A short guide to embodied carbon in building structures

22 Pages·2011·1.236 MB·English

A short guide to
embodied carbon in
building structures
August 2011
Acknowledgements
Figures2and4courtesyofRamboll
Figure5courtesyofArupandTheConcreteCentre
PhotoofvelodromecourtesyofLondon2012
PhotoofBryghusprojektetcopyrightOMA
PublishedbyTheInstitutionofStructuralEngineers
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Firstpublished2011
ISBN978-1-906335-19-9
#2011TheInstitutionofStructuralEngineers
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endeavoredtoensuretheaccuracyofitscontents.However,theguidanceandrecommendations
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Foreword
Thefirstdecadeofthe21stCenturywasmarkedby
therapidlygrowingacceptancethattheworld’s
climatewaschanging,andtheresultsofthese
changeswouldhaveaprofoundlydamagingimpact
ontheenvironmentandlargenumbersofpeople’s
lives.Generallyagreementdevelopedrecognisingthe
severityofthechangesbroughtaboutbyclimate
changewouldberelativetotheabilityoftheworld’s
populationstomitigatethecausesofthesechanges
andinadaptingtoachangingenvironment.A
landmarkagreementsettinglegallybindingtargetsfor
carbonemissionsbyindustrialisedcountrieswas
signedby174countriesinKyotoin1997,knownas
theKyotoProtocol,theseagreementscameinto
forcein2005.TheUKgovernmentpublishedthe
SternReportin2006whichconsideredtheeconomic
impactofclimatechangeontheUK.Thereport
foundthatthecostsofactionfaroutweighedthe
costsofinaction.IntheUK,November2008sawthe
ClimateChangeBillenacted,withcommitmentsto
reduceby80%of1990levels,carbondioxidegreen
housegasemissionswithinaperiodof42years.The
worldforum–COP15heldinCopenhagenin2009
reinforcedthedepthofconcernfeltgloballyatthe
potentialofclimatechangetoimpactontheplanet
anditspeoples.
TheCounciloftheInstitutionofStructuralEngineers
openlydebatedinOctober2009,thecontribution
whichstructuralengineeringandspecificallythe
Institutioncouldmaketothechallengeofglobal
climatechangeandtheUKGovernment’s
commitmenttoreducecarbondioxideemissions.
Theoutcomefromthatdebatewasarequesttothe
TrusteesoftheInstitutiontoconsideractionswhich
couldbetakenwhichwouldempowerstructural
engineerstomakeaneffectivecontributionto
reducingtheimpactofclimatechange.
ThisshortguideisadirectresultoftheTrustees
considerationoftheCouncilsrequest.Thepublication
wascommissioneddirectlybytheTrusteesofthe
InstitutionofStructuralEngineersfromProfessor
RogerPlank,formerHeadofSchoolofArchitecture
atSheffieldUniversityandthethenSeniorVice-
PresidentoftheInstitution.
InproducingthisguidetheTrusteesweremindfulthat
thesustainabilityaspectsofthebuiltenvironment,
bestpracticeandlegislativeframeworks,differacross
theinternationalspectrumandthatallwereevolving
veryrapidly.Theguidancecontainedinthis
publicationshouldbeconsideredasinteriminthis
rapidlyevolvingfieldofknowledgeandtheTrustees
contributiontofurtheringthenecessaryevolutionsto
ourindustry.
