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Triple bottom line assessment of rooftop catchment system Bowling, Jenna; Tattersfield, Susan; Darakjian, Tina Mar 31, 2011

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UBC Social Ecological Economic Development Studies (SEEDS) Student ReportTriple Bottom Line Assessment of Rooftop Catchment SystemJenna BowlingSusan TattersfieldTina DarakjianUniversity of British ColumbiaAPSC 261March 31, 2011Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions,conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report andis not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status ofactivities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the currentstatus of the subject matter of a project/report”.1TRIPLE BOTTOM LINE ASSESSMENT OF ROOFTOP CATCHMENT SYSTEMSubmitted to Dr. Dawn MillsBy Jenna Bowling, Susan Tattersfield, Tina DarakjianSource: Ubyssey, 2011,< http://ubyssey.ca/culture/thinking-inside-the-box-sets-the-stage-for-new-subs-theatre>University of British ColumbiaApplied Science 261March 31 20112ABSTRACT“Triple Bottom Line Assessment of Rooftop Catchment System”By Jenna Bowling, Susan Tattersfield, Tina DarakjianThe University of British Columbia (UBC) plans to implement a rainwater harvestingsystem atop the roof of the new student union building (SUB).  An investigation into the rooftopdesign and potential catchment materials was carried out to determine the associatedeconomic, environmental and social impacts. A material analysis for the water supply anddrainage piping is also considered. A low sloping roof design is chosen for its ability to preventexcessive loading due to factors such as ponding of rainwater.The four potential roofing types studied for a low slope roof design were asphalt,concrete, green roof, and aluminum. Overall, concrete roofing was deemed most appropriatedue to its superior economic and environmental implications. Although green roof is seen asthe more socially viable option, its adverse economic and environmental implications are toogreat to base the roof design solely on appearance. Cast iron piping for the drainage systemappeared most advantageous when compared with acrylonitrile butadiene styrene (ABS) for itslong design life and recyclability. It is also considered more economically and environmentallysound over the lifetime of the SUB building. Polypropylene pipes are recommended for thewater supply piping as they are most cost effective, and strongly support Leadership in Energyand Environmental Design (LEED) initiatives. Lastly, the optimal material for the gutter system,an intermediary of the rooftop and piping systems, is galvanized steel. This is proposed as aresult of its long life span and ability to resist corrosion.3TABLE OF CONTENTSABSTRACT………………………………………………………………………………………………………………………………….iiLIST OF FIGURES………….…...........................……………………………………………………………….………………viLIST OF TABLES..…………………………………………………………………………………….…………………………….....viiGLOSSARY………………...……………………………………………………………….……………………………………………viiiLIST OF ABBREVIATIONS……………………………………………………………………………………………………………ix1.0 INTRODUCTION…..……………………………………………………………………………………………………………….12.0 ROOFTOP CATCHMENT DESIGN….……………………………………………………………………………….……….22.1 Projected Rainfall Accumulation…………………………………………….………..…………………......22.2 Hazards in Potential Loading…………………………………………….………………………………........32.2.1 Climatic Loading Variables for the Greater Vancouver Area….…………………...32.2.2 Water Ponding……………………………………………….………………………………………….42.2.3 Catchment Design………………………………………………..…………………………………...43.0 ECONOMIC MATERIAL ANALYSIS: ROOFING………………….....................................................…..63.1 Asphalt……………………………………………………………………………………………….…….…….……….63.2 Concrete…..……………………………………….……………………………………..……………….……….......63.3 Aluminum……………………………………………………………………………………..……………….…………73.4 Green Roof……………………………………………………………………………………………………………….74.0 ECONOMIC MATERIAL ANALYSIS: PIPE AND GUTTER SYSTEMS………………………………………..…..84.1 Drainage Piping.…………..………………………………………………………………….…….…………………844.1.1 Cast Iron……………………………………………………………….……………………………………84.1.2 ABS…………………………………………………………..………………………………………………..94.2 Water Supply Piping ……………..…………………………………..................................................94.2.1 Copper………………………………………………………………………………….……………………94.2.2 Polypropylene………………………………………………………………………………………….104.3 Gutter System …………….………………………………………….…………….….………………………..….104.3.1 Aluminum versus Galvanized Steel………………………………………..…………………105.0 ENVIRONMENTAL MATERIAL ANALYSIS: ROOFING……………..............................................…..125.1 Concrete …………………………………………………………………………………………..…….…….……….125.2 Asphalt…..……………………………………….…………………………………………..………….……….......135.3 Aluminum…………………………………………………………………………………………………….…………133.4 Green Roof…………………………………………………………………….……………………………………….146.0 ENVIRONMENTAL MATERIAL ANALYSIS: PIPE AND GUTTER SYSTEMS………………………………..156.1 Drainage Piping.…………..……………………………….…….………………………………………….………156.1.1 Cast Iron………………………………………………………………………..…………………………156.1.2 ABS…………………………………………………………………………………………………………..156.2 Water Supply Piping ……………..…………………………………………………….……………..............166.2.1 Polypropylene …………………………………………………………………………………………166.2.2 Copper…………..………………………………………………….…………………………………….166.3 Gutter System …………….……………………….….…………………………………….…………………..….1856.3.1 Aluminum versus Galvanized Steel………………………………………..…………………187.0 SOCIAL IMPLICATIONS OF ROOFING, GUTTER, PIPING MATERIALS...………………………………….197.1 Roofing Materials………………………………………………………………………………………….……….197.1.1 Asphalt…………………………………………………………………………………………………….197.1.2 Aluminum………………………………………………………………..………………………………197.1.3 Concrete………………………………………………………………………………………………….197.1.4 Green Roof………………………………………………………………………………………………207.2 Gutter Materials………………………………….…………………………………….…………….……….......207.2.1 Galvanized Steel………………………………………………….…………………………………..207.2.2 Aluminum…………………………………………………………..……………………………………207.3 Piping Materials………………………………………………………………………….……………….…………217.3.1 Cast Iron…………………………………………….…………………………………………………….217.3.2 ABS…………………………………………………………………………………………………………..217.3.3 Copper……………………………………………………………….…………………………………….217.3.4 Polypropylene………………………………………………….………………………………………218.0 CONCLUSION……….……………………………………………………………………….…………………………..……….22REFERENCES…………………………….