A liquid is one of the fundamental states of matter; it is characterized by being nearly incompressible and conforms to the shape of its container. A liquid mixture is composed of more than one substance, such as liquefied petroleum gas (LPG: propane & butane), or liquefied natural gas (LNG). In the context of flammability properties, the flash point is one of the major properties used to characterize the fire and explosion hazard of a liquid mixture. According to the OSHA website, ‘the flash point is the minimum temperature at which a liquid gives off vapor within a test vessel in sufficient concentration to form an ignitable mixture with air near the surface of the liquid’. In this sense, the flash point is a measure of susceptibility to ignition. Flash points can be estimated mathematically for multi-component liquid mixtures if only one component is flammable and if the flash point of the flammable component is known. For the case of multi-component mixtures with more than one flammable component, it is recommended to determine the flash point experimentally (Crowl and Louvar, 2001).
References:
–https://www.osha.gov/dte/library/flammable_liquids/flammable_liquids.html [Retrieved: 11/05/2015]
– Crowl, D. A. and J. F. Louvar (2001). Chemical process safety: fundamentals with applications, Pearson Education.