based on the findings from the most recent studies, it is difficult to predict which option is the best in terms of improving the environmental performance of old building stock while considering the LCC. The existing studies either focus on large-scale buildings, such as multi-family, office, and warehouse, or they use alternative evaluation parameters other than environmental impacts. On the other hand, the impacts from all stages of a building life cycle have not been fully covered by the previous studies. Furthermore, the level of renovation has not been clearly defined in the previous studies. Therefore, it is necessary to use a life cycle assessment method to assess true emissions projection related to single-family building renovation and reconstruction, with defined scenarios based on pilot project data. The proposed WBLCA method is a perfect tool to be used here to comprehensively evaluate the environmental and economic performances between building renovation and reconstruction. This chapter presents the findings and key lessons learned in a residential renovation and reconstruction study conducted for the aging building stock of Vancouver in British Columbia, Canada. The goal of this study was to compare the life cycle environmental and economic performance of existing old houses (pre-1940) under different renovation or reconstruction scenarios with the proposed WBLCA method introduced in Chapter 4. Several renovation/reconstruction scenarios were defined by the municipality based on the findings of a pilot project, which identified the practical retrofitting possibilities for the above building stock to be considered in the grant program, and the most common and cheapest ways to improve the existing building energy performance. This analysis can be used to identify the best 78 residential development scenarios for the selected aging building stock in BC. The study provides insights for making decisions on renovating older houses or building new houses by decommissioning old houses. The study outcomes are expected to support city planners and urban development planners to make urban development decisions, especially in high population density neighbourhoods. Methods and Procedure This case study strictly applies the proposed WBLCA method to the old single-family building stocks after renovation and new houses by demolishing old building stocks. The overall functional unit of this case study is an average single-family residential building, and the goal is to measure the environmental and economic performance of typical existing building renovation strategies with the proposed WBLCA method. A cradle-to-grave system boundary is applied in this study, including the material manufacturing, construction, operation and maintenance, and demolition. An existing old house and a newly constructed house were selected as typical houses based on the statistics from a city planner. Four renovation scenarios and two reconstruction scenarios were developed based on the two BIM models. The WBLCA results for each scenario were calculated during a 60-year lifespan. The detailed WBLCA calculation process demonstrated in Chapter 4 was applied here. 6.2.1 Typical house selection and BIM model development The focus of this study is the aging single-family residential buildings located in Vancouver, British Columbia, Canada. The BIM models were built up for a typical existing house and a newly built house by using Revit software. 6.2.1.1 Existing house selection and BIM model During the preliminary data analysis, it was identified that heritage houses built prior to 1940 have the highest potential to achieve significant improvement on environment performance with renovation. Approximately 22% of the single-family houses in Vancouver were built prior to 1940 based on the 2019 property tax report [190]. In order to evaluate the performance of these existing houses and measure the renovation output, a typical house needs to be selected. The selected existing house should have the common features of the houses built in that year range. At the same time, the building designs and material selections should represent the most common characters at that time. However, these houses were built over 79 80 years ago, and the building plan and material information records were not comprehensively maintained during this period. In order to acquire the most accurate information, the Vancouver Heritage Foundation that provides practical support to the public about heritage houses conducted a pilot program in 2016. Under this, 18 heritage house owners volunteered to join the renovation program [191]. Based on the building information collected in the pilot program, most of the features regarding building design styles were summarized to represent the existing house conditions built prior to 1940. In order to extract other details that were not identified through the above program, interviews were conducted with experts and city personnel who have expertise in this area, and the information about the material selections and the associated material properties were thus collected. Based on the data collected from the above two methods, a typical house built in 1922 with a total floor area of 185m2, named the existing house, was chosen to conduct the building renovation scenario analysis. Based on one of the as-built drawings and the information collected, the building function database of the existing house was summarized and presented in Figure 6-1. Building PartFoundationExisting house (BIM input)Basement wallFlooringExternal wallInterior wallRoofBuilding Product5'’ compacted granular fill6 mil poly film3.5'’ concrete slabHardwood flooring¾’’ T&G sheathing2x10 wood joists½’’ gypsum wall board2x4 wood studs½’’ gypsum wall boardStucco½’’ plywood sheathing2x4 wood studs3.5'’ F.G. batt insulation6 mil poly film½’’ gypsum wall boardRoof membrance5/8’’ plywood sheathing2x10 wood rafters6'’ rigid insulation6 mil poly film½’’ gypsum wall board8'’ concrete wall with bar 80 Figure 6-1: Materials of the existing house for BIM model input. Based on the data from the as-built drawing and collected information, the BIM model of the existing house was developed. The floor plans of the existing house are depicted from the BIM model and presented in Figure 6-2. Figure 6-2: First (left) and second (right) floor plans of the Existing House from Revit. 6.2.1.2 BIM model of a newly built house Instead of renovating an existing house, the next common approach is to replace it with a newly built house. New house construction in the City of Vancouver has to follow different building standards, such as the BC building code [192], Vancouver Building Bylaws [193], and the City of Vancouver Housing design and technical guidelines [194]. The detailed requirements to build a house are clearly described in these building standards. Moreover, the City of Vancouver is aiming to become the greenest city in the world; all new construction has to meet different environmental requirements [195]. In order to achieve this target, the City of Vancouver conducted a series of pioneering projects, one of which was to measure the economic performance of new construction houses that are meeting the passive house standard [196]. Two typical case study houses were introduced in this project. Based on the house information from this project, the building regulations, and five standard newly constructed building plans provided by the City of Vancouver, a typical newly built single-family house was defined with an average floor area of 300m2, which has two storeys on average with a basement located partially below ground. The building information from regulations and project cases was used to define the building function database of the newly built house summarized and presented in Figure 6-3. 81 Building PartFoundationNewly-built house (BIM input)Basement wallFlooringExternal wallInterior wallRoofBuilding ProductGravel6 mil poly film2.5'’ R5 XPS rigid insulationHardwood flooring¾’’ T&G sheathing2x10 wood joists½’’ gypsum wall board2x6 wood studs½’’ gypsum wall boardStucco½’’ plywood sheathing2x6 wood studsR-20 batt insulation6 mil poly film½’’ gypsum wall boardRoof membrance¾’’ plywood sheathing2x10 wood raftersR-50 loose fill insulation6 mil poly film½’’ gypsum wall board8'’ concrete wall with bar 3.5'’ concrete slab2'’ R-5 XPS rigid insulation2x4 wood studsR-14 batt insulation½’’ Gypsum wall boardSound insulation1x3 wood strapping1.5'’ R-5 XPS rigid insulation½’’ gypsum wall boardAsphalt shingles Figure 6-3: Materials of the newly-built house for BIM model input. Based on the data from the project cases and as-built drawings, the BIM model of the existing house was developed. The floor plans of the existing house are depicted from the BIM model and presented in Figure 6-4. 82 Figure 6-4: Basement (left) and first (middle) and second (right) floor plans of the Newly-built House. 6.2.2 Scenario development Scenario development is one of the most important processes in the proposed WBLCA method. In this case study, the scenarios were carefully defined based on actual data from two projects on existing houses renovation, and from research on one passive house design. Since the maintenance of existing houses built prior to 1940 is important in Vancouver, the Vancouver Heritage Institute conducted a pilot project to provide financial incentives to support volunteering owners to conduct heritage house renovation. Based on the renovation results, the retrofit areas shown in Table 6-1 are the most common and cheapest ways to improve existing building energy performance. Table 6-1: Points of renovation under the existing house renovation pilot project in Vancouver [197]. Participant Retrofits completed #1 Attic, draft-proofing (windows) #2 Wall, draft-proofing (bath fan) #3 Ceilings, floors, draft-proofing (doors, windows, fans), furnace, domestic hot water (DHW) #4 Attic, wall, floor, draft-proofing, DHW #5 Attic, wall, floor, draft-proofing, DHW #6 Attic, walls, draft-proofing #7 Attic, draft-proofing The other project was conducted by a private consultant for the City of Vancouver in 2015. This study summarized the most common existing house energy improvement options as listed in Table 6-2. Table 6-2: Most common renovation locations for the existing old houses in Vancouver [198]. Renovation Type Renovation locations Insulation Attic, basement wall, crawlspace wall, exterior wall Space heating Gas furnace, gas boiler, gas fireplace, heat pump Water heating DHW tank, DHW tankless, DHW solar Windows and doors Windows, doors Based on the renovation strategies listed in Table 6-1 and Table 6-2 from different projects, the renovation strategies for existing old houses can be summarized into three main types: (1) upgrade the furnace and hot water system; (2) improve the insulation property on attic, basements, doors, 83 and windows; (3) upgrade the whole building envelope to reduce air leakage. Based on the three main types, four scenarios were developed in this study to analyse the detailed environmental performance of the existing house. In order to compare the reconstruction option with the renovation strategies developed in Scenarios 1-4, reconstruction Scenarios 5-6 were developed by the municipality based on the passive house design project and the related new building construction regulations. The six potential scenarios are clearly explained as follows: Scenario 1 - Existing house without renovation In this scenario, it is assumed that the existing house is in an acceptable condition as per the as-built drawing shown in Figure 6-2. The existing house was assumed to retain its original doors and single-pane windows. The major building mechanical specification inputs for the existing house was assumed to be as per the typical 1920s construction standard. A summary of the technical specifications of the heating systems and building envelopes are listed in Table 6-3. Scenario 2 – Existing house with basic renovations Data published by Natural Resources Canada indicates that space and water heating applications consume 82% of the total energy used in a single detached house [199,200]. Based on the summary from Table 6-1 and Table 6-2, the existing house defined in Scenario 1 is subjected to the basic renovations related to space and water heating systems under this scenario. After considering the costs of different alternatives for space and water heating, a new high-efficiency furnace and a new high-efficiency hot water heater were installed in Scenario 2. A summary of the technical specifications of the heating systems and building envelopes are listed in Table 6-3. Scenario 3 - Existing house with moderate renovations In addition to the heating system, the total thermal resistance of the house also impacts the building’s energy consumption significantly [201]. Based on the summary from Table 6-1 and Table 6-2, it is assumed that the existing house described in Scenario 2 is further modified with an upgrade to the building envelope. The insulation in the attic space and basement is improved, and single-pane windows are upgraded to double-pane windows in Scenario 3. A summary of the technical specifications of the heating systems and building envelopes are listed in Table 6-3. Scenario 4 - Existing house with extensive renovations In this scenario, the existing house was renovated to meet the BC building code standards. Besides the renovation strategies presented in Scenario 3, the house is subjected to further renovations 84 including the addition of wall insulation and replacement of all windows, etc. in Scenario 4. A summary of the technical specifications of the heating systems and building envelopes are listed in Table 6-3. Scenario 5 - Newly built house compliant with BC building code In this scenario, the existing house was demolished and replaced with the newly constructed house shown in Figure 6-4. The newly built house is based on the most current BC building code. A summary of the technical specifications of the heating systems and building envelopes are listed in Table 6-3. Scenario 6 – Newly built passive House In this scenario, the newly built house was built to meet the passive house standard and the other characters mentioned in the passive house project [202]. Based on the guidelines developed by the Passive House Institute (PHI), the building was designed to meet the following performance criteria benchmarks: 1. Space heat demand: Maximum 15 kWh/m2 per year in heating and cooling demand (Or 10W/m2 peak heat load). 2. Maximum 0.6 Air Change per Hour (ACH) @ 50 Pa, both for under pressure and over pressure during a blower test. 3. Total primary energy used for heating, hot water, and domestic electricity must not exceed 120 kWh/m2 of treated floor per year [203]. In this scenario, the building layout is the same as the newly built house defined in Scenario 5. However, the house insulation materials and mechanical systems were adjusted to meet the passive house criteria, based on the data from a passive house study [204]. A summary of the technical specifications of the heating systems and building envelopes for this scenario is listed in Table 6-3. While the defined scenarios are by no means an exhaustive list of all possibilities, grant programs by local governments and utilities are generally devised on the basis of a generalised set of scenarios, as grant schemes and STEP codes cannot be developed to include all scenarios in the spectrum of possibilities. Each scenario covers a level of renovation in line with Vancouver Building By-laws. As the goal of the study was to present and discuss a practical method for municipalities to tackle the renovation vs. reconstruction decision for aging building stock, the current number of scenarios was deemed to be adequate for the task. 85 Table 6-3: Thermal character of the mechanical systems and building envelopes of each scenario. Mechanical Systems Existing House Existing House (Basic Renovation) Existing House (Moderate Renovations) Existing House (Deep Renovation) New-built House Passive House Scenario 1 Scenario 2 Scenario 3 Scenario 4 Scenario 5 Scenario 6 Furnace Natural Gas Heating - AFUE 65% Natural Gas Heating - AFUE 92% Natural Gas Heating - AFUE 92% Natural Gas Heating - AFUE 92% Natural Gas Combo Heating/DHW - AFUE 92% Electric resistance heaters (5.5 kW Output Capacity) Domestic Hot Water Boiler Natural Gas - Energy Factor 0.57 Natural Gas - Energy Factor 0.78 Natural Gas - Energy Factor 0.78 Natural Gas - Energy Factor 0.78 Combo Heating/DHW - Energy Factor 0.8 Electric energy source DHW tank (Energy Factor: 0.82) Heat Recovery Ventilator (HRV) N/A N/A N/A N/A HRV Efficiency - 65% HRV Efficiency - 90% Air tightness 12 ACH @ 50 Pa 12 ACH @ 50 Pa 8 ACH @ 50 Pa 5 ACH @ 50 Pa 3.5 ACH @ 50 Pa 0.6 ACH @ 50 Pa Envelope Additional Insulation in Attic R=1.69 (No Insulation) R=1.69 (No Insulation) R40 (11.8’’ Batt Insulation) R40 (11.8’’ Batt Insulation) R50 (18’’ Loose Fill Insulation) R60 (18’’ Loose Fill Insulation) Windows Single Glazing Single Glazing Double Glazing with Low E Double Glazing with Low E Double Glazed Low E (USI 1.4) Triple Glazed Low E Argon Filled (USI 0.8) Above-Grade Wall Insulation R8 (2.5’’ Batt insulation) R8 (2.5’’ Batt insulation) R8 (2.5’’ Batt insulation) R14 (3.5’’ Batt insulation) R22 (R28 @ 7’’ Batt Insulation) R28 (3.5’’ Mineral wool Insulation + 5’’ Mineral wool board Insulation) Below-Grade Wall Insulation R=0.57 (No Insulation) R=0.57 (No Insulation) R14 (3.5’’ Batt Insulation) R14 (3.5’’ Batt Insulation) R22 Interior Insulation (2’’ Rigid Insulation + 3.5’’ Batt Insulation) R28 Interior Insulation (2’’ Rigid Insulation + 3.5’’ Batt Insulation) Exterior Door Solid Wood (R=2.21) Solid Wood (R=2.21) Solid Wood (R=2.21) Fiberglass polystyrene core door (R=4.83) Fiberglass polystyrene core door R=4.83 PH Certified Glass Door R=7 Under Basement Slab Insulation R=0.66 (No Insulation) R=0.66 (No Insulation) R=0.66 (No Insulation) R=0.66 (No Insulation) R12 (2.5’’ Rigid Insulation) R30 (6’’ Rigid Insulation) 86 6.2.3 WBLCA data collection In order to conduct comparisons among the six scenarios with the proposed WBLCA method, the first step is to calculate the environmental impacts for each scenario including the manufacturing stage, construction stage, usage stage, and demolition stage. 6.2.3.1 Manufacturing stage In this stage, the environmental impact of the existing house in Scenario 1 is treated as zero since no renovation activities are undertaken in this scenario. Scenario 2 only has minor renovations to the furnace and hot water tank. Therefore, the environmental impacts from disposal of the existing furnace and hot water tank along with new material production are considered in this scenario. The environmental impacts for Scenarios 3 and 4 include emissions from existing material disposal and new material production due to renovation. The environmental impacts for Scenarios 5 and 6 include both emissions from new construction material production and material disposal after demolition of the existing house. In order to calculate the environmental impacts in this stage, the first step was to develop a material list for the existing house and the newly built house. Based on the BIM model developed in Section 2.1, the multi-category material take-off list was generated, including all the building materials needed for the existing house and the newly built house. The EPD information available online for the BC construction industry, such as Canadian Wood Council, Athena Sustainable Materials Institute, and Canada Standard Association (CSA group), is used as a primary source. Ecoinvent 3.3 EPD database from SimaPro 8.3 was used as a secondary source when a primary source was not available, to find environmental emission data for building materials. In addition, material quantities removed because of existing house renovation were also identified using the BIM model. The emissions generated from waste material disposal were also assessed by the Ecoinvent 3.3 database. In all of the above material and process assessments, the Canadian data was used as far as possible to maintain regional applicability. In cases where Canadian data was unavailable, data applicable to the US or North America was used. Equation 10 was used to calculate the total environmental impacts from the manufacturing stage. 𝑬𝑲=𝟏𝟏𝟑 = ∑ 𝒙𝒊𝒂𝒊𝒏𝒊=𝟏 + ∑ 𝒚𝒋𝒃𝒋𝒎𝒋=𝟏 Equation 10 Where,  Ek = Total environmental impacts in different stages for indicator k. 87  xi = Environmental impacts for manufacturing the ith material  ai = Quantity of material used for construction or renovation  yj = Environmental impacts for disposing jth material  bj = Quantity of material disposed during demolition or renovation The Revit-based BIM software was used to automatically generate all the material quantities for each scenario. Table 6-4 and Table 6-5 present the material quantities required for existing building renovation, as well as the quantity of construction waste generated during the renovation for Scenarios 3 and 4. In terms of new house construction, Table 6-6 and Table 6-7 show the material quantities required to build a new house in compliance with the BC building code (Scenario 5) and passive house standard (Scenario 6). The materials generated from existing house demolition were also considered in Scenarios 5 and 6. Table 6-4: Material quantities of existing house renovation and waste disposal for Scenario 3 (Generated from BIM model). Category Location application Material application Unit Quantity Materials Required for Renovation Gypsum Board Ceiling Gypsum Wall Board kg 919.9 Batt Insulation Ceiling 11.8’’ Batt Insulation kg 1685.9 Wood Strip Basement Wall Wood Stud m3 0.4 Batt Insulation Basement Wall 3.5’’ Batt Insulation kg 417.3 Gypsum Board Basement Wall Gypsum Wall Board kg 767.8 Window glazing Wall Double pane glazing m2 21.5 Construction Waste From Renovation Gypsum Board Ceiling Gypsum Wall Board kg 919.9 Single pane glass Wall Single-pane glazing m2 21.5 Table 6-5: Material quantities of existing house renovation and waste disposal for Scenario 4 (Generated from BIM model). Category Location Material application Unit Quantity Materials Required for Renovation Gypsum Board Ceiling Gypsum Wall Board kg 919.9 Batt Insulation Ceiling 11.8’’ Batt Insulation kg 1685.9 Wood Strip Basement Wall Wood Stud m3 0.4 Batt Insulation Basement Wall 3.5’’ Batt Insulation kg 417.3 Gypsum Board Basement Wall Gypsum Wall Board kg 767.8 Windows Exterior Wall Double pane glazing m2 21.5 Windows Exterior Wall Vinyl Frame m2 6.4 External Back Door Exterior Wall Fiberglass Polystyrene Core Door m2 2.4 Gypsum Board Exterior Wall Gypsum Wall Board kg 2395.6 Batt Insulation Exterior Wall 3.5’’ Batt Insulation kg 1302.2 Construction Waste From Renovation 88 Table 6-6: Material quantities of new house construction based on BC building code for Scenario 5 (Generated from BIM model). Category Location Material application Unit Quantity Wood Strip Exterior Wall Wood Strapping m3 20.3 Interior Wall Wood Studs Exterior Wall Wood Framing Roof Structural Truss Stairs Wood Stair Vinyl Windows Vinyl Trim m2 20.1 Asphalt Shingle Roof Asphalt Shingle kg 1870.1 Carpet Upper Floor Carpet Flooring m2 106.3 Concrete Basement Structure Concrete Column m3 45.7 Basement Floor Basement Slab Main Floor Concrete Pad Basement Wall Concrete Entrance Concrete Stairs Wood Door Interior/Exterior Wall Door - Panel/Frame m2 185.0 Wood Flooring Main/Basement Floor Engineered Wood Flooring m3 4.1 Gypsum Board Exterior/Interior Wall/Floor/Ceiling Gypsum Wall Board kg 11058.8 Double Glazing Windows Laminated Double Glazing m2 59.7 Plywood Exterior Wall Plywood Sheathing m3 9.2 Floor/Roof Batt Insulation Exterior Wall Batt Insulation kg 2871.4 Rigid Insulation Floor XPS Rigid Insulation kg 430.0 Steel Rebar Basement Floor Steel Reinforcement kg 1155.8 Basement Wall Stone Tile Exterior Wall Stone Tile kg 3369.3 Wood Joist Main/Upper Floor Structural Wood Joist m 537.2 Stucco Tile Exterior Wall Stucco Tile kg 8204.2 Loose Fill Insulation Ceiling Loose Fill Insulation kg 364 Polyethylene Sheet Exterior Wall Polyethylene Sheet Kg 33.5 Air/Moisture barrier Exterior Wall Tuck Tape m 740 Table 6-7: Material quantities of new house construction based on passive house standard for Scenario 6 (Generated from BIM model). Category Location Material application Unit Quantity Wood Strip Exterior Wall Wood Strapping m3 20.3 Interior Wall Wood Studs Exterior Wall Wood Framing Roof Structural Truss Stairs Wood Stair Existing Gypsum Board Ceiling Gypsum Wall Board kg 919.9 Single pane glass Exterior Wall Single-pane glazing m2 21.5 Existing Back Door Exterior Wall Solid Wood Door m2 2.4 Existing Gypsum Board Exterior Wall Gypsum Wall Board kg 2395.6 Existing Batt Insulation Exterior Wall 2.5’’ Batt Insulation kg 930.1 89 Vinyl Frame Windows Vinyl Trim m2 20.1 Asphalt Shingle Roof Asphalt Shingle kg 1870.1 Carpet Upper Floor Carpet Flooring m2 106.3 Concrete Basement Structure Concrete Column m3 45.7 Basement Floor Basement Slab Main Floor Concrete Pad Basement Wall Concrete Entrance Concrete Stairs Wood Door Interior/Exterior Wall Door - Panel/Frame m2 185.0 Wood Flooring Main/Basement Floor Engineered Wood Flooring m3 4.1 Gypsum Board Exterior/Interior Wall Gypsum Wall Board Kg 11058.8 Floor/Ceiling Triple Glazing Windows Laminated Triple Glazing m2 59.7 Plywood Exterior Wall Plywood Sheathing m3 9.2 Floor/Roof Batt Insulation Exterior Wall Batt Insulation kg 3434.9 Ceiling Batt Insulation Rigid Insulation Exterior Wall XPS Rigid Insulation kg 772.4 Floor Steel Rebar Basement Floor Steel Reinforcement kg 1155.8 Basement Wall Stone Tile Exterior Wall Stone Tile kg 3369.3 Wood Joist Main/Upper Floor Structural Wood Joist m 537.2 Stucco Tile Exterior Wall Stucco Tile kg 8204.2 Loose Fill Insulation Roof Loose Fill Mineral Fibre kg 364 Polyethylene Sheet Exterior Wall Polyethylene Sheet kg 33.5 Air/Moisture barrier Exterior Wall Tuck Tape m 740 6.2.3.2 Construction stage In the construction stage, the impacts are coming from material transport, equipment energy use, and construction waste. The transport distances of each material were estimated based on the distances between the nearest manufacturing factories and the construction site. The energy consumed by the construction equipment was estimated based on the Athena Construction Energy Database, which was calculated by the height of the building and the total mass of the materials. The construction waste factors for each material were also based on Athena Construction Energy Database [148] (listed in Table A2 of Appendix A). 6.2.3.3 Usage stage In this study, the usage stage was divided into operation stage and maintenance as guided from the proposed WBLCA method. In the operation stage, HOT2000 software was used to model the house and evaluate the operational energy use, in order to estimate the environmental impacts due to operational energy 90 use. HOT2000 is a commonly used building energy simulation software for the residential sector, which was developed by Natural Resources Canada (NRCan). It uses long-term monthly weather data in a bin-based method to analyse the thermal performance of a house [205]. Figure 6-5 indicates the required inputs to develop the HOT2000 housing model. Information such as material type, construction method, orientation, and dimensions of all the walls, ceilings, foundations, and windows were given as data inputs to the software. The type of heating/cooling system, the energy sources, and the thermal characteristics of the house in each scenario were selected based on the associated building specifications. The details of the mechanical systems and building envelopes mentioned in Table 6-1 were used in the building model. Figure 6-5: Operational energy simulation details with HOT2000 model. The following occupancy levels and energy use patterns for each scenario were considered for the HOT2000 operational energy simulation based on the standard assumptions of the BC building code.  