What is the maximum flame spread rating for composite materials to qualify as a noncombustible material?

To qualify as a noncombustible material, composite materials must meet strict criteria regarding their flame spread rating. The maximum flame spread rating allowed for composite materials to be classified as noncombustible is indeed 50. This rating is determined through standard testing methods, which assess how quickly flames can spread across the surface of the material.

A flame spread rating of 50 or lower indicates that the material does not readily ignite or allow flames to spread quickly. This is critical not only for the safety of the structure but also for compliance with building codes that aim to protect occupants and property from fire hazards. Understanding these ratings helps inspectors ensure that materials used in construction meet safety standards.