iv TheInstitutionofStructuralEngineersAshortguidetoembodiedcarboninbuildingstructures
Contents
Foreword iv
1 Aimandscope 1
1.1 Aim 1
1.2 Scope 1
2 Introduction 2
3 Whatisembodiedcarbonandembodiedenergy? 3
4 Dataforembodiedcarbonandenergy–lifecycle
inventories(LCls) 4
5 Quantifyingembodiedcarbon 5
6 Sourcesofdata 6
7 Criticalassessmentofdata 8
7.1 Transparency 8
7.2 Differentiation 8
7.3 Currency 8
7.4 Variability 8
7.5 Energysources 9
7.6 Transportandsitework 9
7.7 Allowanceforrecycling 9
7.8 Allowanceforuseofwastematerialsandby-
products 9
7.9 Allowanceformaterialswastedonsite 10
7.10 Treatmentofsequesteredcarbon 10
7.11 Carbonation 10
8 Somepracticaluses 11
8.1 Therelativeimportanceofembodiedcarbon 11
8.2 Baselines 11
8.3 Waste 12
8.4 Experience 12
8.5 Scope–whattoinclude 12
9 Conclusions 13
References 14
Bibliography 16
AppendixA–Workedexamples 17
TheInstitutionofStructuralEngineersAshortguidetoembodiedcarboninbuildingstructures iii
1 Aim and scope
1.1 Aim
Thisshortguideisintendedtoprovidestructural
engineerswithpracticaladviceonhowtheycan
contributedirectlytoreducingtheembodiedcarbon/
energyfootprintoftheprojectstheydesign.
Manystructuralengineershave‘signedup’tothe
principlesofsustainableconstruction,butarenot
surewhattheycandopractically,andmaybe
frustratedbecausethestructuralengineerisnotthe
naturalleaderforsomanyofthekeyissues–for
example,theservicesengineerwillnormallyleadon
thedesignandspecificationofbuildingenvironment
systems(heating,cooling,ventilation)whichare
energyintensive,whilstthearchitectwillgenerallybe
responsibleforform,orientation,glazing,shadingetc.
Whilstthestructuralengineershouldbeawareofall
oftherelevantissues,mostwouldbeuncomfortable
tryingtotakeresponsibilityforthese.Theintentionof
thisguideistoconcentrateonjustthatpartofthe
designwhichthestructuralengineercandirectly
influence,namelytheembodiedenergyandcarbon
associateddirectlywiththestructure.
Ofcourse,embodiedenergyandcarbonshouldnot
beconsideredinisolation,andthisguidewillinclude
referencetootherrelevantissues–notably
operationalenergy–withsomegeneralcomment
abouttheirrelativeimportanceandpotentialtrade-
offs.However,inmanycasesitispossibletomake
clearreductionsintheembodiedcarbonwithout
detrimenttoothermeasuresofsustainability;this
shortguidewillprovidesomeguidanceonthis.
1.2 Scope
Theguideisnotintendedtoprovideanyofthe
following:
– Adirectcomparisonofdifferentmaterialsand
systems
– Acomprehensivetreatmentofsustainable
construction
– Newdatafortheembodiedcarbonandenergyof
differentmaterialsandproducts
– Adetailedcommentaryoflifecycleassessment
Theguideisshortinlength,thereforethereisclearly
noroomtoconsiderthebroaderissuesof
sustainabilityinanydetailnorisitintendedtoprovide
newenergyorcarbondataformaterials.Thefocusis
ondescribingwhatinformationandtoolsareavailable
andhowthesecanbeappliedtoestimate,and
subsequentlyactasavehicletoidentifywaysto
reduceembodiedcarbon.
TheInstitutionofStructuralEngineersAshortguidetoembodiedcarboninbuildingstructures 1
2 Introduction
Thereareanumberofindicatorsandmeasures toexploringpotentialreductions.Duringtheinitial
whichneedtobeconsideredinacomprehensive designphasesthereisthereforeaneedtoestablisha
treatmentofsustainabledevelopment.Manyofthese quickestimatebasedongeneralinformationwithlittle
areoutsidethedirectinfluenceofthestructural detail.Inthecontextofstructuraldesign,the
engineer,butrecentlyattentionhasbecomecentred engineer’sexperienceenablesstructuralconceptsto
onglobalwarmingandclimatechange,andwhatis bedevelopedtodefineform,layout,andtheprincipal
widelyacceptedasbeingoneofthemajor materialswhichwillbeused.Withoutthesame
contributorstothis,namelytheemissionofcarbon experienceofdoingthisforcarbonemissions,
dioxide–oftenabbreviatedsimplytocarbon–into structuralengineersneedquickandeasytoolsto
theatmosphere.Itshouldbenotedthatothergases performrelativelycrudecomparisonsofideas,and
suchasmethane,nitrousoxideandHFCs thisguideprovidessomeguidanceonhowtodo
(hydrofluorocarbons)alsocontributetoglobal this.Overtimebenchmarkdatawillhelpestablish
warming.Insomecircumstances,emissionsofthese rulesofthumbforconceptdesign.
