PrevENt TP-HD-Cap Heat Welded Cap Sheet is constructed with a tough composite reinforcement of non-woven polyester strengthened with a glass fiber scrim in both machine and cross directions. During the manufacturing process, expandable graphite is added above the reinforcement to impart excellent exterior fire resistance properties. Class A-rated PrevENt TP-HD-Cap is coated top and bottom with select SBS polymers and premium quality asphalt to a thickness of 4.0 mm (158 mils). Ceramic coated mineral granules are embedded in the surface of the product to provide protection against ultraviolet radiation. A light mirco-perforated film is bonded to the underside and conveniently disappears upon heat welding. PrevENt TP-HD-Cap can be used as a protective cap for a conventional BUR system, as the top ply in a two-ply TorchflexTM system, or as the top ply in a flashing installation.