ENVIRONMENTALAUDIT.

ENVIRONMENTALAUDIT

CONTENTS.

GlobalEnvironmentalImpact.

LocalEnvironmentalImpact.

CalculatedBuildingFabricHeatLoss.

Transportation.

WasteManagement.

Recycling.

InternalEnvironment.

NaturalLightLevels.

SoundLevelRecordings.

RelativeHumidity.

InternalTemperature.

Recommendations.

GlobalEnvironmentalImpact.

CO2EmissionsPerAnnum.

Belowweseethedataexpressingtheenergyuseandconsequential carbon dioxide emissions produced by

theindividualcasestudyflatsofThackleyEndperyear(Top).

Theaverageusedherein,forcarbondioxideemissionsfrom electricity use, is 0.55kg per kWh of electrical

energyused(Gupta,2008).Thisconversioninfersthattheenergyloadfor10100wattbulbsturnedonforan

hour,wouldproducecarbonemissionsof1/5kg.

Comparing this conversion rate of CO2/energy forelectricity,tothegasconversionrateof0.19kgofCO2per kWh (Gupta, 2008)1, we can see that the

environmental impact of gas ismuch less. The graphshown (Central) indicated the possible carbonfootprint for the individual case study flats had gas

beenusedasthesourceofenergy.

This last graph (Below) illustrates the comparison oftheresultantCO2footprintofgasandelectricalenergysourcing (forThackleyEndcase study flats). It canbe

seenthatallcasestudyflatsperformbadlyinregardstoenvironmentalimpact.Gupta(2008)statesthatitisbadforabuildingtoemitmorethan75kgofCO2per

m2 of floor area.With the electrical energy / CarbonKg conversiononlyoneof the flats (Flat 10) is belowthisthreshold.However,bysourcingtheheatingfrom

gas energy, the CO2 emissions would be greatlyreduced, resulting in ¾ flats being below the 75kg ofCO2 per m2 level.

1Gupta,R.,2008,PostOccupancyEvaluationLectures,10–12/2008,OxfordBrookesUniversity

LocalEnvironmentalImpact.

WaterEfficiency.

A reduced water consumption is beneficial to theenvironment.Environmentallyfriendlyusageofwateris

nottorestrictuse,buttoreducewastage.2

ThackleyEndwaterconsumptionismeteredbyasinglecentralmeter.

ThackleyEndWaterConsumption:8420Litres(perday/totalsite)

153Litres(perday/flat)

IndustryStandardConsumptionperflat:3148Litres(perday/flat)

TheThackleyEndcasestudyflatshadfewwaterefficientappliancesfitted.Thiswouldthereforeresult

in a highr rater of unnecessary water wastage. Occupants did stress interest in improving waterefficiency. Evidence of this keenness to conserve water amongst residents is the use of rainwaterrecycling tanks, on ground floor level that is presumed to be used to water the communal garden

spaces.

Appliances.

Energy efficient appliances can reduce water consumption as well as conserve energy (Waterwise,2006).TheintroductionoftheEUEnergyLabel,broughtintopracticein1996(broughtaboutbytheEU

CouncilDirective92/75/EEC,1992)hadbroughtaboutmandatoryratingofhouseholdapplianceenergyratingbetweenthebandsofA‐G.

AppliancesinthecasestudyflatswerenotallofoptimumArating.Improvingthiswouldimprove,and

consequentlyreduce,waterconsumptionandwastage.FurtherdetailsontheappliancesoftheThackleyEnd case study flats can be found in the Occupant Survey later in this document.2Waterwise(2006)http://www.waterwise.org.uk/reducing_water_wastage_in_the_uk/house_and_garden/saving_water_at_home.html3OxfordshirePartnership(2007)“Oxfordshire’sSustainableCommunityStrategy,Alongtermvisionforthe

county.Briefingpaper6:Environment”

Washingmachinetype Energyrating Energyusagelimitperkgat60oC

Litresperwashbasedon5kgload

Indesit1600WIXE167 A <0.19kWh 30litres

HooverSE220 A <0.19kWh 30litres

UnknownMake A <0.19kWh 30litres

MieleNovotronicW864 D <0.34kWh Approx50litres

UnknownMake D <0.34kWh Approx50litres

Table 1: European energy label ratings.  Energy labels: helping you make the right choice.  Defra, 2005 

Materials.