othergreenhousegasescanbesignificant,for
exampleagriculturalprocessescanoftencause Asthedesigndevelops,moredetailedcarbon
methaneemissions(fromanimalsorfromsoil),nitrous calculationsarealsorequired.Atthelaterstages,the
oxideisassociatedwiththeproductionofnylon,and calculationofembodiedcarboncanrequirealarge
HFCsmaybeusedinthemanufactureofsome inputoftimeandresearchintoquantitiesandvalues
insulants.Theglobalwarmingpotential(GWP)of formaterialsused.Whilstthismaybeoflessvaluein
thesegasesismuchmoreseverethancarbon refiningthedesignconcept,detailedissuessuchas
dioxide,butfortunatelythecorrespondingquantities materialspecification,particularlyforconcrete,can
areverymuchlower.Whereappropriatetheireffect haveasignificantinfluenceontheembodiedcarbon.
onglobalwarmingisgenerallyincludedinfiguresfor Amoredetailedanalysisofembodiedcarbonisalso
embodiedcarbon,representedasacarbondioxide likelytobecomenecessaryasameansofcertifying
equivalent. thecarbonfootprintofthebuilding.Increased
experiencewill,intime,helpdefinehowmuchdetail
Buildingshaveanextremelyimportantroletoplayin willberequired,andidentifythoseaspectswhichare
thedrivetowardsalowcarboneconomy.Asan ofgreatestimportance,andotherswhichmayhavea
example,in2009itisestimatedthatthedomestic negligibleinfluence.
sectoraccountedfor28%ofUKenergydemand,
consuming43.6milliontonnesofoilequivalentand
causing16%ofUKCO emissions;thiscorresponds
2
to75.3milliontonnesCO equivalent1.Estimates
2
vary,butitisgenerallyagreedthatbetweenonethird Planning
andahalfofallcarbondioxideemissionsare
associatedwithbuildingconstructionandoperation
inserviceasillustratedinFigure12.
Concept
Abuilding’scarbonfootprintdescribesitsoverall s
impactintermsofcarbondioxideemissions. sult
e
Ectwwmaeossioratstnmhuniemsluemdtidhafdabeetinictnrlychatcguletouoirotnednehnsemeostorfitbtcuhvepoacee,rrtdrobiapoidienotrnsdoudncoclcifttfefohesastoerhscabteiopynnocprdgbnilnee,ucotr,iwaolfdointmhmiifnocicapagnluhotabdeintliursisnceiiaelgandallsfrtsinbbs,ws,gooohantcnhinc,ieadhwwetedhhdsiacthis sentativeness of EC R DetaTileendd Deersign Potential for reduction
e
isassociatedwiththeenergyusedtoservicethe pr
e
building,principallyforheating,ventilation,cooling R
Construction
andlighting.Embodiedcarbonandhowtoquantifyit,
isthesubjectofthisshortguide.
