Which materials are typically included for fire resistance in low-slope membranes?

The inclusion of aggregate material and mineral granules in low-slope membranes is essential for enhancing fire resistance. Aggregate materials such as gravel or crushed stone serve as a protective layer that helps to shield the underlying roofing materials from the heat and potential flames, thus reducing the risk of ignition. Mineral granules, often found in modified bitumen membranes, also contribute to fire resistance by reflecting heat and providing a barrier that further protects the membrane.

This combination of materials not only improves the roof's ability to withstand fire but also adds durability and longevity to the roofing system. In contrast, other materials such as asphalt and tar, while widely used in roofing, do not offer the same level of fire-resistant properties when used alone without the protective granules. Metal sheets may provide some fire resistance due to their non-combustible nature, but they are not commonly associated with low-slope membranes in the same way that aggregate and mineral granules are. Synthetic fibers and adhesives are generally more focused on structural integrity and adhesion rather than direct fire resistance.

Overall, the choice of aggregate material and mineral granules in low-slope membranes is a critical factor in fire resistance, making these materials vital for roofing applications that prioritize safety against fire hazards.