Three occupants (two adults and one children) who are present 50 percent of the time;  Temperature set-points of 21°C for the main and upper floors, and 19°C for the basement;  Water consumption of 225 litres of domestic hot water per day;  Electricity consumption for lighting and appliances amounting to 24 kilowatt hours (kWh) per day. [206] 91 Information such as building type, foundation soil condition, wall colour, and front orientation were provided as data inputs to the model based on building layouts and house specification. Furthermore, building location, which is Vancouver, British Colombia, was used to determine the weather details in the building energy simulation. In maintenance, emissions from material replacement are the major contribution. The emissions associated with construction for replacement are not considered due to their negligible influence. The replacement is based on the service life of each material. Table 6-8 lists the life expectancy of different building materials. During the 60 years of building assessment period defined in this study [207], the replacement time can be calculated for the materials with a life expectancy shorter than 60 years. The embodied emissions from manufacturing the replacement materials and disposing of the original materials were calculated using Equation 10 developed in the manufacturing stage with the Ecoinvent 3.3 database. Table 6-8: Lifespan of different building materials for single house [208] 6.2.3.4 Demolition stage In this study, the environmental emissions at the end of life stage include the transportation of all materials to landfill and recycling, and the material disposals. The material disposal list, including the waste materials from existing house renovations in Scenarios 2-4 and existing house demolitions in Scenarios 5-6, is based on the building assembly information from the BIM model. The major recycling materials and percentages for the old house replacement and at the demolition Building components Life expectancy (year) Building components Life expectancy (year) concrete 120 polyethylene sheet 80 wood door 30 moisture barrier 100 wood flooring 20 wood studs 100 glazing 30 asphalt shingles 20 carpet 10 exterior door 120 gypsum board 30 gypsum board 30 plywood 100 plywood sheathing 100 batt insulation 120 steel bar 100 rigid insulation 120 stone tile 70 stucco tile 60 tuck tape 80 window framing 30 hot water tank 20 gas furnace 20 92 stage were assigned based on the data from city officials and construction managers and listed in Table 6-9. The construction wastes that are not recycled are assumed to be landfilled. The total GHG emissions in this stage were also calculated based on the Ecoinvent 3.3 database. In this case study, the recycling percentage was based on the regulations from City of Vancouver. In general, when applying WBLCA method into different case studies, the recycling percentage should be summarized based on the local regulations and available recycling facilities. Table 6-9: Recycling materials and percentages from house demolition. Material Weight Percent Recycled Concrete 50 tones 95% Wood 40 tones 50% Metal 0.5 tones 100% Drywall 2 tones 95% Roof Shingles 2 tones 0% Siding – stucco 5 tones 0% The WBLCA environmental performance of each scenario was calculated by adding the environmental emissions in the manufacturing, construction, usage, and demolition stages. The total emission results were used to select the best scenario for existing building renovation strategies in term of environmental performance. 6.2.4 Life Cycle Impact Assessments The above-discussed methods were used to assess the environmental and economic impacts resulting from the material production, house construction, operation and maintenance, and demolition phases. The comparison results of the embodied, operational, and life cycle emissions for the six scenarios are presented in the next sections. The comparisons for WBLCA results between Scenarios 3 and 4 are also presented to propose the best renovation strategies in terms of environment and costs. 6.2.4.1 Manufacturing stage (A1-A3) In order to calculate the environmental impacts in the manufacturing stage, the quantities of materials listed from Table 6-4 to Table 6-7 were used to multiply the unit environmental impact of each material for each environment indicator by using Equation 10 in this chapter. The unit environmental impacts of material manufacturing in the product stage were collected from online sources mentioned above as well as the EPD database in SimaPro 8.3 software and presented in Table 6-10. 93 Table 6-10: Unit environmental impacts of the materials for newly built house construction and existing house renovation (Derived from website resource and Ecoinvent 3.3 EPD database). Construction Material Manufacturing Unit Global warming potential Ozone depletion potential Acidification potential Eutrophication potential Smog potential Abiotic depletion potential for fossil fuels Renewable primary energy use Non-renewable primary energy use Secondary materials Net use of fresh water Waste disposed Components for re-use Materials for recycle Asphalt Shingle Kg 8.88E-01 5.75E-08 3.44E-03 2.30E-03 4.23E-02 6.06E-01 1.80E+00 7.75E+00 0.00E+00 6.08E-03 7.02E-02 0.00E+00 0.00E+00 Stucco Tile Kg 9.67E-02 1.15E-08 6.18E-04 1.92E-04 8.49E-03 1.41E-01 6.00E-02 1.35E+00 0.00E+00 3.23E-04 1.57E-02 0.00E+00 0.00E+00 Concrete m3 3.51E+02 1.79E-05 9.52E-01 3.31E-01 1.68E+01 1.78E+02 1.13E+02 1.86E+03 3.60E+02 3.66E+00 4.54E+01 0.00E+00 0.00E+00 Gypsum Board Kg 4.08E-01 2.97E-08 2.61E-03 1.11E-03 2.67E-02 3.32E-01 9.33E-01 4.80E+00 0.00E+00 2.18E-03 3.13E-02 0.00E+00 0.00E+00 Vinyl Window Frame m2 2.77E+02 1.48E-05 1.77E+00 8.77E-01 1.62E+01 5.22E+02 2.89E+02 5.53E+03 0.00E+00 1.30E+01 4.50E+01 0.00E+00 0.00E+00 Wood Door m2 6.25E+01 6.02E-06 3.94E-01 2.13E-01 4.28E+00 7.15E+01 1.30E+03 8.73E+02 0.00E+00 6.41E-01 1.01E+01 0.00E+00 0.00E+00 Double Glazing m2 3.83E+01 5.30E-06 2.96E-01 9.14E-02 3.23E+00 4.79E+01 3.06E+01 4.73E+02 0.00E+00 3.67E-01 7.76E+00 0.00E+00 0.00E+00 Carpet Kg 2.56E+01 9.67E-05 1.30E-01 1.06E-01 1.24E+00 1.30E-01 7.59E+01 2.96E+02 0.00E+00 2.19E+00 1.08E+00 0.00E+00 0.00E+00 Wood Strip m3 9.42E+01 2.17E-05 8.05E-01 1.36E-01 2.24E+01 1.93E+02 1.61E+04 1.44E+03 0.00E+00 1.52E+00 2.89E+01 0.00E+00 0.00E+00 Plywood m3 3.97E+02 6.89E-05 3.31E+00 9.95E-01 4.70E+01 8.68E+02 3.40E+04 6.97E+03 0.00E+00 1.88E+01 6.06E+01 0.00E+00 0.00E+00 Wood Flooring m3 6.30E+00 9.06E-07 5.80E-02 4.24E-03 8.81E-01 6.57E+00 0.00E+00 9.31E+01 0.00E+00 1.79E-02 0.00E+00 0.00E+00 0.00E+00 Wood Joist m 1.76E+00 2.57E-07 1.23E-02 4.64E-03 2.42E-01 3.69E+00 1.37E+02 3.22E+01 0.00E+00 4.74E-02 3.08E-01 0.00E+00 0.00E+00 Batt Insulation Kg 1.13E+00 6.26E-08 8.38E-03 3.28E-04 3.68E-02 9.81E-01 6.09E-01 1.24E+01 0.00E+00 1.58E-03 5.48E-02 0.00E+00 0.00E+00 Rigid Insulation Kg 1.12E+01 1.53E-04 1.76E-02 6.10E-03 2.01E-01 1.26E+01 1.97E+00 1.01E+02 0.00E+00 8.11E-02 2.17E-01 0.00E+00 0.00E+00 94 Steer Rebar Kg 1.03E+00 0.00E+00 3.07E-03 1.63E-04 2.13E-02 5.84E-01 0.00E+00 1.06E+01 1.00E+00 3.82E-03 0.00E+00 0.00E+00 0.00E+00 Stone Tile Kg 9.67E-02 1.15E-08 6.18E-04 1.92E-04 8.49E-03 1.41E-01 6.00E-02 1.35E+00 0.00E+00 3.23E-04 1.57E-02 0.00E+00 0.00E+00 Loose Fill Insulation kg 3.87E-01 4.30E-08 5.11E-03 4.25E-03 4.26E-02 3.82E-01 1.93E+00 1.02E+02 1.00E+00 2.41E-01 3.07E-01 0.00E+00 0.00E+00 Polyethylene Sheet Kg 1.30E-01 2.06E-08 6.88E-04 1.90E-04 1.37E-02 3.56E-01 6.93E-02 2.79E+00 0.00E+00 9.44E-04 5.39E-02 0.00E+00 0.00E+00 Tuck Tape Air Barrier m 2.74E-01 2.42E-08 1.57E-03 1.03E-03 1.50E-02 1.57E-03 3.23E-01 4.26E+00 0.00E+00 3.28E-03 0.00E+00 0.00E+00 0.00E+00 Garage Door m2 1.28E+02 9.22E-06 9.61E-01 4.48E-01 7.96E+00 9.82E+01 9.76E+02 1.41E+03 0.00E+00 1.11E+00 2.14E+01 0.00E+00 0.00E+00 Gypsum board landfill Kg 1.27E-02 4.42E-09 7.54E-03 2.90E-05 2.47E-03 4.04E-02 2.87E-02 2.95E-01 0.00E+00 2.69E-04 1.00E+00 0.00E+00 0.00E+00 Glass landfill Kg -2.16E+02 -8.22E-06 -1.58E+00 -6.36E-01 -1.27E+01 -9.73E+01 -4.42E+02 -2.32E+03 0.00E+00 -1.91E+00 6.51E+02 0.00E+00 0.00E+00 Batt insulation landfill Kg 5.32E-03 2.38E-09 4.62E-05 9.91E-06 1.09E-03 2.21E-02 4.00E-03 1.62E-01 0.00E+00 1.70E-04 1.00E+00 0.00E+00 0.00E+00 Wood landfill Kg 6.27E-02 3.93E-09 8.99E-05 7.25E-03 1.94E-03 3.77E-02 1.72E-02 2.96E-01 0.00E+00 3.21E-04 1.00E+00 0.00E+00 0.00E+00 Roof shingle landfill Kg 4.27E-03 2.34E-09 3.87E-05 1.05E-05 9.83E-04 2.13E-02 1.08E-02 1.53E-01 0.00E+00 1.78E-04 9.99E-01 0.00E+00 0.00E+00 Siding stucco landfill Kg 4.27E-03 2.34E-09 3.87E-05 1.05E-05 9.83E-04 2.13E-02 1.08E-02 1.53E-01 0.00E+00 1.78E-04 9.99E-01 0.00E+00 0.00E+00 Drywall recycling Kg 3.49E-03 8.29E-10 3.32E-05 6.97E-06 9.70E-04 7.36E-03 2.82E-03 5.37E-02 0.00E+00 1.73E-05 -2.70E-05 0.00E+00 0.00E+00 Wood recycling Kg -1.76E+00 -2.57E-07 -1.23E-02 -4.64E-03 -2.42E-01 -3.69E+00 -1.37E+02 -3.22E+01 0.00E+00 -4.74E-02 -3.08E-01 0.00E+00 0.00E+00 Concrete recycling Kg 4.02E-03 9.82E-10 3.91E-05 4.72E-06 1.17E-03 8.69E-03 3.49E-04 6.25E-02 0.00E+00 8.06E-06 6.14E-05 0.00E+00 0.00E+00 Metal recycling Kg -1.67E+00 -8.80E-08 -6.93E-03 -4.11E-03 -8.80E-08 -6.23E-01 -3.32E-01 -1.57E+01 0.00E+00 -3.28E-03 -1.66E+01 0.00E+00 0.00E+00 Concrete landfill Kg 1.24E-02 4.08E-09 1.03E-04 1.92E-05 2.69E-03 3.71E-02 5.38E-03 2.74E-01 0.00E+00 1.88E-04 1.00E+00 0.00E+00 0.00E+00 Drywall landfill (= gypsum board) Kg 1.27E-02 4.42E-09 7.54E-03 2.90E-05 2.47E-03 4.04E-02 2.87E-02 2.95E-01 0.00E+00 2.69E-04 1.00E+00 0.00E+00 0.00E+00 95 Based on the information from Error! Reference source not found. to Table 6-10, the environmental impacts from new product manufacturing and existing material disposal in different scenarios were calculated and listed in Table 6-11. There are no environmental impacts in Scenarios 1 and 2 since no renovation was carried out on the building itself. In Scenarios 3 and 4, the environmental impacts are from renovations to the building envelope. The environmental impacts in Scenario 4 are slightly higher than the values in Scenario 3 since more materials were involved in the renovation. The environmental impacts in Scenarios 5 and 6 are much higher than the other scenarios since the existing house was demolished and replaced with a new house. Scenario 6 has the highest environmental impacts since passive house design requires a thicker building envelope to achieve higher thermal properties. The environmental impacts in Scenarios 3 and 4 are in the range of 5-10% of the values in Scenarios 5 and 6. Table 6-11: Summary of environmental impacts at product manufacturing stage GWP ODP AP EP SP ADP RPE NRPE SM FW WD CU MR kg CO2 eq. kg CFC11 eq. kg SO2 eq. kg N eq. kg O3 eq. MJ surplus MJ MJ KG M3 KG KG KG Scenario 1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Scenario 2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Scenario 3 3928.1 0.0 35.7 4.6 203.3 3768.6 9991.2 45096.7 0.0 15.8 1291.9 0.0 0.0 Scenario 4 8325.5 0.0 83.2 13.9 435.9 9470.2 18063.0 110991.7 0.0 108.4 5088.8 0.0 0.0 Scenario 5 93095.3 0.2 480.7 404.8 5701.2 73337.6 1108042.4 1122008.6 17968.2 3332.0 32464.8 0.0 69900.0 Scenario 6 97568.9 0.2 491.4 407.0 5790.8 78206.7 1109060.8 1163490.7 17968.2 3360.7 32569.8 0.0 69900.0 6.2.4.2 Construction stage (A4-A5) Based on the calculation method mentioned above, the environmental impacts from the construction stage were calculated and are presented in Table 6-12. Only the new construction impacts were considered here; the construction impacts during renovations in Scenarios 2-4 were not included due to the minimal impacts. The construction impacts of Scenarios 5 and 6 are similar since the building layouts are the same. The results show that the environmental impacts from construction stage are 5-10% of the values from the product manufacturing stage. 96 Table 6-12: Summary of environmental impacts at construction stage GWP ODP AP EP SP ADP RPE NRPE SM FW WD CU MR kg CO2 eq. kg CFC11 eq. kg SO2 eq. kg N eq. kg O3 eq. MJ surplus MJ MJ KG M3 KG KG KG Scenario 1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Scenario 2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Scenario 3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Scenario 4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Scenario 5 5799.5 0.0 34.6 14.3 953.3 10141.5 66850.0 82942.0 0.0 316.0 361.7 0.0 0.0 Scenario 6 5863.2 0.0 35.0 14.4 963.7 10252.8 67583.7 83852.3 0.0 319.4 365.6 0.0 0.0 6.2.4.3 Usage stage (B1-B5) The annual energy consumptions at the operational stage for each scenario were calculated from the HOT2000 software. As shown in Figure 6-6, the annual energy consumption of the existing house in Scenario 1 was 246.2 GJ. With the upgrades of the space and water heating system in the existing house, the annual energy consumption in Scenario 2 was reduced to 151.6 GJ, which is 38% lower than the existing house condition in Scenario 1. Scenario 3, with basic renovation, has operational energy consumption of 82.9 GJ per year. Scenario 4, with extensive renovation, has operational energy consumption of 68.7 GJ per year, which is 72% less than the energy consumption of the existing house in Scenario 1. In terms of newly built houses, the annual operational energy use in Scenarios 5 and 6 are 58.3 GJ and 45.7 GJ, respectively. Based on the annual energy uses listed in Figure 6-6, the associated environmental impacts were calculated based on the unit environmental impacts. They are presented in Table 6-13. Figure 6-6: Annual operational energy consumptions in each scenario 050100150200250300Scenario 1 Scenario 2 Scenario 3 Scenario 4 Scenario 5 Scenario 6Annual Operational Energy Consumption(GJ./year)Opertaing energy97 Table 6-13: Summary of annual environmental impacts at operational stage GWP ODP AP EP SP ADP RPE NRPE SM FW WD CU MR kg CO2 eq. kg CFC11 eq. kg SO2 eq. kg N eq. kg O3 eq. MJ surplus MJ MJ KG M3 KG KG KG Scenario 1 21488.77 0.00 35.61 18.60 332.83 49359.71 43615.52 355044.44 0.00 219.92 416.69 0.00 0.00 Scenario 2 13586.23 0.00 23.75 14.24 228.63 30744.29 41597.56 223733.46 0.00 205.06 336.00 0.00 0.00 Scenario 3 7891.38 0.00 15.13 10.96 152.52 17355.15 39362.60 129147.47 0.00 190.67 273.81 0.00 0.00 Scenario 4 6716.28 0.00 13.35 10.28 136.81 14592.61 38894.10 109630.48 0.00 187.66 260.94 0.00 0.00 Scenario 5 5707.71 0.00 12.22 10.49 129.11 12074.24 42951.44 92643.30 0.00 206.08 272.96 0.00 0.00 Scenario 6 2712.14 0.00 3.54 5.27 45.54 868.24 27625.95 11065.24 0.00 130.57 149.63 0.00 0.00 Maintenance happens when the lifespan of building materials is less than the building lifespan. When the lifespan of a material ends, the existing material will be removed and new material will be installed. Based on the calculation method described in the methodology section, the environmental impacts during maintenance were calculated and listed in Table 6-14. The existing buildings in Scenarios 1-4 have the same maintenance impacts, and the new buildings in Scenarios 5 and 6 have the same maintenance impacts. Table 6-14: Summary of annual environmental impacts during maintenance GWP ODP AP EP SP ADP RPE NRPE SM FW WD CU MR kg CO2 eq. kg CFC11 eq. kg SO2 eq. kg N eq. kg O3 eq. MJ surplus MJ MJ KG M3 KG KG KG Scenario 1 8771.2 0.0 52.0 25.7 552.8 9933.1 60448.4 117460.6 0.0 138.7 1131.5 0.0 0.0 Scenario 2 8771.2 0.0 52.0 25.7 552.8 9933.1 60448.4 117460.6 0.0 138.7 1131.5 0.0 0.0 Scenario 3 8771.2 0.0 52.0 25.7 552.8 9933.1 60448.4 117460.6 0.0 138.7 1131.5 0.0 0.0 Scenario 4 8771.2 0.0 52.0 25.7 552.8 9933.1 60448.4 117460.6 0.0 138.7 1131.5 0.0 0.0 Scenario 5 38186.6 0.0 223.5 128.7 2298.8 32617.0 297779.1 509433.6 0.0 1379.7 4299.5 0.0 0.0 Scenario 6 38186.6 0.0 223.5 128.7 2298.8 32617.0 297779.1 509433.6 0.0 1379.7 4299.5 0.0 0.0 6.2.4.4 Disposal stage (C1-C4) At the end of a 60-year building lifespan, the buildings in each scenario are assumed to be demolished and materials to be reused, recycled, or disposed of in landfill. Based on the BoQ of the building model, environmental impacts at the disposal stage were calculated and are listed in 98 Table 6-15. Based on the building plan, the existing building floor area is much smaller than the new building. However, the metal recycling in new buildings creates more negative environmental impacts than existing buildings during the disposal stage, which makes some of the environmental impact values in new building disposals lower than existing building disposals. Table 6-15: Summary of annual environmental impacts at disposal stage GWP ODP AP EP SP ADP RPE NRPE SM FW WD CU MR kg CO2 eq. kg CFC11 eq. kg SO2 eq. kg N eq. kg O3 eq. MJ surplus MJ MJ KG M3 KG KG KG Scenario 1 7667.4 0.0 42.0 177.6 599.3 9103.1 43941.3 103421.2 0.0 88.0 23706.8 0.0 0.0 Scenario 2 7667.4 0.0 42.0 177.6 599.3 9103.1 43941.3 103421.2 0.0 88.0 23706.8 0.0 0.0 Scenario 3 7667.4 0.0 42.0 177.6 599.3 9103.1 43941.3 103421.2 0.0 88.0 23706.8 0.0 0.0 Scenario 4 7667.4 0.0 42.0 177.6 599.3 9103.1 43941.3 103421.2 0.0 88.0 23706.8 0.0 0.0 Scenario 5 6574.5 0.0 42.3 167.9 671.3 9226.5 42053.3 95193.8 0.0 85.3 25052.6 0.0 0.0 Scenario 6 6579.3 0.0 42.4 167.9 672.3 9246.5 42056.9 95340.7 0.0 85.4 25958.2 0.0 0.0 6.2.5 LCC assessment The unit processes and flows involved during the WBLCA results calculations were also used to conduct LCC assessment. The detailed calculation processes were presented in Chapter 4. The discount rate for this study is set at 4.65% per year. The material costs and construction costs are based on the RSMeans cost database 2019 version [154]. Table A7 lists all the initial costs collected from RSMeans based on the building materials derived from the BIM model. Transportation costs are also cited from the Canadian Trucking Alliance [155]. Utility costs are based on unit prices from FortisBC and BC Hydro [156,157]. Construction waste disposal costs are based on information from the City of Kelowna website [158]. The material quantities listed from Table 6-4 to Table 6-7 are used to calculate the manufacturing and construction costs. The maintenance and disposal information listed in Table 6-8 and Table 6-9 is also used to calculate costs in the usage and disposal stages. WBLCA results By adding all the environmental impact values summarized in the product stage, construction stage, operational stage, maintenance, and disposal stage, the total environmental impacts of six scenarios during the building lifespan were calculated and are listed in Table 6-16. 99 Table 6-16: WBLCA results from all the life cycle stages GWP ODP AP EP SP ADP RPE NRPE SM FW WD CU MR kg CO2 eq. kg CFC11 eq. kg SO2 eq. kg N eq. kg O3 eq. MJ surplus MJ MJ KG M3 KG KG KG Scenario 1 1305764.8 0.2 2230.4 1319.4 21121.8 2980618.9 2721320.9 21523548.1 0.0 13422.0 49839.9 0.0 0.0 Scenario 2 831612.5 0.1 1518.7 1057.7 14869.8 1863693.6 2600243.0 13644889.5 0.0 12530.1 44998.2 0.0 0.0 Scenario 3 493849.5 0.1 1037.4 865.4 10506.8 1064114.0 2476136.7 8014826.5 0.0 11682.5 42558.6 0.0 0.0 Scenario 4 427740.6 0.1 978.2 834.1 9796.7 904063.0 2456098.7 6909702.0 0.0 11595.0 45583.3 0.0 0.0 Scenario 5 486118.5 0.3 1514.0 1344.9 17371.3 849777.0 4091811.4 7368176.2 17968.2 17477.7 78556.3 0.0 69900.0 Scenario 6 310921.7 0.3 1004.8 1034.1 12456.8 182397.4 3174034.1 2515884.9 17968.2 12979.1 71265.2 0.0 69900.0 GWP is a common indicator to evaluate the environmental performance if the whole set of environmental indicators are not considered, including global warming, carbon taxes, and carbon neutral [209,210]. Based on the total GWP value shown in Table 6-16, Scenario 6 has the least GWP value among the six scenarios in 60 years of lifespan, which is less than 25% of the total GWP values in Scenario 1. Scenario 4, with extensive renovation strategies, has less GWP than Scenario 5 with new construction strategy. Figure 6-7 shows the detailed GWP from different life cycle stages for each scenario. It is obvious that the major contribution for existing building scenarios is the operational stage, which contains over 95% of the WBLCA results. In Scenarios 5 and 6, the contributions from the product stage and maintenance stage also contains 26% and 43% of the total emissions, respectively. Even though the passive house in Scenario 6 has the highest GWP, it shows the lowest life cycle GWP increment in its lifetime among the six scenarios, due to the low operational GWP. The annual operational GWP of the newly built house (Scenario 5) is less than that of all the other renovation scenarios (Scenario 1, 2, 3, and 4). However, due to the high-embodied GWP, the newly built house in Scenario 5 has a higher life cycle GWP than the existing house with extensive renovation in Scenario 4 within a 60-year lifetime. 100 Figure 6-7: Details of total GHG emission from different life cycle stages Besides the GWP indicator, the performance of other indicators shown in Table 6-16 also has similar patterns as GWP. In Scenarios 1-4, the major contribution for the other indicators is at the operational stage, except for the waste disposed indicator. In Scenarios 5 and 6, the operational stage and product stage are the two main contributors, while the other life cycle stages also have various percentage of contributions in different indicators. For example, in the ODP indicator in Scenario 5, 63% of the contributions are from the product stage, while 20% and 16% of the contributions are from the operational stage and maintenance. In the RPE indicator in Scenario 5, 27% of the contributions are from the product stage, while 63% and 7% of the contributions are from the operational stage and maintenance. Since there are over 13 indicators with different scales of performance, it is still challenging to conclude which scenario has the best overall environmental performance based on the results shown in Table 6-16. Therefore, TOPSIS is selected to conduct the MCDM analysis for a series of LCA data with various indicators under different scenarios, which is the same as the MCDM method applied in Chapter 5. There are seven steps included in a classical TOPSIS method, based on the literature review [144]. With the decision matrix shown in Table 6-16, the weight of criteria is evenly assigned to the three 0.0200.0400.0600.0800.01000.01200.01400.0Scenario 1 Scenario 2 Scenario 3 Scenario 4 Scenario 5 Scenario 6Life Cycle GHG Emission (ton)DisposalstageMaintenanceOperationalstageConstructionstageProductstage101 categories: environmental impacts (1/3), resource use (1/3), and waste disposal (1/3). There are six, four, and three indicators under each category, and each indicator has a weighting factor of 1/18, 1/12, and 1/9 respectively. After normalization, adding weights, and indicator aggregation, the final results and rankings for each scenario are listed in Table 6-17. Based on the TOPSIS results, the passive house in Scenario 6 has the best overall environmental performance with the consideration of 13 indicators, followed by the extensive renovation in Scenario 4. The new construction in Scenario 5 performs slightly worse than Scenario 4 and better than Scenario 3 on a small scale. Table 6-17: WBLCA results rankings with TOPSIS method Final TOPSIS Value Ranking Scenario 1 0.372 6 Scenario 2 0.447 5 Scenario 3 0.551 4 Scenario 4 0.575 2 Scenario 5 0.553 3 Scenario 6 0.750 1 It was calculated in Chapter 5 that more materials used in the design will lead to higher costs. It is obvious that the two new construction scenarios will definitely have much higher costs than the renovation Scenarios 3 and 4. Therefore, reconstruction options in Scenarios 5 and 6 are definitely not as favourable as the renovation scenarios if both the environmental and economic performance are considered. However, renovation Scenarios 2-4 have similar environmental impacts, and the most popular renovation steps only involved limited materials, as shown in Table 6-4 and Table 6-5. It is necessary to calculate the LCCs for these three scenarios, compare the WBLCA results that include LCA and LCC, and find the best solution considering both environment and costs. By following the detailed calculation processes described in Chapter 4 and the LCC data collection method mentioned above, the LCC results were calculated and WBLCA results for Scenarios 2-4 are listed in Table 6-18. Based on the scenarios developed in the method section, the cost data are gathered accordingly. In Scenario 2, there is no renovation to the building materials. The major material costs are from the replacement of furnaces and hot water tanks every 10 years. In Scenario 3, there are some renovations to the ceilings and basement walls. However, since the energy consumption per year in Scenario 2 is much higher than Scenario 3,tThe LCC of Scenario 2 is still higher than Scenario 3. In Scenario 4, more materials are involved since the interior parts of the 102 main walls were renovated. Even though the life span energy costs in Scenario 4 are lower than the costs in Scenario 3, the LCC of Scenario 3 is around 15% lower than Scenario 4. From the cost perspective, Scenario 3 would be a more favourable solution. Table 6-18: WBLCA results for scenarios 2-4 GWP ODP AP EP SP ADP RPE NRPE SM FW WD CU MR LCC kg CO2 eq. kg CFC11 eq. kg SO2 eq. kg N eq. kg O3 eq. MJ surplus MJ MJ KG M3 KG KG KG C$ Scenario 2 831612.5 0.1 1518.7 1057.7 14869.8 1863693.6 2600243.0 13644889.5 0.0 12530.1 44998.2 0.0 0.0 59,500 Scenario 3 493849.5 0.1 1037.4 865.4 10506.8 1064114.0 2476136.7 8014826.5 0.0 11682.5 42558.6 0.0 0.0 58,560 Scenario 4 427740.6 0.1 978.2 834.1 9796.7 904063.0 2456098.7 6909702.0 0.0 11595.0 45583.3 0.0 0.0 64,540 Since the rankings of Scenarios 2-4 between environmental and economic performances are different, another TOPSIS-based MCDM analysis should be conducted to analyze the WBLCA results. Based on the standard TOPSIS procedures described in Chapter 5, the WBLCA results were normalized, weighted, and accumulated. The final results are presented in Table 6-19, which shows that if the decision maker leans towards environmental reduction, then Scenario 4 is a better solution than Scenario 3. If the decision maker leans towards less cost, Scenario 2 is a better solution. However, if the decision maker treats both environmental and economic impacts equally, then Scenario 3 is definitely the best solution. Table 6-19: WBLCA results rankings with TOPSIS method Environment/cost weighting ratio 5:5 3:7 7:3 Scenario 2 0.757 0.848 0.667 Scenario 3 0.828 0.897 0.760 Scenario 4 0.797 0.841 0.753 Discussions The above results demonstrate how embodied and operational energy use and related emissions vary for different renovation and reconstruction scenarios for residential buildings. It can be noted that when the total life cycle performance is considered, the passive house scenario shows the best environmental performance. On the other hand, reconstruction options are not always better than 103 renovation options, and it all depends on the renovation strategies applied. Especially when economic performance is considered, renovation options are more preferable. Although new construction is usually associated with a large amount of embodied emissions, the drastic improvement in operational energy consumption can offset