Ifthestructuraldesignistobeinformedbytheneed
Use
toreduceembodiedcarbon,itisimportantthatsome
considerationisgivenveryearlyinthedesignprocess
Figure2 Inordertoachievethebestresultsitisimportant
thatembodiedcarbonestimatesareundertakenearlyinthe
designprocess,althoughasignificantcontributioncanbemade
Buildings 46% ateverystage
Agriculture 1%
Industrial processes 23%
Transport 30%
Figure1 Sourcesofcarbondioxideemissionsbysector
2 TheInstitutionofStructuralEngineersAshortguidetoembodiedcarboninbuildingstructures
3 What is embodied carbon and embodied energy?
Inthecontextofconstruction,embodiedcarbon
(oftenabbreviatedtoECorECO )isameasureofthe
2
carbondioxideemissionsassociatedwithcreating
thebuildingfabric.Itshouldthereforeincludethe
carbonemittedwhensourcingandprocessingraw
materials,thatemittedtomanufacturetheminto
constructionproducts,deliverthemtosite,and
assemblethemtoformthebuilding.Ideallyitshould
alsoallowforanyreplacementorrefurbishment
duringthebuilding’slife,anddismantlingor
demolitionattheendoflifeandrecycling.Ofcourse
thismaybedifficulttopredictpreciselysoisoften
accountedforsimplybyincludingapercentage
increaseintheinitialcalculation.Howanappropriate
allowanceshouldbemadeforsuchreplacementand
refurbishmentisacentralpartoftheworkofthe
EuropeanCENcommitteeTC350whichis
developingaEuropeanstandardforfullbuildinglife
cycleanalysis.Thiswillhopefullyleadtogreaterclarity
andconsistencyoftreatment.
Embodiedenergy(EE)isthecorrespondingmeasure
ofenergyusedintheseprocesses.Theshiftfrom
energytocarbonasaunittomeasuretheembodied
impactofaproductormaterialisduetothegrowing
importanceattachedtoglobalwarmingandclimate
change.Inmanyinstancesthereisaclosecorrelation
betweencarbonandenergysinceahighproportion
ofman-madecarbonemissionsresultsfromthe
burningoffossilfuels.Thisisparticularlythecase
whenconsideringtheoperationalimpactofa
building.However,insomecasessignificantcarbon
emissionsoccurasaresultofthechemistryof
productionforaparticularprocess.Themostobvious
examplefortheconstructionsectoristheproduction
ofcementwhichinvolvestheconversionofcalcium
carbonatetocalciumoxide,withcarbondioxideasa
by-product.Insuchcasesthetotalembodiedcarbon
isthesumofthatassociatedwiththeenergyusedin
manufacture,andthecarbondioxideemittedasa
resultofthechemicalreactions.Thisisillustratedin
Table1whichcomparesembodiedenergyand
embodiedcarbonfiguresforthemostcommon
structuralmaterials.
Inaddition,differentenergysources,forexample
nuclearandfossilfuels,canhavequitedifferent
carbonfootprints,sincecarbonemissionsarenot
necessarilydirectlyproportionaltoenergy
consumption,andthisisillustratedinFigure3.The 1000
exactrelationshipdependsontheenergysourceand 900
DEFRAintheUKpublishesrelevantfactors4. 800
700
600
Table1 Typicalvaluesforembodiedenergyand 500
embodiedcarbonforcommonstructuralmaterials. 400
(Source:UniversityofBathICEv2.03) 300
200
Construction Embodiedenergy Embodiedcarbon
100
material (MJ/kg) (kgCO /kg)
2 0
CSteemelent 240..51 10..3773 Coal OilNatural gasGeothermal NucleaHrydroelectricPhotovoltaic Wind
Brick 3.0 0.23
Figure3 IndicativelevelsofcarbondioxideemissionsperkWhassociatedwithdifferent
Timber 10.0 0.3
energysources
TheInstitutionofStructuralEngineersAshortguidetoembodiedcarboninbuildingstructures 3
4 Data for embodied carbon and energy – life cycle
inventories (LCIs)
Theembodiedcarbonandenergyforabasic Preciselywhichstagesofaproduct’slifeareincluded
materialsuchassteelorcementcanbedetermined inLCIdatasetscanvary.Thisiswhatisreferredto
byidentifyingalltherelevantproductionprocesses asthe‘systemboundaries’.Mostdataisquotedas
includingtheextractionofrawmaterials, ‘cradle-to-gate’inwhichcaseitwillincludethe
transportationandprocessing.Foreachsingle carbonemissionsassociatedwithallstagesfrom
processstep,therawmaterialsused,energy extractionthroughprocessing,butexcludeany
consumedetc.arequantified,andthe transportationtositeandsubsequentassembly.It
correspondingimpactsaredetermined.Theseare will,however,generallyallowfortransportassociated
typicallyrepresentedasMJ/kgandkgCO /kgfor withtheproductionprocessitself,soforexample,in
2
embodiedenergyandcarbonrespectively.Clearly thecaseofconcrete,the‘gate’isnormallythatofthe
therecanbesignificantvariationsdependingonthe ready-mixplant.Manycarboncalculatorscombine
processesusedbyindividualmanufacturer/ figuresforcradle-to-gate;thismeansthatinevitable
suppliers,andtheparticularmaterialspecification– variationsintheimpactsassociatedwithtransportto
forexamplestainlesssteelorcarbonsteel,and siteanddisposalattheendoflifeareavoided;these
glulaminatedorsawntimber.Inthecaseof shouldbeconsideredseparately,takingintoaccount
concrete,individualdatafortheconstituent relevantinformationsuchasthespecificproject
aggregates,cementandwateriscombined.For location.