………..…………………………………………………………………………….………236LIST OF FIGURESFigure 1. Annual rainfall accumulation as determined by Google Earth Software …………………………..…..2Figure 2. Free Body Diagram of Deflection of Roofing Material due to Water Ponding…….…………….4Figure 3. Four Possible Orientations of Catchment Slope…………………………………………..………….……….5Figure 4. Average pH Chart. …………………………………………………………………………………………………...….13Figure 5. Green Roof…….……………………………………………………………………………………………………………14Figure 6. Emissions in Air…………………………………………..………………………………………………….….……….17Figure 7. Emissions in Water……………………………………………………………………………………………………..17Figure 8. Emissions in Soil…….……………………………………………………………………………………………..…….17Figure 9. Energy Equivalent Value……………………………..…………………………………………..………….……….187LIST OF TABLESTable 1.  Maximum Loads due to Wind, Rain, and Snow……………………………………………………………......3Table 2. Comparative Material Cost Analysis……………...……………………………………………………………......7Table 3. Comparative Material Cost Analysis: Pipes…...……………………………………………………………....10Table 4. Comparative Material Cost Analysis: Gutter System……………………………………………………....118GLOSSARYGalvanize Add layers of zinc to protect from corrosionGalvanic Anodes The main component of a system used to protect buried or submergedmetal structures from corrosionBitumen Naturally occurring impure mixtures of hydrocarbonsCistern The tank in which the collected rainwater is being storedBiofilm An aggregate of microorganisms in which cells adhere to each otherand/or to a surfaceCarcinogenic Compounds Agents directly involved in cancerDisinfected Byproducts Water Pollutants9LIST OF ABBREVIATIONSUBC University of British ColumbiaLEED Leadership in Energy and Environmental DesignSUB Student Union BuildingABS Acrylonitrile Butadiene StyreneSEEDS Social, Ecological, Economic, Development StudiesFBD Free Body DiagramPAH Polycyclic Aromatic HydrocarbonsSCM Supplementary Concrete MaterialsUSGBC United States Green Building CouncilCSA Canadian Standards Association1.0 INTRODUCTIONThe roof catchment atop the new SUB is proposed to span 2719m2, which isapproximately half the total projected roof area. The scope of this project includes acomparison of various roof designs and materials, along with the gutter and piping systems. Asit is primarily a flat roof, a few simple designs to reduce extensive loading are discussed.  Ananalysis of several possible roofing materials is conducted including asphalt, concrete, greenroof, and aluminum. The advantages and disadvantages of galvanized steel and aluminum10gutter systems are assessed. There are two separate piping systems  which will be in place, onewhich carries water from the rooftop into the cistern where the water will be stored, and onewhich carries the water out of the cistern and to into the new building. Upon consideringpossibilities for building materials we will explore their long-term economic, environmental andsocial repercussions. This provides a basis for a triple bottom line assessment and will allow foroptimal material choice in order to successfully meet LEED standards for the New SUB.2.0 ROOFTOP CATCHMENT DESIGNA simple rooftop design is suggested to minimize rooftop loading due to wind, rain and snow.2.1 PROJECTED RAINFALL ACCUMULATIONTo determine the net rainwater accumulated per annum Google Earth software was utilised.The region highlighted in red (Figure 1) represents the catchment area of the new Student UnionBuilding. The building below the shaded zone is the existing SUB.11Figure 1: Annual rainfall accumulation as determined by Google Earth Software.Google Earth uses satellite data and precipitation records collected by the Government of Canada toestimate the net annual accumulation into this region. The program provided an estimate of a total of1300mm of rainwater to collect in this catchment zone over an average year, which is equivalent to36525450 litres of water.To provide a more practical understanding of this very large volume, the problem wasinterpreted as the total number of possible toilet flushes. If the average toilet uses about 6 litres ofwater per use then the total number of possible flushes can be calculated as:flushlitreslitres/636525450 6087575 flushes from one year of rainwater harvestThese numbers are quite substantial and provide evidence that there is excellent opportunity inexploitation of rainwater resources for the New SUB catchment zone.2.2 HAZARDS IN POTENTIAL LOADINGA simple catchment design is proposed to reduce loading as well as maximize rainfall potential.122.2.1 CLIMATIC LOADING VARIABLES FOR THE GREATER VANCOUVER AREAThe new SUB catchment must be designed to withstand the following loading factors forVancouver’s climate and hydrology (Table 1):WIND Maximum loads of 0.48 kPaRAIN A maximum of 124mm (0.2 kpa)  accumulationwithin a 24 hour periodSNOW Maximum loads of 1.9kPaTable 1: Maximum loads due to wind, rain and snowNote: the above values are quoted from the SUB 75% Schematic Design GuidelinesFrom the data provided in the table above it can be concluded that the strength of the roofingmaterial must be able to withstand a maximum load of 1.9kPa. Although snow provides a greatermaximum instantaneous impact on the roof structure, rainfall is a prominent climate feature and willtherefore be the most consistent forcing mechanism. The minimum temperatures are rarely abovefreezing and rainfall occurs almost constantly throughout the seasons. However, the annual averagetemperatures remain above zero degrees Celsius (Environment Canada).  Although rainfall appliessmaller instantaneous loads than both snow and wind, the duration of loading is much longer. For thisreason, rainwater is the most critical loading factor for the design and structural integrity of the rooftopof the New SUB. The average wind speed is also quite constant as Vancouver is sheltered by coastalmountain ranges.Overall, snow loads create the greatest maximum loads of all three climatic mechanisms. It may,however, be noted that periods of sub zero temperatures are very uncommon compared to idealconditions for rainfall accumulation.2.2.2 WATER PONDINGWater ponding is caused by concentrated snow and rainwater loads which act to deform thestructural integrity of flat roofs. This has the potential to prevent the catchment area from effectivelytransmitting flows into the gutter system.  