the initial emissions within the building lifetime. However, Scenario 4, which involves extensive renovations to the existing house, performs better than the code-specified new construction (Scenario 5) under the overall environmental performance shown in Table 6-17. Therefore, it can be assumed that the significant embodied emissions associated with new construction do not deliver commensurate benefits compared to extensive renovations, which deliver significant operational emission reductions with lower embodied energy and materials use. These code-specified building development standards ensure that the operational energy performance of new construction is much better than that of the existing houses in Scenarios 1-4. On the other hand, the renovation strategies in Scenarios 2-4 create much lower environmental emissions than the existing house condition, which should also be considered when reconstruction is not an option. In Figure 6-7, the GWP in reconstruction scenarios is much higher than the emissions in the extensive renovation in Scenario 4. Therefore, the embodied emissions in the reconstruction scenario are a target for further improving the life cycle environmental performance of houses in future development. Using more “green” or low impact and recyclable materials can reduce the embodied emissions of reconstruction. It is also shown in Figure 6-7 that the existing house scenarios have low GWP, while the newly constructed house scenarios have much higher GWP during the maintenance stage. One of the major reasons is that the newly built house uses carpet flooring, which has high embodied GWP and a short lifespan, while the existing house uses hardwood flooring, which has low GWP and a long lifespan. Therefore, the designer needs to pay close attention to the properties and environmental performance of the building materials. Choosing materials with Environmental Product Declaration (EPD) reports can potentially reduce the GWP of building construction since all the emission data about the declared materials are clearly presented in the report [211]. In Figure 6-6, the operational energy consumed by the code-specified house in Scenario 5 is similar to the passive house in Scenario 6. However, the GWP in Scenario 6 is much lower than the emissions in Scenario 5. The major reason is due to the differences in energy sources. The HVAC system in the passive house uses electric energy, while the system in the code-specified house uses 104 gas energy. The emission factor for electricity production in BC is 11.7g CO2eq./kWh, which is much lower than the natural gas production. This is not the same for other provinces in Canada. For example, the emission factors for the provinces of Alberta and Ontario are 900g CO2eq./kWh and 40g CO2eq./kWh electricity, respectively [212]. Therefore, policy makers need to update the building code based on the available energy resources that are the best for the environment. Since the house built according to the BC building code does not perform as well as the passive house, there is also a need to upgrade the building standards to meet environmental needs. The BC step code is a big commitment the BC government made to further improve the new building to net-zero energy ready by 2032 [184]. In Figure 6-7, the embodied GWP of extensive renovation in Scenario 4 contributes less than 5% to life cycle emissions, and the percentages in other existing houses (Scenario 1-3) are even lower. Therefore, it is significant to lower the operational GWP in existing houses. By upgrading the furnace and hot water heater, the life cycle GWP of the existing house can be reduced by over 240 ton. By upgrading the furnace and hot water heater, putting insulation on the attic and basement, and replacing single-pane doors with double-pan doors, the life cycle GWs of the existing house can be reduced by over 410 ton, which is almost 2/3 of the emissions of the existing house. Therefore, it is necessary to set up policies to enforce basic renovations and create incentives to promote moderate renovations on existing houses. The embodied GWP of the newly built house in Scenario 5 is around 30% of the life cycle GHG emissions. Iddon and Firth [213] stated that the embodied GWP of a 4-bedroom house in the UK is around 20% to 26% of the life cycle emissions for a 50-year lifespan. Koezjakov et al. [214] also stated that the embodied GWP of energy efficient homes in Holland is around 36% - 46% of the life cycle emissions for a 60-year lifespan. Thus, the results from this study lie in a comparable range with the results from other countries. On the other hand, the GWP per unit area of the existing house in Scenario 4 is 48% of the GWP per unit area for the newly built house in Scenario 5. Marique and Rossi from Belgium did a similar case study comparing renovation and reconstruction of an office building, and the embodied GWP per unit area from renovation was over 56% of the amount generated from reconstruction [178]. One of the possible reasons for the variance is the materials used for construction between these two case studies, as different materials can significantly change the total GWP [215]. Differences between building types and geographic locations might be other reasons for the variance. 105 As shown in Figure 6-7 and Table 6-16, it is obvious that the newly built houses in Scenario 5 and 6 have better WBLCA results per square meter, since new houses are much bigger than existing houses. However, the performance of the renovated existing houses in Scenario 3 and 4 is also excellent compared with the existing house without any renovation. The unit life cycle GWP for the existing house is over 4 times more than the emissions in the newly built house in Scenario 5. With the upgrade to the furnace and hot water tank, emissions become just 2 times higher than emissions in Scenario 5. Therefore, it is still valuable to promote renovation of existing houses in terms of life cycle GWP intensities. Beside the size of the house, the occupancy rate of the house also has an influence on GHG emissions on a larger scale. The existing houses in Scenarios 1-4 are around 185 m2, and the newly built houses in Scenarios 5-6 are over 300 m2. However, all the houses in Scenarios 1-6 are single-family houses with the same occupancy rate of 4 person/house. If the newly built houses have a higher occupancy rate, the same number of houses can accommodate more persons. Then, the housing issue can be solved easily without building as many houses, which will reduce overall environmental impacts at the city level. The ranking results in Table 6-17 show that the new construction scenarios are generally better than the renovation scenarios in terms of environmental performance. However, this does not mean that demolishing an existing house and building a new house is always a better choice than renovating the existing house when economic impacts are considered. The LCC of the renovation strategies was also calculated in this case study to consider the building owner’s perspective, since the policy has to be made to ensure that building owners have enough motivation to take action to improve environmental performance. As described in the LCC calculation stage, the reconstruction options cost much more than the renovation options. It is stated in the 2018 Canada cost guide that building a single-family residential house in Vancouver costs around $1400/m2 - $2475/m2 ($130/ft2 - $230/ft2) [216]. For the new house analyzed in this study, the total cost for the reconstruction option is approximately 420 thousand to 742 thousand dollars without considering the demolition and accommodation costs. The renovation costs for Scenarios 2-4 are less than 20% of the reconstruction costs. The annual energy consumption is around 16,000 kWh for reconstruction based on HOT2000 results, which is much lower than the consumption of the existing house (68,400 kWh). Based on the unit residential energy cost in BC, the annual energy bill for the newly built house in Scenario 5 is around $7,000 less than the existing 106 house in Scenario 1 [217]. When considering the cost-benefit payback period, the energy savings still could not balance the capital cost of construction within a 60 year lifespan. Therefore, it is not reasonable to promote reconstruction based on this cost-benefit estimate. However, the cost-benefit estimate on these renovation scenarios is totally different due to the much lower capital cost of renovation. As per the LCC results based one RSMeans database, the renovation cost in Scenario 2 is less than $10,000, and the renovation cost in Scenario 3 is less than $30,000. Based on the simulation results for operational energy consumption from HOT2000, annual energy consumption after renovations in Scenarios 2 and 3 are around 42,000 kWh and 23,000 kWh each. The annual energy cost savings due to renovations in Scenarios 2 and 3 are around $3500 and $6400 individually. Therefore, house owners need less than 10 years to balance the cost of renovation from the energy bill savings in either Scenario 2 or 3. With the incentives the government provides to encourage renovation on existing houses and the cost-benefit estimate results, renovation Scenarios 2 and 3 are much better options to motivate the owners. The LCC values of the extensive renovation in Scenario 4 are higher than Scenarios 2 and 3. However, the results in Table 6-19 show that Scenarios 2-4 could have different rankings when considering the environmental emissions and costs together, which depends on the weightings assigned between environment and cost. From the owner’s perspective, Scenario 2 would be more preferable than Scenario 4, since building owner would put more weight on costs. From the municipality’s perspective, Scenario 4 would be more favourable for developing a greener community. Scenario 3 is always the best option no matter how much the weighting factors changed. Therefore, the decision maker should promote the moderate renovation strategy described in Scenario 3 with policy supports. As shown in Table 6-16, the existing house in Scenario 1 has significantly higher life cycle GWP than the other five scenarios. In Canada, over 30% of houses are over 50 years old [218], and the existing house could have double the GWP of the new house. In order for Canada to reach its GHG emission target, the federal, provincial, and municipal governments should pay more attention to the energy efficiency of older buildings. Some municipalities already have incentive policies, such as an energy rebate for a new furnace or a tax deduction for house renovations to reach energy consumption targets. More policies should be mandatory for older buildings, especially those that haven’t been renovated, to conduct the Scenario 3 renovation by installing new HVAC systems, replacing windows, and insulating the attic and crawl space. The ranking results show that the 107 overall environmental performance in Scenario 3 is already very close to the new build scenarios. This would be a very important strategy for future development on aging building stock. Furthermore, as mentioned in the methodology section, the life cycle impact data can be different based on the origin of the materials used in the renovation and reconstruction activities. Material sourced from some locations can have higher life cycle impacts due to different extraction and production practices. This needs to be taken into account in decision making endeavours for building stock renovation and replacement activities. The 60-year assessment period was used in the renovation scenarios as well, since routine maintenance is conducted to keep the functionality of a house. Expert opinion suggests that houses older than 60 years can be maintained in a functional state with routine maintenance. Furthermore, the existing house analysed in this study was built before 1940, which is defined as a heritage/character house. The municipality encourages homeowners to maintain their house’s heritage status by introducing incentives. At the same time, this analysis is trying to investigate the performance between different renovation scenarios and new-built scenarios in terms of life cycle environmental performance. As recommended by the municipality representatives, assuming the same lifespan for a newly built house and an existing house allows for comparable analysis with more useful results. In reality, the lifespan of an old house after renovation varies greatly depending on the condition of the house before renovation. This is a limitation in this study that requires further research to address it. While the reconstruction options may appear to be the best choice from an environmental standpoint, the renovation options perform better than reconstruction options when environment and cost are considered together. The heritage value of the buildings and public perception would necessitate a renovation approach to retain certain older buildings. In addition, while passive constructions are identified as high performing in terms of the environment, there are concerns regarding human health and occupant wellbeing in these buildings. Moreover, residential development is subjected to numerous uncertainties in the macro-environment, including energy and material prices and availabilities, renovation technologies, and changes to building codes. These aspects also need to be integrated into future decision making. In addition, this study only considered the reconstruction that related to thermal energy improvements, as the heating load contributes to the most significant fraction of residential energy consumption. Other renovation strategies such as lighting and appliance efficiency improvements should be considered in future. 108 Summary This case study evaluated the life cycle environmental and economic impacts related to the renovation and reconstruction of existing houses using the proposed WBLCA method. The results demonstrate that the proposed WBLCA method is a great solution to define the best renovation strategies for existing building stock in consideration of environmental emissions and costs. Six scenarios were developed and analysed to represent different renovation and reconstruction strategies. Scenarios 1-4 considered renovation options at different levels, and Scenarios 5 and 6 considered reconstruction options that follow the BC building code and passive house standards, respectively. The results show that new construction in a passive house design scenario has the best environmental performance, while the extensive renovations in Scenario 4 have the second best, followed by the new construction in Scenario 5. When the economic impacts are also considered, Scenarios 2-4 have better overall performance than the reconstruction scenarios. The results also show that operational emissions contain over 95% of the overall life cycle emissions in renovation Scenarios 1-4, while product stage, operation, and maintenance are two main contributors to overall environmental emissions. However, reconstructing an old house to BC Building Code standards does not result in a significant improvement in overall environmental performance when compared to the extensive renovation scenario. Based on this, it can be concluded that when considering the older existing building stock, a careful weighing of options must take place before making the decision to replace them with new construction. The simple assumption of replacement with code-constructed new buildings being better than maintaining old buildings may not necessarily be true. The findings can be useful to local governments and policymakers in Canada and similar contexts in devising a practical approach to their urban planning and building stock management issues. The houses selected in this study were located in an urban centre with high population density. The applicability of the results may vary based on geographic location, the dominant energy supply sources in the region, and grid emissions factors. Moreover, the scenarios defined in the study can be subjected to various uncertainties with changes occurring in the macro-environment. Even though the reconstruction strategies perform better than the renovation strategies from an environmental perspective, the life cycle cost and social considerations of these strategies should be considered before making decisions to renovate or replace existing houses. 109 Chapter 7: Uncertainty Analysis for WBLCA A version of this chapter is under preparation for a peer-reviewed journal paper, as an article titled “BIM-based whole-building life cycle assessments between standard and net-zero energy single family buildings: A MCDM approach” that will be submitted to the Journal of Energy and Building in August 2020. Background In the previous sections, the proposed WBLCA was developed to create comprehensive and reliable LCA/LCC results at a building level. The proposed WBLCA was first applied to new residential building designs to develop a design improvement framework by considering the overall environmental and economic performance. The proposed WBLCA was then applied to existing building renovations to develop the best renovation strategies for residential buildings under different scenarios. However, the uncertainty issue, which is always related to LCA, hasn’t been discussed in the previous two case studies. In order to ensure the reliability of the WBLCA results, it is necessary to address the LCA-related uncertainty. Therefore, this chapter proposes a method to conduct WBLCA uncertainty analysis with a case study. The uncertainties in WBLCA results are mainly because of the complications of the LCA development process and the complexity of building structures [25][219]. Due to the variety of LCA methods and databases, LCA results could be significantly different with uncertainty. On the other hand, the variances in building materials and cut-off rules could lead to LCA result uncertainty, and the reference service life of the building could also result in a variation of WBLCA results. The proposed WBLCA method applied the EPD and EN 15978 standard to minimize systematic uncertainties. The proposed WBLCA method also integrated the BIM technique to control assessment errors coming from the building systems. However, the assumptions and scenarios in the WBLCA studies could not be avoided, which created a reasonable level of uncertainty in the final results. At the same time, data limitations and the designed impact assessment methods already embedded some uncertainties, which become part of the WBLCA results. Therefore, it is necessary to propose a method to further reduce the uncertainty and improve the reliability of the WBLCA results. There are different ways to reduce the LCA uncertainties, such as Monte Carlo simulations used in SimaPro software, and the pedigree matrix approach used in openLCA software [220,221]. Data 110 uncertainty and stochastic uncertainties are critical issues faced by any LCA study, but they can be addressed through fuzzy-based techniques [176,207]. Fuzzy approaches have been shown to improve results reliability through uncertainty treatment, and Fuzzy logic is also a useful tool for modeling complex systems with uncertain information [222,223]. Fuzzy set theory, initially proposed by Zadeh [224], has been extensively applied to objectively reflect the ambiguities in human judgment and effectively resolve the uncertainties in the available information in an ill-defined multiple criteria decision making environment. Numerous studies have been conducted to handle uncertainty using fuzzy set theory, and the application of fuzzy set theory to MCDM methods has proven to be an effective approach [225,226]. MCDM is an analytic method to evaluate the advantages and disadvantages of alternatives based on multiple criteria [226]. A fuzzy MCDM model is used to assess alternatives versus selected criteria through a committee of decision makers, where suitability of alternatives versus criteria, and the importance weights of criteria, can be evaluated in linguistic values represented by fuzzy numbers [227]. As mentioned above, the WBLCA method proposed in this study could mitigate the LCA uncertainty dramatically, while the nature of LCA studies throughout the lifespan would associated with unknown factors and data variances. What happened in the future of building lifespan could only be estimated based on the current knowledge, and the data variances due to the available selections could also lead to uncertain LCA results. However, the WBLCA results are still valuable if we can consider the possible values of each input at a fuzzy scale with a lower and higher value and a likely value. At the same time, the possible weightings could be assigned based on the requests from different stakeholders, and different options could be selected accordingly. For example, Assigning different weights based on the requests from build owners and city planners. In this study, a fuzzy-based MCDM approach is applied to treat the multiple criteria results among different scenarios with uncertainties. The detailed method to apply fuzzy-based MCDM is explained in the following section. Method and procedure In the proposed WBLCA method, the embodied emissions were collected from the EPD database based on the material list of the building design. Even though EPD represents more accurate LCA data for building materials than general data from LCA database, the material uses in any building design could still be different from the declared material in EPD. The operational performance was predicted based on the simulation software for 60 years of lifespan. Besides the material properties, 111 occupant behaviour was set with standard value to conduct the simulation. In reality, detailed values such as occupancy rate, room temperature, hot water temperature setup, shower frequency, etc. all fluctuate in different households. These variances would be the input information for the fuzzy-based MCDM approach. 7.2.1 Fuzzy-based MCDM method Based on the input variances described above, the results calculated from the proposed WBLCA method in Chapters 5 and 6 are the most likely values. If data is available for a most likely value, a triangular fuzzy number (a, b, c) can be defined [146]. 𝐟𝐌(𝐱) = {𝟎𝐱 − 𝐚 𝐛 − 𝐚⁄𝐜 − 𝐱 𝐜 − 𝐛⁄ ; 𝐱 < 𝐚, 𝐱 > 𝐜; 𝐚 ≤ 𝐱 < 𝐛; 𝐛 ≤ 𝐱 < 𝐜 Equation 11 There are numerous studies that demonstrate the percentage of embodied emissions over life cycle emissions [213,228,229]. Koezjakov et al. mentioned that the embodied emissions contains 36% - 46% of the overall life cycle emissions for an energy efficient home [214]. Therefore, the variance from this study was used to define the lower and upper value for embodied emissions in the product stage to form the triangular fuzzy number. The life cycle impacts from the construction stage, usage stage, and disposal stage were adjusted accordingly to create the triangular fuzzy number. The operational emissions in the usage stage were also adjusted by assigning lower and upper values to the occupancy rate, showering rate, room temperature, and hot water temperature based on the BC building code and ASHRAE 55-2013 standard [230–232]. Due to these variances, the building level upper and lower values in terms of environmental emissions and costs could be developed. The triangular fuzzy numbers can be treated with fuzzy arithmetic principles for algebraic computations, which are represented in the equations given below [233]. If there are two triangular fuzzy numbers A = (a1, a2, a3) and B = (b1, b2, b3): Addition: A+B = (a1+b1, a2+b2, a3+b3) Subtraction: A-B = (a1-b3, a2-b2, a3-b1) Multiplication: A(.)B = (a1b1, a2b2, a3b3) Division: A÷B = (a1/b3, a2/b2, a3/b1) Scalar multiplication: kA = (ka1, ka2, ka3); if k>0 kA = (ka3, ka2, ka1); if k<0 112 In the next step, the fuzzy-based WBLCA results were normalized. If the WBLCA results for the ith scenario under the jth environmental indicator is represented by a fuzzy number X𝑖𝑗, then the normalized fuzzy decision matrix P = [Pij] is represented as follows: 𝐩𝐢𝐣 = {(𝐱𝐢𝐣𝟏−𝐱𝐦𝐢𝐧𝐱𝐦𝐚𝐱−𝐱𝐦𝐢𝐧,𝐱𝐢𝐣𝟐−𝐱𝐦𝐢𝐧𝐱𝐦𝐚𝐱−𝐱𝐦𝐢𝐧,𝐱𝐢𝐣𝟑−𝐱𝐦𝐢𝐧𝐱𝐦𝐚𝐱−𝐱𝐦𝐢𝐧) ; 𝐟𝐨𝐫 𝐛𝐞𝐧𝐞𝐟𝐢𝐭 𝐜𝐫𝐢𝐭𝐞𝐫𝐢𝐚(𝐱𝐦𝐚𝐱−𝐱𝐢𝐣𝟏𝐍𝐱𝐦𝐚𝐱−𝐱𝐦𝐢𝐧,𝐱𝐦𝐚𝐱−𝐱𝐢𝐣𝟐𝐱𝐦𝐚𝐱−𝐱𝐦𝐢𝐧,𝐱𝐦𝐚𝐱−𝐱𝐢𝐣𝟑𝐱𝐦𝐚𝐱−𝐱𝐦𝐢𝐧) ; 𝐟𝐨𝐫 𝐜𝐨𝐬𝐭 𝐜𝐫𝐢𝐭𝐞𝐫𝐢𝐚 Equation 12 Where, xmax = max(xij3) and xmin = min(xij1) The normalized values pij was multiplied by the weight factors. If the weight assigned to the jth environmental indicator is W𝑗 , then the weighted normalized value of the ith scenario under the jth environmental indicator is represented by 𝐕𝐢𝐣 = 𝐫𝐢𝐣(. )𝐖𝐣 Equation 13 In this study, the weighting factors were assigned to three environmental sub-categories—environmental impacts, resource use, and waste disposal—and one LCC category, since they are all important parameters that are considered in the proposed WBLCA method. However, stakeholders have different opinions on the weighting factors. For example, the building owners would be more sensitive to the cost of new buildings or renovations, and more weights should be assigned to the LCC indicator. On the other hand, the municipalities that plan the city from the overall review needs to pay more attention to the environment, and more weights should be assigned to the environment indicators. The building designers, the connectors between building owners and municipalities, have to accommodate the requests from both parties, and the balanced weights should be assigned between environment and cost. After multiple interviews with various building owners, architectural designers, and city staff, the weighting factors were developed and listed in 7-1. Table 7-1: Weighting factors assigned based on different stakeholders. Stakeholders Weighting factors Environmental impacts (LCA) Economic impacts (LCC) Homeowner’s perspective 30% 70% Designer’s perspecitve 50% 50% Municipality’s perspective 70% 30% The overall environmental and economic impact score (Pi) of one scenario considering m number of indicators can be calculated by the following formula: 113 𝐏𝐢 = ∑ 𝐫𝐢𝐣 ∗ 𝐖𝐢𝐣𝒎𝒋=𝟏 Equation 14 In order to identify the best scenario among the different alternatives, the triangular fuzzy number Pi needs to be ranked. One method which has been widely used in the literature for ranking fuzzy numbers under similar contexts is the maximising set and minimising set method [207,234]. The method can be used to select the most environment-friendly building design with the consideration of budgets using the fuzzy appropriateness index (Fi: I = 1, 2 …. n), which represents the overall environmental performance score. Maximizing set M can be defined using the following equations, where fM(x) is the membership of x to M [234]. 𝐌 = {(𝐱, 𝐟𝐌(𝐱))|𝐱 ∈ 𝐑} Equation 15 Where, 𝐟𝐌(𝐱) = {𝐱− 𝐱𝐦𝐢𝐧𝐱𝐦𝐚𝐱− 𝐱𝐦𝐢𝐧 , 𝐱𝐦𝐢𝐧 ≤ 𝐱 ≤ 𝐱𝐦𝐚𝐱 𝟎 , 𝐨𝐭𝐡𝐞𝐫𝐰𝐢𝐬𝐞 Equation 16 Minimizing set G can be defined using the following equations, where fG(x) is the membership of x to G [234]. 𝐆 = {(𝐱, 𝐟𝐆(𝐱))|𝐱 ∈ 𝐑} Equation 17 Where, 𝐟𝐆(𝐱) = {𝐱− 𝐱𝐦𝐚𝐱𝐱𝐦𝐢𝐧− 𝐱𝐦𝐚𝐱 , 𝐱𝐦𝐢𝐧 ≤ 𝐱 ≤ 𝐱𝐦𝐚𝐱 𝟎 , 𝐨𝐭𝐡𝐞𝐫𝐰𝐢𝐬𝐞 Equation 18 Where, xmin = infS; xmax = supS; S = ⋃Fi; Fi = {x|fFi(x) > 0}mi=1; i = 1,2, … ,m For the i th building design scenario, the right environmental/economic impact value, left environmental/economic impact value, and the total environmental/economic impacts can be represented as UM(Fi), UG(Fi), and UT(Fi). These parameters are defined below. 