The buildings of the Thackley End site showed

considerable issues that would be detrimental toenergy conservation. The notable concerns werecold bridging through the specified single glazing

andmetalwindow frames and exposed structuralconcreteblockwork.

Externalwalls:

Dualskinof100mmconcreteblockswitha50mmcavity inbetween. Itmustbenotedthatthecavity

does not run the full height of the wall.In someplacesthere isnothermalbreakbetween internaland external surfaces (this would result in cold

bridging).Someoccupantshavereducedtheirheatlossesbyinstallinginsulationintothiscavitywhichhasprovensuccessful.

The floor slab is a 255m thick concrete slab that

runs through the building continuously frominternaltoexternalsurfaces.Whenwarmairrisesinsidetheflatstheheatenergyconductsthroughthisslabandoutofthebuilding.Severaloftheinternal

walls also penetrate to the external environment.Thiscoldbridgingisadetrimentalformofheatloss.

Illustration 1: Building fabric and cold bridging 

Whilst itcanbearguedthatadditionalheat lossmethods insummermonths(andperiodsofextremesolar gain) could be beneficial, this conduction of energy through the building fabric promotes the

penetrationofmoistureintheairintomaterialswhichisundesirable.

Thesingleglazingofthebuildingsoriginalspecifications, thatsomeoftheflatsstillhave,arecauseofconsiderable energy losses. As mentioned before, the single glazing promotes considerable energylosses when the internal / external ratio is high. The high amounts of single glazing also promotes

considerableheatgains inperiodsofhighsolar irradiation, furtheraffectedbythe limitedamountsofshadingontheseglazedsurfaces.

Some residents replaced this existing single glazing (and it’s metal frame which also has a highconductance)withdoubleandtripleglazingtocombatthisheatloss.

Evidence of these extreme solar gains can be seen in the colour bleaching of the soft furnishings

(notably the curtains) in the areas around the glazing in the flats. The curtains in Flat 38 wereparticularlyaffectedinthisway.

This photo illustrates the colour bleaching in the living room curtains of Flat 38. 

CalculatedBuildingFabricHeatLoss.

Flat10.

TheSankeydiagramandresultantpiechartillustratestheheatenergyincontactanddistributedwithin/throughtheflatinquestion.TheSankey

diagramshowsevendistributionofenergylossesthroughthewindowandwalls.ThisisexplainedbythesimilarareaandUvaluesofbothexposedwallsandwindows.

Atacostof£0.09perkWhofelectricity(Gupta,2008),flat10islosing£1.80perannuminwastedheat,andemitting11kgthroughlostheat.

Flat29.

ItcanbeassumedthatthegreaterpartoftheheatlossfromFlat29isconductedthroughtheroof:ithasalargeareaandconsiderablecoldbridgingissues.Thewindowsaredoubleglazedandthereforeshowareductioninlosseswhencomparedtothesingleglazedunits.

Atacostof0.09perkWhofelectricity(Gupta,2008),Flat29islosing£*.37perannuminwastedheat,andemitting51kgofCO2throughlostheat.

WindowArea:16.8m2

WindowUValue:2.7WallArea:15.2m2

WallUValue:3.03

RoofArea:46.64m2

RoofUValue:3.5WallArea:35m2

WallUValue:3.03

WindowArea:15.84m2WindowUValue:2.7

Flat38.

ThearearatioofwindowtowallinFlat38isverysimilartotheproportionsofFlat10.HoweverthewindowsinFlat38aresingleglazed(andconsequentiallyhaveahighUvalue)thereforeresultingina

higherrateofheatlossisthroughtheglazing.

Atacostof£0.09perkWhofelectricity(Gupta,2008),Flat38islosing£3.96perannuminwastedheat,andemitting22.55kgofCO2throughlostheat.

Flat50

AswithFlat29,itcanbeassumedthatthegreaterpartoftheheatlossfromFlat29isconductedthroughtheroof(ithasalargeareaandconsiderablecoldbridgingissues)withacalculated54.7kWhbeinglosteachyear.Thewindowsaredoubleglazedandthereforeshowareductioninlosseswhen

comparedtothesingleglazedunits.

Atacostof£0.09perkWhofelectricity(Gupta,2008),Flat29islosing£9.36perannuminwastedheat,andthereforeemitting57.2kgthroughlostheat.

WallArea:15.2m2WallUValue:3.03

WindowArea:16.02m2

WindowUValue:5.6

WindowArea:16.8m2

WindowUValue:2.7WallArea:34.32m2

WallUValue:3.03

Transportation.

