b'PMRAFollowingthis,simulatedrainfall atfourintensities(0.25,0.5,1and2By comparing thermal performance in wet and dry mm/hr) was applied for 24 hours at a steady 14C to evaluate heat loss due to precipitation. The goal was to determine states, the study provides key insights into howU ,theincreaseinheattransfer raincaused by water infiltrating beneath therainfall affects the insulating capacity of PMRAs, insulation or at the membrane level.By comparing thermal performancesupporting improved design guidance and futurein wet and dry states, the study provides keyinsightsintohowrainfallaffects theinsulatingcapacityofPMRAs,code development.supportingimproveddesignguidance and future code development.Figure5illustratessampleresults fromGHBtestingforfourPMRAs evaluatedinSource1(S1),illustrating howrainfallimpactstheirthermal performance. In this study, each PMRA system was constructed with two layers of shiplap insulation. The base assem-bliesincludedPMRA-1,whichhada flatbottominsulationboardwithno drainage channels, and PMRA-2, which incorporated drainage grooves designed tofacilitatewaterflow.TwomodifiedRoof Consulting ServicesvariantsPMRA-5 and PMRA-6were developed from PMRA-2, with PMRA-5 adding a filter fabric layer and PMRA-6 includinganadditionaldrainagelayerThird Party Rooftop Quality AssuranceProject Management & Administrationwith surface dimples. Substrate Structural TestingAsbestos TestingAdhesion & Fastener Testing Plaza Decks & ParkadesRoof Condition AssessmentRoof Anchor Design & TestingUnderdryconditions,PMRA-1Roong Design & Specications Green Roofs & Photovoltaicdemonstratedaslightlyhighereffec-tive R-value (34.3F ft 2hr BTU-1 [6.04604.295.8070rimkus.comm 2 KW-1])comparedtoPMRA-2 (32.1F ft 2hr BTU-1 [5.65 m 2K W-1]). However, when subjected to 24 hours ofsimulatedrainfall,PMRA-1exhib-ited a more significant decline in thermal performance, losing up to 73 per cent of its R-value, while PMRA-2 showed asmallerlossofupto65percent. This difference is largely due to the flat insulationsurfaceinPMRA-1,which allowedwatertospreadmorebroadlyFrom heavy-performance roofing andincreasethesurfaceareaforheatunderlayments and leak barriers transfer. In contrast, the drainage chan- to reliable floor protection,nels in PMRA-2 helped to direct waterFT Solutions has you covered.awaymoreefficiently,minimizingits contact with the insulation surface andYou have a job to do.thus reducing thermal bridging. We have the materials.Themodifiedassemblies,PMRA-5 andPMRA-6,demonstratedevenwww.ftsolutionsroof.comgreater reductions in R-value, with losses ranging from 58 per cent to 76 per cent depending on rainfall intensity. Although www.rcabc.orgl25'