What technical requirements define firestone modified bitumen for asphalt or bitumen modification?

Firestone modified bitumen is defined by specific technical requirements including the use of SBS (styrene-butadiene-styrene) or APP (atactic polypropylene) as modifiers, which enhance flexibility and durability. The material must meet ASTM D6164 standards for performance, ensuring resistance to UV degradation, temperature fluctuations, and mechanical stress. Additionally, it should exhibit low-temperature flexibility and high-temperature stability, with a minimum tensile strength and elongation specified to ensure reliable performance in roofing and waterproofing applications.