A free body diagram of this occurrence is provided in Figure 2below. The deflection in the centermost part of the catchment volume (V) is a function of the total13length and net applied loads (Blaauwendraad, 2007). Potential designs to reduce the possible adverseeffects associated with such loads on a flat roof may be found in section 2.2.3 below.Figure 2: Free Body Diagram of deflection of roofing material due to water ponding.2.2.3 CATCHMENT DESIGNThe optimal catchment design for the New SUB reduces the possible adverse effects associatedwith rain and snow loads, while increasing the rainwater catchment potential. Orientations A, B, C and D(Figure 3) illustrate four different structural options frequently used in rooftop design. The triangularregion above each profile represents the net loading shadow imposed on the catchment surface. Thesedistributions have been determined using an equilibrium relationship of various force vectors acting onthe 2D plane. For the flat roof (A), a uniform and horizontal load results, while B, C and D carry atriangular loading pattern. Option B clearly has the smallest loading area, thus it is the most effectivedesign for minimising the applied load.The implementation of a sloped roof appears to be optimal, however if the roof is too steep itwill increase the water velocity and may lead to possible overflow and potential loss of collectedrainwater. Thus, option B oriented between 10-30 degrees is the most ideal orientation for careful flowinto the gutters and finally to the underground cistern.14Figure 3: Four possible orientations of catchment slope.3.0 ECONOMIC MATERIAL ANALYSIS: ROOFINGThis section encompasses a breakdown of several roofing materials, distinctive materialproperties and their initial costs, along with their expected lifespan. The total cost of materials is basedon the 100 year expected design life of the New SUB, thus it includes the cost of all replacements15needed. Through further investigations beyond the scope of this report it can be determined that extraexpenses due to maintenance are consistent for all roofing materials except green roofs.3.1 ASPHALTAsphalt is generally used to describe asphalt concrete, a combination of bitumen and aconglomeration of various minerals (Trumbore et al., 2005). This type of roofing is best suited for colderweather climates due to its dark colour and ability to absorb heat. A comparative cost analysis is shownin Table 2 below.  The expected lifetime of asphalt is 20-30 years, leading to extra expenses associatedwith the need for multiple replacements. Although it appears to be the most economically viable option,further social and environmental analysis will prove it inadvisable.3.2 CONCRETEConcrete is the most resistant of all materials and has been proven to last for long periods oftime in many roofing applications. There are no anticipated replacement expenses if concrete is used asthe rooftop of the New SUB. As well, there are little to no related maintenance costs as it does not rustor burn. Concrete is generally an impermeable material, dependent primarily on the grain size of theaggregate used (Hoseini, Bindiganavile, & Banthia, 2009). If exposed to extensive chemical ormechanical weathering, the design life may be greatly reduced. Due to Vancouver’s milder climate thereis low risk of these adverse processes such as freeze thaw weathering. As it is a fairly heavy material,initial transportation costs may be high. This may be easily balanced by the lack of replacementsneeded. With a minimal total cost of $29 900, it is the recommended rooftop material from a well-informed economic standpoint. As there is extensive loading associated with this roof type, thisrecommendation is highly dependent on the structural materials chosen for the entire New SUB, and isbased on the proposed 75% schematic design.3.3 ALUMINUMAluminum roofing is highly resistant to corrosion and is a very lightweight yet durable materialused in many roofing applications. This material also has the unique ability to reflect light in the summerseason, which will help keep the New SUB building cool (Alvarado & Martínez, 2008). Aluminum roofs,16however, are significantly more prone to the occurrence of damage and deformation. The installationprocess may be quite costly as further insulation would be needed to prevent excessive noise due toweather. It is difficult to find many, if any, commercial roofing applications which use aluminum for largeareas of flat roof. As a result of its high initial cost, and potential need for extensive maintenance,aluminum is not the economically favourable material for the rooftop catchment of the New SUB.3.4 GREEN ROOFA green roof is undoubtedly the most environmentally friendly and socially pleasant roofingmaterial on the market. However its use as a roofing material for rainwater catchment systems is still awidely debated topic (Czemiel Berndtsson, 2010). A green roof consists of a vegetated rooftop surfacewith an impermeable layer below. With the initial cost of a green roof at $25.00 per square foot, it is themost expensive material included in this analysis. This cost includes the addition of the abovementioned impermeable layer needed. The green roof is the only option requiring maintenance on aweekly basis, adding an additional yearly cost of 30000 dollars. This type of roofing has a design life ofaround 40 years as the base layer deteriorates (Carter & Keeler, 2008). From an economic standpoint, itwould be near impossible to balance the economic implications with the environmental and socialbenefits arising from such a materialTABLE 2: COMPARATIVE MATERIAL COST ANALYSISProduct Cost per ft2($)InitialCost ($)Lifetime(Years)ReplacementsNeededReplacementCost ($)Total Cost($)Asphalt 0.86 2300 20-30 4 9200 11 500Concrete 11.00 m3 29 900 100 0 0 29 900Aluminum 9.50 25 800 40+ 1 25 800 51 600Green Roof 25.00 67 900 40+ 1 67 900 135 800Table 2 shows a comparative cost analysis of the initial and replacement costs for all four roofingmaterials over the catchment area (2719 m2). Transportation costs are not included as they are oftennegated due to the general trend of heavier materials having a much longer design life.4.0 ECONOMIC MATERIAL ANALYSIS: PIPE AND GUTTER SYSTEMS17A general analysis of the materials to