Maintaining color and structural integrity, PHASE-2® PVC Siding, Roofing, and Louver Panels are heavy gauge PVC extruded sheets with Non-Combustible Flame Spread Rating of 12. FM-approved for unlimited height use without need for sprinkler protection, completely UV-resistant panels also resist corrosive conditions. Impact- and completely UV-resistant UNITREX® Polycarbonate Panels provide long term durability against denting, cracking, and peeling. Non-combustible flame spread rating is 6.