noncombustibility

Noncombustibility refers to the property of a material to resist ignition and to not sustain combustion when exposed to fire conditions. In building and construction, noncombustible materials are preferred for structural elements and fire barriers because they contribute little or nothing to flame development, heat release, or smoke production.

Classification and testing: Standards such as ASTM E136 and ISO 1182 are used in the United States and internationally to determine noncombustibility. Under EN 13501-1, materials can be classified as A1 or A2 noncombustible, indicating no significant contribution to fire.

Common examples include concrete, brick, stone, ceramic, glass, and many metals. Mineral wool and other mineral-based insulation products are often rated noncombustible. Many organic materials are combustible, but some composites designed with noncombustible cores or facings may also be rated noncombustible under the relevant standard.

Limitations and scope: Noncombustibility does not equate to fire resistance, which is about maintaining properties under fire exposure for a specified period. A noncombustible component can fail structurally under prolonged heat, and coatings or fasteners may still be affected by fire. Local building codes define where noncombustible materials are required and how they are tested.