be used for both the piping and gutters systems for thecatchment of rainwater was executed, along with a cost analysis. A material lifetime and expensesummary can be found in Table 3 below.4.1 DRAINAGE PIPINGDrainage piping consists of the pipes exiting the underground cistern, and may be composed ofeither cast Iron or ABS (Acrylonitrile Butadiene Styrene). The pipes will most likely be locatedunderground and thus subject to external loading.4.1.1 CAST IRONCast Iron is most commonly seen in older model buildings, such as those built in the 19thcentury, and is often replaced today by ductile iron pipe which is very similar in composition (Bilgin &Stewart, 2009). The greatest benefit is its long service life, as it is expected to last from 75 to 100 yearsproviding that a few measures are taken in order to prevent corrosion. Corrosion occurs because ofphysical and chemical weathering, and may be reduced by methods of coating or casing the pipes or bygalvanic anodes (Cenoz, 2010). The price of cast iron piping quoted at $9.60 per foot with a four inchdiameter includes protection against corrosion. The long life of this material is largely due to the factthat its strength is not compromised by time. Cast iron has a low value for thermal expansion, allowingfor little to no deformation under an applied load and only breaks down through weathering orcorrosion. As fewer joints are needed to allow for expansion due to decreased deformation, the costmay be minimized. Cast iron piping needs to originate near the site of development, as shipping byweight can be very costly. The density of iron is beneficial due to its ability to dampen noise when thepipes are in use, though this may not be a concern with the pipes location being underneath thebuilding. This material is often used in commercial applications for its many advantages and as such it isour recommendation for the drainage piping in the New SUB. Although comparatively it appears to betwice the cost of ABS piping, its long life expectancy and resistance to loads makes it the ideal materialfrom an economic standpoint.4.1.2 ABS (ACRYLONITRILE BUTADIENE STYRENE)18This plastic piping material is lightweight and inexpensive with its cost approximately half that ofcast iron. The need to replace ABS piping after 50 years effectively makes ABS and cast iron costequivalent (Lu, Davis, & Burn, 2003). The long life of ABS may be attributed to the reduced internalfriction and turbulence in the pipe, thus reducing the required pumping energy. Smooth walls are alsomuch less likely to collect debris or bacteria which may still be in the filtered rainwater. ABS pipes arerendered useless in the case of fire and must be replaced. As well, this type of piping is subject todeformation under loading (Burn, Davis, & Gould, 2009). If too much load is applied, there is a possibilityof brittle failure and consequent pipe burst. ABS has a high coefficient of thermal expansion, leading topotential weakening over time due to cycles of expansion and contraction (Rosík, Kovářová, & Pospíšil,1996). This apparent incompatibility with varying temperature along with the possibility of brittle failureleads to the conclusion that ABS pipes are not the most economically viable option for drainage piping.4.2 WATER SUPPLY PIPINGThe water supply piping is that which carries the rainwater from the rooftop catchment into thecistern. These pipes will not be subject to any external loads.4.2.1 COPPERAlthough copper is an excellent drainage piping material due to its ability to resist corrosion, it’sextremely high cost makes it an economically unviable option for the New SUB (Hultquist et al., 2011).With the value of copper sitting at 4.50 cents per pound, the cost of copper piping is of a comparativelyhigh rate at $62.50 per one foot with a four inch diameter. It is nearly impossible to set a definite budgeton a future project when the material value remains unpredictable which is the case for most metals.With a projected design life of greater than 75 years, copper is a nearly ideal material to fit the NewSUB’s 100 year lifespan. The addition of copper piping would increase the value of this project providingit maintained its current worth or continued rising. It is more favourable than its counterpart,polypropylene, due to its recyclable value. Although at this time copper piping is not recommended dueto its high cost, there are several material benefits which must not be overlooked. Copper, like mostmetals, is fire resistant and will not burn in the event of a fire nor create noxious fumes (Swain, 2007).Due to the high temperature soldering of joints, the full length of piping will remain intact, greatlyreducing the probability of replacement and the costs associated. Copper also has a unique ability toresist the formation of bacteria such as biofilm which may form within the pipe (Lehtola et al., 2004).4.2.2 POLYPROPYLENE19The proposed type of polypropylene to be used is the Aquatherm Lilac pipe. Sitting at a cost ofonly $14.40 per foot with a four inch diameter, this is the recommended material for the New SUBbuilding due to its adaptability. It is the obvious choice for this building as the developing companyworks closely with the USGBC (United States Green Building Council) to design sustainable materialswith the LEED (Leadership in Energy and Environmental Design) program. Lilac piping is specificallydesigned for rainwater harvesting and irrigation. As such, it is highly resistant to corrosion by means ofrainwater which has the potential to be highly oxygenated (Aquatherm, 2011). As it is an inert material,there is little risk of corrosion or the leaching of chemicals. It has a design life of 50 years, and wouldonly need to be replaced once in the lifetime of the New SUB.TABLE 3: COMPARATIVE COST ANALYSIS: PIPESProduct Cost ($),[Dimensions]Lifetime ComparativeValue ($) [4” 1’]Replacements Total Cost ($)ABS 37.99, [4” 10’] 50 years 4.20 1 8.40Cast Iron 96.30, [4” 10’] 100+ years 9.60 0 9.60Polypropylene 236.20, [4”16.4’] 50 years 14.40 1 28.80Copper 249.96, [4”4’] 75+ years 62.50 0 125.00Table 3 shows the comparative costs of all four piping materials for a one foot section approximatelyfour inches in diameter.4.3 GUTTER SYSTEMThe gutter system will divert the rooftop water directly towards the water supply pipes, where it willthen be transported into the basement cistern. An expense summary can be found in Table 4 below.4.3.1 ALUMINUM VERSUS GALVANIZED STEELAlthough aluminum is the material of choice for most residential gutter systems, it is not alwaysbest suited for large commercial applications. This is due to its short service life of about 40 years, lessthan half the lifespan of steel.  