The significance of flash point as a measurement of flammability hazard of flammable liquids and multicomponent solutions and its experimental determination were evaluated. Experimentally determined flash points were found to be in good agreement with values which were calculated from theoretical principles. The results confirm that liquid hydrocarbon solutions follow the laws of Dalton, Raoult, and LeChatelier governing the vapor pressure, composition, and flammability limits above a liquid of two or more components, and also confirm the concept of flash point as that temperature at which the vapor concentration above a liquid is equal to that at its lower flammability limit. (Author).