AvailablepublictransporttoThackleyEndSite:

BusRoutes:

2,7Services:OxfordandKidlington.

27,59Services:Oxford,Bicester/WaterEtonPark&Ride.

BusStoplocatedverynearthe

ThackleyEnddriveway.

Thackley End occupants were asked if they used the buses; 10/11 saidtheydid.Thepurposesoftheirbususewereasfollows:

Travellingtowork:4/11 Otherdailyactivities:4/11

WeekendLeisure:6/11From the case study resident’s opinion, we were able to assume that

manyoftheoccupantsofThackleyEndcycle.Thereisabikestoreonthedevelopment,andanotherisbeingbuiltbypopulardemand.

Bicycle Overflow from bike store 

WasteManagement.

Thewastebins are emptiedweekly by theOxfordshireCity Council. Residents dispose of waste via rubbishchutes thatare locatedon the first landing levelof the

stairwell.Theseareutilizedbythemajorityofoccupantsasked, however there were concerns regarding beingunabletoseeifthewastestorebelowisfull.

Thereisrealconcernthattheeasy‐accesschutesystem

may discourage residents to walk to the bins furtherawayonsitatgroundfloorlevel.

Recycling.

Survey results showeda largemajorityof the residentsof Thackley End actively recycle. There is a generousrecycling unit that caters for all recycling needs and

materials such as glass, plastics,metal cans, paper andcardboard. The Oxford City Council empties the binsweekly.

Thereisalsoacompostingfacilityavailabletoresidents

butitisnotaswellusedastheotherrecyclingfacilities.

Bothrecyclingandwastemanagementarecoveredin

greaterdetailintheOccupantSurveylateroninthisdocument.

InternalEnvironment.

InternalCarbonDioxideLevels.

ComparingtheunitstobenchmarksitbecameclearthattheflatsinThackleyEndwereabovetheCIBSEgoodairqualitylevel.GenerallytheCO2ratingseitherreachedorjustexceededtheBSRIAcontrollevelforacceptableindoorqualityforshorttermexposure.Theseundesirablelevelsofcarbondioxidewould

ordinarilybeacauseforconcern.Howeveranomalies intheresultscouldhavebeencausedfromtheconsiderable increase in human activity – and consequential CO2 levels from the research team’sinteractionwiththeinternalflatenvironment.

ThehigherlevelsofCO2couldbecauseofpoorventilationintheflats.Thelateroccupantsurveygives

indicationtothisbeingapossibility.Occupantsseemedconcernedofheatlossesoverventilationneedswithinwintermonths and consequently overlook air quality in favour of reducing heating gains. TherecordingsweretakeninOctoberwhenthiswouldhavebeenthecase.

It however must be noted that, whilst CO2 levels are higher than the optimum level, they are not

significantlyhazardous.

Carbondioxideconcentrationpermillionparticules

Levels

300‐400 Typicalbackground(atmospheric)concentrations

600 Goodindoorairquality

800 BSRIAcontrollevelforacceptableindoorairquality(short‐termexposure)

1000 WHO(1984)concentrationoflimitedornoconcern(short‐termexposure)

NaturalLightLevels.

Theflatsseemedtohavebeendesignedwiththeintentionofallowingconsiderablelightpenetrationononefaçade(throughfloortoceilingglazing),tobleedintotheinternalspacescausinghighvisibilityand

thermaldelight.Theopposingfaçadeoffers lessnatural lightingaswindowscouldbeaprivacybreachduetothewalkwayastridetheentrancesandfacades.Thishashadthedetrimentaleffectofmakingtheinternalspacesconnectedtothisfaçade–oftenthebathroomandkitchen–darker.Thisglazedbalcony

accessed facade has also led to problems; the glazing causes uncomfortably high heat gains in thesummer months and consequential bleaching of the hard and soft furnishings. The glazing also isaccredited to severe heat losses in the evenings and winter months. These extreme reactions to

temperatureandsolargainareheightenedintheflatsthatstillutilizetheoriginalsingleglazing.

Thebelowgraphshowstheaverageddaylightfactorsinthreekeyenvironmentsinthefourflatsthatlightinglevelswererecordedin.