Aluminum is also approximately half the cost of the alternative,galvanized steel. For comparison, the cost of aluminum gutter is $4.00 per linear foot compared to $7.00for steel.20It can be determined that the difference in price may be negated due to the additionalreplacement expenses associated with aluminum gutters in the 100 year projection of the New SUB.Galvanized steel is a heavier material, increasing the initial transportation costs. This extra cost may bedeemed insignificant when multiple replacements of the aluminum are taken into account. Aluminum’sshort lifespan may be attributed to a high coefficient of expansion, about two times larger than that forsteel products. As it is generally stretched into thin sheets, it can become easily dented or deformedwhich may compromise the materials integrity. Unfinished aluminum may form a layer of aluminumoxide on its surface which acts to prevent further corrosion.Galvanized steel is a strong metal material with a long design life of approximately 100 years. Itis subject to corrosion after long periods of time, when extensive weathering processes have acted todecrease the effectiveness of the incorporated protective zinc layers (Gosset & Buchlin, 2007). Ideally itsincorporation into the New SUB would provide a reliable gutter system which need not be replaced.TABLE 4: COMPARATIVE COST ANALYSIS: GUTTER SYSTEMProduct Cost ($) Lifetime(years)Aluminum 5” 4.00 linear ft 40Galvanized5”Steel7.00 linear ft 100Table 4 shows the comparative cost and lifetime of the two proposed gutter materials.5.0 ENVIRONMENTAL MATERIAL ANALYSIS: ROOFING21The quality of the rainwater collected varies greatly with the type of roofing material used forthe catchment system being applied to the new SUB. Materials that have less impact on theenvironment are favourable due to the aspiration of maximizing LEED points as well as the effect thematerial will have on the catchment and ecosystem. In order to determine the most feasible roofingmaterial, a few common materials were analyzed and compared for the impacts each has on collectedrainwater as well as the environment.5.1 CONCRETEConcrete is one of the most common construction materials utilized. Its ability to take any formas well as its durability and weather repelling properties make it an ideal product for most structuretypes. Certain production facilities separate and reuse wet concrete and, if hardened, crush and use it ashardcore or aggregate (Brocklesby & Davison, 2000). This is, however, only significant in the case thatconcrete from construction sites is returned to the manufacturer, which only occurs if the mix is notsuitable for the pour location and cannot be fixed on-site. In fact, waste is minimal when manufacturingconcrete due to the fact the production process is quite efficient with most of the material deliveredbeing used. Lastly, rainwater experiences an increase in pH of about 1.5 after contacting a concretecatchment, (Mendez et al., 2011) which is still within the standard range of secondary drinking water(See Figure 4).Conversely, although concrete is a fairly eco-friendly material, its construction process is ratherharmful to the environment when considering transportation and machinery. Overall, approximately1200 kg of CO2 per unit is emitted during the construction process. This is equivalent to driving over3800 km in an average sized car (Mendez, et al., 2011).22Figure 4: Average pH Chart (Mendez, et al.). (Concrete material is outlined in red. Black bars representquality of first flush. Grey bars represent quality after first flush. Dotted lines represent USEPA standardrange of drinking water (pH 6.5 – 8.5). Dashed line represents the ambient sampler.)5.2 ASPHALTA material often used for roads, asphalt is the foundation for most construction. Its efficiency inpaving makes it an ideal candidate for transportation engineering as well as other construction projects.However, efficiency may not necessarily mean eco-friendly. In fact, asphalt is quite harmful to both theenvironment and the paving crew. Its main hazardous components are PAHs (Polycyclic AromaticHydrocarbons) and alkyl PAHs which are toxic pollutants that can often leach into the ecosystem andinjure or kill wildlife and humans when ingested .  Also, asphalt contains carcinogenic compounds whichare known to be agents directly involved in cancer (Irwin, 1997). This risk is greatly amplified whenasphalt and petroleum fumes are inhaled by the paving crew during the construction process. For thesereasons, asphalt is not seen to be an appropriate construction material under LEED standards.5.3 ALUMINUMAluminum roof, also known as the “Cool Roof”, is favourable in many hot temperature climates.This is mainly due to the fact that aluminum works as a good insulator when keeping cool air inside aswell as reflecting the heat from the sun outwards. In perspective, this roofing material is known to lowerthe amount of energy consumed to condition homes which, in return, correlates to improving theenvironment by using less resources. In fact, aluminum exhibits a 5 degrees Celsius decrease of23temperature in a home due to natural convection and heat reflection (Alvarado & Martínez, 2008).However, one can see the problem that arises with this form of thermal insulation. As the SUB is beingconstructed in Vancouver, a generally cold city, aluminum roofing would be deemed counter-productivesince the goal is to contain thermal heat indoors and exclude exterior cool air. Otherwise, constantheating during cold months would be necessary thus consuming large quantities of energy and, in turn,harming the environment. On the other hand, aluminum roofs are considered good candidates forrainwater harvesting due to the fact that they have little effect on the quality of rainwater in acatchment (Mendez, et al., 2011).5.4 GREEN ROOFGreen Roofs have recently become trending topics for eco-friendly