This specification covers Grades G (granule surfaced) and S (smooth surfaced) prefabricated bituminous sheet materials reinforced with a combination of polyester fabric and glass fiber, and modified with atactic polypropylene (APP), intended for use in the fabrication of multiple ply roofing and waterproofing membranes. This specification is intended as a material specification only, and does not address issues regarding the suitability of specific roof constructions or application techniques. The specified tests and property limits used to characterize the sheet materials covered by this specification are intended to establish minimum properties. Also, in-place roof system design criteria such as fire resistance, field strength, impact/puncture resistance, material compatibility, uplift resistance, the need for field applied coatings, and others are factors beyond the scope of this material specification. The physical properties for which sheet materials shall be tested on and consequently conform to are peak load before and after heat conditioning, elongation at peak load, tear strength, low temperature flexibility, dimensional stability, compound stability, granule embedment, water absorption, moisture content, and low temperature unrolling. This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.