What contributes most to fire resistance in low-slope roofing membranes?

In low-slope roofing membranes, aggregate or mineral granule surfacing plays a crucial role in enhancing fire resistance. This surfacing material contributes to the durability and overall performance of the roofing system, providing a protective layer that helps prevent the spread of fire. The granules create a barrier that can withstand high temperatures and resist direct flame contact, thereby extending the time it takes for fire to penetrate through to the underlying materials.

The granule surfacing also serves to reflect heat and UV rays, adding to the longevity of the membrane and further decreasing the risk of thermal degradation, which could lead to increased fire risk. This characteristic makes aggregate or mineral granule surfacing essential for maintaining a safe and effective roofing system in accordance with building codes and standards that require fire-resistive qualities, especially in low-slope applications.

In contrast, plastic sheeting is more associated with moisture barriers than fire resistance, while reflective roof coatings primarily focus on energy efficiency and temperature regulation rather than fire protection. Fiberglass insulation is beneficial for thermal performance but does not directly contribute to the fire resistance of the roofing membrane.