buildingcomponentssuchasasteelbeamor
reinforcingbar,additionalprocessingneedstobe Alternativeboundariesaresometimesusedincluding:
included,andforcomponentssuchasprecast ‘cradle-to-grave’whichincludesallstagesfrom
concreteunits,datafordifferentmaterialsneedsto extraction(‘cradle’),manufacture,installation,anduse
becombined.Inthiswayembodiedcarbonand throughtodisposalphase(‘grave’);and‘cradle-to-
energydatacanbedevelopedforthebasic cradle’,whichextendscradle-to-graveassessmentto
elementscommonlyusedinconstruction.Thisdata allowforrecycling(seeFigure4).Theseboundaries
formswhatisknownasaLifeCycleInventory(LCI) aremoreoftenappliedtoproductswhichdonot
–adatabaseforarangeofmaterialsandbasic havethecomplexityofabuildingorstructure,and
components,containinginformationsuchasthe wherethesubsequentimpactsareclearer(for
emissionsofavarietyofpollutantsassociatedwith exampleconsumergoodsorproductssuchas,
theproduct–andthisisanessentialpartof fridge/freezersorcomputers).Whatisimportantis
calculatingembodiedcarbon. thatthesystemboundariesforthebasicdataare
known,andthatallotherstagesthroughthelifecycle
Whenconsideringalternativestructuralsystems, areconsidered,ensuringthatthereisnoduplication
directcomparisonofthesefiguresisofcourse oromission;althoughinsomecasesitmaybe
meaningless,becauseofthevariationinloadcarrying reasonabletoneglectaparticularstage,ortousea
capabilitiesofdifferentmaterials–asteelbeamfor simplifiedallowance,forexamplesimplyaddinga
examplewillgenerallybemuchlighterthanthe percentageincreasetoaccountfortransportationor
equivalentreinforcedconcretebeamtoperformthe siteconstruction.
samefunction.Itisthereforeimportanttoconsider
thetotalembodiedenergy/embodiedcarbonforthe
equivalentfunctionalunitsratherthansimply
comparingtheseforthesamequantityofdifferent EXTRACTION
materials. VE TE LETOTE
GRA O SI RAD GA
DrealetavafnotrparnocLeCsIsreesquthirreosudgehtoauiltedevceorynssitdaegreatoiofnthoeflaiflel MANUFACTURE E TO DLE T C
oenfvairpornomdeunctta.lTahnisalryesqisuiorefsthaeqpuroandtuitcattitvoemeasurea TRANSPORTATION RADL CRA
C
rangeofimpacts,oftenincludingglobalwarming
potential,ozonelayerdepletion,eutrophication,and
CONSTRUCTION
depletionofmineralsandfossilfuels.Itincludesall
theproductionprocessesandservicesassociated
withtheproductthroughitslifecycle. DISPOSAL
Inordertoquantifythedifferentimpactsavery
detailedknowledgeoftheprocessesinvolvedatthe Figure4 Schematicrepresentationofdifferentsystem
variousstagesofproduction,theenergy(typeand boundaries
quantity)usedandanychemicalchangeswhichmay
giverisetocarbondioxideisclearlyrequired.
