Firestone APP 180 FR is a granule-surface APP modified bitumen roofing membrane designed to be heat-welded. It consists of select asphalt, modified with atactic polypropylene, and strengthened with a fiber glass reinforced polyester nonwoven mat (190 g/m² (3.9 Lbs./100 ft²) made with 100% recycled PET fibers. APP 180 FR is a membrane that is strong and stable, and resistant to natural forces and other factors on the roof-top. The addition of fire-retardant materials increases the fire resistance of the membrane. APP 180 FR is ideal for both new construction and reroofing applications as a cap sheet or as a flashing sheet in single or multi-ply APP applications.