b'Energy LossesROOF ASSEMBLY MINIMUM EFFECTIVE R-VALUE Towards the effort of enhancingsulationboards.Combiningthebox (CHB) at the Dynamic Roof-the energy efficiency of commer- outputs from both these tasks, theingFacility(DRF)energylabto NECB ZONESMETRICIMPERIALcial roofs, the National Researchfinal goal was to generate code- determine the effective thermal re-(m 2 KW) (ft 2 FhrBtu) CouncilCanada(NRC)devel- compliant solutions that could besistance of roofing assemblies. The opedanindustryconsortium:applicable to roof thermal designsresults from Task 1 are published 4 R-4.4 R-25 Energy Resistance of Commercialtoensureenergy-efficientandin the conference paper 10submit-Roofs (ERCR). These partners in- code-compliant roofs. This paperted to the ASTM D08 Ninth Sym-5 R-5.5 R-31 clude the International Institute offocuses on Task 2thermal bridg- posium on Roofing Research and BuildingEnclosureConsultantsing from fasteners, where it quan- Standards Development.(IIBEC),theNationalRoofingtifiesthethermaleffectofroofIn Task 2, thermal bridging, the 6 R-6.2 R-35 Contractors Association (NRCA),fastenersincommonconfigura- objective was to quantify the heat CanadianRoofingContractorstions within widely implementedlossesfromfastenersandtheir 7A/7B R-6.2 R-35 Association(CRCA),Roofingroof assemblies.associated impact on the energy Contractors Association of Britishdesignofroofs.Theinsulation 8 R-7.1 R-40 Columbia(RCABC),Sika,Tru- Methodology thickness and layout remain the fast, EPS Industry Alliance, Rock- The methodology followed insame as described in Task 1 (Ta-Table 1: NECB zone thermal requirements. 9 wool,Soprema,2001CompanyTask 2 is an extension of Task 1, soble 3), with the exception of test and the Natural Resources Canadathis section will begin with a briefspecimen size. The testing for the ROOF ASSEMBLY MINIMUM EFFECTIVE R-VALUE Program of Energy Research andoverviewofTask1,followedbyquantificationofthermalbridg-Development (PERD). the Task 2 experimental approach. ing was focussed on 1.2- by 1.2-ASHRAE ZONES METRICIMPERIALTheERCRconsortiumproj- In Task 1, the thermal transmit- m (4- by 4-ft.) insulation aboard (m 2 KW) (ft 2 FhrBtu) ect had two major tasks. In Tasktance of roofing systems that areandwasconductedonthe1.2- 1, the objective was to evaluatedesigned with the energy codesby 1.2-m (4- by 4-ft.) horizontal 1 R-3.7 R-21 the effective thermal resistance ofprescriptiverequirementswasguarded hot box (GHB) (Figure current roof designs and validatedetermined.Thiswasachieved3). The GHB has been designed, 2/3 R-4.5 R-26 their compliance with the energyby a three-step approach. In theconstructed and calibrated in ac-code requirements. In Task 2, thefirst step, the prescriptive thermalcordancewithASTMC1363, 4/5/6 R-5.4 R-31 aim was to quantify the impacttransmittancerequirementsforStandardTestMethodforThermal of two factors: thermal bridgingroofs as specified in the NECBPerformanceofBuildingMaterials (Table1)andASHRAE90.1- and Envelope Assemblies by Means 7/ 8 R-6.3 R-36 fromfastenersandthermalby- 2013(Table2)aresummarizedof a Hot Box Apparatus. 11The test-passfromgapsbetweenthein- and consolidated into three cat- ing on the GHB allows for the Table 2: ASHRAE zone thermal requirements. egories:R-26,R-31andR-36.isolation of a component and the ASHRAEclimaticzone1andin-depth analysis on the thermal BOARD THICKNESS R-25.21 R-30.21 R-35.21 NECB climatic zone 8 were ex- performance of that component cluded from the study. It shouldanditsinteractionwithother be noted that R-26, R-31 and R-36roofing components.Polyisocyanurate (polyiso) 51 mm + 64 mm 51 mm + 84 mm 51 mm + 102 mm are effective R-values that includeMorethan100experiments [2 in. + 2.5 in.] [2 in. + 3 1/3 in.] [2 in. + 4 in.] both the outside and inside sur- wereconductedonthermal face air films. Excluding air films,bridging, highlighting the impact Expanded Polystyrene (EPS) 80 mm + 80 mm 98 mm + 98 mm 117 mm + 117 mm the design thermal resistance forof fastener density, fastener loca-[3 1/8 in. + 3 1/8 in.] [3 7/8 in. + 3 7/8 in.] [4.625 in. + 4.625 in.] the roofing assemblies are R-25.21,tion,fastenerdiameterandfas-R-30.21 and R-35.21, respectively.tener penetration depth. All ther-Stone Wool/Mineral Wool 64 mm + 102 mm 102 mm + 102 mm 140 mm + 102 mm The energy codes require the roofmal bridging tests included a steel [2.5 in. + 4 in.] [4 in. + 4 in.] [5.5 in. + 4 in.] assemblies to be designed to meetdeckasthestructuralsubstrate, these minimum effective R-valuesfiberglass mat gypsum roof cover Table 3: Design insulation nominal thickness for achieving the respective R-value (determined by ERCR members). to achieve a specific level of energyboardandthermoplasticmem-efficiency. This design is achievedbrane as the waterproofing layer. using R-values of the componentsAll experiments were conducted measuredatastandardaverageatameantemperatureof24C temperature of 24C (75F).(75F),withclimaticchamber The second step was the selec- maintained at 4C (39F) and me-tionanddesignofroofassem- tering chamber at 44C (111F).blies.TheERCRsteeringcom-mitteemembersdesignedthreeImpact of Fastener Densitydifferent conventional low-slopedTounderstandtherelation-membraneroofingsystems:ad- shipbetweenfastenerdensity hesive-appliedroofingsystemsand thermal bridging, experimen-(AARS), a fastener-free assembly,taltestingwasconductedwith PARS, and seam-fastened MARS.three different fastener densities: Using the insulation R-values per2.69, 4.04 and 6.73 fasteners/m 2inch provided by the manufactur- (0.25,0.38and0.63fasteners/ers,theoverallinsulationthick- ft. 2 ) installed on the three design nesses (top and bottom layers) forcategoriesR-26, R-31 and R-36 these three design categories wereroofconfigurations(Figure4). determined by the ERCR steeringFastener #14 (Head- 11.13 mm committee as shown in Table 3.[0.438 in.], shank- 6.02 mm The third step in Task 1 was de- [0.237 in.]) was the standard fas-signing 36 assemblies from Steps 1tenerusedforthisinvestigative and 2 and testing them on the 8-study. Metal fastener plates with a by 20-ft horizontal calibrated hot76-mm (3-in.) diameter were used 22ONTARIO ROOFING NEWSISSUE 1 2020 THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ORN'