Considerablereliancehasthereforebeenplacedon
manufacturerstoundertakethisanalysisortoengage
lifecycleassessmentexpertstodoso,ontheir
behalf,andprovidethenecessarydata.Thishas
beensupplementedbyindependentstudies,bothto
generatenewdataandcheckthevalidityofindustry
figures.
4 TheInstitutionofStructuralEngineersAshortguidetoembodiedcarboninbuildingstructures
5 Quantifying embodied carbon
Atitssimplestlevel,theessentialcomponents
requiredtoquantifyembodiedcarbonofabuilding
areadatabaseofindividualmaterialemissions(kgs.
ofcarbonperkgofmaterial)–asdetailedinaLife
CycleInventory(LCI)–andquantitiesofmaterials.
Thetotalembodiedcarbonisthenthesumofall
buildingquantitiesbrokendownbymaterial,including
anappropriateallowanceforsitewaste,multipliedby
theirunitimpact.
Inprincipletheprocessisthereforeverysimple,and
canbeapplied,forexample,byenteringtotal
quantitiesintoaspreadsheetcontainingembodied
carbondataforallmaterialsorproducts–the
difficultyisassemblingtheembodiedcarbondatafor
eachmaterial.Anumberoforganisationshave
developedLCIsbasedontheprinciplesoutlined
above,andhavemadetheseavailableformore
generaluse.Thisdatamaybepresentedforthe
basicmaterialsandproductsofconstruction,but
somesetsofdataarepresentedforcomponentsand
systems.Thesemightinclude,forexample,a
particularprecastfloorsystemaccountingfor
concrete,steelandincludingthecastingprocess,or
ahalfbrickmasonrywall,accountingforbothbricks
andmortar.Insuchcasesthedatamaybe
expressedinawaywhichisconsistentwithstandard
methodsofmeasurementusedfornormalestimating,
andusingappropriateunitssuchaskgs.ofcarbon
dioxidepersq.m.
TheInstitutionofStructuralEngineersAshortguidetoembodiedcarboninbuildingstructures 5
6 Sources of data
Thereareonlyafewsuchinventoriesproviding circumstancessuggestadifferentvalueshouldbe
sourcesofthismaterialdataandsomeoftheseare used,andnewinformationcanbeadded,givingboth
notreadilyavailablebecausetheyformpartof flexibilityandtransparency.Asimilarcombinationof
comprehensivelifecycleassessmentsoftware,orare economicandcarbondataforeverymaterialandunit
forinternalusewithinaparticularorganisation. ofworkisincludedinTheInstitutionofCivil
Engineer’slatesteditionofitsCivilEngineering
Oneimpartial,openandfreelyavailableinventoryis StandardMethodofMeasurement–CESMM3
theInventoryofCarbonandEnergy(ICE)developed Carbon&PriceBook7.
