Materials required to be noncombustible must be tested in accordance with which standard?

Materials that are required to be noncombustible must be tested in accordance with ASTM E 136. This standard specifically evaluates the noncombustibility of building materials by determining their performance when exposed to a specified heat source. The test measures whether the material ignites, burns, or produces significant amounts of smoke or toxic byproducts.

This testing is crucial because it helps ensure that materials used in construction do not contribute to fire hazards, thereby enhancing the safety of commercial buildings. Noncombustible materials can be crucial in building design and fire protection systems, particularly in areas that are subject to high fire risks.

In contrast, the other standards listed serve different purposes. ASTM E 84, for example, is used to determine the surface burning characteristics of building materials but does not specifically address noncombustibility. UL 723 is similar in scope to ASTM E 84 and pertains to surface burning characteristics as well. UL 725 deals with the classification of materials, but not directly with determining their noncombustible properties. Therefore, ASTM E 136 is the appropriate standard for testing noncombustibility in building materials.