Flammability is the ability of a chemical to burn or ignite, causing fire or combustion. The degree of difficulty required to cause the combustion of a chemical is quantified through fire testing. Usually materials are rated as highly flammable, flammable and non-flammable.
Important issues to consider when determining the use of a material for an application, especially with polymers, are the thermal properties. Among these properties are the ignition temperature and flammability. In general flammability refers to a substances ability to support combustion or burn.
Flammability is dependent on a materials specific heat, thermal conductivity, decomposition and ignition temperatures, and the heat produced (heat of combustion) as the material burns. In order to make comparisons between different materials, any flammability tests should provide results that can be expressed as numbers. Given the above mentioned factors that influence flammability, there are numerous tests that are conducted on materials. The following is a list of some standard tests.
ignitability - ignition temperatures;
tunnel or panel tests - flame spread;
cone calorimetry - heat release;
limiting oxygen index (LOI) - flame resistance;