What technical requirements define 2 ply modified bitumen roof membrane for asphalt or bitumen modification?

A 2-ply modified bitumen roof membrane typically requires specific technical standards, including a minimum thickness of 180 mils for the combined layers. The membrane must exhibit flexibility at low temperatures, with a low-temperature flexibility of -15°C (5°F) or lower. Additionally, it should have a tensile strength of at least 200 psi and elongation of 30% or more. The materials used must comply with ASTM D6162 or D6163 standards for performance and durability.