bytheUniversityofBath3,5.Thiscontainscradleto
gatedataforbothembodiedenergyandcarbonand Aruphasadoptedasimilarapproach,andhasalso
hasbeenlargelyassembledfrompublished includedfiguresrelevanttoproductsuppliers
informationandlifecycleassessmentsprovidedbya outsidetheUK.Althoughthisdataisnotpublished
varietyofsources.Thedatapresentedisasynthesis infullasaseparateinventory,itisintegratedinto
ofamuchbroaderrangeofdatacollectedbythe thecommerciallyavailableOasysstructural
authors;withindividualentriesbasedonanumberof software8.Thedataincludesmoreprecisefigures
differentstudiesforeachmaterial.Inevitablydatafor fordifferentconcretespecificationswhichAruphas
thesamematerialfromdifferentsourcesshowed usedinwholebuildingstudiesincollaborationwith
somevariation–partlyasaresultofvariationsinLCA theConcreteCentre8–10.Thesestudiesshowed
methodologies,butmoreparticularlybecauseofeven justhowmuchvariationtherecanbein
largerdifferencesinproductionmethods.Theauthors calculationsforembodiedcarbonasaresultof
havethereforehadtousetheirexpertjudgementto variationsinbothmaterialspecificationand
presentexplicitvaluesratherthanadatarange,but methodologyasillustratedinFigure5.Thisled
theresultsareconsistentwithotherdatabases.The naturallytotheconclusionthatitisimportantfor
authorsalsoacknowledgethattheembodiedcarbon engineerstoconsiderthedetailedspecificationof
datahasoftenhadtobecalculatedbasedon concreteratherthanusinggenericfiguresforthe
publishedinformationonenergyandthismay material,withreductionsashighas200kgCO /m2
2
thereforecompromiseaccuracyalittle.Despitethese achievedinextremecases.
reservationstheICEdatabaseisgenerallyrecognised
asprovidinggoodqualitydatafortheUK,anditis BREhasderivedindependentembodiedcarbon
freelyavailableinasuitableformat.Itistherefore figuresforstructuralandarchitecturalcomponents,
widelyused,andanumberoforganisationshave ratherthanbasicmaterialsandthesearepublishedin
useditasthebasisfordevelopingtheirowntoolsfor theGreenGuidetoSpecification11.Theinformationis
estimatingembodiedcarbon,butaswithany categorisedbybuildingelementorsystem,anduses
database,itslimitationsshouldbeunderstood.The alettergradingtorepresentthecombinationof
inventoryappearstobeactivelyupdatedwith thirteendifferentenvironmentalimpacts,including
revisionsappearingroughlyeveryyear,sousers embodiedcarbon.Thelatestedition(4th,pub.2009)
shouldensuretheyhavethelatestversion.Abrief oftheguidedoesincludeabsolutevaluesof
extractoftheICEdatabaseisshowninTable1. embodiedcarbonperfunctionalunit(typicallyone
However,itshouldbenotedthatthedatabase squaremetreoffloororwall)ofdifferentsystems,but
providesaconsiderabledegreeofrefinement,for
examplequotingdifferentdataforparticularconcrete
strengthsandspecifications.
450
Somecompanieshavepublishedtheirown
inventories,sometimesbasedontheICE,butrefining 400
thedatatosuittheirownapplications. Range of data
350
associated with
Asuspapnleemxeanmtipnlge,itMwoitthtMinadceDpoennadlednhtadsatuasewdhitchhetIhCeEy, 2g/m) 300 material specification
k
havesourcedthemselvesandinformationfrom O (2 250
manufacturers,tocreateadatabaseofcarbon C
e
dioxideemissionsforallactivitiesofconstruction al 200
work.Thisisincludedalongsideunitpricesinthe uctur 150 Range of data
latesteditionoftheannualpricebookwhichthey Str associated with
prepare6.Theinformationisrelatedtostandard 100 methodology
methodsofmeasurementforestimatingmaterial
quantities.Individualmaterialimpactshavetherefore 50
hadtobeprocessedandcombinedasnecessaryto
0
providedataforstandardelementsofconstruction.
Allbasedataiscradle-to-gate,sotransportationto
siteandotherdownstreamimpactsareignored,but Figure5 Variationsintheembodiedcarbonofthestructureof
appropriateplantonsiteisincluded.Aswiththe awholereinforcedconcreteframedbuilding,principallyasa
UniversityofBathdatabase,wheretheauthorshada resultofdifferencesinconcretespecification(CourtesyofArup).
rangeofdataforaparticularproduct,theyused (Themethodologyforaccountingforrecyclabilityofsteeland
somejudgementandpresentedasinglefigure.All thevariationsinmanufacturingmethodsusedisdiscussedin
datacanbemodifiedbytheuserifparticular Section7)
6 TheInstitutionofStructuralEngineersAshortguidetoembodiedcarboninbuildingstructures