construction due mainly tothe fact that it involves creating a natural habitat on the roof of a building (as seen in Figure 5). Thisunique form of construction is greatly beneficial to the environment as it allows growth of agriculture,creation of animal habitat, plants, and organisms. This roofing style also improves the air quality throughoxygen production. This can also result in a decrease in disease rates such as asthma due to thepollutant and carbon dioxide filtration from surrounding air. Green Roofs also work as thermal insulatorswhich can maintain cooler temperatures during the summer time and warmer temperatures during thewinter season. However, old buildings of poor insulation benefit most from thermal insulation. Incontrast, when considering the effects of a Green Roof on rainwater harvesting, supplementary filtrationmust be considered due to the chemical runoff from the soil. Although the plant life may serve as a filterfor some rainwater pollutants, it can also be a source of chemicals such as nitrates, nitrogen, phosphate,and copper (Gregoire & Clausen). Manure and vegetation are often sources of these chemicals and mayimpact the quality of the rainwater runoff. Green Roofs can also be a source of dissolved organic carboncompounds in harvested rainwater which are precursors of regulation disinfected byproducts, morecommonly known as water pollutants (Mendez, et al., 2011).Figure 5: Green Roof <http://www.scholtensroofing.com/Rooftypes-Vancouver/Green-Roofing>246.0 ENVIRONMENTAL MATERIAL ANALYSIS: PIPE AND GUTTER SYSTEMSThe environmental impacts of various pipe and gutter materials were analyzed forappropriateness and feasibility when considering LEED standards. Each material was compared in orderto determine a catchment system with the least negative impact on the collected rainwater as well asthe environment.6.1 DRAINAGE PIPING(See Section 4.1 for drainage piping definition)6.1.1 CAST IRONCast Iron is one of the oldest materials in engineering history. It came into great use towards theend of the 19th century and has been serving many cities for long periods of time. However, since then,some cast iron pipes have become superseded by newer ductile iron material due to signs ofdeterioration resulting in breaks and leaks in water mains (Bilgin & Stewart, 2009). These deteriorationsare mainly due to external corrosion from the environment which often weakens the pipe walls andcauses malfunction. On the other hand, cast iron material is generally known to oxidize slowly which, inturn, delays corrosion and maintains quality over time. In an ideal environment with, perhaps, propersealant, the lifespan of cast iron can be quite high and, over time, insignificant amounts of metalpollutants (in comparison to other materials) can be traced in the water supply. This approach can assistin maintaining the quality of rainwater throughout transportation as well as decrease the amount ofmaterial being replaced. When considering pipe material with a long lifespan, a general positiveenvironmental impact can be seen over time throughout processes like pipe maintenance, waste, andcorrosion. Minimizing these three categories consequentially minimizes energy input as well as harmfulchemical pollutants.6.1.2 ABS (ACRYLONITRILE BUTADIENE STYRENE)ABS pipe and fittings have been the choice material since the 1960’s due to their reliability andeconomical feasibility. However, this product poses negative impacts on the environment andecosystem due to its lack of durability as well as chemical seepage over time. Pollution of plastic is atdangerous levels and is now accumulating in massive amounts in desolate ocean areas. Although mostplastic waste can be recycled, some may not and will eventually occupy landfills. Also, with the general25production of plastic products, some plastic nodules “escape” into the ecosystem and get washed outinto the ocean where they become mistaken for food and can be fatal if ingested (Addicted to Plastic,2008). ABS pipe’s brittleness and low hardness (Moore, 1973) can also mean constant maintenancewhich exerts energy and, in turn, expends resources. Along with this, chemical wearing over time mayalso affect the quality of water by leaching harmful chemicals into the system (Chang, Tanong, Xu, &Shon, 2011).6.2 WATER SUPPLY PIPING(See Section 4.2 for water supply piping definition)6.2.1 POLYPROPYLENEPolypropylene pipe is often used for industrial purposes due to its resistance to strong acids andhighly active oxidizers. Not only is this material very durable, it is also recyclable and is CSA approvedand LEED recognized. This is a key factor when replacing the material which, as a polymer, can becontinuously heated and formed and reused in other means. When considering the impact this materialhas on the environment, polypropylene produces emission factors of approximately 2.5 in air, 3.2 inwater, and 2 in soil (as seen in Figures 6, 7, and 8). Overall, polypropylene piping produces an average ofless than 50% the emissions as copper piping and requires less than 50% of energy to manufacture (asseen in Figure 9) (Aquatherm, 2011). With this, it is also recommended to implement high-quality,polypropylene, Lilac pipe due to its resistance to corrosion and chemical breakdown. This can maintainthe overall quality of the rainwater passing through the system.6.2.2 COPPERCopper pipe, a material introduced in the 1900’s, is both durable and recyclable. However,problems arise when considering its corrosion over time. As copper can be quite harmful if seeped intothe environment or ingested by humans, this material is not ideal for rainwater harvesting. In fact,copper does not break down in the environment which causes serious threats when it accumulates inplants and animals.Also, considering the impact copper has on the environment, it can produce emission factors ofapproximately 15 in air, 3.5 in water, and 12 in soil (as seen in Figures 6, 7, and 8). On average, theseimpacts are greater than those polypropylene produces by a factor of 50% (Aquatherm, 2011).26Figure 6: Emissions in Air, (Aquatherm, 2011)Figure 7: Emissions in Water, (Aquatherm, 2011)27Figure 8: Emissions in Soil, (Aquatherm, 2011)Figure 9: Energy Equivalent Value, (Aquatherm, 2011)6.3 GUTTER SYSTEM(See Section 4.3 for gutter system