||The English used in this article may not be easy for everybody to understand. (April 2012)|
The flash point of a volatile substance is the lowest temperature at which it can vaporize to form an ignitable mixture in air. Measuring a flash point requires an ignition source. At the flash point, the vapor may cease to burn when the source of ignition is removed.
The flash point is different than the autoignition temperature, which does not require an ignition source, or the fire point, the temperature at which the vapor continues to burn after being ignited. Neither the flash point nor the fire point is dependent on the temperature of the ignition source, which is much higher.
The flash point is part of the description of liquid fuel. It helps to measure the fire hazards of liquids. “Flash point” refers to both flammable liquids and combustible liquids. There are different standards for each term. Liquids with a flash point less than 60.5 °C (140.9 °F) or 37.8 °C (100.0 °F)—depending upon the standard being applied—are considered flammable, while liquids with a flash point above those temperatures are considered combustible.
Chemists have set standard test methods to measure the flash points. These test methods define: the required equipment, key test parameters, the procedure to follow, and the precision of the test method.
Standard test methods are written and controlled by a number of national and international committees and organizations. The three main bodies are the CEN / ISO Joint Working Group on Flash Point (JWG-FP), ASTM D02.8B Flammability Section, and the Energy Institute's TMS SC-B-4 Flammability Panel.
- NFPA 30: Flammable and Combustible Liquids Code, 2012 Edition Retrieved January 23, 2012.