selfextinguish

Self-extinguish, or self-extinguishing, describes a property of materials or systems that cease burning once the ignition source is removed. This behavior reduces the risk of fire spread and is desirable in textiles, plastics, foams, and other fuels. It is often contrasted with materials that sustain flame or require external intervention to stop burning.

The self-extinguishing behavior arises from mechanisms that limit heat feedback, fuel supply, or oxygen availability. These include the formation of a protective char layer that insulates underlying material, endothermic decomposition that absorbs heat, release of water or other volatiles that dilute flammable gases, and the use of additives that suppress flame propagation. The effectiveness depends on material composition, thickness, and exposure conditions such as heat flux and air flow.

In practice, self-extinguishing properties are evaluated with standardized flammability tests. For textiles, tests like NFPA 701 assess flame propagation and afterflame time. For plastics and other polymers, tests such as UL 94 classify the tendency to stop burning. Building materials may be tested to meet fire safety codes as well. It is important to note that self-extinguishing does not imply the material is nonflammable; under sufficient heat or flame exposure, ignition can still occur again or the material may continue to burn until fuel is exhausted.

Related terms include flame retardants, flame propagation, and char formation.