definition)6.3.1 ALUMINUM VERSUS GALVANIZED STEELAs mentioned in section 4.3.1, Galvanized Steel is essentially steel material coated with aprotective layer of zinc which decreases the prevalence of corrosion in the pipe. The excellent corrosionprotection that zinc provides greatly improves the durability and lifetime of galvanized steel which, inturn, conserves natural resources (International Zinc Association, 2000). Galvanized steel is also recycledin mass amounts and can be manufactured from scrap material. Aluminum, on the other hand, is amuch less durable material and can oxidize significantly over time. The accumulation of aluminum in theecosystem can be quite detrimental to plants and wildlife and is also known to contaminate fish fromhigh concentrations in lakes. Overall, it is recommended to implement galvanized steel instead ofaluminum for all gutter systems in the new SUB.287.0 SOCIAL IMPLICATIONS OF ROOFING, GUTTER, PIPING MATERIALSCare must be taken in choosing materials which enforce a positive community environment andpromote sustainable initiatives on campus. Ideally, they should not provide any serious injury to workersinvolved in production, assemble or installation. This discussion is divided into the three structuralcomponents for our analysis: Roofing, Gutter and Piping material. Each material considered for thedesign of these components is then critiqued for its ability to meet the aforementioned criteria.7.1 ROOFING MATERIALSTo begin this discussion the four roofing materials Aluminum, Asphalt, Concrete and Green Roofing areaddressed.7.1.1 ASPHALTLocal residents in an Idaho community (2006) complained that the smell and odour of asphaltproduction plants to be highly intolerable. Residents living a maximum of 3.2 km downwind of the plantcomplained of the odour, caused by the escape of hydrogen sulphide gas (Cook, Apel, & Gostomski,1999). This is emitted when blending and heating latex polymers in order to create asphalt.The used of this product also has many environmental activists concerned, as the use of largevolumes of petroleum in asphalt production is inadvisable with the current peak oil crisis. In addition,there is the less than ideal emission of fossil fuels which is a major concern to all living organisms.7.1.2 ALUMINUMPolycyclic Aromatic Hydrocarbons (PAH) exposure is a common among workers in the aluminumindustry. The PAH are released by the evaporation of carbon electrode materials used in electrolysisprocesses from the metal production. A case study in a large Canadian cohort indicated that there wasan increased risk of bladder and lung cancer due to exposure to PAH. Additional harmful substancesused in Aluminum production include asbestos, fluorides and sulphur dioxide gas (Boffetta, Jourenkova,& Gustavsson, 1997).297.1.3 CONCRETECurrently initiatives are being undertaken by the Federal Government of Canada to limit the CO2emissions associated with concrete production. Concrete consist of a slurry of carbonate minerals whichare mixed with a variety of aggregates. To reduce the environmental footprint of these concretemanufacturing facilies, more sustainable aggregates, Supplementary Cementing Materials (SCM) will berequired. These regulations would be set by guidelines published by the Federal Government of Canada.The environmental regulation of concrete manufacture should provide some incentive for  thepurchase of this product from Canadian production companies. The increase in sustainable practicewould mean an accumulation of LEED points with is one of the SEEDS initiatives for the construction ofnew campus infrastructure. Additionally, by purchasing Canadian concrete for the SUB constructionsocial concerns regarding the country’s current recessional trend will be addressed as more employmentopportunities are provided for local workers7.1.4 GREEN ROOFGreen Roofing is a highly beneficial community project. The construction of such a project couldrequire involvement from the UBC community and other environmental groups which would help topromote a sustainable culture within the campus community. This would significantly enhance theappearance of the roof and provide habit for birds, bugs, worms and all sorts of organisms (Oberndorferet al., 2007).7.2 GUTTER MATERIALSBelow are the materials analyzed for the intermediary gutter system.7.2.1 GALVANIZED STEELGalvanised steel production involves the immersion of steel strips into a boiling zinc bath. Studieshave shown that there are no significant health risks associated with this process. In addition to safemanufacture, this material is a more aesthetically attractive option as it provides a more cohesive anduniform appearance.   The protective coating Tin Oxide coating can also be coloured with dies to providea variety of attractive colour pallets (Gosset & Buchlin, 2007).307.2.2 ALUMINUMPlease refer to the aforementioned analysis found in section 6.1.2.7.3 PIPING MATERIALSFor drainage piping, cast iron and ABS piping are analyzed below along with Aluminum andPolypropylene for water supply piping.7.3.1 CAST IRONNo evidence of health or environmental concerns for society at large were found regarding thispiping material.7.3.2 ABSABS piping can be hazardous in high temperatures as it may become combustible and very highvolumes of smoke may be emitted (Smith, 1972). If the new SUB were to ever catch fire, these pipescould provide challenges for the fire crew in quenching the flames.7.3.3 COPPERCopper is an antibacterial agent and effective germicide. Enzymes within the metal are abletarget the bacteria by binding to reactive groups, resulting in their precipitation and inactivation(Zevenhuizen, Dolfing, Eshuis, & Scholten-Koerselman, 1979).In particular, copper is widely used as an algicide for water filtration systems in mineralsanitizers, swimming pools and spas. The reaction of copper alloys with many strains of bacteria couldbe highly beneficial as a means of providing sanitization for the grey water which is enters thecatchments cistern system. Cleaner water will expand opportunity for grey water application with in thebuilding, benefiting the users of the new SUB at large.7.3.4 POLYPROPYLENENo evidence of health or environmental concerns for society at large were found regarding thispiping material.318.0 CONCLUSIONAfter analyzing