b'Pavers (Ballast) Filter layer /Water flow resisting layer (optional) Insulation Drainage layer (optional) Roofing Membrane Structural DeckPMRAFigure 3: Cross-sectional schematic of the DRF Energy guarded hot box (GHB). loss due to precipitationa factor exper- the test method for measuring thermalThisinnovativetestingapproachimentally determined using guarded hotperformanceofbuildingenvelopeenabledresearcherstoquantifyU , rainbox(GHB)testing.TheGHBappa- assemblies using a hot box. thechangeinthermaltransmittanceratusattheDynamicRoofingFacilityIn this study, however, the standardduetomoistureintroducedbyrain. (DRF)EnergyatNRCisalarge- GHBsetupwascustom-modifiedtoThe results offer valuable data on how simulaterainfallconditionsofvaryingPage 1 of 4 scale,horizontallyorientedtestsetupPMRA systems perform thermally under measuring eight feet by 20 feet, specif- steady-state heat flow conditions while intensities on PMRAs (Figure 3). These ically designed to evaluate heat transfermodifications allowed for simultaneoussubjectedtosimulatedwet-weather through full-scale roof assemblies under exposuretocontrolledprecipitationscenarios, thereby enhancing our under-controlled conditions. andheat-flowmeasurement,providingstandingofin-serviceperformance Foradetailedexplanationoftheinsight into how realistic weather eventsunder real-world climate exposure.GHBs standard operation, readers areinfluence the thermal behaviour of theNinePMRAswereselectedfor referred to ASTM C1363, which outlinesroof system. thermalperformancetestingusing Roong solutions, when and where you need them. BURPAKWith our nationwide network, count on fast, reliable delivery anywhere in Canada.ByGet started with QXO11155St-CatherineStreetEastServing contractors across British Columbia Montreal-East,QC H1B0A4Surrey | Burnaby and more Tel.:514645-4561bitumar.com22 lROOFINGBClFALL 2025'