𝐔𝐌(𝐅𝐢) = 𝐬𝐮𝐩 (𝐟𝐅𝐢(𝐱)⋂𝐟𝐌(𝐱)) , 𝐢 = 𝟏, 𝟐, … ,𝐦 Equation 19 𝐔𝐆(𝐅𝐢) = 𝐬𝐮𝐩 (𝐟𝐅𝐢(𝐱)⋂𝐟𝐆(𝐱)) , 𝐢 = 𝟏, 𝟐, … ,𝐦 Equation 20 114 𝐔𝐓(𝐅𝐢) =𝐔𝐌(𝐅𝐢)+𝟏−𝐔𝐆(𝐅𝐢)𝟐 Equation 21 If the fuzzy appropriateness index of the ith solution is denoted as Fi = [ai, bi, ci], then the general form of Fi, fM and fG can be represented in Figure 7-1. Figure 7-1. Fuzzy ranking based on maximising set and minimising set The building design plan that has the maximum total environment/economic impact (UG(Fi)) value will be selected as the best scenario. In order to demonstrate how this fuzzy-based MCDM method is applied to actual WBLCA research, a case study was conducted in the following section with the proposed WBLCA method and fuzzy-based MCDM approach. Case study The uncertainties exist on WBLCA of new building designs and existing building renovations. In new building design LCA, the materials selected for buildings are not certain although the material types are determined. The transportation distances of building materials would depend on the suppliers selected which are uncertain. The building operations and conditions totally depend on the building occupants which are hard to quantify with a specific value. The building demolitions have various options depending on the facility availability near construction sites. Therefore, assessing the life cycle impacts of new building design with fuzzy triangular numbers (minimum, likely, and maximum) would create more reliable and comprehensive WBLCA results. The 115 uncertainties mentioned above also apply to existing building renovations. Furthermore, the building deteriorations and building lifespan after renovations are different between existing building and new buildings. Therefore, it is necessary to consider uncertainty analysis at both new building designs and existing building renovations. In this study, a new building design, net zero energy building (NZEB), was selected to evaluate the fuzzy-based MCDM method. The concept of NZEBs has become popular in the building sector to promote energy efficient buildings. NZEBs were defined in this chapter as producing at least as much energy as the building consumes in a year [235–237]. NEZBs are buildings that need to reduce the energy needs greatly through efficient HVAC systems and high thermal properties for the envelope so that the additional energy needs can be supplied by renewable energies such as solar panels [238]. Another similar term is “net zero energy ready building,” which means the building has efficient energy performance and is ready to be independent from the grid if the renewable energy source is installed onsite [207]. Renewable energy sources and efficient HVAC systems have both been investigated with residential NZEBs to achieve zero energy consumption. Since residential NZEBs are becoming popular in the residential sector, it is important to know if this is the right direction in terms of building level life cycle environmental and economic performance. Therefore, the comparisons between standard buildings that follow the BC building code and NZEBs were investigated in this chapter. Natural gas and electricity are the two most commonly used energy resources in BC [239]. Therefore, it is vital to investigate the environmental and economic performance of NZEBs between natural gas-based HVAC systems and electricity-based HVAC systems. Furthermore, the most commonly used onsite renewable energy sources in residential buildings in BC are solar PV panels [240]. It is environmentally friendly that solar PV panels generate renewable energy to replace the use of grid electricity, while production of PV panels creates negative environmental impacts. It is also important to investigate if the use of PV panels has positive environmental impacts beside the energy savings, and what is the overall environmental and economic impacts of PV panels. Therefore, it is necessary to understand the differences between residential NZEBs and net zero energy ready buildings on building-level life cycle environmental performance. Based on the statements described above, five scenarios were proposed in this chapter to investigate the environmental and economic performances of code-specified buildings and NZEBs with BIM-based WBLCA method and fuzzy-based MCDM. 116 Scenario 1: Typical single-family residential building in compliance with BC building code In this scenario, a typical design from a new neighbourhood development project in Kelowna, BC was selected, which represents the most commonly proposed residential building designs received by the City of Kelowna building department, based on information from staff. The building layout was developed by Revit software and is presented in Figure 7-2. Figure 7-2: 3D and 2D layouts for a typical single family building in Kelowna BC 117 In order to meet the BC building code, the following building specifications were used in this scenario and are listed in Table 7-2. Table 7-2: Design specifications of building evelope and HVAC system in scenario 1 Building components Specification details Basement slab insulation 2.4’’ rigid XPS insulation Above-grade wall insulation R-24 batt walls, 2lb sprayed joist ends Below-grade wall insulation R-24 batt insulation Windows Vinyl double glazed windows c/w 180 low E Attic insulation R-50 blown in ceilings Furnace 92% efficient natural gas furnace with HRV system + central split air conditioning system Domestic hot water boiler 189.3 L integrated heat pump (HP COP 1.9) Air tightness 1.5 air change per hour (ACH) Scenario 2: NZEBs with natural gas based HVAC system In this scenario, the building layout was set up to be the same as the design in Scenario 1. However, the thermal design and the HVAC systems are different since the building needs to be more energy-efficient so that the annual energy required can be balanced by the energy produced by PV panels. In order to meet this requirement, the following building specifications are used in this scenario and listed in Table 7-3. Table 7-3: Design specifications of building evelope and HVAC system in scenario 2 Building components Specification details Basement slab insulatoin 2.4’’ rigid XPS insulation Above-grade wall insulation 2’’ styrofoam wall sytem c/w R14 batt insulation Below-grade wall insulation 12’’ insulated conrete form foundation wall Windows Vinyl tripple glazed windows c/w double 366 low E Attic insulation R-20 batted and R-50 blown in ceilings, 2 lb urethane spray at joist ends Furnace 98.5% efficient natural gas furnace with HRV system Domestic hot water boiler 150 L high-efficient natural gas hot water tank (energy factor 0.82) Air tightness 0.5 air change per hour (ACH) Renewable energy source CSUN Quasar 260 PV panel with 16.1% module efficiency – connected to the electric grid Scenario 3: Net zero energy ready building with natural gas-based HVAC system In this scenario, the design specifications and HVAC system were exactly the same as in Scenario 2. The only difference is no solar PV panel installed in this building. 118 Scenario 4: NZEBs with electricity-based HVAC system In this scenario, the building layout was set up to be the same as the design in Scenario 1. The building thermal design was the same as the values in Scenario 2. However, the HVAC system in this scenario was switched from natural gas to electricity. The following building specifications were used in this scenario and are listed in Table 7-4. Table 7-4: Design specifications of building evelope and HVAC system in scenario 4 Building components Specification details Basement slab insulation 2.4’’ rigid XPS insulation Above-grade wall insulation 2’’ styrofoam wall sytem c/w R14 batt insulation Below-grade wall insulation 12’’ insulated conrete form foundation wall Windows Vinyl tripple glazed windows c/w double 366 low E Attic insulation R-20 batted and R-50 blown in ceilings, 2 lb urethane spray at joist ends Furnace 100% efficient electric furnace with HRV system + air heat pump Domestic hot water boiler 150 L high-efficient electric hot water tank (energy factor 0.9) Air tightness 0.5 air change per hour (ACH) Renewable energy source CSUN Quasar 260 PV panel – connected to the electric grid Scenario 5: Net-zero energy ready building with electricity based HVAC system In this scenario, the design specifications and HVAC system were exactly the same as in Scenario 4. The only difference is no solar PV panel installed in this building. 7.3.1 WBLCA calculations With the scenarios set up above, the environmental performance of each scenario is different since the materials list and the thermal characteristics in each building are not the same. Based on the proposed WBLCA method demonstrated in Chapter 4, the WBLCA calculations of each scenario were conducted and are presented in the following section. The functional equivalent of the WBLCA is the 2-level single family house shown in Figure 7-2. The study period is 60 years, and the system boundary is from cradle to grave including the manufacturing stage, construction stage, operation and maintenance stage, and demolition stage. 119 7.3.1.1 Manufacturing stage (A1-A3) Based on the building layout of the single-family house shown in Figure 7-2, the Autodesk Revit 2018 version was used to generate the accurate material BoQ. The detailed BoQ for the typical building in Scenairo 1 is presented in Appendix C Table C1. The material list presented in Table C1 will be directly used to calculate the construction stage, usage stage, and disposal stage. The material lists in Scenario 2-5 are mostly the same as the list in Scenario 1, and the differences among the five scenarios are listed in Table 7-5 based on the scenario development. Table 7-5: The differences of material list among five scenarios Building family and type Scenario 1 Scenario 2 Scenario 3 Scenario 4 Scenario 5 Basic Wall: Exterior Wall - basement 8'' concrete wall + R24 batt insulation 12'' insulated concrete form foundation wall Same as scenario 2 Same as scenario 2 Same as scenario 2 Basic roof: Generic roof - 300 mm R50 loose fill spray over living spaces R20 batted insulation + R50 loose fill spray over living spaces Same as scenario 2 Same as scenario 2 Same as scenario 2 Basic wall: Exterior Wall - Main R24 batt insulation 2'' styrofoam wall sytem c/w R14 batt insulation Same as scenario 2 Same as scenario 2 Same as scenario 2 Exterior windows Double glazing + Vinyl frame Triple glazing + vinyl frame Same as scenario 2 Same as scenario 2 Same as scenario 2 7.3.1.2 Construction stage (A4-A5) In the construction stage, the impacts are coming from material transport, equipment energy use, and construction waste. The transport distances of each material were estimated based on the distances between the nearest manufacturing factories and the construction site. The detailed information is listed in Table C2 of Appendix C. The energy consumed by the construction equipment was estimated based on the Athena Construction Energy Database, which was calculated by the height of the building and the total mass of the materials. The construction waste factors for each material were also based on Athena Construction Energy Database [148] (listed in Table C3 of Appendix C). 120 7.3.1.3 Usage stage (A4-A5) Since the lifespan of the house was defined as 60 years, the maintenance, repair, and replacement activities were assumed to happen at different frequencies. Based on the calculation method described in the methodology section, the quantity of new materials needed for maintenance (B1), repair (B2), and replacement (B3) can be calculated based on the task frequency and the material use percentage. Table C4 of Appendix C presents the task frequency and the material use percentage of each material in each activity. In terms of the operational energy use, the HOT2000 energy simulation software, one of the most popular energy simulation tools for single-family houses in Canada, was adopted to estimate the annual energy consumption [241]. Based on the material lists in Table C1 and Table 7-5, the simulation models for each scenario were developed, and the results were calculated and are listed in Table 7-6. Since Scenario 1 is the standard building that follows the BC building code, the HVAC system with the energy source of natural gas and electricity was applied and no solar panel was installed. In Scenarios 2 and 4, the single-family building was designed to meet net-zero energy building with natural gas sourced and electricity sourced HVAC individually. Solar PV panels were installed to balance the energy consumed by the building. Table 7-6: Annual energy use of single-family building in different scenarios (Output from HOT2000 simulation) Annual energy use Scenario 1 Scenario 2 Scenario 3 Scenario 4 Scenario 5 Natural gas (m3) 2164.8 1916.9 2035.8 0 0 Electricity (kwh) 12705.6 7764.6 7768.2 16491.5 16464.3 PV generation 0 28950.8 0 16491.5 0 PV panel installation area (ft2) 0 1901 0 1090 0 7.3.1.4 Disposal stage (C1-C4) In the disposal stage, the existing building is assumed to be torn down, and the construction waste materials need to be sorted for reuse, recycling, or landfilling. The energy used by the demolition equipment (C1) was assumed based on the data from citations and evaluated by industrial professionals. Considering material recycling and reuse, equipment with fuel consumption of 35 L/h needs 40 hours to demolish the single-family house [242]. Based on the availability of recycling and landfill facilities that are closest to the site, the transport distance of waste materials 121 (C2) to different facilities was estimated and is listed in Table C5 of Appendix C. The processing facility equipment energy use can be calculated based on the quantity of waste materials that are treated as reuse and recycle materials (C3). The percentage of waste materials for reuse and recycling are listed in Table C6 of Appendix C. The impacts from landfilling (C4) were estimated based on the quantity of materials that were sent to landfill centre. The percentage of waste materials for landfilling are also listed in Table C6. 7.3.2 Life cycle impact assessment After the data collection for each module from A1-C4, the whole building LCIA can be conducted in three aspects based on the reported environmental indicators listed in EN 15978. The environmental impacts considered in this case study were evaluated based on the proposed WBLCA method described in Chapter 4. 7.3.3 LCC assessment The unit processes and flows involved during the WBLCA environmental results calculations were also used to conduct LCC assessment. The detailed calculation processes were presented in Chapter 4. The discount rate for this study is set at 4.65% per year. The material costs and construction costs are based on the RSMeans cost database 2019 version [154]. Table A7 lists all the initial costs collected from RSMeans based on the building materials derived from the BIM model. Transportation costs are also cited from the Canadian Trucking Alliance [155]. Utility costs are based on the unit prices from FortisBC and BC Hydro [156,157]. Construction waste disposal costs are based on the information from the City of Kelowna website [158]. Material quantities and transport distances listed in Table C1 and C2 were used to calculate the manufacturing and construction costs. The maintenance and disposal information listed in Table C3 -C6 was also used to calculate the costs in the usage and disposal stages. The LCC differences among the five scenarios are mainly due to the variances in HVAC systems, renewable energy sources, and operational energy consumption. 7.3.4 Fuzzy MCDM approach for WBLCA results comparison With the detailed method described in Chapter 4, the total WBLCA results for each scenario could be acquired with the defined indicators shown in Chapter 4. An evaluation matrix with 5 alternatives (5 scenarios) and 14 criteria (14 indicators) was created, and a MCDM problem was formulated with the available alternatives and performance indicators. The fuzzy-based MCDM 122 method described in section 7.2.1 was applied here to support the comparisons of these five scenarios in terms of environmental and economic impacts. Results After the calculation of environmental and economic impacts from each life cycle module (A1-C4), the WBLCA impacts could be summarized by adding the values in each module together. Table C7 - Table C11 in Appendix C present the likely WBLCA results of single-family buildings from Scenario 1 to Scenario 5 respectively, including the results in each life cycle module. Table C7 presents the WBLCA results for a standard single-family detached house in compliance with the BC building code. The results show that over 90% of environmental impacts are from the product stage and operational energy use. Among them, 10-20% of the emissions are contributed by raw material manufacturing, and 70-80% of the emissions are contributed by operational energy use. The negative value in the waste processing module means that construction waste recycling at the end of the building lifespan creates positive environmental impacts by reducing the use of raw materials. Meanwhile, most of the material recycling and reuse happened at the waste processing stage. It is worth mentioning that transportation during the construction stage and the waste disposal stage only contain less than 1% of the total WBLCA results since most of the materials are from local markets. Table C8 presents WBLCA results for a NZEB (Scenario 2). In this scenario, the solar panels were used to generate onsite renewable energy to meet the net-zero energy requirement. The natural gas-based furnace and hot water tank were used in this scenario, which is the most popular setup in the current markets due to cheap natural gas prices. The electricity generated by solar panels in this scenario are used to satisfy the basic electricity load, as well as to balance the energy consumed through natural gas. The environmental impacts of onsite electricity are negative since it reduces electricity use from the grid. Therefore, the operational energy use in Table C8 was dramatically reduced to less than 50%. Moreover, 6 indicators (AP, EP, SP, RPE, FW, and WD) even have negative values. Due to the large amount of positive impacts created by the solar panels, the total results of WBLCA in terms of EP, RPE, and FW are negative as well. Table C9 lists WBLCA results for a net zero ready building. In this scenario, the building layout is the same as the layout in Scenario 1. However, more insulation was added to the walls, attic, and windows to create more efficient building design with less operational energy requirement. The overall performance of Scenario 3 is similar to Scenario 1 in terms of the contributions from 123 different life cycle modules. Over 90% of the environmental impacts are from the product stage and the usage stage. Compared to Scenario 1, the environmental impacts from the product stage in Scenario 3 increase by 5-15% due to the additional insulation materials, while the environmental impacts due to operational energy use reduce between 5-15%. In the end, the total WBLCA results in scenario 3 is 10% lower than the results in scenario 1 except ODP. The ODP value in Scenario 3 is nearly 2.5 times greater than the value in Scenario 1 since insulation material is one of the main contributions to this environmental indicator. Table C10 presents the WBLCA results for a NZEB with electric air-sourced heat pump and hot water tank in scenario 4, and the annual electrify requirements of this house was completely supplied by solar panels. Therefore, the environmental emissions from operational energy use is 0% contribution to the total WBLCA results. However, the product stage and replacement module in usage stage each contribute around 40% of the environmental impacts. Since the lifespan of solar panels is defined as 25 years based on the specification, there are 2 replacements occurring during the 60 years of the building life span. Since solar panels have fairly high embodied impacts compared to other building materials, the overall contribution from the replacement module was up dramatically. Besides the product stage and the replacement module, the repair module in the usage stage also contributes over 10% of the total impacts, since the total WBLCA results in Scenario 4 are generally much lower than the first three scenarios. Table C11 shows the WBLCA results for the same building in Scenario 5 as described in Scenario 4 without the solar panel installation. Since electricity is the main energy source for the HVAC system in this scenario, the contribution from operational energy use is much different from the values in Scenario 3. The GWP, ODP, ADP, and NRPE indicator values in the operational stage in Scenario 5 are around 20-30% of the values in Scenario 3, while the EP, FW, and WD indicator values in the operational stage in Scenario 5 are 1.5-2 times of the values in Scenario 3. Therefore, the selection of different energy sources for the HVAC system leads to different types of impacts. Overall, around 50-60% of impacts are from operational energy use, while 20-30% of impacts are from the product stage. The repair and replacement modules contribute around 15-20% of impacts together. In terms of LCC results, since the basic building design in these five scenarios is the same, the differences in cost are mainly from the HVAC system, the PV panels, and the operational energy consumption. In Scenarios 1, 3, and 5, the HVAC systems are a mix of electricity and natural gas: 124 a full natural-gas based, and a full electricity-based. The costs of the furnace and hot water tank are similar. However, the energy consumption between them is totally different, since electricity-based heat pumps could reach a much higher coefficient of performance (CoP). As shown in Table C12, the likely LCC values of Scenarios 1, 3, and 5 are around $408K, $401K, and $395K respectively. It is obvious that the electricity-based HVAC systems have lower LCC. Scenarios 2 and 4 have PV panels installed to create NZEB, and the LCC values are $467K and $439K respectively, which are higher than the other three scenarios without PV panels. Even though the PV panels reduce natural gas/electricity usage during the life span, the PV panel installation costs are so high that the utility cost savings are not enough to balance it. While the likely WBLCA and LCC results were represented and illustrated above, the overall performance among these five scenarios still could not be ranked. Therefore, the fuzzy-based MCDM approach was introduced here to achieve this goal. Based on the calculation method described in section 7.2.1, the triangular fuzzy numbers of the final WBLCA results were generated by calculating the lower and upper values of each environmental indicator from all the life cycle modules. Table 7-7 presents the fuzzy numbers of the total WBLCA results, and Table 7-8 presents the normalized decision matrix based on the fuzzy-based normalization method described in Equation 12 above. 125 Table 7-7: Triangular fuzzy number of WBLCA results Global warming potential Ozone depletion potential Acidification potential Eutrophication potential Smog potential kg CO2 eq. kg CFC11 eq. kg SO2 eq. kg N eq. kg O3 eq. Lower Likely Upper Lower Likely Upper Lower Likely Upper Lower Likely Upper Lower Likely Upper Scenario 1 545086.58 600378.46 658443.93 0.08 0.09 0.10 1499.72 1637.54 1764.53 1064.94 1169.10 1285.75 17872.47 19482.08 20827.13 Scenario 2 337952.15 412933.89 511867.66 0.18 0.20 0.23 778.99 945.53 1147.77 -215.25 -118.25 -8.53 6997.61 8785.01 10884.65 Scenario 3 522134.50 554715.65 649361.21 0.20 0.22 0.24 1419.32 1476.76 1654.81 957.64 955.98 1043.78 16924.54 17554.06 19407.09 Scenario 4 153941.43 174231.30 185312.81 0.15 0.16 0.18 857.22 953.96 1007.39 515.24 613.66 647.71 10963.19 12241.66 12963.52 Scenario 5 224812.39 243263.56 263479.11 0.16 0.17 0.19 1147.52 1233.74 1328.26 1144.43 1235.51 1338.92 15579.68 16760.84 18048.65 Abiotic depletion potential for fossil fuels Renewable primary energy use Non-renewable primary energy use Secondary materials Net use of fresh water MJ surplus MJ MJ KG M3 Lower Likely Upper Lower Likely Upper Lower Likely Upper Lower Likely Upper Lower Likely Upper Scenario 1 1049577.49 1158748.84 1280615.01 3767113.74 4300760.46 4781418.32 8467505.38 9329345.20 10273091.29 24537.40 27408.82 30280.23 32455.90 34370.95 36750.64 Scenario 2 709250.35 864648.11 1076559.44 -5215638.88 -4878324.47 -4537664.17 5182402.30 6365215.11 7946168.92 24537.40 27408.82 30280.23 -6947.92 -5813.07 -4646.20 Scenario 3 1001665.61 1073746.50 1281713.50 3225688.59 3225938.26 3554209.60 8043384.94 8549489.73 10070341.30 24537.40 27408.82 30280.23 29944.64 29337.86 30317.46 Scenario 4 145234.33 166958.52 178070.33 433649.09 978165.96 1185015.06 1925935.29 2192759.63 2324335.21 24537.40 27408.82 30280.23 18256.08 20275.50 20699.00 Scenario 5 235718.10 255727.21 277769.71 5134228.32 5699466.98 6329404.97 2997882.94 3239083.69 3506198.97 24537.40 27408.82 30280.24 38727.70 40771.16 43120.40 126 Waste disposed Components for re-use Materials for recycle LCC KG KG KG C$ Lower Likely Upper Lower Likely Upper Lower Likely Upper Lower Likely Upper Scenario 1 88120.40 91481.57 94471.32 28060.24 31959.27 35858.30 110404.80 125745.79 141086.78 388,755 408,192 427,630 Scenario 2 48390.43 51189.62 54219.06 28061.11 31960.27 35859.42 110405.68 125746.79 141087.90 424,354 445,571 466,789 Scenario 3 85902.70 86310.38 88966.92 28061.99 31961.27 35860.54 110406.56 125747.79 141089.02 382,294 401,408 420,523 Scenario 4 72665.09 75934.60 77375.24 28062.87 31962.27 35861.66 110407.44 125748.79 141090.14 398,830 418,771 438,713 Scenario 5 93133.74 96338.91 99894.49 28063.75 31963.27 35862.79 110408.32 125749.79 141091.27 377,081 395,935 414,789 127 Table 7-8: Normalized decision matrix after fuzzy-based normalization Global warming potential Ozone depletion potential Acidification potential Eutrophication potential Smog potential Abiotic depletion potential for fossil fuels Renewable primary energy use Lower Likely Upper Lower Likely Upper Lower Likely Upper Lower Likely Upper Lower Likely Upper Lower Likely Upper Lower Likely Upper Scenario 1 0.00 0.12 0.22 0.89 0.95 1.00 0.00 0.13 0.27 0.03 0.11 0.18 0.00 0.10 0.21 0.00 0.11 0.20 0.13 0.18 0.22 Scenario 2 0.29 0.49 0.64 0.11 0.27 0.41 0.63 0.83 1.00 0.87 0.94 1.00 0.72 0.87 1.00 0.18 0.37 0.50 0.94 0.97 1.00 Scenario 3 0.02 0.21 0.27 0.00 0.16 0.25 0.11 0.29 0.35 0.19 0.25 0.25 0.10 0.24 0.28 0.00 0.18 0.25 0.24 0.27 0.27 Scenario 4 0.94 0.96 1.00 0.41 0.49 0.57 0.77 0.82 0.92 0.44 0.47 0.53 0.57 0.62 0.71 0.97 0.98 1.00 0.45 0.46 0.51 Scenario 5 0.78 0.82 0.86 0.35 0.43 0.52 0.44 0.54 0.63 0.00 0.07 0.13 0.20 0.29 0.38 0.88 0.90 0.92 0.00 0.05 0.10 Non-renewable primary energy use Secondary materials Net use of fresh water Waste disposed Components for re-use Materials for recycle LCC Lower Likely Upper Lower Likely Upper Lower Likely Upper Lower Likely Upper Lower Likely Upper Lower Likely Upper Lower Likely Upper Scenario 1 0.00 0.11 0.22 0.00 0.50 1.00 0.13 0.17 0.21 0.77 0.84 0.89 0.00 0.50 1.00 0.00 0.50 1.00 0.44 0.65 0.87 Scenario 2 0.28 0.47 0.61 0.00 0.50 1.00 0.95 0.98 1.00 0.00 0.05 0.11 0.00 0.50 1.00 0.00 0.50 1.00 0.00 0.24 0.47 Scenario 3 0.02 0.21 0.27 0.00 0.50 1.00 0.26 0.26 0.28 0.73 0.74 0.79 0.00 0.50 1.00 0.00 0.50 1.00 0.52 0.73 0.94 Scenario 4 0.95 0.97 1.00 0.00 0.50 1.00 0.45 0.46 0.50 0.47 0.53 0.56 0.00 0.50 1.00 0.00 0.50 1.00 0.31 0.54 0.76 Scenario 5 0.81 0.84 0.87 0.00 0.50 1.00 0.00 0.05 0.09 0.87 0.93 1.00 0.00 0.50 1.00 0.00 0.50 1.00 0.58 0.79 1.00 128 After adding weights and conducting aggregations based on Equations 13 and 14, the overall environmental and economic performance index was summarized and is presented in Figure 7-3. Figure 7-3: The overall WBLCA performance index after fuzzy-based calculations With the information presented in Figure 7-3, the maximizing and minimizing set method was used to rank the five scenarios with Equations 15-21, and the final ranking results were presented in Table 7-9. The No.1 rank is the scenario that has the best overall environmental/economic performance after considering the 13 environmental impact values and LCC results together. Therefore, the building design in Scenario 5 that uses an electricity-based HVAC system without solar panels is the optimal solution to achieve the best overall environmental and economic performance while meeting the net-zero energy ready target. The building design in Scenario 4 that uses an electricity-based HVAC system with solar panels is the second best option, and the net zero energy design in Scenario 2 with a natural gas-based HVAC system and solar panels is the last option among the five scenarios. 