CIBSEDaylightFactorGrading:4

TooDark/CauseForArtificialLight:0‐2%ComfortableDaylightfactor:2‐5%

TooBright/CauseForGlare:+5%Surprisingly,consideringthehighwalltowindowratiosoftheflatstheoverallconsensusisthattheflats

are too dark. The light penetrates into the window at a considerable level, but attenuates quickly.Artificial lighting is required to light the areas under 5%. It however must be noted that the abovereadingsweretakeninNovember,resulting inconsiderably lowersolar irradiance.Hadthesereadings

beentakeninpeaksummermonths,theAuthorbelievestherewouldbeconsiderableproofofglareinglazedspaces.

SoundLevelRecordings.

Soundqualitywasnotmuchcauseforconcern within the flats of ThackleyEnd. The author did not find external

noise pollution within the interiorspaces of the flats disturbing. Somelight traffic noises could be heard but

nothingtoointrusive.

There was a slight increase in trafficnoises in the blocks closest to theBanbury Road, but nothing of a

considerablelevel.

4CIBSE(1997)“BritishLightingGuide”UK

Itshouldbenotedhowever,betweensomeofthebuildingswithintheThackleyEnddevelopmenttherewasslightechoingofsound.Thismayaccentuatethesoundsofcarspassingintothedevelopmentthat

couldbeaudiblethroughthesingleglazedbedroomwindowsfrontingthecarparkingspacesanddrives.Occupantshoweverdidnotpasscomment.

 

Table 2: dBa volume levels,  

Mike Wilson, sound physics 

 lecture on 03/11/08 

 

 

 

 

Table 3: dBa volume levels  

recommended by CIBSE 

  Guide A : Environmental  

Design,2008 

RelativeHumidity.

Due to occupants concern for heat retention in winter months (as a result of considerable losses

through glazing and cold bridging), there is a considerable reduction in ventilation. This results inhumidityfromcooking/bathroomactivity,thatisunabletopassoutintotheexternalenvironment.

Itislaterrecorded,intheOccupantSurvey,thatcondensationoftenformedontheinternalsurfacesoftheglazing, inferringahighhumidity in the coldwinterperiods. Theauthornotedoneof the flats to

haveadehumidifierinthemonthofOctober.

Occupants were also recorded in saying that, during summermonths, the flats were well ventilated(fromactingagainsttheincreasingsolargains),andthereforetheinternalspacessufficientlypenetratedbyfreshairforhumiditytocollectorsettle.

DecibelVolume Comparisons

61dBa levelofaconversation

84dBa levelforstreettraffic

100dBa levelforapneumaticdrillat7mdistance

DecibelVolume Comparisons

31dBa levelforabedroom

36dBa levelforalivingroom

41dBa levelforalibrary,bank,museum

64dBa levelofalightengineeringworkshop

InternalTemperature.

Flat10.

Thetemperature inFlat10remains relativelyconstant.Despitesomefluctuation, itdoesnotseemtoalter temperature too rapidly in comparison to other flats. The occupant does not use under‐floor

heatingwhichwould ordinarily insinuate a constant regulated temperature, but uses a large electricheater to caterhis thermalneeds. Itmust alsobenoted that this flat is considerably colder than theothers,whichbringstheinternalclosertotheexternaltemperature,resultinginalessrapidheatloss.

Flat29.

Flat29showserraticchanges intemperature,notably inthediningandlivingroomareasthatshowasteep incline / increase in temperature in themornings. The occupant complained of excessive solargainsresultinginuncomfortablesolargain.Thisdatagivesevidenceofthis.Theoccupantcombatedthis

problembyclosinginternalcurtainstoscreenfromthesun.Thishoweverdoesnot impedesolargains

andalthoughperceivedcomfortisimproved,thetemperatureisstillincreasing.

GraphforFlat29overleaf.

Flat38.

Flat 38 is heated by under floor heating that is turned on between 7pm and 7am using off peak(cheaper)electricalpower inthenighttimehours.Kitchenand livingareasshowagradual increase in

temperatureintheeveningtoapeakataround10.30.Thetemperaturethengraduallydecreasesduringthe day. This is not to the occupants satisfaction who claimed to be uncomfortably warm on somemorningsanduncomfortablycoldinsomeevenings.

Flat38showsfluctuationsinthelivingroomarea.Thesesteadychangesoftemperaturebetween24.5–21oC(atworst),giveafluctuatingtemperaturedifferenceof3.5oCwhichisoutsidetherecommended

limit.5 The orientation of the flat (predominantly glazed façade iswest facing) so there could also besomecauseoftemperature increaseaccreditedtosolargains.Thebedroomspace,separatefromtheliving / dining room spaces, seems to be amore constant temperature, which shouldmost likely be

resultanttoseparateheatingcontrolsandinternalpartitions(walls)allowingittomaintainaseparatethermalenvironment.

