b'PHOTOVOLTAICS PHOTOVOLTAICSBY JAMES KLASSEN ON ROOFS Planning andA sbuildingdesignsturneverphotovoltaics: planning for photovol-moresharplytowardenergytaics, designing for roof system perfor-conservation and clean energymance,buildingforsaferoofmain-designing forgeneration,aflurryofinno- tenance and securing the PV system. vations, demand and ad hoc adaptationsForamorecomprehensivetechnical success has placed rooftop photovoltaics in thereference, read the CSA Standard for construction spotlight. Yet, there are fewphotovoltaicinstallation,SPE-900-13, accessible standards to guide the designSolarphotovoltaicrooftop-installationbest process.Thisarticleiswrittenaboutpractices guideline.roofing and roof design, for those whoDefinedtermsareitalicized;look want to know how to design a roof thattotheRoofingPracticesManualfor supports photovoltaics, so that both thedefinitions. We use the acronym PV roof and the photovoltaic system realizeand refer to clusters of PV panels as maximum benefits for the owner. an array. Arrays are made up of two or Thisarticleisnotacomprehen- more panels mounted on racking systems sivestudyofthesubject,andinsteadwhich, in turn, are attached to support touches on four key elements necessarystructures that secure the PV array to the to design a resilient roof that supportsroofassembly or system.26lROOFINGBC l FALL 2020'