00.10.20.30.40.50.60.70.80.910.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90MembershipScenario 1Scenario 2Scenario 3Scenario 4Scenario 5129 Table 7-9: Final scenario rankings with maximizing and minimizing set method Um Ug Ut Rank Scenario 1 0.622 0.616 0.503 4 Scenario 2 0.510 0.743 0.383 5 Scenario 3 0.660 0.575 0.542 3 Scenario 4 0.689 0.540 0.575 2 Scenario 5 0.772 0.456 0.658 1 Discussion Due to the environmental impacts and energy usage in the building sector, building designs are moving towards energy independent and carbon neutral. In order to reduce life cycle energy use, it is necessary to develop a building system with less operational energy use. Therefore, additional attention needs to be paid to high-efficiency HVAC systems as well as better insulated building envelopes. At the same time, onsite renewable energy, such as solar panels and a geothermal heat pump, should be considered. In order to achieve better environmental performance, building materials that have higher thermal properties and greener energy sources should be considered. However, the best design in energy performance does not always lead to the best environmental performance. This section analyzed the relationships among a standard building design and four NZEB designs with different combinations of HVAC systems, and onsite renewable energy sources. The fuzzy MCDM approach was applied to select the best design scenario that can achieve better performance both in energy use and environmental emissions. The WBLCA results comparison between Scenarios 1 and 3 demonstrates that the additional insulation materials on exterior walls and attic, as well as windows with more glass layers will reduce the energy needs for heating and cooling, and emissions. However, the embodied emissions from the product stage increase. The overall WBLCA results ranking shows that the standard building design performs better than the NEZB design in Scenario 2 in terms of the overall environmental and cost impacts. The results demonstrate that energy efficient buildings, such as net zero energy ready buildings, are not always the better solution in terms of environmental performance, especially when the cost factor is also considered. Instead of increasing the building insulation layers, further attention should be paid to the efficiency of HVAC systems and their energy source. The WBLCA results analysis between Scenarios 2 and 3 demonstrate the different environmental and economic performance of two energy efficient building designs, with and without solar panels. 130 Scenario 2 is the NZEB design in which the amount of kWh energy consumed on site was balanced by the renewable energy produced on site by solar panels. Since the energy source for the HVAC system in these two scenarios was natural gas, a larger amount was consumed to keep the building functioning, since the gas furnace has much lower energy efficiency. In order to produce as much energy as the quantity acquired from natural gas, 1901 ft2 of solar panels were needed. However, the overall roof area is nearly 1500 ft2, which means some of the solar panels have to be installed vertically on the wall facing south. Despite the feasibility of this design option, the large solar panel application leads to a significant increment in embodied emissions from the product stage. The WBLCA results show that the embodied emissions from the product stage in Scenario 2 are 50-70% more than the values in Scenario 3, and some of the values in Scenario 2 even doubled. At the same time, the additional PV panels installed dramatically increased the LCC values. Therefore, Scenario 2 is the least favourable solution despite being a NZEB design. Scenarios 2 and 4 are both NZEB designs with solar panel installation. Scenario 2 has a natural gas-based HVAC system, while Scenario 4 has an electricity-based HVAC system. The Coefficient of Performance (CoP) of natural gas reaches as close as 1, while the CoP of the air source heat pump used in Scenario 4 can reach 2-4 on average [243]. Due to the differences in HVAC efficiencies, Scenario 2 needs an additional 900 ft2 of solar panels installed to achieve net zero energy consumption. From both environmental and cost perspectives, the electricity-based HVAC system is apparently a better solution than the natural gas-based HVAC system. In the future, a ground sourced heat pump and any other HVAC systems with high CoP should be recommended. It is shown from the results that operational emissions in Scenario 4 are nearly zero since the whole house is designed to use electricity, which can be supplied by the onsite solar panels. However, the operational emissions in Scenario 2 still have a large contribution to the final WBLCA results. The reason is that the building in Scenario 2 is a NZEB in which the annual kWh energy supplied is balanced by the annual kWh energy consumed. In terms of emissions, the negative environmental impacts from supplying the grid with electricity from solar panels could not balance the environmental emissions from using natural gas. The EP and REP indicators in the final WBLCA results perform better in Scenario 2 than Scenario 4 because of the negative environmental impacts from supplying electricity to the grid. In BC, most of the electricity production is hydro based, which is very clean. However, if fossil fuel is the primary source to 131 produce grid electricity, such as in Alberta, Canada, replacing the grid electricity consumption with natural gas would be a more sustainable solution. Based on the fuzzy MCMD calculation, the overall performance of the five scenarios with different environmental indicators and LCC impact was evaluated. The results show that the NZEB design with electricity-based HVAC system without solar panels is the optimal solution. The proposed fuzzy-based MCDM approach is well suited to addressing uncertainty issues in the proposed WBLCA method. Variations in the key parameters throughout the building life cycle are gathered and represented with lower and higher value rates. With fuzzy logic, these variable values provide a more reasonable and sensitive data environment when conducting building-level comparisons for the proposed WBLCA results. The fuzzy MCDM method provides a more comprehensive analysis of the final results and successfully addresses the uncertainties of WBLCA. Building designers have just started to improve operational energy performance, and the environmental performance of individual building materials has rarely been considered. This study addresses the gap by adopting EPD into the building-level environmental performance assessment. The building materials with better environmental performance will have a better chance to be selected. Furthermore, secondary materials and waste material recycling were considered as environmental indicators, which is as important as a GWP indicator. This approach will push building designers to consider the final destination of the building materials and the recycled components used in each material. Since the LCC was also a significant impact category, in addition to environmental performance, to measure the overall performance of these five scenarios, the final WBLCA results will provide more reasonable design solutions for clients to improve the environment while accepting it on the budget. There are some limitations associated with this study. The environmental performance with different combinations of HVAC systems and solar panels were analyzed. However, only PV solar panels were considered as the renewable energy source. In future studies, other renewable energy sources, such as wind energy and geothermal energy, should be integrated to select the best building designs. While conducting life cycle impact assessments, EPD reports are not always available for each building material. With the development of the EPD concept in the US and Canada, a full EPD database for local building materials should be established. Future studies can be conducted to compare the WBLCA results between the general LCA database and localized EPD database. 132 Summary LCA uncertainty is always a challenging issue in conducting life cycle environmental and economic assessments. With the comprehensive WBLCA method proposed in Chapter 4, this chapter proposed a fuzzy-based MCDM approach to address the potential uncertainties that accumulate during the WBLCA processes. The building designs of NZEBs and net zero energy ready buildings with different HVAC systems and PV panel installations were used as case studies to demonstrate the fuzzy MCDM method. Six scenarios were developed to analyze the environmental and economic performance with the options of onsite renewable energy, and electricity- or natural gas-based HVAC systems. The proposed WBLCA method was used to calculate the overall building life cycle performance from material production to waste disposal. The WBLCA results show that the fuzzy-based MCDM method is well suited to addressing LCA uncertainties as well as the challenges of building-level LCA/LCC comparisons. The case study results also show that the environmental impacts from the product stage and operational energy use module contribute over 90% of the overall impacts in Scenarios 1, 3, and 5 without solar panel installations. The NEZB with a natural gas-based HVAC system in Scenario 2 would need 1900ft2 of solar panels installed to reach energy independence, while only 1090ft2 of solar panels are required for the NEZB with electricity-based HVAC system in Scenario 4. The fuzzy MCDM results show that the residential NZEB with an electricity-based HVAC system without PV panels is the best design in terms of environmental and economic performance. The net zero energy ready building with a natural gas-based HVAC system without PV panels is the least favorable design. It is suggested from the results that a net-zero energy building is not always better than a standard building in terms of environmental performance. It is also recommended that high-efficiency HVAC systems, such as air-source and ground-sourced heat pumps, should replace low-efficiency systems, such as gas furnace or gas hot water tank. Further studies should be conducted to analyze the life cycle cost of different building design scenarios with the proposed WBLCA method to provide more practical suggestions to the building owners. 133 Chapter 8: Conclusions and Recommendations Increased concerns regarding environmental impacts in different life cycle stages of the residential building sector have resulted in a dire need for developing a comprehensive whole-building life cycle assessment method to reduce overall impacts with reliable and systematic LCA results. This research proposed a novel approach for building-level environmental and economic performance assessment, and it developed a systematic design improvement framework for building designers to improve building design with the most efficient improvement strategies. The proposed approach enhances new-building design decision making by identifying the best intervention strategy to achieve optimum environmental and economic performance while balancing the overall emissions from different life cycle modules. The proposed approach also supports community-level decision making in existing building renovations to improve existing building environmental performance within an affordable budget. The outcome of this study will provide decision makers with necessary technical supports to achieve sustainable communities in terms of new building design and existing building renovation strategies. Summary and Conclusions A summary of the specific study sections and the main conclusions are given below.  Chapter 3: A thorough review was conducted on building life cycle assessment and its associated limitations, as well as EPD, BIM, and LCC integration knowledge and the potential to apply them to building-level environmental performance assessment. The findings of this chapter were used in identifying the research gap and needs in the building sector, and defining the research concepts and methodologies.  Chapter 4: A comprehensive WBLCA method was developed by integrating the regulated EPD development process as well as BIM and LCC techniques. The proposed method is a systematic approach to calculating accurate building-level environmental and economic impacts with a full set of environmental indicators. The proposed WBLCA method addresses a number of shortcomings in the current building-level environmental and economic performance evaluation methods. Additionally, the use of the EPD method ensures the reliability of the WBLCA results by presenting clear and complete LCA development procedures. This approach would assist building designers in assessing and managing the performance of existing building renovation and new building design. The proposed WBLCA 134 method can also be used by researchers and practitioners to evaluate different types of building designs using the same assessment process, and further establish a comprehensive WBLCA database to reform the building-level regulations for environmental parameters while considering budgets from the building owner’s perspective.  Chapter 5: A new building design improvement framework was developed to assist designers in building environmental and economic performance improvement. The WBLCA method proposed in Chapter 4 was applied to evaluate and improve building-level performance in terms of environmental impact, resource use and waste flow, and LCC. The WBLCA results from the proposed method were clearly interpreted so that the critical contribution factors that dominate the WBLCA results were highlighted. Furthermore, building design improvement scenarios were developed to reduce the impacts from the critical factors, and the WBLCA results comparisons among these scenarios were conducted to select the optimal design with the best LCA/LCC performance. The proposed framework is a step further than the current WBLCA studies in that it provides a solution for the designer to improve the building design efficiently with consideration of all life cycle impacts. Considering LCC impacts in the proposed framework is also an innovative approach that assists building-level environmental improvement decision making with economic impact consideration.  Chapter 6: A systematic approach for existing-building retrofit strategies was suggested in conjunction with the proposed WBLCA method. This study explored the most feasible renovation strategies for existing buildings based on the best environmental and economic selections. The overall environmental and economic performance of each renovation strategy was calculated with the proposed WBLCA method, and the final results at each life cycle module were investigated and calculated using the TOPSIS-based MCDM method. The best renovation strategies were selected based on a comprehensive analysis of the WBLCA results. The community-level existing building renovation regulations were proposed to support decision makers in achieving environmental targets in the building sector with an acceptable budget.  Chapter 7: This chapter proposes a fuzzy-based MCDM approach to address uncertainty issues of the WBLCA method. The proposed approach enables a comparison of overall environmental and economic performance among different building designs with the consideration of data variances, and facilitates the selection of optimal design solutions among 135 the most important influence factors. The proposed approach mitigates the limitations associated with current LCA results interpretations. The proposed approach also addresses the uncertainties that are associated with WBLCA calculations. Moreover, fuzzy-based results encompass detailed information regarding possible WBLCA results, which enables planning for possible adverse scenarios in the future. The followed case studies show that presenting the overall environmental and economic impacts from all life cycle stages provides a better picture while comparing different design strategies, and the proposed fuzzy-based MCDM approach is well suited to reducing the LCA/LCC result uncertainties while comparing the overall results at a building level. Figure 8-1 shows where the aforementioned methods would fit into the strategy map. The proposed methods would mainly support building owners, building designers, and city planners in achieving the climate action targets of the building sector after investigating the overall environmental impacts and performance from all life cycle stages. Having such standardized procedures for implementation would reinforce the spreading of environmentally-friendly building design and management approaches while considering the building owner’s perspectives. 136 Figure 8-1: Proposed strategic map Originality and Contributions This research delivers the following unique contributions, which will assist in developing environment-oriented and budget-conscious communities through a thorough building-level LCA/LCC practice. 137 A comprehensive implementation strategy for WBLCA: While building-level environmental assessment has been conducted globally to assess the overall environmental performance, a systematic approach that incorporates all life cycle stages with detailed assessment processes is lacking. Decision makers are hindered in building sector planning for low-emission targets due to a lack of expertise, assessment tools, and complete information. This has also led to a perception of risk regarding green community planning. The proposed WBLCA implementation strategy fills this gap by providing decision makers with a comprehensive assessment process that strictly follows international standards and provides a detailed process that covers each and every life cycle stages, while adding the LCC as an additional impact category. An efficient design improvement framework for low-emission building designs: Current building design still does not pay enough attention to reducing the overall building environmental and economic impacts by considering the whole life cycle at the early design stage. Due to the complexity of WBLCA and the limited knowledge and tools for LCA, the current practice might guide designers into poor design of low-emission buildings. The proposed framework combines the EPD knowledge and the BIM platform into the LCA to ensure reliability and comprehensiveness in the assessment results, while highlighting the most efficient ways to improve building design without creating unpredicted increments in any other life cycle stage. The proposed framework also considers the LCC impacts while designing buildings with best environmental performance to ensure the design affordability for building owners. The proposed framework can help designers to easily monitor emission performance while conducting the building design, and provide suggestions for achieving low-emission targets with little additional cost and time. A scenario-based approach to existing-building renovation strategies: Environmental performance of existing buildings is an important factor in reducing emissions in the building sector, while the current practice does not have a systematic approach to guiding renovations of residential buildings in Canada. This study proposed a renovation strategy to help building owners conduct the most appropriate building improvement plan based on building conditions and personal requirements by using the proposed WBLCA method. The existing building renovations were categorized into different levels based on the willingness of building owners at a pilot project, and the emission reductions and LCC were calculated for each level and compared with the reconstruction option. This approach would help building owners achieve reductions in energy use 138 and emissions with the least cost and effort. This approach would also support city planners in making regulations and incentives to promote low-emission existing buildings. A fuzzy MCDM approach to study WBLCA uncertainties: The proposed WBLCA is a comprehensive and innovative approach to measure and improve building-level sustainability performance by considering the LCA and LCC results. Due to the complexity of building structures and the LCA/LCC declaration processes, many uncertainties exist among the calculations. There are limited studies that propose a systematic method to address the WBLCA uncertainties, and the fuzzy-based MCDM approach was used here for the first time to address the uncertainties of building-level LCA/LCC analysis. The potential variations in different input data and the assumption limits on the method developments were fully considered in the proposed fuzzy MCDM approach to ensure the WBLCA results comparisons are reasonable. Limitations The following challenges and limitations have been identified concerning the present study. Adjustments were made in the course of the study to mitigate their impacts. Data limitations: It is always a challenge to collect data for LCA and LCC studies. In this study, the EPD reports for environmental emission data of building materials, operational emissions, and waste disposal were not always available. The EPD data on secondary material use and waste materials for recycling/reuse are minimal for local building materials, while the waste disposal is a critical factor monitored in the proposed WBLCA method. In this study, the existing database from commercial software was used when the local data was not available, and reasonable assumptions and approximations were made when data was unavailable. While specific data for the Canadian context would yield the most relevant and accurate results in the impact assessment, approximations were made with data developed for other regions where Canada-specific data was unavailable. North American data was the preferred substitute for Canadian data, due to the geographical proximity and similar macro-environmental conditions. Scenario uncertainty is a major limitation associated with this approach. Scenario development methods specified in the literature were used to define the scenarios used in this study. Furthermore, expert opinion was sought to assess the plausibility of scenarios. There are also data limitations on operational energy simulation. Energy simulation software incorporates energy principles, thermodynamic equations, and many assumptions. The accuracy 139 of the building energy simulation results depend, in turn, on the accuracy of input data for the simulation [244]. Input data for the building energy model includes building geometry, internal loads, HVAC systems and components, weather data, operating strategies and schedules, and simulation-specific parameters. If certain assumptions are not satisfied in the simulation or data is not matched in real life, the simulation results could turn out to be incorrect. This study tried to provide data input based on real case information as well as Canada-based building standards, such as the BC building code and the National building code of Canada, to reduce the data uncertainty as much as possible. Fuzzy logic was also used to account for data uncertainty. This research mainly assumed triangular fuzzy numbers for uncertain data. Even though representing data using fuzzy numbers is the more reliable method (as opposed to crisp values), there is still a degree of uncertainty associated with it. This uncertainty could be minimized by using more reliable data and consulting experts with substantial experience. The above aspects were considered to be beyond the scope of this research. Limited to only single-family residential buildings: The study is limited to single-family residential building case studies, where only single-family residential building structures, material types, and operational emission styles were summarized. However, the residential building structures and material types in Canada are similar among single-family and multiple-family residential buildings. Therefore, the proposed WBLCA method can also be applied to multiple-family residential buildings as long as building information is available. While the developed tools can also be adapted to commercial and industrial building emission planning applications, further work needs to be conducted in data collection and LCA/LCC process design for the above contexts. The proposed WBLCA method and the design improvement framework can be easily adapted by revising the goal and scope details, updating building layout and detail setup for LCI, as well as matching associated operational performance inputs. The functional equivalent needs to be clearly defined in commercial and industrial buildings due to a variety of functions among buildings. Limited to only environmental and cost performance of buildings: In order to design the best residential building, it might not be enough to consider only the environmental and economic impacts. It would be appropriate if city planners also used designs to assess green buildings by considering the building owner’s perspective. Even if a building design achieves the best environmental performance with the least LCC, it still might not be the most favourable option in 140 terms of social impacts. Therefore, the life cycle sustainability assessment, which focuses on environmental, economic, and social impacts, should be considered in future studies. However, with the complexity of building-level LCA, this study focused on providing a comprehensive and systematic assessment method for residential buildings with enough focus on environment and cost. The social life cycle cost could be assessed when community- or neighbourhood-level building design and planning are needed, which can be done as future studies. Based on best available technologies: The developed decision frameworks only consider the best available technologies. However, radical changes may occur in the building sector, changing the current status drastically. An example is the integration of technology and digital construction into residential buildings. The environmental and economic assessment method presented in this study incorporated the most current material selections and most advanced building design technologies, in addition to existing mature technologies. Moreover, the developed design improvement framework can accommodate design revolutions in terms of environmental performance, making them more applicable for dynamic, low-emission building design and planning. Future Research Further research areas were identified as potential extensions of this research. Life cycle sustainability assessment: The current practice in the building design industry focuses heavily on operational energy use, and there is a trend to start looking at operational and embodied energy use together to avoid shifting the environmental burden from one stage to another. However, there are some concerns about the comfort of residential buildings with optimal operational performance. Limited studies have focused on the overall performance of buildings from a social/health impact perspective. Therefore, it is vital to measure building performance in terms of environmental, economic, and social impacts to achieve the most sustainable buildings. Life cycle assessment of new technology applications in the building sector: With the involvement of technology in the building sector, and new building concepts such as smart buildings, digital fabrications, and 3D printings, it is important to monitor the environmental impacts of new technology applications compared to conventional building designs. There is still limited focus on this direction, so future research should focus on the impacts of these new technologies on embodied emission, construction efficiencies and emissions, operational and maintenance impacts, and potential impacts of new technology disposal. 