Recommendations.

NoCost

Improvethemanagementofthecompostheaptoencourageoccupantstoutilizethismethodofrecycling(notablyforfoodandgardenwaste)more.

Installcisterndisplacementdevicesintoiletstoreducewaterconsumption.

LowCost

Improveeaseofrecyclingbyaddingrecyclingchutestothestairwell,thereforeencouragingmoreoccupantstorecycle.

Installwaterefficientbathroomandkitchenfittingstoreducewaterwastageandconsequential

consumption.Pricesforketfixturesareasfollows:

Room Item Unitcost Totalcost

5Gupta,R.,2008,PostOccupancyEvaluationLectures,10–12/2008,OxfordBrookesUniversity

Bathroom Toiletwatersaver(ekohut,2008a) 12.33 x1=12.33

Efficientshowerhead(ekohut,2008b) 5.95 x1=5.95

Tapaerator(ekohut,2008c) 6.45 x2=12.9

Kitchen Tapaerator(ekohut,2008c) 6.45 x2=12.9

Totalperflat £44.08

MediumCost

Improvebicyclestoragefacilitiestoimproveoccupantsatisfactionandtoencouragecyclingover

otherlesssustainablemethodsoftransport.

Improvelightingintherearoftheflatsbyinstallingfrontdoorswithglazing(frostedifprivacyisaconcern):Costofafrontdoorwithglazingisapproximately£160.6

Upgrade washing machines and dishwashers to A Rated Energy Efficiency to reduce waterwastageandenergyconsumption:ARatedwashingmachineisapproximately£160.7

ARateddishwasherisapproximately£250.8

HighCost

Install double/triple glazing to replace single glazing. This reduces heat losses and thereforeenergyspaceheatingconsumptionandcosts.

Professional assessment of the high levels of carbon dioxide within the flats, and install any

resultantimprovedventilationifnecessary.

Install gas infrastructure for heating and cooking purposes to reduce CO2 emissions (asmentionedearlier (Gupta,R,2008)electricityproductionproducessignificantlyhigherratesofCO2perkWhthangas).ToretainsustainableethosofThackleyEndresidentstheenergysource

shouldideallybechanged.

6Doorwarehouse(2008)http://www.doorwarehouse.co.uk/showdoor2.php?args=EALIMA3U00~(A3)~(E)~ 

(.)~(001)~(M)~(.)~(.) UK. 7Amazon.co.uk(2008)Hotpoint‐FDW85A‐FDW85‐Dishwasher, http://www.amazon.co.uk/ 

Hotpoint‐FDW85A‐FDW85‐Dishwasher/dp/B0002TTKFU/ref=sr_1_4ie=UTF8&s=kitchen&qid 

=1229223576&sr=1‐4.UK.Accessed13December2008.

8Amazon.co.uk(2008)Indesit‐Washing‐Machine‐WIA101, http://www.amazon.co.uk/Indesit‐Washing‐Machine‐WIA101/dp/B000ILZ286/ref=sr_1_1?ie=UTF8&s=kitchen&qid=1229223469&sr=1‐1 UK.Assessed13December2008.

Introducesolarshadingdevicestoreducetheinternalsolarheatgainsthataremajorcauseforconcern.Therecanbearangeofsolutionstoamendthis(externalshutters,glazinglaminates,

awningsetc.).Theestimatedaveragecost isapproximately£180/m.Thisresultstoanaveragecostof£1296perflat.9

Reduce building fabric heat loss by over cladding with hempcrete. Cost: £145/m2. 10

9GreenSpec(2008)http://www.greenspec.co.uk/html/durability/solar_shading.html UK.Assessed13December.10Wilburn,G.(2008)“1960’s Concrete Framed Housing : Barriers and opportunities when sourcing materials from 

within Oxfordshire, to over‐clad and improve the envelopes’ thermal performance.”UK.

Room Item Unitcost Totalcost

Bathroom Toiletwatersaver(ekohut,2008a) 12.33 x1=12.33

Efficientshowerhead(ekohut,2008b) 5.95 x1=5.95

Tapaerator(ekohut,2008c) 6.45 x2=12.9

Kitchen Tapaerator(ekohut,2008c) 6.45 x2=12.9

Totalperflat £44.08