several design components of the new student union building, building materialrecommendations were made in order to maximize LEED points and improve overall quality of thebuilding and surrounding environment. By assessing social, economic, and environmental impacts ofeach material, an overall verdict in response to roofing, gutters, and piping material is made. Theserecommendations are based solely on the individual research and suggestions of the team members.The materials recommended with respect to their social implications are as follows: green roof,cast iron drainage piping, polypropylene water supply piping, and galvanized steel gutters.The materials recommended with respect to their economic and environmental implications arecoincidentally similar. They are as follows: concrete roof, cast iron drainage piping, polypropylene watersupply piping, and galvanized steel gutters. These similarities are mainly due to the fact that economicand environmental impacts vary greatly with the durability of construction materials. A durable materialwill, in the long run, be more economically efficient and, in turn, require less energy input to maintainand replace.The overall recommendations of material when considering social, economic, andenvironmental implications are as follows: concrete roof, cast iron drainage piping, polypropylene watersupply piping, and galvanized steel gutters. Although a green roof is seen as a more socially appropriatematerial, its adverse economic and rainwater quality implications do not outweigh the overallenvironment benefits.32REFERENCESAlvarado, J. L., & Martínez, E. (2008). Passive cooling of cement-based roofs in tropical climates. Energyand Buildings, 40(3), 358-364.Aquatherm. (2011). Aquatherm Piping Systems LEED Reference Guide. Retrieved fromhttp://www.aquathermpipe.com/includes/user/documents/Aquatherm%20LEED%20v.3.pdfBilgin, O., & Stewart, H. E. (2009). Pullout Resistance Characteristics of Cast Iron Pipe. [Article]. Journalof Transportation Engineering-Asce, 135(10), 730-735.Blaauwendraad, J. (2007). Ponding on light-weight flat roofs: Strength and stability. EngineeringStructures, 29(5), 832-849.Boffetta, P., Jourenkova, N., & Gustavsson, P. (1997). Cancer Risk from Occupational and EnvironmentalExposure to Polycyclic Aromatic Hydrocarbons. Cancer Causes & Control, 8(3), 444-472.Brocklesby, M. W., & Davison, J. B. (2000). The environmental impacts of concrete design, procurementand on-site use in structures. Construction and Building Materials, 14(4), 179-188.Burn, S., Davis, P., & Gould, S. (2009). Risk Analysis for Pipeline Assets—The Use of Models for FailurePrediction in Plastics Pipelines. In J. W. Martin, R. A. Ryntz, J. Chin & R. A. Dickie (Eds.), ServiceLife Prediction of Polymeric Materials (pp. 183-204): Springer US.Canada, E. (March 15 2011). Weather Office - British Columbia.   Retrieved March 20, 2011, fromhttp://www.weatheroffice.gc.ca/forecast/canada/index_e.html?id=BCCarter, T., & Keeler, A. (2008). Life-cycle cost-benefit analysis of extensive vegetated roof systems.Journal of Environmental Management, 87(3), 350-363.Cenoz, I. (2010). Cathodic protection for water pipes. [Article]. Materials Performance, 49(2), 40-41.Chang, C.-Y., Tanong, K., Xu, J., & Shon, H. (2011). Microbial community analysis of an aerobic nitrifying-denitrifying MBR treating ABS resin wastewater. Bioresource Technology, 102(9), 5337-5344.Cook, L. L., Apel, W. A., & Gostomski, P. A. (1999). Biofiltration of asphalt emissions: Full-scale operationtreating off-gases from polymer-modified asphalt production. Environmental Progress, 18(3),178-187.Czemiel Berndtsson, J. (2010). Green roof performance towards management of runoff water quantityand quality: A review. Ecological Engineering, 36(4), 351-360.Gosset, A., & Buchlin, J.-M. (2007). Jet Wiping in Hot-Dip Galvanization. Journal of Fluids Engineering,129(4), 466-475.Gregoire, B. G., & Clausen, J. C. Effect of a modular extensive green roof on stormwater runoff and waterquality. Ecological Engineering, In Press, Corrected Proof.Hoseini, M., Bindiganavile, V., & Banthia, N. (2009). The effect of mechanical stress on permeability ofconcrete: A review. Cement and Concrete Composites, 31(4), 213-220.Hultquist, G., Graham, M. J., Szakalos, P., Sproule, G. I., Rosengren, A., & Gråsjö, L. (2011). Hydrogen gasproduction during corrosion of copper by water. Corrosion Science, 53(1), 310-319.Lehtola, M. J., Miettinen, I. T., Keinänen, M. M., Kekki, T. K., Laine, O., Hirvonen, A., et al. (2004).Microbiology, chemistry and biofilm development in a pilot drinking water distribution systemwith copper and plastic pipes. Water Research, 38(17), 3769-3779.Lu, J. P., Davis, P., & Burn, L. S. (2003). Lifetime prediction for ABS pipes subjected to combined pressureand deflection loading. Polymer Engineering and Science, 43(2), 444-462.Mendez, C. B., Klenzendorf, J. B., Afshar, B. R., Simmons, M. T., Barrett, M. E., Kinney, K. A., et al. (2011).The effect of roofing material on the quality of harvested rainwater. Water Research, 45(5),2049-2059.Moore, J. D. (1973). Acrylonitrile-butadiene-styrene (ABS) - a review. Composites, 4(3), 118-130.33Oberndorfer, E., Lundholm, J., Bass, B., Coffman, R. R., Doshi, H., Dunnett, N., et al. (2007). Green Roofsas Urban Ecosystems: Ecological Structures, Functions, and Services. BioScience, 57(10), 823-833.Rosík, L., Kovářová, J., & Pospíšil, J. (1996). Lifetime prediction of ABS polymers based onthermoanalytical data. Journal of Thermal Analysis and Calorimetry, 46(2), 465-470.Smith, E. (1972). Measuring rate of heat, smoke and toxic gas release. Fire Technology, 8(3), 237-245.Swain, D. (2007, Dec 18, 2007). Advantages and Disadvantages of Copper Pipe Plumbing. fromhttp://www.associatedcontent.com/article/483021/advantages_and_disadvantages_of_copper.html?cat=6Trumbore, D., Jankousky, A., Hockman, E. L., Sanders, R., Calkin, J., Szczepanik, S., et al. (2005). Emissionfactors for asphalt-related emissions in roofing manufacturing. Environmental Progress, 24(3),268-278.Zevenhuizen, L. P. T. M., Dolfing, J., Eshuis, E. J., & Scholten-Koerselman, I. J. (1979). Inhibitory effects ofcopper on bacteria related to the free ion concentration. Microbial Ecology, 5(2), 139-146.

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