141 Impact of climate change: The increase in atmospheric temperature due to global warming has adversely affected energy performance, indoor air quality, thermal comfort, and sustainability of commercial buildings. Current and future buildings should be capable of adapting to changes in local climatic conditions throughout the building’s service life. It is predicted that more cooling and less heating will be required in the future. As an example, a study in Australia identified that from 2020-2080, building energy consumption will change from -0.6% to 8.3%, and cooling equipment capacity should be increased by 9.1% to 25% due to climate change. Hence, more accurate weather data considering future patterns can be an important determinant in future building designs. Future research should focus on the aforementioned focus areas. Behavioural considerations: Limited studies have focused on the rebound effect of energy consumption due to a reduction in energy cost. An increase in energy demand could trade off the benefits of energy cost reduction. Therefore, it is vital to look at the potential of human actions to improve or diminish the environmental impacts of residential buildings. Further research should focus on examining, experimenting with , and optimizing different environmental and economic performance strategies and occupancy interventions for residential buildings, as well as commercial and industrial buildings. Health Product Declaration (HPD) with EPD: HPD is a disclosure statement of potential chemicals of concern in products by comparing product ingredients to a set of priority “hazard” lists. HPD provides accurate, reliable and consistent reporting of health associated information about building materials. Besides the detailed environmental information at the building level, the health information of the building materials that are directly related to the occupants’ living condition should be considered together with EPD to ensure the improvement on environmental performance won’t compromise the human health. WBLCA in Community Planning: The application of WBLCA in support of new building design and existing building renovation to improve the environmental performance were evaluated in this study. In the future, WBLCA could be used by city planners for community planning. WBLCA could support city planners to issue policies to regulate consulting industry to develop environmental-friendly buildings. At the same time, WBLCA method could also be used by community planners to provide incentives and issue policies to encourage the most necessary and affordable renovation strategies. 142 References [1] Natural Resources Canada. Sustainable Development Strategy 2007- 2009 2013. [2] Yale University. 2020 Environmental Performance Index 2020. https://epi.yale.edu/epi-results/2020/component/epi (accessed June 22, 2020). [3] David Suzuki Foundation. The Maple Leaf in the OECD: canada`s Environmental Performance 2010. [4] Environmental Canada. Planning for a Sustainable Future: A Federal Sustainable Development Strategy for Canada 2013–2016 2013. http://publications.gc.ca/collections/collection_2013/ec/En4-136-2013-eng.pdf. [5] Government of Canada. National and Provincial/Territorial Greenhouse Gas Emission Tables. Canada Energy Regul 2017. https://www.cer-rec.gc.ca/nrg/sttstc/lctrct/rprt/2016cndrnwblpwr/prvnc/bc-eng.html (accessed September 25, 2019). [6] Munson J. Canada will miss 2020 climate target, says environment commissioner 2017. [7] Environmental Canada. National Inventory Report 1990-2013 2015. http://publications.gc.ca/collections/collection_2016/eccc/En81-4-2013-1-eng.pdf (accessed October 16, 2017). [8] Industry Canada. Buildings. Corp Soc Responsib 2011. [9] Kumar P, Skouloudis AN, Bell M, Viana M, Carotta MC, Biskos G, et al. Real-time sensors for indoor air monitoring and challenges ahead in deploying them to urban buildings. Sci Total Environ 2016;560–561:150–9. doi:10.1016/j.scitotenv.2016.04.032. [10] National Energy Board of Canada. Canada’s Energy Future 2016: Province and Territory Outlooks. 2016. doi:ISSN 2369-1479. [11] Najjar M, Figueiredo K, Hammad AWA, Haddad A. Integrated optimization with building information modeling and life cycle assessment for generating energy efficient buildings. Appl Energy 2019. doi:10.1016/j.apenergy.2019.05.101. [12] Belussi L, Barozzi B, Bellazzi A, Danza L, Devitofrancesco A, Fanciulli C, et al. A review of performance of zero energy buildings and energy efficiency solutions. J Build Eng 2019. doi:10.1016/j.jobe.2019.100772. 143 [13] Shan M, Hwang B gang. Green building rating systems: Global reviews of practices and research efforts. Sustain Cities Soc 2018. doi:10.1016/j.scs.2018.02.034. [14] Al-Ghamdi SG, Bilec MM. Life-cycle thinking and the LEED rating system: Global perspective on building energy use and environmental impacts. Environ Sci Technol 2015;49:4048–56. doi:10.1021/es505938u. [15] Scofield JH. Do LEED-certified buildings save energy? Not really... Energy Build 2009;41:1386–90. doi:10.1016/j.enbuild.2009.08.006. [16] Nwodo MN, Anumba CJ. A review of life cycle assessment of buildings using a systematic approach. Build Environ 2019:106290. doi:10.1016/j.buildenv.2019.106290. [17] Hoxha E, Habert G, Lasvaux S, Chevalier J, Le Roy R. Influence of construction material uncertainties on residential building LCA reliability. J Clean Prod 2017. doi:10.1016/j.jclepro.2016.12.068. [18] Weißenberger M, Jensch W, Lang W. The convergence of life cycle assessment and nearly zero-energy buildings: The case of Germany. Energy Build 2014;76:551–7. doi:10.1016/j.enbuild.2014.03.028. [19] Kylili A, Ilic M, Fokaides PA. Whole-building Life Cycle Assessment (LCA) of a passive house of the sub-tropical climatic zone. Resour Conserv Recycl 2017;116:169–77. doi:10.1016/j.resconrec.2016.10.010. [20] Khasreen MM, Banfill PFG, Menzies GF. Life-cycle assessment and the environmental impact of buildings: A review. Sustainability 2009;1:674–701. doi:10.3390/su1030674. [21] Abd Rashid AF, Yusoff S. A review of life cycle assessment method for building industry. Renew Sustain Energy Rev 2015;45:244–8. doi:10.1016/j.rser.2015.01.043. [22] Natural Resources Canada. Residential Housing Stock and Floor Space 2019. [23] Dixit MK. Life cycle embodied energy analysis of residential buildings: A review of literature to investigate embodied energy parameters. Renew Sustain Energy Rev 2017;79:390–413. doi:10.1016/j.rser.2017.05.051. [24] Iyer-Raniga U, Wong JPC. Evaluation of whole life cycle assessment for heritage buildings in Australia. Build Environ 2012;47:138–49. doi:10.1016/j.buildenv.2011.08.001. 144 [25] Feng H, Liyanage DR, Karunathilake H, Sadiq R, Hewage K. BIM-based life cycle environmental performance assessment of single-family houses: Renovation and reconstruction strategies for aging building stock in British Columbia. J Clean Prod 2020. doi:10.1016/j.jclepro.2019.119543. [26] Hélias A, Esnouf A, Finkbeiner M. Consistent normalization approach for Life Cycle Assessment based on inventory databases. Sci Total Environ 2020;703. doi:10.1016/j.scitotenv.2019.134583. [27] Pizzol M, Laurent A, Sala S, Weidema B, Verones F, Koffler C. Normalisation and weighting in life cycle assessment: quo vadis? Int J LIFE CYCLE Assess 2017;22:853–66. doi:10.1007/s11367-016-1199-1. [28] Ibn-Mohammed T, Greenough R, Taylor S, Ozawa-Meida L, Acquaye A. Operational vs. embodied emissions in buildings - A review of current trends. Energy Build 2013. doi:10.1016/j.enbuild.2013.07.026. [29] Beerepoot M. Energy policy instruments and technical change in the residential building sector. Delft University Press; 2007. [30] Bruce-Hyrkäs T, Pasanen P, Castro R. Overview of Whole Building Life-Cycle Assessment for Green Building Certification and Ecodesign through Industry Surveys and Interviews. 25th CIRP Conf. Life Cycle Eng. , CIRP LCE 2018, 2018. doi:10.1016/j.procir.2017.11.127. [31] Ingrao C, Messineo A, Beltramo R, Yigitcanlar T, Ioppolo G. How can life cycle thinking support sustainability of buildings? Investigating life cycle assessment applications for energy efficiency and environmental performance. J Clean Prod 2018;201:556–69. doi:10.1016/j.jclepro.2018.08.080. [32] Chau CK, Leung TM, Ng WY. A review on Life Cycle Assessment , Life Cycle Energy Assessment and Life Cycle Carbon Emissions Assessment on buildings 2015;143:395–413. doi:10.1016/j.apenergy.2015.01.023. [33] Bayraktar ME, Owens CR. LEED implementation guide for construction practitioners. J Archit Eng 2010;16:85–93. [34] Negishi K, Tiruta-Barna L, Schiopu N, Lebert A, Chevalier J. An operational 145 methodology for applying dynamic Life Cycle Assessment to buildings. Build Environ 2018;144:611–21. doi:10.1016/j.buildenv.2018.09.005. [35] Al-Ghamdi SG, Bilec MM. Green Building Rating Systems and Whole-Building Life Cycle Assessment: Comparative Study of the Existing Assessment Tools. J Archit Eng 2017;23:04016015. doi:10.1061/(ASCE)AE.1943-5568.0000222. [36] Zabalza Bribián I, Aranda Usón A, Scarpellini S. Life cycle assessment in buildings: State-of-the-art and simplified LCA methodology as a complement for building certification. Build Environ 2009;44:2510–20. doi:10.1016/j.buildenv.2009.05.001. [37] Kristjansdottir TF, Heeren N, Andresen I, Brattebø H. Comparative emission analysis of low-energy and zero-emission buildings. Build Res Inf 2018. doi:10.1080/09613218.2017.1305690. [38] Atmaca A, Atmaca N. Life cycle energy (LCEA) and carbon dioxide emissions (LCCO<inf>2</inf>A) assessment of two residential buildings in Gaziantep, Turkey. Energy Build 2015;102:417–31. doi:10.1016/j.enbuild.2015.06.008. [39] Evangelista PPA, Kiperstok A, Torres EA, Gonçalves JP. Environmental performance analysis of residential buildings in Brazil using life cycle assessment (LCA). Constr Build Mater 2018;169:748–61. doi:10.1016/j.conbuildmat.2018.02.045. [40] Wang J, Yu C, Pan W. Life cycle energy of high-rise office buildings in Hong Kong. Energy Build 2018;167:152–64. doi:10.1016/j.enbuild.2018.02.038. [41] Häfliger IF, John V, Passer A, Lasvaux S, Hoxha E, Saade MRM, et al. Buildings environmental impacts’ sensitivity related to LCA modelling choices of construction materials. J Clean Prod 2017;156:805–16. doi:10.1016/j.jclepro.2017.04.052. [42] Oregi X, Hernandez P, Hernandez R. Analysis of life-cycle boundaries for environmental and economic assessment of building energy refurbishment projects. Energy Build 2017;136:12–25. doi:10.1016/j.enbuild.2016.11.057. [43] Citherlet S, Defaux T. Energy and environmental comparison of three variants of a family house during its whole life span. Build Environ 2007;42:591–8. doi:10.1016/j.buildenv.2005.09.025. [44] Rauf A, Crawford RH. Building service life and its effect on the life cycle embodied 146 energy of buildings. Energy 2015;79:140–8. doi:10.1016/j.energy.2014.10.093. [45] Skullestad JL, Bohne RA, Lohne J. High-rise Timber Buildings as a Climate Change Mitigation Measure - A Comparative LCA of Structural System Alternatives. Energy Procedia 2016;96:112–23. doi:10.1016/j.egypro.2016.09.112. [46] Chastas P, Theodosiou T, Kontoleon KJ, Bikas D. Normalising and assessing carbon emissions in the building sector: A review on the embodied CO2emissions of residential buildings. Build Environ 2018;130:212–26. [47] Chastas P, Theodosiou T, Kontoleon KJ, Bikas D. The effect of embodied impact on the cost-optimal levels of nearly zero energy buildings: A case study of a residential building in Thessaloniki, Greece. Energies 2017;10. doi:10.3390/en10060740. [48] Thiel CL, Campion N, Landis AE, Jones AK, Schaefer LA, Bilec MM. A materials life cycle assessment of a net-zero energy building. Energies 2013;6:1125–41. doi:10.3390/en6021125. [49] Cuéllar-Franca RM, Azapagic A. Environmental impacts of the UK residential sector: Life cycle assessment of houses. Build Environ 2012;54:86–99. doi:10.1016/j.buildenv.2012.02.005. [50] Asdrubali F, Baldassarri C, Fthenakis V. Life cycle analysis in the construction sector: Guiding the optimization of conventional Italian buildings. Energy Build 2013;64:73–89. doi:10.1016/j.enbuild.2013.04.018. [51] Proietti S, Sdringola P, Desideri U, Zepparelli F, Masciarelli F, Castellani F. Life Cycle Assessment of a passive house in a seismic temperate zone. Energy Build 2013;64:463–72. doi:10.1016/j.enbuild.2013.05.013. [52] Karami P, Al-Ayish N, Gudmundsson K. A comparative study of the environmental impact of Swedish residential buildings with vacuum insulation panels. Energy Build 2015. doi:10.1016/j.enbuild.2015.10.031. [53] Bastos J, Batterman SA, Freire F. Life-cycle energy and greenhouse gas analysis of three building types in a residential area in Lisbon. Energy Build 2014. doi:10.1016/j.enbuild.2013.11.010. [54] Wan Omar WMS. A hybrid life cycle assessment of embodied energy and carbon 147 emissions from conventional and industrialised building systems in Malaysia. Energy Build 2018. doi:10.1016/j.enbuild.2018.02.045. [55] Wu X, Peng B, Lin B. A dynamic life cycle carbon emission assessment on green and non-green buildings in China. Energy Build 2017. doi:10.1016/j.enbuild.2017.05.041. [56] Gómez de Cózar JC, Martínez AG, López ÍA, Alfonsea MR. Life cycle assessment as a decision-making tool for selecting building systems in heritage intervention: Case study of Roman Theatre in Itálica, Spain. J Clean Prod 2018. doi:10.1016/j.jclepro.2018.09.169. [57] Tulevech SM, Hage DJ, Jorgensen SK, Guensler CL, Himmler R, Gheewala SH. Life cycle assessment: a multi-scenario case study of a low-energy industrial building in Thailand. Energy Build 2018;168:191–200. doi:10.1016/j.enbuild.2018.03.011. [58] Wrålsen B, O’Born R, Skaar C. Life cycle assessment of an ambitious renovation of a Norwegian apartment building to nZEB standard. Energy Build 2018. doi:10.1016/j.enbuild.2018.07.036. [59] ISO14024. Envrionmental labels and declarations - Type I environmental labelling - Principles and procedures. Int Organ Stand 1999. [60] ISO14021. Environmental labels and declarations - Self-declared environmental claims (Type II environmental labelling). Int Organ Stand 1999. [61] ISO14025. Environmental labels and declarations - Type III environmetal declarations - Principles and procedures. Int Organ Stand 2006. [62] Braune A, Merl A, Kreißig J, Kieselbach S. Environmental Product Declarations: How Transparent, Rigor and Useful are the Facts and Figures? Cent Eur Towar Sustain Build 2013" Sustain Build Refurb Next Gener 2013:1–4. doi:ISBN 978-80-247-5018-7. [63] UNSD. CPC Ver.2 Detailed structure and correspondences of CPC Ver.2 subclasses to ISIC Rev.4 and HS 2007 2008. [64] Gelowitz MDC, McArthur JJ. Investigating the Effect of Environmental Product Declaration Adoption in LEED® on the Construction Industry: A Case Study. Procedia Eng 2016;145:58–65. doi:10.1016/j.proeng.2016.04.014. [65] Strazza C, Borghi A Del, Blengini GA, Gallo M. Definition of the methodology for a Sector EPD (Environmental Product Declaration): Case study of the average Italian 148 cement. Int J Life Cycle Assess 2010;15:540–8. doi:10.1007/s11367-010-0198-x. [66] Allison C, Carter A. Study on different types of Environmental Labelling (ISO Type II and III Labels): Proposal for an Environmental Labelling Strategy 2000. [67] Bovea MD, Ibáñez-Forés V, Agustí-Juan I. Environmental product declaration (EPD) labelling of construction and building materials. Eco-Efficient Constr Build Mater Life Cycle Assess (LCA), Eco-Labelling Case Stud 2014:125–50. doi:10.1533/9780857097729.1.125. [68] ISO21930. Sustainability in building construction - Environmental declaration of building products. Int Organ Stand 2007. doi:10.1109/IEEESTD.2007.4288250. [69] Pacheco-Torgal F, Cabeza LF, Labrincha J, de Magalhaes A. Eco-efficient construction and building materials: Life cycle assessment (LCA), eco-labelling and case studies. 2013. [70] CEN. Product Category Rule for Type III environmental productc declaration of construction products to EN 15804. Eur Comm Stand 2013:1–43. [71] Achenbach H, Diederichs SK, Wenker JL, Rüter S. Environmental product declarations in accordance with EN 15804 and EN 16485 — How to account for primary energy of secondary resources? Environ Impact Assess Rev 2016;60:134–8. doi:10.1016/j.eiar.2016.04.004. [72] IBU. What is the ECO Platform? Inst Bau Und Umwelt eV 2016. http://ibu-epd.com/en/faq-items/what-is-the-eco-platform/ (accessed February 28, 2017). [73] ECOPlatform. The ECO Platform EPD 2014. http://www.eco-platform.org/eco-epd-40.html (accessed February 28, 2017). [74] Gelet JL, Gauchon J. Facing global-warming, manufacturers are invited to think to eco-design. Environmental product declaration also concerns fuses. 8th Int. Conf. Electr. Fuses their Appl. ICEFA, 2007, p. 197–205. doi:10.1109/ICEFA.2007.4419987. [75] Bogeskär M, Carter A, Nevén C-O, Nuij R, Schmincke E, Stranddorf HK. Evaluation of Environmental Product Declaration Schemes. J Environ Eng Sci 2002;1:119. doi:10.1139/s02-035. [76] Ibáñez-Forés V, Pacheco-Blanco B, Capuz-Rizo SF, Bovea MD. Environmental Product Declarations: Exploring their evolution and the factors affecting their demand in Europe. J 149 Clean Prod 2016;116:157–69. doi:10.1016/j.jclepro.2015.12.078. [77] Hunsager EA, Bach M, Breuer L. An institutional analysis of EPD programs and a global PCR registry. Int J Life Cycle Assess 2014;19:786–95. doi:10.1007/s11367-014-0711-8. [78] Bergman R, Taylor A. Epd-Environmental: Product Declarations for Wood Products—an Application of Life Cycle Information About Forest Products. For Prod J 2011;61:192–201. doi:10.13073/0015-7473-61.3.192. [79] Passer A, Lasvaux S, Allacker K, De Lathauwer D, Spirinckx C, Wittstock B, et al. Environmental product declarations entering the building sector: critical reflections based on 5 to 10 years experience in different European countries. Int J Life Cycle Assess 2015;20:1199–212. doi:10.1007/s11367-015-0926-3. [80] INIES. Environmental and health reference data for building 2017. http://www.inies.fr/home/ (accessed March 6, 2017). [81] METL. de décoration et des équipements électriques, électroniques et de génie climatique destinés à un usage dans les ouvrages de bâtiment. Site Réglementaire Des Déclarations Environnementales Des Prod Constr 2017. http://www.declaration-environnementale.gouv.fr/ (accessed March 6, 2017). [82] JEMAI. EcoLeaf Environmental Label. Japan Environ Manag Assoc Ind 2012. http://www.ecoleaf-jemai.jp/eng/ (accessed March 6, 2020). [83] KEITA. Environmental Declaration of Products. Korea Environ Ind Technol Institue 2008. [84] AustralasiaEPD. The Australasian EPD Programme 2017. http://www.epd-australasia.com/using-epds (accessed March 6, 2017). [85] Layne Evans. Wood and Environmental Product Declarations 2011:1–32. [86] FPInovations. 2015-2016 Annual Report 2017. https://web.fpinnovations.ca/wp-content/uploads/2015-2016-annual-report.pdf (accessed April 12, 2020). [87] Minkov N, Schneider L, Lehmann A, Finkbeiner M. Type III Environmental Declaration Programmes and harmonization of product category rules: Status quo and practical challenges. J Clean Prod 2015;94:236–46. doi:10.1016/j.jclepro.2015.02.012. [88] Almeida MI, Dias AC, Demertzi M, Arroja L. Contribution to the development of product 150 category rules for ceramic bricks. J Clean Prod 2015;92:206–15. doi:10.1016/j.jclepro.2014.12.073. [89] UL Environment. EPD Development Process 2017. http://industries.ul.com/environment/transparency/epd-development-process (accessed March 8, 2017). [90] The International EPD System. Five Steps to create an EPD 2017. http://www.environdec.com/en/Creating-EPD/Five-steps-to-EPD/ (accessed March 8, 2017). [91] Subramanian V, Koffler C, Imbeault-Tétreault H, Mahelle L. Guidance for Product Category Rule Development. Prod Categ Rule Guid Dev Initiat 2013. doi:10.13140/2.1.3007.1844. [92] BSI EN 15804. BS EN 15804:2012 - Standards Publication Sustainability of construction works — Environmental product declarations — Core rules for the product category of construction products. Int Stand 2014:70. [93] Lasvaux S, Gantner J, Wittstock B, Bazzana M, Schiopu N, Saunders T, et al. Achieving consistency in life cycle assessment practice within the European construction sector: the role of the EeBGuide InfoHub. Int J Life Cycle Assess 2014;19:1783–93. doi:10.1007/s11367-014-0786-2. [94] Architecture 2030. The 2030 Challenge For Products 2017. http://architecture2030.org/2030_challenges/products/ (accessed March 6, 2017). [95] Architecture 2030. 2030 Challenge for Products: Critical Points 2011:5. https://architecture2030.org/2030_challenges/embodied/products_adopters_supporters/ (accessed April 12, 2020). [96] Ingwersen WW, Subramanian V. Guidance for product category rule development: process, outcome, and next steps. Int J Life Cycle Assess 2013;19:532–7. doi:10.1007/s11367-013-0659-0. [97] USGBC. LEED v 4 for Building Design and Construction. US Green Build Counc 2014. [98] GreenGlobes. Green Globes: Design for New Buildings. ECD Energy Environ Canada Ltd 2004. 151 [99] Building Research Establishment Ltd. BREEAM for Communities Technical Guidance Manual. BREEAM Website 2011. [100] BRE. BREEAM New Construction:Non-Domestic Buildings 2018. https://www.breeam.com/NC2018/content/resources/output/10_pdf/a4_pdf/print/nc_uk_a4_print_mono/nc_uk_a4_print_mono.pdf (accessed April 12, 2020). [101] HQE. Référent Certification HQETM 2016. http://www.behqe.com/schemes-and-documents (accessed March 7, 2017). [102] SGBC. Miljöbyggnad. Sweden Green Build Counc 2016. https://www.sgbc.se/var-verksamhet/miljoebyggnad (accessed March 7, 2017). [103] GBCA. Life Cycle Assessment in Green Star. Green Build Counc Aust 2015. http://new.gbca.org.au/life-cycle-assessment-lca-and-environmental-product-declarations-epd/ (accessed March 7, 2017). [104] Fuller SK, Petersen SR. LCCosting Manual for the Federal Energy Management Program. NIST Handb 135 1996. doi:10.1108/eb006413. [105] Dara C, Hachem-Vermette C, Assefa G. Life cycle assessment and life cycle costing of container-based single-family housing in Canada: A case study. Build Environ 2019. doi:10.1016/j.buildenv.2019.106332. [106] Ahmed IM, Tsavdaridis KD. Life cycle assessment (LCA) and cost (LCC) studies of lightweight composite flooring systems. J Build Eng 2018. doi:10.1016/j.jobe.2018.09.013. [107] ISO 15686-5. ISO 15686-5. Int Stand Build Constr Assets-Service Life Planning Part 5 Life Cycle Costing 2008. [108] Berardi U. Sustainable Construction: Green Building Design and Delivery. Intell Build Int 2013. doi:10.1080/17508975.2012.756388. [109] Sharif SA, Hammad A. Simulation-Based Multi-Objective Optimization of institutional building renovation considering energy consumption, Life-Cycle Cost and Life-Cycle Assessment. J Build Eng 2019. doi:10.1016/j.jobe.2018.11.006. [110] Luerssen C, Gandhi O, Reindl T, Sekhar C, Cheong D. Life cycle cost analysis (LCCA) of PV-powered cooling systems with thermal energy and battery storage for off-grid 152 applications. Appl Energy 2020. doi:10.1016/j.apenergy.2020.115145. [111] Islam H, Jollands M, Setunge S, Ahmed I, Haque N. Life cycle assessment and life cycle cost implications of wall assemblages designs. Energy Build 2014. doi:10.1016/j.enbuild.2014.07.041. [112] Kneifel J. Life-cycle carbon and cost analysis of energy efficiency measures in new commercial buildings. Energy Build 2010;42:333–40. doi:10.1016/j.enbuild.2009.09.011. [113] Ristimäki M, Säynäjoki A, Heinonen J, Junnila S. Combining life cycle costing and life cycle assessment for an analysis of a new residential district energy system design. Energy 2013;63:168–79. doi:10.1016/j.energy.2013.10.030. [114] Marzouk M, Azab S, Metawie M. BIM-based approach for optimizing life cycle costs of sustainable buildings. J Clean Prod 2018. doi:10.1016/j.jclepro.2018.03.280. [115] Santos R, Costa AA, Silvestre JD, Pyl L. Integration of LCA and LCC analysis within a BIM-based environment. Autom Constr 2019. doi:10.1016/j.autcon.2019.02.011. [116] Santos R, Costa AA, Silvestre JD, Pyl L. Informetric analysis and review of literature on the role of BIM in sustainable construction. Autom Constr 2019. doi:10.1016/j.autcon.2019.02.022. [117] Soust-Verdaguer B, Llatas C, García-Martínez A. Critical review of bim-based LCA method to buildings. Energy Build 2017. doi:10.1016/j.enbuild.2016.12.009. [118] Santos R, Costa AA, Silvestre JD, Vandenbergh T, Pyl L. BIM-based life cycle assessment and life cycle costing of an office building in Western Europe. Build Environ 2020. doi:10.1016/j.buildenv.2019.106568. [119] Wang E, Shen Z, Berryman C. A Building LCA Case Study Using Autodesk Ecotect and BIM Model. ASC Annu Int Conf Proc 2011. [120] Basbagill J, Flager F, Lepech M, Fischer M. Application of life-cycle assessment to early stage building design for reduced embodied environmental impacts. Build Environ 2013. doi:10.1016/j.buildenv.2012.11.009. [121] Jalaei F, Jrade A. An Automated BIM Model to Conceptually Design, Analyze, Simulate, and Assess Sustainable Building Projects. J Constr Eng 2014. doi:10.1155/2014/672896. [122] Jrade A, Abdulla R. Integrating Building Information Modeling and Life Cycle 153 Assessment Tools to Design Sustainable Buildings. Proc 29th Int Conf CIB W78 2012. [123] Jrade A, Jalaei F. Integrating building information modelling with sustainability to design building projects at the conceptual stage. Build Simul 2013. doi:10.1007/s12273-013-0120-0. [124] Oti AH, Tizani W. BIM extension for the sustainability appraisal of conceptual steel design. Adv Eng Informatics 2015. doi:10.1016/j.aei.2014.09.001. [125] Shin YS, Cho K. BIM application to select appropriate design alternative with consideration of LCA and LCCA. Math Probl Eng 2015. doi:10.1155/2015/281640. [126] Kreiner H, Passer A, Wallbaum H. A new systemic approach to improve the sustainability performance of office buildings in the early design stage. Energy Build 2015. doi:10.1016/j.enbuild.2015.09.040. [127] Liu S, Meng X, Tam C. Building information modeling based building design optimization for sustainability. Energy Build 2015;105:139–53. doi:10.1016/j.enbuild.2015.06.037. [128] Yung P, Wang X. A 6D CAD model for the automatic assessment of building sustainability. Int J Adv Robot Syst 2014. doi:10.5772/58446. [129] Antón LÁ, Díaz J. Integration of life cycle assessment in a BIM environment. Procedia Eng., 2014. doi:10.1016/j.proeng.2014.10.525. [130] Díaz J, Antön LÁ. Sustainable construction approach through integration of LCA and BIM tools. Comput. Civ. Build. Eng. - Proc. 2014 Int. Conf. Comput. Civ. Build. Eng., 2014. doi:10.1061/9780784413616.036. [131] Braune A, Kreissig J, Sedlbauer K, Braganca L, Pinheiro M, Jalali S, et al. The Use of EPDs in Building Assessment - Towards the complete picture. Port Sb07 - Sustain Constr Mater Pract Chall Ind New Millenn Pts 1 2 2007:299–304. [132] Hong T, Wang Z, Luo X, Zhang W. State-of-the-art on research and applications of machine learning in the building life cycle. Energy Build 2020;212:109831. doi:10.1016/j.enbuild.2020.109831. [133] Barlish K, Sullivan K. How to measure the benefits of BIM - A case study approach. Autom Constr 2012. doi:10.1016/j.autcon.2012.02.008. 