b'SOLAR REFLECTIVITY Average Temperature Max Temperature1 12 23 34 4Distance from Wall (ft)Distance from Wall (ft)5 56 67 78 89 910 1011 115 6 7 8 9 1011 12 13 14 15 16 17 18 19 20 5 6 7 8 9 1011 12 13 14 15 16 17 18 19 20RoofTemperature ( C) o RoofTemperature ( C) oTime (24) Time (24)0-10 10-20 20-30 30-40 40-50 50-60 60-70 70-80 80-90Figure 9: Modeling shows high temperatures (60C to 80C+) extending well into the roof field over a period of four or more hours (Evoke/Morrison Hershfield).significantly impact design expec- Solutions choose a membrane that can accom-tations with respect to roof systemAlthoughthedatadoesnotsuggestmodate elevated temperatures.longevity and performance and mayimmediatesolutions,therearesome3. Incorporateoverhangsorother emergingideasandstrategiesthat generate a concurrent adjustmentmightservetomitigatehighroofshadingdevicesontheaffected to RoofStar Guarantee Standards.membrane temperatures: building faade (above the glazing 6.Vegetatedroofcoveringsurvival1. Protect the membrane with over- orintegratedintothecurtainwall assembly) to reduce solar reflectivity.could be severely impacted, simplyburdenmaterialssuchaspavers from high temperatures, or becauseor gravel. On the Horizonofacceleratedtrans-evaporation2.If the membrane must be exposedAlthoughthefinalreportfrom (Figure 9). (conventionally insulated assemblies),Morrison Hershfield and Evoke is not yet published, RCABC plans to review their findings with the RGC Technical Committee. At the very least, the MH/Evoke study will generate recommenda-tions for building and roof design and may eventually be summarized in a tech-nical bulletin.The modeling tool used by Morrison HershfieldandEvokeshowspromise asaninvestigativeinstrumentwhere membrane damage appears to coincide with reflective glazing. It may also serve as an effective interventionist design tool to anticipate issues before a design goes to tender.For further information on this study, contact RCABC at technical@rcabc.org, KatieHay(MorrisonHershfield)at KHay@morrisonhershfield.com, or Patrick Roppel(EvokeBuildingsEngineering) at proppel@EvokeBuildings.com. 28lROOFINGBC l SUMMER 2021'