b'ENERGY EFFICIENCYvalidate their performance relative toproofinglayer.Allexperimentswereprovide the relation between gap height, the code requirements. The test matrixconducted at Tmean=24 C (75 F).gap width, and overall thermal perfor-comprisedadhesiveappliedroofingThe objective of the thermal bypassmance of the roof assembly. The study systems(AARS),partiallyadheredstudywastoquantifytheheatlossidentified that the presence of the gaps roofsystems(PARS),andmechani- throughthegapsanddevelopappro- betweentheinsulationboardslowers callyattachedroofsystems(MARS)priategapimpactfactorsrelatingthethe overall thermal performance of the designedwiththreedifferentinsula- gap geometry with the thermal perfor- roof assembly. The combined effect of tion types: Polyisocyanurate (Polyiso),mance. More than 70 experiments werethermalbridgingandthermalbypass ExpandedPolystyrene(EPS)andconductedtogatherthermalperfor- isfoundtohaveuptoa20-per-cent Stone Wool (SW).mancedataontheeffectofgapsindecrease in the overall thermal efficiency Thetestprotocolinvolvedtheroofingassemblies.Fourparametersofroofassemblies.Thesedeveloped measurement of the thermal resistancewere evaluated, the width of the gaps,thermal impact factor curves will allow of the insulation component and effec- theheightofthegaps,theimpactofdesignerstousethesefactorsinthe tive thermal resistance of the roofingthroughgapsvs.staggeredgapsandthermal resistance calculation of the roof assembliesatfourdifferentmeantheimpactofgapoffsetinstaggeredassembliestowardsdeterminingtheir temperatures representing a very coldlayouts.Theexperimentalsetupandenergy resistance and code compatibility.climate to solar-heated climatic condi- testing of the thermal bypass study wereIn this era of net-zero buildings and tions.Allthetestingwasconductedsimilartothethermalbridgingexceptclimateresiliency,everydetailtowards on the 8 ft x 20 ft Calibrated Hot Boxwithout fasteners.enhancing the energy efficiency of the (CHB) located at the NRCs DynamicTask1revealedthattheenergybuilt environment should be accounted RoofingFacilityEnergy(DRF-E)resistance of 80 per cent of the testedforandacknowledgedatthedesign lab. The experimental research high- assemblies was below the target designstage. To benefit the roofing community, lightedtwoinfluencingparametersvalues. In Task 2thermal bridging, aeffortsareunderwaytowardscodifica-thatarecurrentlynotconsideredingeneralized fastener impact factor curvestion of this research-generated thermal the energy design of the roof: one ishighlightingtherelationshipbetweenperformancedata,andalsodevelop-thetemperaturedependencyperfor- fastener density and effective R-value ofment of a web calculator, Energy-Roof mance of insulation and its impact ontheroofassemblywasdeveloped. TheCalculatorontheInternet(Energy the effective R-value, and the second iscurves emphasize that thermal bridgingRCI),thatwouldprovidesolu-the thermal bridging of fasteners.increases with the fastener density. Thetionstodevelopenergy-efficientcode InTask2,twothermalimpactrelative quantity of thermal bridging alsocompatible roofs.factors (TIF)thermal bridging fromincreases with increasing thermal resis- Sudhakar Molleti is a research officer, fastenersandthermalbypassfromtance (and thickness) of the insulation.CivilEngineering-RoofatResearch gapsbetweentheinsulationboardsSimilarly, for the thermal bypass, gapCouncil Canada and Bas Baskaran is a werequantified.Allthetestingforimpact factor curves were developed togroup leader at Research Council Canada.thequantificationoftheTIFswas conductedonthe1.2mx1.2m (4 ft. x 4 ft.) horizontal Guarded Hot Chamber(GHB).Thesmallscale testing on the 1.2 m x 1.2 m (4 ft. x 4 ft.) GHB allows for the isolation of acomponentfromafull-scaleroof assemblyandthein-depthanalysis ofthethermalperformanceofthatSetting the Standard forcomponentanditsinteractionwithElectronic Leak Detectionother roofing components. In assessing the impact of thermal bridging, more than 100 experiments were conducted, highlighting the effect of fastener density, fastener location, fastenerdiameterandfastenerpene-trationdepth.Allthermalbridging tests included a steel deck as the struc-tural substrate, fibre-glass faced dens deck as the cover board over the three insulation types as tested in Task 1 and www.detecsystems.comthermoplastic membrane as the water-www.rcabc.org l33'