154 [134] Bryde D, Broquetas M, Volm JM. The project benefits of building information modelling (BIM). Int J Proj Manag 2013. doi:10.1016/j.ijproman.2012.12.001. [135] CEN. EN 15978: 2011 Sustainability of construction works - Assessment of environmental performance of buildings - Calculation method. 2011. [136] ISO14044. Environmental management — Life cycle assessment — Requirements and guidelines. Int Stand 2006:1–8. https://www.iso.org/standard/38498.html (accessed April 12, 2020). [137] CSI. A Uniform Classification of Construction Systems and Assemblies 2010. https://graphisoft.akamaized.net/cdn/ftp/techsupport/downloads/interoperability/UniFormat_2010m.pdf (accessed April 12, 2020). [138] CSI. A Uniform Classification of Construction Systems and Assemblies 2010. [139] Guldbrandsson F, Bergmark P. Opportunities and limitations of using life cycle assessment methodology in the ICT sector. Electron. Goes Green 2012+ (EGG), 2012, 2012. [140] Langdon D. Life Cycle Costing (LCC) as a contribution to sustainable construction: a common methodology 2007. file:///Users/haibofeng/Desktop/Report-LCC-sustainable-construction-methodology-May2007_en.pdf (accessed July 23, 2020). [141] Campos-Guzmán V, García-Cáscales MS, Espinosa N, Urbina A. Life Cycle Analysis with Multi-Criteria Decision Making: A review of approaches for the sustainability evaluation of renewable energy technologies. Renew Sustain Energy Rev 2019. doi:10.1016/j.rser.2019.01.031. [142] Norris GA. The requirement for congruence in normalization. Int J Life Cycle Assess 2001. doi:10.1007/BF02977843. [143] Shih H-S, Shyur H-J, Lee ES. An extension of TOPSIS for group decision making. Math Comput Model 2007;45:801–13. doi:10.1016/j.mcm.2006.03.023. [144] Roszkowska E. Multi-Criteria Decision Making Models By Applying the Topsis Method To Crisp and Interval Data. Mult Criteria Decis Making/University Econ Katowice 2011. [145] García-Cascales MS, Lamata MT. On rank reversal and TOPSIS method. Math Comput Model 2012;56:123–32. doi:10.1016/j.mcm.2011.12.022. 155 [146] Kahraman C. Fuzzy Multi-Criteria Decision Making. vol. 16. Boston, MA: Springer US; 2008. doi:10.1007/978-0-387-76813-7. [147] Firth P. Environmental Product Declarations. Environ Des Constr 2012:33–9. [148] Athena. LCA and EPD Reports. Athena Sustain Mater Inst 2012. http://www.athenasmi.org/resources/publications/ (accessed April 12, 2020). [149] Natural Resources Canada. HOT2000 for general use 2019. https://www.nrcan.gc.ca/energy-efficiency/energy-efficiency-homes/professional-opportunities/tools-industry-professionals/20596?_ga=2.177181798.237070956.1574995829-1906128209.1574995829#general (accessed November 28, 2019). [150] Government of Canada. Residential water use 2017. https://www.canada.ca/en/environment-climate-change/services/environmental-indicators/residential-water-use.html (accessed November 28, 2019). [151] Kuikka S. LCA of the Demolition of a Building-An assessment conducted at IVL Swedish Environmental Research Institute 2012. [152] PRé. SimaPro Database Manual Methods Library 2018. https://simapro.com/wp-content/uploads/2019/02/DatabaseManualMethods.pdf. [153] Ontario Teachers’ Pension Plan. Discount Rate 2020. https://www.otpp.com/corporate/plan-funding/funding-valuations/discount-rate (accessed October 19, 2020). [154] Gordian. Building Construction Costs with RSMeans data 2019. https://www.rsmeans.com/ (accessed July 24, 2020). [155] Canadian Trucking Alliance. Freight Recession’s Over: Analyst 2017. http://cantruck.ca/freight-recessions-over-analyst/#:~:text=The reefer rate was %242.02,the first week of June. (accessed July 24, 2020). [156] FortisBC. British Columbia Utilities Commission regulates FortisBC 2020. https://www.fortisbc.com/about-us/regulatory-affairs (accessed July 24, 2020). [157] BC Hydro. BC Hydro residential rates 2019. https://app.bchydro.com/accounts-billing/rates-energy-use/electricity-rates/residential-rates.html (accessed June 10, 2019). 156 [158] City of Kelowna. Landfill tipping fees and rates 2020. https://www.kelowna.ca/city-services/waste/glenmore-landfill/tipping-fees-or-rates (accessed July 24, 2020). [159] Vishwakarma V, Ramachandran D. Green Concrete mix using solid waste and nanoparticles as alternatives – A review. Constr Build Mater 2018. doi:10.1016/j.conbuildmat.2017.11.174. [160] Liew KM, Sojobi AO, Zhang LW. Green concrete: Prospects and challenges. Constr Build Mater 2017;156:1063–95. doi:10.1016/j.conbuildmat.2017.09.008. [161] Alzetto F, Pandraud G, Fitton R, Heusler I, Sinnesbichler H. QUB: A fast dynamic method for in-situ measurement of the whole building heat loss. Energy Build 2018. doi:10.1016/j.enbuild.2018.06.002. [162] Canadian choice windows and doors. Double pane or triple pane windows 2020. https://www.windowscanada.com/whitepages/double-pane-or-triple-pane-windows.html#:~:text=How does this compare to,t include the installation costs. (accessed July 28, 2020). [163] Cavalliere C, Hollberg A, Dell’Osso GR, Habert G. Consistent BIM-led LCA during the entire building design process. IOP Conf Ser Earth Environ Sci 2019;323. doi:10.1088/1755-1315/323/1/012099. [164] Gomes V, Barros NN, Ruschel RC. Building Information Modelling for Whole-Building LCA: BIM4LCA. IOP Conf Ser Earth Environ Sci 2019;290. doi:10.1088/1755-1315/290/1/012044. [165] Hollberg A, Genova G, Habert G. Evaluation of BIM-based LCA results for building design. Autom Constr 2020. doi:10.1016/j.autcon.2019.102972. [166] Santos R, Costa AA, Silvestre JD, Vandenbergh T, Pyl L. BIM-based life cycle assessment and life cycle costing of an office building in Western Europe. Build Environ 2019;169:106568. doi:10.1016/j.buildenv.2019.106568. [167] Hasik V, Escott E, Bates R, Carlisle S, Faircloth B, Bilec MM. Comparative whole-building life cycle assessment of renovation and new construction. Build Environ 2019;161:106218. doi:10.1016/j.buildenv.2019.106218. [168] Pärn EA, Edwards DJ. Conceptualising the FinDD API plug-in: A study of BIM-FM 157 integration. Autom Constr 2017. doi:10.1016/j.autcon.2017.03.015. [169] Rodrigues F, Teixeira J, Matos R, Rodrigues H. Development of a web application for historical building management through BIM technology. Adv Civ Eng 2019. doi:10.1155/2019/9872736. [170] Bueno C, Fabricio MM. Comparative analysis between a complete LCA study and results from a BIM-LCA plug-in. Autom Constr 2018. doi:10.1016/j.autcon.2018.02.028. [171] Najjar M, Figueiredo K, Palumbo M, Haddad A. Integration of BIM and LCA: Evaluating the environmental impacts of building materials at an early stage of designing a typical office building. J Build Eng 2017. doi:10.1016/j.jobe.2017.10.005. [172] Röck M, Hollberg A, Habert G, Passer A. LCA and BIM: Visualization of environmental potentials in building construction at early design stages. Build Environ 2018. doi:10.1016/j.buildenv.2018.05.006. [173] FSC Canada. Why become certified? 2019. https://ca.fsc.org/en-ca/certification/why-become-certifiednbsp (accessed December 5, 2019). [174] Jang H, Jones L, Kang J. Prioritisation of old apartment buildings for energy-efficient refurbishment based on the effects of building features on energy consumption in South Korea. Energy Build 2015. doi:10.1016/j.enbuild.2015.03.027. [175] Jie P, Zhang F, Fang Z, Wang H, Zhao Y. Optimizing the insulation thickness of walls and roofs of existing buildings based on primary energy consumption, global cost and pollutant emissions. Energy 2018. doi:10.1016/j.energy.2018.06.179. [176] Ruparathna R, Hewage K, Sadiq R. Economic evaluation of building energy retrofits: A fuzzy based approach. Energy Build 2017;139:395–406. doi:10.1016/j.enbuild.2017.01.031. [177] Jensen PA, Maslesa E, Berg JB, Thuesen C. 10 questions concerning sustainable building renovation. Build Environ 2018. doi:10.1016/j.buildenv.2018.06.051. [178] Marique AF, Rossi B. Cradle-to-grave life-cycle assessment within the built environment: Comparison between the refurbishment and the complete reconstruction of an office building in Belgium. J Environ Manage 2018;224:396–405. doi:10.1016/j.jenvman.2018.02.055. 158 [179] Thibodeau C, Bataille A, Sié M. Building rehabilitation life cycle assessment methodology–state of the art. Renew Sustain Energy Rev 2019. doi:10.1016/j.rser.2018.12.037. [180] Semprini G, Gulli R, Ferrante A. Deep regeneration vs shallow renovation to achieve nearly Zero Energy in existing buildings: Energy saving and economic impact of design solutions in the housing stock of Bologna. Energy Build 2017. doi:10.1016/j.enbuild.2017.09.044. [181] Alba-Rodríguez MD, Martínez-Rocamora A, González-Vallejo P, Ferreira-Sánchez A, Marrero M. Building rehabilitation versus demolition and new construction: Economic and environmental assessment. Environ Impact Assess Rev 2017. doi:10.1016/j.eiar.2017.06.002. [182] Weiler V, Harter H, Eicker U. Life cycle assessment of buildings and city quarters comparing demolition and reconstruction with refurbishment. Energy Build 2017. doi:10.1016/j.enbuild.2016.11.004. [183] Gaspar PL, Santos AL. Embodied energy on refurbishment vs. demolition: A southern Europe case study. Energy Build 2015. doi:10.1016/j.enbuild.2014.11.040. [184] The Government of British Columbia. BC Energy Step Code 2018. [185] Bristow DN, Bristow M. Retrofitting for resiliency and sustainability of households. Can J Civ Eng 2017;44:530–8. doi:10.1139/cjce-2016-0440. [186] Gamtessa SF. An explanation of residential energy-efficiency retrofit behavior in Canada. Energy Build 2013;57:155–64. doi:10.1016/j.enbuild.2012.11.006. [187] Dong B, Kennedy C, Pressnail K. Comparing life cycle implications of building retrofit and replacement options. Can J Civ Eng 2005;32:1051–63. doi:10.1139/l05-061. [188] Kamari A, Corrao R, Kirkegaard PH. Sustainability focused decision-making in building renovation. Int J Sustain Built Environ 2017;6:330–50. doi:10.1016/j.ijsbe.2017.05.001. [189] Canadian Broadcasting Corporation (CBC). New energy efficient buildings aren’t enough, experts say — we have to retrofit the old ones, too 2019. [190] City of Vancouver. Property tax report 2019. https://opendata.vancouver.ca/explore/dataset/property-tax-159 report/table/?dataChart=eyJxdWVyaWVzIjpbeyJjb25maWciOnsiZGF0YXNldCI6InByb3BlcnR5LXRheC1yZXBvcnQiLCJvcHRpb25zIjp7InJlZmluZS56b25lX2NhdGVnb3J5IjoiT25lIEZhbWlseSBEd2VsbGluZyIsInJlZmluZS5yZXBvcnRfeWVh (accessed September 25, 2019). [191] Vancouver Heritage Foundation. Heritage Energy Retrofit Grant 2016. https://www.vancouverheritagefoundation.org/get-a-grant/heritage-energy-retrofit-grant/ (accessed September 25, 2019). [192] The Government of British Columbia. BC Building Code 2018 2018. [193] City of Vancouver. 2019 Vancouver Building Bylaw 2019. https://vancouver.ca/your-government/vancouver-building-bylaw.aspx (accessed September 27, 2019). [194] City of Vancouver. Housing design and technical guidelines. 2018. [195] City of Vancouver. Greenest City - 2020 Action Plan. City Vancouver 2012:82. [196] RDH Building Science. Costing study on passive house for single family homes in Vancouver. 2016. [197] Vancouver Heritage Foundation. Heritage Energy Retrofit Grant 2016. [198] CityGreen Solutions. City of Vancouver EnerGuide Rating System Existing Homes Data Analysis Report. 2015. [199] Natural Resources Canada. Canada’s GHG Emissions by Sector, End use and Subsector 2018. http://oee.nrcan.gc.ca/corporate/statistics/neud/dpa/showTable.cfm?type=HB&sector=aaa&juris=ca&rn=3&page=0 (accessed September 24, 2019). [200] Natural Resource Canada. Energy Fact Book 2018 - 2019. Ottawa: 2018. [201] Marini A, Passoni C, Belleri A, Feroldi F, Metelli G, Riva P, et al. Combining seismic retrofit with energy refurbishment for the sustainable renovation of RC buildings : a proof of concept. Eur J Environ Civ Eng 2017;8189:1–21. doi:10.1080/19648189.2017.1363665. [202] RDH Building Science. Costing study on passive house for single family homes in Vancouver. 2016. [203] Passive house institute. Passive House requirements 2019. 160 https://passiv.de/en/02_informations/02_passive-house-requirements/02_passive-house-requirements.htm (accessed February 12, 2019). [204] City of Vancouver. Passive House Guidelines for RS-1. 2015. [205] Mohazabieh SZ, Ghajarkhosravi M, Fung AS. Energy Consumption and Environmental Impact Assessment of the Energy Efficient Houses in Toronto, Canada. Procedia Eng 2015;118:1024–9. doi:10.1016/j.proeng.2015.08.544. [206] Natural Resources Canada. After your EnerGuide home evaluation 2017. [207] Karunathilake H, Hewage K, Brinkerhoff J, Sadiq R. Optimal renewable energy supply choices for net-zero ready buildings: A life cycle thinking approach under uncertainty. Energy Build 2019. doi:10.1016/j.enbuild.2019.07.030. [208] Athena Sustainable Material Institute. LCA and EPD Reports 2012. [209] Andersson R, Stripple H, Gustafsson T, Ljungkrantz C. Carbonation as a method to improve climate performance for cement based material. Cem Concr Res 2019;124. doi:10.1016/j.cemconres.2019.105819. [210] Skaar C, Labonnote N, Gradeci K. From Zero Emission Buildings (ZEB) to Zero Emission Neighbourhoods (ZEN): A Mapping Review of Algorithm-Based LCA. SUSTAINABILITY 2018;10. doi:10.3390/su10072405. [211] Palmieri M, Ragaglia F, Patanè S, Piana P, Ingrao C, Bertino A. Environmental product declaration as a strategy to apply bio economy in the sustainable steel sector. Procedia Environ Sci Eng Manag 2017;4:149–54. [212] Environment and Climate Change Canada. National Inventory Report 1990-2016: Greenhouse Gas Sources and Sinks in Canada. Gatineau: 2018. [213] Iddon CR, Firth SK. Embodied and operational energy for new-build housing: A case study of construction methods in the UK. Energy Build 2013;67:479–88. [214] Koezjakov A, Urge-Vorsatz D, Crijns-Graus W, van den Broek M. The relationship between operational energy demand and embodied energy in Dutch residential buildings. Energy Build 2018;165:233–45. doi:10.1016/j.enbuild.2018.01.036. [215] Upton B, Miner R, Spinney M, Heath LS. The greenhouse gas and energy impacts of using wood instead of alternatives in residential construction in the United States. 161 Biomass and Bioenergy 2008;32:1–10. doi:10.1016/j.biombioe.2007.07.001. [216] Altus Group. Canadian Cost Guide. Toronto: 2017. [217] BC Hydro. Residential Rates 2019. [218] Statistics Canada. Households and the Environment: Energy Use. Ottawa: 2011. doi:ISSN 1920-7522. [219] Tecchio P, Gregory J, Olivetti E, Ghattas R, Kirchain R. Streamlining the Life Cycle Assessment of Buildings by Structured Under-Specification and Probabilistic Triage. J Ind Ecol 2019;23:268–79. doi:10.1111/jiec.12731. [220] Goedkoop M, Oele M, Leijting J, Ponsioen T, Meijer E. Introduction to LCA with SimaPro. San Francisco: 2016. [221] Ciroth A, Winter S, Berlin G. openLCA 1 . 4 overview and first steps. GreenDelta Berlin 2014. [222] Rivera SS, Baziuk PA, NúñezMcLeod JE. Fuzzy uncertainties in human reliability analysis. Proc. World Congr. Eng. 2011, WCE 2011, 2011. [223] Konstandinidou M, Nivolianitou Z, Kiranoudis C, Markatos N. A fuzzy modeling application of CREAM methodology for human reliability analysis. Reliab Eng Syst Saf 2006. doi:10.1016/j.ress.2005.06.002. [224] Zadeh LA. Fuzzy sets. Inf Control 1965. doi:10.1016/S0019-9958(65)90241-X. [225] Chen MF, Tzeng GH, Ding CG. Combining fuzzy AHP with MDS in identifying the preference similarity of alternatives. Appl Soft Comput J 2008. doi:10.1016/j.asoc.2006.11.007. [226] Chen VYC, Lien HP, Liu CH, Liou JJH, Tzeng GH, Yang LS. Fuzzy MCDM approach for selecting the best environment-watershed plan. Appl Soft Comput J 2011. doi:10.1016/j.asoc.2009.11.017. [227] Chu TC, Lin Y. An extension to fuzzy MCDM. Comput Math with Appl 2009. doi:10.1016/j.camwa.2008.10.076. [228] Ramesh T, Prakash R, Shukla KK. Life cycle energy analysis of buildings: An overview. Energy Build 2010;42:1592–600. doi:10.1016/j.enbuild.2010.05.007. 162 [229] Thormark C. Energy and resources, material choice and recycling potential in low energy buildings. Int CIB Conf SB07 Sustain Constr Mater Pract 2007:1–8. [230] British Columbia Codes. BC Building Code 2018 2018. http://www.bccodes.ca/building-code.html (accessed April 12, 2020). [231] Glicksman LR, Taub S. Thermal and behavioral modeling of occupant-controlled heating, ventilating and air conditioning systems. Energy Build 1997. doi:10.1016/S0378-7788(96)01019-5. [232] ASHRAE. Standard 55 - Thermal environmental conditions for human occupancy 2013. https://www.ashrae.org/technical-resources/bookstore/standard-55-thermal-environmental-conditions-for-human-occupancy. [233] Banerjee S. Arithmetic Operations on Generalized Trapezoidal Fuzzy Number and its Applications. Turkish J Fuzzy Syst 2012;3:16–44. [234] Salahshour S, Abbasbandy S, Allahviranloo T. Ranking fuzzy numbers using fuzzy maximizing-minimizing points. EUSFLAT-LFA 2011, 2011, p. 763–9. [235] Wu W, Skye HM. Net-zero nation: HVAC and PV systems for residential net-zero energy buildings across the United States. Energy Convers Manag 2018. doi:10.1016/j.enconman.2018.09.084. [236] Sartori I, Napolitano A, Voss K. Net zero energy buildings: A consistent definition framework. Energy Build 2012. doi:10.1016/j.enbuild.2012.01.032. [237] Marszal AJ, Heiselberg P, Bourrelle JS, Musall E, Voss K, Sartori I, et al. Zero Energy Building - A review of definitions and calculation methodologies. Energy Build 2011. doi:10.1016/j.enbuild.2010.12.022. [238] Torcellini P, Pless S, Deru M, Crawley D. Zero Energy Buildings: A Critical Look at the Definition. 2006 ACEEE Summer Study Energy Effic. Build., Pacific Grove, CA: 2006. [239] RDH Building Science Inc. Energy Consumption in Low-Rise Multi-Family Residential Buildings in Bc 2017:1–45. [240] Clean Energy BC. Solar photovoltaic power 2020:2. https://www.cleanenergybc.org/about/clean-energy-sectors/solar (accessed June 9, 2020). [241] Natural Resources Canada. HOT2000 for general use 2019. 163 [242] Kuikka S. LCA of the Demolition of a Building-An assessment conducted at IVL Swedish Environmental Research Institute 2012. [243] NRCan. Heating and Cooling with a Heat Pump 2017. https://www.nrcan.gc.ca/energy/publications/efficiency/heating-heat-pump/6831 (accessed June 18, 2020). [244] Maile T, Fischer M, Bazjanac V. Building Energy Performance Simulation Tools - a Life-Cycle and Interoperable Perspective. Cent Integr Facil Eng 2007:1–49. [245] Athena. User Manual and Transparency Document 2014. www.athenasmi.org (accessed April 12, 2020). 164 Appendices Appendix A : Data collection scenario tables for Chapter 5 Table A1: Transport from material factory to construction site (covers A4, B1, B2, and B3) Materials Short haul by road (km) Long haul by road (km) Cast-in-place concrete 13 2.4'' Rigid Insulation 12 605 Poly vapour barrier 12 605 Crushed granular fill 37 Wood strip 14 R24 Batt insulation 12 207 1/2'' Gypsum wall board 12 386 Paint finish 13 357 Hardie board siding 12 657 Plywood sheathing 14 Laminated flooring 14 Engineered I-joist 64 Cellulose fibre insulation 12 885 Vinyl decking 12 605 Torch-on waterproof membrane 12 605 perforated soffit 12 386 Asphalt Shingles 12 906 Engineered trusses 64 Double-pane glazing window 12 380 Aluminum frame from windows 12 380 Glazed sliding door 12 380 Wood door 12 357 Garage door 20 394 Steel rebar 63 165 Table A2: Material waste factor during construction (covers A5, B1, B2, and B3)1 Materials Construction waste factor Cast-in-place concrete 1.05 2.4'' Rigid Insulation 1.05 6 mil Poly vapour barrier 1.05 Crushed granular fill 1 Wood strip 1.08 R24 Batt insulation 1.05 1/2'' Gypsum wall board 1.1 Paint finish 1.02 Hardie board siding 1.01 Plywood sheathing 1.01 Laminated flooring 1.05 Engineered I-joist 1.01 Cellulose fibre insulation 1.05 Vinyl decking 1.03 Torch-on waterproof membrane 1.03 perforated soffit 1.05 Asphalt Shingles 1 Engineered trusses 1 Double-pane glazing window 1 Aluminum frame from windows 1 Glazed sliding door 1 Wood door 1 Garage door 1 Steel rebar 1.01 1 The construction waste factors are estimated from the Athena Construction Waste Factor Database. 166 Table A3: Building maintenance, repair and replacement details (covers modules B1-B3)2 Material Maintenance Repair Replacement Task frequency (year) Material use (%) Task frequency (year) Material use (%) Task frequency (year) Material use (%) Cast-in-place concrete 15 2 120 100 2.4'' Rigid Insulation 17 15 120 100 6 mil Poly vapour barrier 15 2 80 100 Crushed granular fill N/A N/A 100 100 Wood strip 10 2 100 100 R24 Batt insulation 10 2 120 100 1/2'' Gypsum wall board 20 2 30 100 Paint finish 10 50 15 2 75 100 Hardie board siding 10 2 75 100 Plywood sheathing 20 2 100 100 Laminated flooring 9 2 20 100 Engineered I-joist N/A N/A 75 100 Cellulose fibre insulation 1 1.5 20 100 Vinyl decking 1 3 20 100 Waterproof membrane 1 3 20 100 perforated soffit 10 3 20 100 Asphalt Shingles 1 1.5 20 100 Engineered trusses N/A N/A 75 100 Double-pane glazing window 1 3 30 100 Aluminum frame from windows 1 3 30 100 Glazed sliding door 12 12 50 100 Wood door N/A N/A 30 100 Garage door 17 15 20 100 Steel rebar N/A N/A 100 100 2 Data are estimated from Athena Impact Estimator [245] 167 Table A4: Construction waste transport distance (covers modules A5, B2-B4, C2)3 Waste type Distance to reuse (km) Distance to recycle (km) Distance to landfill (km) Distance to incineration (km) Concrete products 13 23 Crushed granular fill 37 Wood strip 23 Wood products 14 23 Gypsum board 380 23 Hardie board siding 23 Steel rebar 14 23 Glass products 23 Asphalt shingles 62 23 Insulation products 23 Other products 23 Table A5: Demolition waste treatment rules (covers A5, B2-B4, C2)4 Waste type Reuse (%) Recycle (%) Landfill (%) Incineration (%) Concrete products 70 30 Crushed granular fill 50 Wood strip 100 Wood products 80 20 Gypsum board 95 5 Hardie board siding 100 Steel rebar 70 30 Glass products 100 Asphalt shingles 95 5 Insulation products 100 Other products 100 3 The transport distance was estimated based on the available recycling and landfilling facilities. 4 The default values from Athena IE4B database and the availability of recycling facilities. 168 Table A6: Yearly operational energy and water usage (covers B6-B7)5 Utility type Unit Annual usage Water usage M3 274.8 Natural gas usage GJ 61.3 Electricity usage MWh 12 5 The annual operational energy consumptions are derived from HOT2000 simulation software, and annual water consumptions are based on the data from Government of Canada [150]. 169 Table A7: Unit cost of building materials and constructions based on RSMeans6 Assembly Description Family and Type RSMeans # Detailed processes Unit Material costs Labor Equipment Total Total incl. O&P Standard Foundations Basic Wall: Foundation - Concrete footing 1 0311 1345 0050 Form in place - footing SFCA 3.85 3.56 7.41 9.65 0321 1160 0500 Reinforced steel in place-footings Ton 1025 835 1860 2400 0330 5340 3825 Cast in place concrete-footing C.Y 227 128 63 355.63 445 0311 1910 0130 Insulating concrete SF 3.76 1.08 4.84 5.75 Basic Wall: Foundation - Concrete footing 2 (1') 0311 1345 0050 Form in place - footing SFCA 3.85 3.56 7.41 9.65 0321 1160 0500 Reinforced steel in place-footings Ton 1025 835 1860 2400 0330 5340 3825 Cast in place concrete-footing C.Y 227 128 63 355.63 445 Slab on Grades Floor: Floor - Basement level 0311 1365 1400 Form in place - slab on grade SFCA 0.94 1.31 2.25 3.01 0321 1160 0600 Reinforced steel in place-slab on grade Ton 1025 765 1790 2275 0330 5340 5001 Cast in place concrete-slab on grade SF 1.6 0.89 0.01 2.5 3.11 0726 1010 0900 Polyvinyl chloride sheets, plain Sq. 3.87 11.15 15.02 21 0305 1325 0450 Aggregate, stone ton 18.65 18.65 20.5 Floor: Patio floor - Basement level 0311 1345 0050 Form in place - footing SFCA 3.85 3.56 7.41 9.65 0321 1160 0500 Reinforced steel in place-footings Ton 1025 835 1860 2400 0330 5340 3825 Cast in place concrete-footing C.Y 227 128 63 355.63 445 Floor: Floor - main entrance 0311 1345 0050 Form in place - footing SFCA 3.85 3.56 7.41 9.65 0321 1160 0500 Reinforced steel in place-footings Ton 1025 835 1860 2400 0330 5340 3825 Cast in place concrete-footing C.Y 227 128 63 355.63 445 Basement Walls Basic Wall: Foundation - 300mm Concrete wall 0311 1385 0600 Form in place - walls SFCA 1.41 1.57 2.98 3.92 0321 1160 0700 Reinforced steel in place-walls Ton 1025 585 1610 2000 0330 5340 4200 Cast in place concrete-walls C.Y 187 223 19 429 560 6 The unit cost does not consider the tax (5%), general contractor cost (10%), contingency (5%), bond (13.2‰), and location factor (material 113%, installation 87%), which are added later in LCC calculation. 