Principles of Fire Extinguishment
This information applies to portable fire extinguishers.
GeneralThe provisions of this policy apply to the selection, distribution, inspection, maintenance and testing of portable extinguishing equipment. The requirements given herein are minimums. Portable extinguishers are intended as a first line of defense to cope with fires of limited size. They are needed even when a facility is equipped with automatic sprinklers, standpipe and hose, or other fixed protection equipment. Fire extinguisher training is provided by contacting Environment, Health & Safety – Fire Safety and Emergency Response Section.
DefinitionsThe basic types of fires are Classes A, B, C, and D as defined in the following:
- Class A: Ordinary combustible materials, such as wood, cloth, paper, rubber, and many plastics.
- Class B: Flammable and combustible liquids.
- Class C: Energized electrical equipment.
- Class D: Combustible metals, such as magnesium, titanium, zirconium, sodium, and potassium.
Classification and Ratings of Fire ExtinguishersPortable fire extinguishers are classified for use on Class A, B, C, or D fires and rated by nationally recognized testing laboratories for relative extinguishing effectiveness. The classification and rating are based upon the preceding classification of fires and the fire-extinguishment potentials as determined by fire tests.
Selection of ExtinguishersThe selection of extinguishers for a given situation is determined by the character of the fires anticipated.
Distribution of ExtinguishersFire extinguishers shall be provided for the protection of the building and for the occupancy hazard contained therein:
- Required building protection shall be provided by fire extinguishers suitable for Class A fires
- Protection against occupancy hazard shall be provided by fire extinguishers suitable for such Class A, B, C, or D fire potentials as may be present