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:- Category I flammable liquids are those with boiling points ≤ 95 °F and flash points < 73 °F
- Category II flammable liquids are those with boiling points > 95 °F and flash points < 73 °F
- Category III flammable liquids are those with flash points > 73 °F and ≤ 140 °F
- Category IV flammable liquids are those with flash points > 140 °F and ≤ 199.4 °F
Labeling
Both GHS and OSHA require the labeling of flammable liquids, on containers and safety data sheets, as follows:Category I | Category II | Category III | Category IV | |
Symbol | Flame | Flame | Flame | none |
Signal Word | Danger | Danger | Warning | Warning |
Hazard Statement | Extremely flammable liquid and vapour | Highly flammable liquid and vapor | Flammable liquid and vapour | Combustible liquid |