170 Basic Wall: Exterior Wall - basement (at garage) 0611 1040 6140 Wall framing - studs M.B.F 640 900 1540 2050 0721 1620 0182 Blanket insulation for walls SF 0.66 0.36 1.02 1.27 0713 5310 2400 Polyvinyl chloride sheets, plain SF 0.15 1.24 1.39 2.24 0929 1030 0350 Gypsum board on walls & ceilings SF 0.39 0.86 1.25 1.73 0991 2372 1240 Interior painting - walls and ceilings SF 0.22 0.53 0.75 1.04 Basic Wall: Exterior Wall - basement 0746 4610 0020 Fibre cement siding SF 1.31 1.99 3.3 4.45 0727 1310 0200 Modified bituminous sheet air barrier SF 0.73 0.46 1.19 1.49 0616 3610 0500 Sheathing - on walls SF 0.61 0.69 1.3 1.72 0611 1040 6140 Wall framing - studs M.B.F 640 900 1540 2050 0721 1620 0182 Blanket insulation for walls SF 0.66 0.36 1.02 1.27 0713 5310 2400 Polyvinyl chloride sheets, plain SF 0.15 1.24 1.39 2.24 0929 1030 0350 Gypsum board on walls & ceilings SF 0.39 0.86 1.25 1.73 0991 2372 1240 Interior painting - walls and ceilings SF 0.22 0.53 0.75 1.04 Floor Construction Floor: Floor - main level 0964 2910 0020 Wood strip flooring SF 3.55 1.62 5.17 6.35 0616 2310 0200 Sheathing- subfloor SF Flr 0.94 0.66 1.6 2.03 0611 1018 3010 Joist framing - compsite wood M.L.F 2025 940 2965 3650 0721 2310 0021 Loose fill insulation - cellulose SF 0.17 0.41 0.58 0.81 0929 1030 0350 Gypsum board on walls & ceilings SF 0.39 0.86 1.25 1.73 0991 2372 1240 Interior painting - walls and ceilings SF 0.22 0.53 0.75 1.04 Floor: Garage floor - Main level 0311 1365 1400 Form in place - slab on grade SFCA 0.94 1.31 2.25 3.01 0321 1160 0600 Reinforced steel in place-slab on grade Ton 1025 765 1790 2275 0330 5340 5001 Cast in place concrete-slab on grade SF 1.6 0.89 0.01 2.5 3.11 0726 1010 0900 Polyvinyl chloride sheets, plain Sq. 3.87 11.15 15.02 21 0305 1325 0450 Aggregate, stone ton 18.65 18.65 20.5 Patio floor - main level 0615 2310 0020 Laminated roof decking SF 5.65 1.94 7.59 9.15 0712 1320 0012 Membrane waterproffing SF 0.43 0.79 0.17 1.39 1.98 0616 2310 0200 Sheathing- subfloor SF Flr 0.94 0.66 1.6 2.03 0611 1018 3010 Joist framing - compsite wood M.L.F 2025 940 2965 3650 0951 1310 0100 Ceiling, fibreglass board SF 1.31 0.66 1.97 2.44 171 Roof Construction Basic roof: Generic roof - 300 mm 0731 1310 0150 Asphalt roof shingles Sq. 79 65.5 144.5 196 0727 1310 0200 Modified bituminous sheet air barrier SF 0.73 0.46 1.19 1.49 0611 1030 7300 Roof framing M.B.F 720 1075 1795 2450 0616 3610 0100 Sheathing - on roofs S.F 0.63 0.59 1.22 1.59 0721 2310 0022 Loose fill insulation - cellulose SF 0.28 0.52 0.8 1.09 0713 5310 2400 Polyvinyl chloride sheets, plain SF 0.15 1.24 1.39 2.24 0929 1030 0350 Gypsum board on walls & ceilings SF 0.39 0.86 1.25 1.73 0991 2372 1240 Interior painting - walls and ceilings SF 0.22 0.53 0.75 1.04 Exterior Walls Basic wall: Exterior Wall - Main 0746 4610 0020 Fibre cement siding SF 1.31 1.99 3.3 4.45 0727 1310 0200 Modified bituminous sheet air barrier SF 0.73 0.46 1.19 1.49 0616 3610 0500 Sheathing - on walls SF 0.61 0.69 1.3 1.72 0611 1040 6140 Wall framing - studs M.B.F 640 900 1540 2050 0721 1620 0182 Blanket insulation for walls SF 0.66 0.36 1.02 1.27 0713 5310 2400 Polyvinyl chloride sheets, plain SF 0.15 1.24 1.39 2.24 0929 1030 0350 Gypsum board on walls & ceilings SF 0.39 0.86 1.25 1.73 0991 2372 1240 Interior painting - walls and ceilings SF 0.22 0.53 0.75 1.04 Exterior Windows Fixed windows 2' x 4' (3 pieces) 0851 1320 3100 Aluminum window single-hung Ea. 260 89.5 349.5 430 Double windows 5' x 5' (2 pieces) 0851 1320 5500 Aluminum window sliding Ea. 725 112 837 980 Fixed windows 2' x 4' (7 pieces) 0851 1320 3100 Aluminum window single-hung Ea. 260 89.5 349.5 430 Fixed windows 6' x 2' (2 pieces) 0851 1320 3400 Aluminum window single-hung Ea. 475 112 587 700 Double windows 6' x 6' (3 pieces) 0851 1320 5500 Aluminum window sliding Ea. 725 112 837 980 Exterior Doors Glass sliding door 8' x 6'8'' 0832 1310 0500 Sliding aluminum framed glass doors Ea. 1775 275 2050 2375 Glass sliding door 8' x 8' 0833 1310 0500 Sliding aluminum framed glass doors Ea. 1775 275 2050 2375 Main entrance door 3' x 8' 0817 2310 0340 Pre-hung entrance door Ea. 325 55 380 440 Garage door 16' x 8' 0836 1320 0300 Residential garage door Ea. 1650 138 1788 2025 172 Partitions Basic Wall: Interior - Basement + main level 0991 2372 1240 Interior painting - walls and ceilings SF 0.22 0.53 0.75 1.04 0929 1030 0350 Gypsum board on walls & ceilings SF 0.39 0.86 1.25 1.73 0611 1040 6140 Wall framing - studs M.B.F 640 900 1540 2050 0929 1030 0350 Gypsum board on walls & ceilings SF 0.39 0.86 1.25 1.73 0991 2372 1240 Interior painting - walls and ceilings SF 0.22 0.53 0.75 1.04 Interior Doors Wood sliding door 5' x 6'8'' (2 pieces) 0814 3320 2780 Interior closet bifold Ea. 117 75 192 243 Standard door 2'8'' x 6'8'' (5 pieces) 0814 1609 0025 Smooth wood doors Ea. 57 48.5 105.5 136 Standard door 2'8'' x 6'8'' (6 pieces) 0814 1609 0025 Smooth wood doors Ea. 57 48.5 105.5 136 Wood sliding door 2'10'' x 6'8'' (1 piece) 0814 3320 2780 Interior closet bifold Ea. 117 75 192 243 Wood sliding door 5' x 6'8'' (1 piece) 0814 3320 2780 Interior closet bifold Ea. 117 75 192 243 Stair Construction 0616 2310 0200 Sheathing- subfloor SF Flr 0.94 0.66 1.6 2.03 0964 2910 0020 Wood strip flooring SF 3.55 1.62 5.17 6.35 173 Table A8: Environmental impacts of building materials and constructions based on EPD reports Environmental Impacts GWP ODP AP EP SP ADP RPE NRPE SM FW WD CRU MR Unit kg CO2 eq. kg CFC11 eq. kg SO2 eq. kg N eq. kg O3 eq. MJ surplus MJ MJ KG M3 KG KG KG Cast-in-place concrete 350.57 0 0.95 0.33 16.75 177.83 112.92 1856.9 360 3.66 45.41 0 0 2.4'' Rigid Insulation 11.21 0 0.02 0.01 0.2 12.61 1.97 100.82 0 0.08 0.22 0 0 Poly vapour barrier 0.13 0 0 0 0.01 0.36 0.07 2.79 0 0 0.05 0 0 Crushed granular fill 0 0 0 0 0 0 0.04 0.05 0 0 0 0 0 Wood strip 94.16 0 0.81 0.14 22.37 192.81 16127.24 1444.14 0 1.52 28.93 0 0 R24 Batt insulation 1.13 0 0.01 0 0.04 0.98 0.61 12.35 0 0 0.05 0 0 1/2'' Gypsum wall board 0.41 0 0 0 0.03 0.33 0.93 4.8 0 0 0.03 0 0 Paint finish 6.75 0 0.04 0.04 0.35 6.99 18.85 80.68 0 0.08 1.8 0 0 Hardie board siding 1.33 0 0 0 0.06 1.13 2.13 11.98 0 0.01 0.22 0 0 Plywood sheathing 397.41 0 3.31 1 47.02 867.67 33992.78 6967.25 0 18.79 60.57 0 0 Laminated flooring 524.92 0 4.83 0.35 73.38 547.8 0 7759.1 0 1.49 0 0 0 Engineered I-joist 1.76 0 0.01 0 0.24 3.69 136.83 32.2 0 0.05 0.31 0 0 Cellulose fibre insulation 0.39 0 0.01 0 0.04 0.38 1.93 102.38 1 0.24 0.31 0 0 Vinyl decking 5.12 0 0.05 0.08 0.56 13.25 2.22 115.58 0 0.09 0 0 0 Torch-on waterproof membrane 5.12 0 0.05 0.08 0.56 13.25 2.22 115.58 0 0.09 0 0 0 perforated soffit 5.12 0 0.05 0.08 0.56 13.25 2.22 115.58 0 0.09 0 0 0 Asphalt Shingles 0.89 0 0 0 0.04 0.61 1.8 7.75 0 0.01 0.07 0 0 Engineered trusses 94.16 0 0.81 0.14 22.37 192.81 16127.24 1444.14 0 1.52 28.93 0 0 Double-pane glazing window 38.33 0 0.3 0.09 3.23 47.87 30.6 472.98 0 0.37 7.76 0 0 Aluminum frame from windows 885.86 0 5.26 2.49 47.44 559.06 1109.46 9331.05 0 7.43 102.93 0 0 Glazed sliding door 38.33 0 0.3 0.09 3.23 47.87 30.6 472.98 0 0.37 7.76 0 0 Wood door 62.53 0 0.39 0.21 4.28 71.49 1301.77 872.78 0 0.64 10.08 0 0 Garage door 128.47 0 0.96 0.45 7.96 98.2 975.88 1409.27 0 1.11 21.42 0 0 Steel rebar 1.03 0 0 0 0.02 0.58 0 10.63 1 0 0 0 0 174 Appendix B : WBLCA results of the case study for Chapter 5 Table B1: WBLCA results from the material manufacturing stage (A1-A3) Environmental Impacts Unit Cast-in-place concrete 2.4'' Rigid Insulation Poly vapour barrier Crushed granular fill Wood strip R24 Batt insulation 1/2'' Gypsum wall board Paint finish Hardie board siding Plywood sheathing Laminated flooring Engineered I-joist GWP kg CO2 eq. 21014 622 168 147 3280 489 1829 1223 4308 3895 928 598 ODP (x 10^-5) kg CFC11 eq. 107 849 3 2 76 3 13 24 29 68 13 9 AP kg SO2 eq. 57 1 1 1 28 4 12 0 15 32 9 4 EP kg N eq. 20 0 0 0 5 0 5 8 9 10 1 2 POCP kg O3 eq. 1004 11 18 20 779 16 120 153 201 461 130 82 ADP MJ surplus 10660 699 458 180 6717 426 1491 4000 3649 8504 969 1253 RPE MJ 6769 109 89 1390 561811 265 4188 490 6884 333146 0 46462 NRPE (x 10^3) MJ 111 6 4 2 50 5 22 2 39 68 14 11 SM KG 21580 0 0 0 0 0 0 0 0 0 0 0 FW M3 219 4 1 18 53 1 10 108 27 184 3 16 WD KG 2722 12 70 58 1008 24 140 13 713 594 0 105 CRU KG 0 0 0 0 0 0 0 0 0 0 0 0 MR KG 0 0 0 0 0 0 0 0 0 0 0 0 175 Table B1: WBLCA results from the material manufacturing stage (A1-A3) (Continued) Environmental Impacts Unit Cellulose fibre insulation Vinyl decking Waterproof membrane perforated soffit Asphalt Shingles Engineered trusses Double-pane glazing window Aluminum windows frame Glazed sliding door Wood door Garage door Steel rebar GWP kg CO2 eq. 171 102 102 102 967 527 928 4288 422 1938 1542 1442 ODP (x 10^-5) kg CFC11 eq. 2 1 1 1 6 12 13 22 6 19 11 0 AP kg SO2 eq. 2 1 1 1 4 5 7 25 3 12 12 4 EP kg N eq. 2 2 2 2 3 1 2 12 1 7 5 0 POCP kg O3 eq. 19 11 11 11 46 125 78 230 36 133 96 30 ADP MJ surplus 168 265 265 265 660 1080 1158 2706 527 2216 1178 819 RPE MJ 851 44 44 44 1957 90313 740 5370 337 40355 11711 0 NRPE (x 10^3) MJ 45 2 2 2 8 8 11 45 5 27 17 15 SM KG 440 0 0 0 0 0 0 0 0 0 0 1402 FW M3 106 2 2 2 7 9 9 36 4 20 13 5 WD KG 135 0 0 0 76 162 188 498 85 312 257 0 CRU KG 0 0 0 0 0 0 0 0 0 0 0 0 MR KG 0 0 0 0 0 0 0 0 0 0 0 0 176 Appendix C : Data collections of WBLCA results of different scenario analysis in Chapter 7 Table C1: BoQ of the single family building in scenario 1 derived from BIM model Assembly Code Assembly Description Family and Type Area (m2) Detailed Layers Basic Wall: Foundation - Concrete footing 2 (1') 34 8'' Concrete footing A1030 Slab on Grades Floor: Floor - Basement level 144 4'' reinforced concrete slab 144 6 mil poly vapour barrier 144 6'' compacted granular fill Floor: Patio floor - Basement level 27 4'' concrete footing Floor: Floor - main entrance 18 4'' concrete footing A2020 Basement Walls Basic Wall: Foundation - 300mm Concrete wall 146 8'' concrete wall Basic Wall: Exterior Wall - basement (at garage) 146 2x6 back-framing at 16'' O.C. 146 R24 batt insulation 146 6 mil poly vapour barrier 146 1/2'' standard gypsum wall board 146 Paint finish Basic Wall: Exterior Wall - basement 93 Hardie board siding 93 Building paper (air barrier) 93 7/16'' O.S.B sheathing 93 2x6 S.P.F. #1/2 studs @ 16'' O.C. 93 R24 batt insulation 93 6 mil poly vapour barrier 93 1/2'' standard gypsum wall board 93 Paint finish B1010 Floor Construction Floor: Floor - main level 144 Finished flooring 144 3/4'' T&G spruce plywood sheathing 144 11 7/8'' engineered I-joists @ 16'' O.C. 144 Cell spray foam to 3 3/8'' depth in I-joists 144 1/2'' C.D board to finish area 144 Painted - lightly textured finish Floor: Garage floor - Main level 42 4'' reinforced concrete slab 177 42 6 mil poly vapour barrier 42 6'' compacted granular fill Patio floor - main level 27 vinyl decking 27 torch-on waterproof membrane 27 3/4'' T&G spruce plywood sheathing 27 7 1/2'' LSL'S AT 12'' O.C. 27 Perforated soffit B1020 Roof Construction Basic roof: Generic roof - 300 mm 306 Shingles 306 building papers 306 engineered trusses c/w H-clips 306 1/2'' T&G sheathing 223 R50 loose fill spray over living spaces 223 6 mil poly. Vapour barrier 223 1/2'' C.D. gypsum board 223 painted B2010 Exterior Walls Basic wall: Exterior Wall - Main 217 Hardie board siding 217 Building paper (air barrier) 217 7/16'' O.S.B sheathing 217 2x6 S.P.F. #1/2 studs @ 16'' O.C. 217 R24 batt insulation 217 6 mil poly vapour barrier 217 1/2'' standard gypsum wall board 217 Paint finish B2020 Exterior Windows fixed windows 2' x 4' (3 pieces) 13 Double glazing + Vinyl frame double windows 5' x 5' (2 pieces) 2 Double glazing + Vinyl frame fixed windows 2' x 4' (7 pieces) 11 Double glazing + Vinyl frame fixed windows 6' x 2' (2 pieces) 4 Double glazing + Vinyl frame double windows 6' x 6' (3 pieces) 1 Double glazing + Vinyl frame B2030 Exterior Doors glass sliding door 8' x 6'8'' 6 glass door glass sliding door 8' x 8' 5 glass door main entrance door 3' x 8' 2 wood door 178 Garage door 16' x 8' 2 garage door C1010 Partitions Basic Wall: Interior - Basement + main level 5 Paint 12 1/2'' standard gypsum board 203 2x4 (or 2x6) studs at 16'' O.C. 203 1/2'' standard gypsum board 203 Paint C1020 Interior Doors wood sliding door 5' x 6'8'' (2 pieces) 203 wood door standard door 2'8'' x 6'8'' (5 pieces) 203 wood door standard door 2'8'' x 6'8'' (6 pieces) 3 wood door wood sliding door 2'10'' x 6'8'' (1 piece) 20 wood door wood sliding door 5' x 6'8'' (1 piece) 6 wood door C2010 Stair Construction 1 3/4'' T&G spruce plywood sheathing 2 laminated flooring (stair tread) 179 Table C2: Transport from material factory to construction site (covers A4, B1, B2, and B3) Materials Short haul by road (km) Long haul by road (km) Cast-in-place concrete 13 2.4'' Rigid Insulation 12 605 Poly vapour barrier 12 605 Crushed granular fill 37 Wood strip 14 R24 Batt insulation 12 207 1/2'' Gypsum wall board 12 386 Paint finish 13 357 Hardie board siding 12 657 Plywood sheathing 14 Laminated flooring 14 Engineered I-joist 64 Cellulose fibre insulation 12 885 Vinyl decking 12 605 Torch-on waterproof membrane 12 605 perforated soffit 12 386 Asphalt Shingles 12 906 Engineered trusses 64 Double-pane glazing window 12 380 Aluminum frame from windows 12 380 Glazed sliding door 12 380 Wood door 12 357 Garage door 20 394 Steel rebar 63 180 Table C3: Material waste factor during construction (covers A5, B1, B2, and B3)7 Materials Construction waste factor Cast-in-place concrete 1.05 2.4'' Rigid Insulation 1.05 6 mil Poly vapour barrier 1.05 Crushed granular fill 1 Wood strip 1.08 R24 Batt insulation 1.05 1/2'' Gypsum wall board 1.1 Paint finish 1.02 Hardie board siding 1.01 Plywood sheathing 1.01 Laminated flooring 1.05 Engineered I-joist 1.01 Cellulose fibre insulation 1.05 Vinyl decking 1.03 Torch-on waterproof membrane 1.03 perforated soffit 1.05 Asphalt Shingles 1 Engineered trusses 1 Double-pane glazing window 1 Aluminum frame from windows 1 Glazed sliding door 1 Wood door 1 Garage door 1 Steel rebar 1.01 7 The construction waste factors are estimated from the Athena Construction Waste Factor Database. 181 Table C4: Building maintenance, repair and replacement details (covers modules B1-B3)8 Material Maintenance Repair Replacement Task frequency (year) Material use (%) Task frequency (year) Material use (%) Task frequency (year) Material use (%) Cast-in-place concrete 15 2 120 100 2.4'' Rigid Insulation 17 15 120 100 6 mil Poly vapour barrier 15 2 80 100 Crushed granular fill N/A N/A 100 100 Wood strip 10 2 100 100 R24 Batt insulation 10 2 120 100 1/2'' Gypsum wall board 20 2 30 100 Paint finish 10 50 15 2 75 100 Hardie board siding 10 2 75 100 Plywood sheathing 20 2 100 100 Laminated flooring 9 2 20 100 Engineered I-joist N/A N/A 75 100 Cellulose fibre insulation 1 1.5 20 100 Vinyl decking 1 3 20 100 Waterproof membrane 1 3 20 100 perforated soffit 10 3 20 100 Asphalt Shingles 1 1.5 20 100 Engineered trusses N/A N/A 75 100 Double-pane glazing window 1 3 30 100 Aluminum frame from windows 1 3 30 100 Glazed sliding door 12 12 50 100 Wood door N/A N/A 30 100 Garage door 17 15 20 100 Steel rebar N/A N/A 100 100 8 Data are estimated from Athena Impact Estimator [245] 182 Table C5: Construction waste transport distance (covers modules A5, B2-B4, C2)9 Waste type Distance to reuse (km) Distance to recycle (km) Distance to landfill (km) Distance to incineration (km) Concrete products 13 23 Crushed granular fill 37 Wood strip 23 Wood products 14 23 Gypsum board 380 23 Hardie board siding 23 Steel rebar 14 23 Glass products 23 Asphalt shingles 62 23 Insulation products 23 Other products 23 Table C6: Demolition waste treatment rules (covers A5, B2-B4, C2)10 Waste type Reuse (%) Recycle (%) Landfill (%) Incineration (%) Concrete products 70 30 Crushed granular fill 50 Wood strip 100 Wood products 80 20 Gypsum board 95 5 Hardie board siding 100 Steel rebar 70 30 Glass products 100 Asphalt shingles 95 5 Insulation products 100 Other products 100 9 The transport distance was estimated based on the available recycling and landfilling facilities. 10 The default values from Athena IE4B database and the availability of recycling facilities. 183 Table C7: WBLCA results for building design scenario 1 – Standard building Product stage Construction stage Usage Stage End of life stage Total Raw material supply, transport Transport Construction Maintenance Repair Replacement Operational energy use Operational water use Demolition Transport Waste Processing Disposal Environmental Impacts Unit Abbre. A1-A3 A4 A5 B1 B2 B3 B4 B5 C1 C2 C3 C4 Global warming potential kg CO2 eq. GWP 52803.06 1258.14 4534.87 13701.35 15419.83 18481.31 497718.03 2100.34 4990.18 762.38 -11908.99 517.97 600378.46 Ozone depletion potential kg CFC11 eq. ODP 0.00 0.00 0.00 0.00 0.00 0.00 0.08 0.00 0.00 0.00 0.00 0.00 0.09 Acidification potential kg SO2 eq. AP 264.83 3.29 35.13 76.35 96.14 127.94 1033.45 12.47 48.47 1.89 -67.22 4.80 1637.54 Eutrophication potential kg N eq. EP 102.23 1.24 5.85 83.81 46.87 63.91 850.66 7.27 5.86 0.72 -20.86 21.54 1169.10 Smog potential kg O3 eq. SP 4019.72 47.52 961.11 704.04 1036.83 1353.91 10790.03 122.39 1454.21 26.63 -1153.54 119.23 19482.08 Abiotic depletion potential for fossil fuels MJ surplus ADP 50770.80 2855.95 7592.36 14189.33 13629.31 17375.72 1064819.67 2315.67 10771.94 1702.02 -29034.28 1760.35 1158748.84 Renewable primary energy use MJ RPE 1271435.02 282.16 58035.58 38298.90 102220.55 89081.85 3384221.34 29822.32 432.23 169.19 -673054.75 -183.93 4300760.46 Non-renewable primary energy use MJ NRPE 569862.70 21223.34 61000.16 163885.18 212803.74 322951.88 8097718.86 28197.41 77461.15 12656.59 -249580.38 11164.56 9329345.20 184 Secondary materials KG SM 23536.22 0.00 1120.74 0.00 1743.86 1008.00 0.00 0.00 0.00 0.00 0.00 0.00 27408.82 Net use of fresh water M3 FW 818.37 3.92 31.72 155.53 252.69 390.44 16270.04 16706.03 9.99 2.29 -277.83 7.76 34370.95 Waste disposed KG WD 7938.27 1313.55 320.06 3649.47 2215.86 2349.24 21933.84 501.95 76.16 649.12 -1273.39 51807.43 91481.57 Components for re-use KG CRU 0.00 0.00 127.60 0.00 401.53 597.88 0.00 0.00 0.00 0.00 30832.26 0.00 31959.27 Materials for recycle KG MR 0.00 0.00 5438.73 0.00 7243.04 6154.48 0.00 0.00 0.00 0.00 106909.54 0.00 125745.79 185 Table C8: WBLCA results for building design scenario 2 – NZEB with natural gas HVAC and solar panels Product stage Construction stage Usage Stage End of life stage Total Raw material supply, transport Transport Construction Maintenance Repair Replacement Operational energy use Operational water use Demolition Transport Waste Processing Disposal Environmental Impacts Unit Abbre. A1-A3 A4 A5 B1 B2 B3 B4 B5 C1 C2 C3 C4 Global warming potential kg CO2 eq. GWP 96750.76 2242.58 2108.99 13701.35 18458.40 92787.03 190329.14 2100.34 4990.18 853.33 -11908.99 520.79 412933.89 Ozone depletion potential kg CFC11 eq. ODP 0.11 0.00 0.00 0.00 0.04 0.02 0.02 0.00 0.00 0.00 0.00 0.00 0.20 Acidification potential kg SO2 eq. AP 477.17 6.10 8.82 76.35 100.94 530.69 -255.23 12.47 48.47 2.15 -67.22 4.83 945.53 Eutrophication potential kg N eq. EP 286.81 2.26 2.79 83.81 48.52 425.71 -982.79 7.27 5.86 0.82 -20.86 21.55 -118.25 Smog potential kg O3 eq. SP 6190.30 89.64 161.29 704.04 1091.36 5449.94 -5474.99 122.39 1454.21 30.51 -1153.54 119.87 8785.01 Abiotic depletion potential for fossil fuels MJ surplus ADP 95437.84 5154.84 2003.62 14189.33 17043.66 91460.86 651616.22 2315.67 10771.94 1914.17 -29034.28 1774.24 864648.11 Renewable primary energy use MJ RPE 1374945.56 506.90 57856.77 38298.90 102756.82 293673.48 -6103575.37 29822.32 432.23 189.94 -673054.75 -177.27 -4878324.47 186 Non-renewable primary energy use MJ NRPE 1156988.00 38287.83 21130.27 163885.18 240135.52 1374795.69 3488418.78 28197.41 77461.15 14231.45 -249580.38 11264.21 6365215.11 Secondary materials KG SM 23536.22 0.00 1120.74 0.00 1743.86 1008.00 0.00 0.00 0.00 0.00 0.00 0.00 27408.82 Net use of fresh water M3 FW 2407.06 7.18 28.63 155.53 274.64 3470.16 -28604.92 16706.03 9.99 2.59 -277.83 7.88 -5813.07 Waste disposed KG WD 11149.29 2676.98 284.49 3649.47 2274.68 8505.69 -29886.22 501.95 76.16 773.91 -1273.39 52456.61 51189.62 Components for re-use KG CRU 0.00 0.00 127.60 0.00 401.53 597.88 0.00 0.00 0.00 0.00 30832.26 0.00 31959.27 Materials for recycle KG MR 0.00 0.00 5438.73 0.00 7243.04 6154.48 0.00 0.00 0.00 0.00 106909.54 0.00 125745.79 187 Table C9: WBLCA results for building design scenario 3 – Net zero energy ready building with natural gas HVAC Product stage Construction stage Usage Stage End of life stage Total Raw material supply, transport Transport Construction Maintenance Repair Replacement Operational energy use Operational water use Demolition Transport Waste Processing Disposal Environmental Impacts Unit Abbre. A1-A3 A4 A5 B1 B2 B3 B4 B5 C1 C2 C3 C4 Global warming potential kg CO2 eq. GWP 59597.91 1292.26 4882.38 13701.35 18458.40 18481.31 441834.95 2100.34 4990.18 764.77 -11908.99 520.79 554715.65 Ozone depletion potential kg CFC11 eq. ODP 0.10 0.00 0.01 0.00 0.04 0.00 0.07 0.00 0.00 0.00 0.00 0.00 0.22 Acidification potential kg SO2 eq. AP 275.79 3.38 35.76 76.35 100.94 127.94 856.16 12.47 48.47 1.89 -67.22 4.83 1476.76 Eutrophication potential kg N eq. EP 105.91 1.27 6.04 83.81 48.52 63.91 631.96 7.27 5.86 0.72 -20.86 21.55 955.98 Smog potential kg O3 eq. SP 4142.28 48.97 969.50 704.04 1091.36 1353.91 8674.36 122.39 1454.21 26.71 -1153.54 119.87 17554.06 Abiotic depletion potential for fossil fuels MJ surplus ADP 58395.28 2935.50 7990.34 14189.33 17043.66 17375.72 968281.81 2315.67 10771.94 1707.30 -29034.28 1774.24 1073746.50 Renewable primary energy use MJ RPE 1272649.74 289.94 58096.99 38298.90 102756.82 89081.85 2307571.76 29822.32 432.23 169.72 -673054.75 -177.27 3225938.26 Non-renewable primary energy use MJ NRPE 631066.09 21813.88 64180.86 163885.18 240135.52 322951.88 7225418.07 28197.41 77461.15 12695.86 -249580.38 11264.21 8549489.73 188 Secondary materials KG SM 23536.22 0.00 1120.74 0.00 1743.86 1008.00 0.00 0.00 0.00 0.00 0.00 0.00 27408.82 Net use of fresh water M3 FW 867.20 4.03 34.18 155.53 274.64 390.44 11163.49 16706.03 9.99 2.30 -277.83 7.88 29337.86 Waste disposed KG WD 8071.06 1360.15 326.82 3649.47 2274.68 2349.24 15866.73 501.95 76.16 650.90 -1273.39 52456.61 86310.38 Components for re-use KG CRU 0.00 0.00 127.60 0.00 401.53 597.88 0.00 0.00 0.00 0.00 30832.26 0.00 31959.27 Materials for recycle KG MR 0.00 0.00 5438.73 0.00 7243.04 6154.48 0.00 0.00 0.00 0.00 106909.54 0.00 125745.79 189 Table C10: WBLCA results for building design scenario 4 – NZEB with electric HVAC and solar panels Product stage Construction stage Usage Stage End of life stage Total Raw material supply, transport Transport Construction Maintenance Repair Replacement Operational energy use Operational water use Demolition Transport Waste Processing Disposal Environmental Impacts Unit Abbre. A1-A3 A4 A5 B1 B2 B3 B4 B5 C1 C2 C3 C4 Global warming potential kg CO2 eq. GWP 80900.70 1837.16 4900.53 13701.35 18458.40 61086.91 -3171.61 2100.34 4990.18 815.55 -11908.99 520.79 174231.30 Ozone depletion potential kg CFC11 eq. ODP 0.10 0.00 0.01 0.00 0.04 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.16 Acidification potential kg SO2 eq. AP 391.26 4.94 35.93 76.35 100.94 358.87 -14.91 12.47 48.47 2.04 -67.22 4.83 953.96 Eutrophication potential kg N eq. EP 209.64 1.84 6.07 83.81 48.52 271.36 -22.17 7.27 5.86 0.78 -20.86 21.55 613.66 Smog potential kg O3 eq. SP 5316.58 72.29 974.79 704.04 1091.36 3702.50 -191.71 122.39 1454.21 28.89 -1153.54 119.87 12241.66 Abiotic depletion potential for fossil fuels MJ surplus ADP 79634.83 4208.03 8029.53 14189.33 17043.66 59854.83 -3655.19 2315.67 10771.94 1825.92 -29034.28 1774.24 166958.52 Renewable primary energy use MJ RPE 1331304.37 414.34 58098.57 38298.90 102756.82 206391.10 -116301.98 29822.32 432.23 181.31 -673054.75 -177.27 978165.96 Non-renewable primary energy use MJ NRPE 932620.47 31259.75 64462.68 163885.18 240135.52 926060.64 -46583.35 28197.41 77461.15 13576.34 -249580.38 11264.21 2192759.63 190 Secondary materials KG SM 23536.22 0.00 1120.74 0.00 1743.86 1008.00 0.00 0.00 0.00 0.00 0.00 0.00 27408.82 Net use of fresh water M3 FW 1750.13 5.84 34.21 155.53 274.64 2156.30 -549.67 16706.03 9.99 2.47 -277.83 7.88 20275.50 Waste disposed KG WD 9836.06 2115.20 327.10 3649.47 2274.68 5879.24 -629.91 501.95 76.16 721.43 -1273.39 52456.61 75934.60 Components for re-use KG CRU 0.00 0.00 127.60 0.00 401.53 597.88 0.00 0.00 0.00 0.00 30832.26 0.00 31959.27 Materials for recycle KG MR 0.00 0.00 5438.73 0.00 7243.04 6154.48 0.00 0.00 0.00 0.00 106909.54 0.00 125745.79 191 Table C11: WBLCA results for building design scenario 5 – Net zero energy ready building with electric HVAC Product stage Construction stage Usage Stage End of life stage Total Raw material supply, transport Transport Construction Maintenance Repair Replacement Operational energy use Operational water use Demolition Transport Waste Processing Disposal Environmental Impacts Unit Abbre. A1-A3 A4 A5 B1 B2 B3 B4 B5 C1 C2 C3 C4 Global warming potential kg CO2 eq. GWP 59597.91 1292.26 4882.38 13701.35 18458.40 18481.31 130382.86 2100.34 4990.18 764.77 -11908.99 520.79 243263.56 Ozone depletion potential kg CFC11 eq. ODP 0.10 0.00 0.01 0.00 0.04 0.00 0.02 0.00 0.00 0.00 0.00 0.00 0.17 Acidification potential kg SO2 eq. AP 275.79 3.38 35.76 76.35 100.94 127.94 613.14 12.47 48.47 1.89 -67.22 4.83 1233.74 Eutrophication potential kg N eq. EP 105.91 1.27 6.04 83.81 48.52 63.91 911.49 7.27 5.86 0.72 -20.86 21.55 1235.51 Smog potential kg O3 eq. SP 4142.28 48.97 969.50 704.04 1091.36 1353.91 7881.14 122.39 1454.21 26.71 -1153.54 119.87 16760.84 Abiotic depletion potential for fossil fuels MJ surplus ADP 58395.28 2935.50 7990.34 14189.33 17043.66 17375.72 150262.51 2315.67 10771.94 1707.30 -29034.28 1774.24 255727.21 Renewable primary energy use MJ RPE 1272650.00 289.94 58096.99 38298.90 102756.82 89081.85 4781100.22 29822.32 432.23 169.72 -673054.75 -177.27 5699466.98 Non-renewable primary energy use MJ NRPE 631066.10 21813.88 64180.86 163885.18 240135.52 322951.88 1915012.02 28197.41 77461.15 12695.86 -249580.38 11264.21 3239083.69 192 Secondary materials KG SM 23536.22 0.00 1120.74 0.00 1743.86 1008.00 0.00 0.00 0.00 0.00 0.00 0.00 27408.82 Net use of fresh water M3 FW 867.20 4.03 34.18 155.53 274.64 390.44 22596.78 16706.03 9.99 2.30 -277.83 7.88 40771.16 Waste disposed KG WD 8071.06 1360.15 326.82 3649.47 2274.68 2349.24 25895.26 501.95 76.16 650.90 -1273.39 52456.61 96338.91 Components for re-use KG CRU 0.00 0.00 127.60 0.00 401.53 597.88 0.00 0.00 0.00 0.00 30832.26 0.00 31959.27 Materials for recycle KG MR 0.00 0.00 5438.73 0.00 7243.04 6154.48 0.00 0.00 0.00 0.00 106909.54 0.00 125745.79 Table C12: Total LCC results for each scenario Total LCC Scenario 1 408192.26 Scenario 2 445571.28 Scenario 3 401408.20 Scenario 4 418771.34 Scenario 5 395935.28 193 Appendix D : Data collections of WBLCA results of different scenario analysis in Chapter 6 Table D-1: Natural gas cost calculation method. Unit Unit Cost ($) Basic charge Per day 0.4085 Delivery Per GJ 4.596 Storage Per GJ 1.019 Cost of gas Per GJ 1.549 Municipal operating fee % 3.09% Carbon Tax Per GJ 1.9864 GST % 5% Table D-2: Electricity cost calculation method. Unit Unit Cost ($) Basic charge Per day 0.2069 In two months First 1350 kwh 0.0935 Next 650 kwh 0.1403 194 Table D-3: Total costs in Scenario 2 Material cost Quantity RSMeans # Material Labor Total Total incl O&P LCC Subtotal Furnace 1 2354 1613 3100 785 274 1059 1275 3261 Hot water tank 1 2234 3013 2040 1775 253 2028 2325 5949 Operational costs 50215.3069 Total 59425.3069 Table D-4: Total costs in Scenario 3 Material costs Quantity RSMeans # Material Labor Total Total incl O&P LCC Subtotal Furnace 1 2354 1613 3100 785 274 1059 1275 3130 Hot water tank 1 2234 3013 2040 1775 253 2028 2325 5709 Gypsum board (ft2) 922 0929 1030 0350 0.39 0.86 1.25 1.73 1595.06 Batt insulation (ft2) 922 0721 1610 2100 0.41 0.59 1 1.34 1235.48 Wood strip (M.B.F) 0.1512 0611 1040 6140 640 900 1540 2050 309.96 Batt insulation (ft2) 769.5 0721 1620 0182 0.66 0.36 1.02 1.27 977.265 Gypsum board (ft2) 769.5 0929 1030 0350 0.39 0.86 1.25 1.73 1331.235 fixed windows 2' x 4' (3 pieces) 3 0851 1320 3100 260 89.5 349.5 430 1290 double windows 5' x 5' (2 pieces) 2 0851 1320 5500 725 112 837 980 1960 fixed windows 2' x 4' (7 pieces) 7 0851 1320 3100 260 89.5 349.5 430 3010 double windows 6' x 6' (3 pieces) 2 0851 1320 5500 725 112 837 980 1960 Operational costs 36058.9005 Total 58566.9005 195 Table D-5: Total costs in Scenario 4 Material costs Quantity RSMeans # Material Labor Total Total incl O&P LCC Subtotal Furnace 1 2354 1613 3100 785 274 1059 1275 3130 Hot water tank 1 2234 3013 2040 1775 253 2028 2325 5709 Gypsum board (ft2) 922 0929 1030 0350 0.39 0.86 1.25 1.73 1595.06 Batt insulation (ft2) 922 0721 1610 2100 0.41 0.59 1 1.34 1235.48 Wood strip (M.B.F) 0.1512 0611 1040 6140 640 900 1540 2050 309.96 Batt insulation (ft2) 769.5 0721 1620 0182 0.66 0.36 1.02 1.27 977.265 Gypsum board (ft2) 769.5 0929 1030 0350 0.39 0.86 1.25 1.73 1331.235 fixed windows 2' x 4' (ea.) 3 0851 1320 3100 260 89.5 349.5 430 1290 double windows 5' x 5' (ea.) 2 0851 1320 5500 725 112 837 980 1960 fixed windows 2' x 4' (ea.) 7 0851 1320 3100 260 89.5 349.5 430 3010 double windows 6' x 6' (ea.) 2 0851 1320 5500 725 112 837 980 1960 Exterior back door (ea.) 1 0811 1610 0520 900 450 1350 1700 1700 Gypsum board (ft2) 2400 0929 1030 0350 0.39 0.86 1.25 1.73 4152 Batt insulation (ft2) 2400 0721 1620 0182 0.66 0.36 1.02 1.27 3048 operational costs 33130.1766 Total 64538.1766
Thesis/Dissertation
eng
Civil Engineering
Vancouver : University of British Columbia Library
Attribution-NonCommercial-NoDerivatives 4.0 International
Graduate
Whole building life cycle assessment for residential buildings : a design improvement framework
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