Flammable liquid


A flammable liquid is a combustible liquid which can be easily ignited in air at ambient temperatures, i.e. it has a flash point at or below nominal threshold temperatures defined by a number of national and international standards organisations.
The Occupational Safety and Health Administration of the United States Department of Labor defines a liquid as flammable if it has a flash point at or below 199.4 °F. Prior to bringing regulations in line with the United Nations Globally Harmonized System of Classification and Labeling of Chemicals in 2012, OSHA considered flammable liquids to be those with a flash point below 100 °F. Those with flash points above 100 °F and below 200 °F were classified as combustible liquids. Studies show that the actual measure of a liquids flammability, its flash point, is dependent on altitude.

Categorization

Both OSHA and GHS further divide flammable liquids into 4 categories:
These categorizations are dependent upon a set altitude and atmospheric pressure, as both boiling point and flash point change with changes in pressure.

Labeling

Both GHS and OSHA require the labeling of flammable liquids, on containers and safety data sheets, as follows:
Category ICategory IICategory IIICategory IV
SymbolFlameFlameFlamenone
Signal WordDangerDangerWarningWarning
Hazard StatementExtremely flammable liquid and vapourHighly flammable liquid and vaporFlammable liquid and vapourCombustible liquid