What does Class C flame spread represent in terms of numerical range?

Class C flame spread represents materials that fall within the numerical range of 76 to 200. This classification is part of the ASTM E84 (Standard Test Method for Surface Burning Characteristics of Building Materials), which evaluates the flame spread characteristics of various materials.

Materials that are rated Class C indicate a moderate level of fire risk; they can ignite and spread flames at a speed that is higher than Class A or Class B materials. Understanding flame spread classifications is crucial for building inspectors as it helps to ensure that appropriate materials are selected for construction to maintain safety standards. In contrast to Class C, materials designated as Class A reflect lower flame spread ratings (0-25) and Class B ratings (26-75) signify a moderate, but safer, response to fire.