Classes of Extinguishers

Fires are organized according to class, based on their fuel source. It is important to understand that operating a fire extinguisher that does not match the class of fire for which it was made can actually increase the fire hazard and endanger the user and those nearby. Multi-purpose, dry chemical, portable fire extinguishers are suitable for use on classes A, B, and C.

Portable fire extinguishers may carry an A rating. The A rating is a water equivalency rating. Each A is equivalent to 1.25 gallons of water. The National Fire Protection Association (NFPA) recommends that locations, such as offices, classrooms, and assembly halls that contain mainly Class A combustible materials, have one 2-A extinguisher for every 3,000 square feet.

Locations that contain Class B flammables, such as workshops, storage areas, research operations, garages, warehouses, or service and manufacturing areas, must have a portable fire extinguisher installed within a 50-foot travel distance of employees.

Class C extinguishers are required where energized electrical equipment is used. The extinguisher size and spacing is based on its Class A or B hazard.

Locations where combustible metal powders, flakes, shavings, or similarly sized materials are generated at least once every two weeks must install Class D portable fire extinguishers not more than 75 feet from the hazard.

Locations where potential fire hazards from combustible cooking exist must install Class K extinguishers at a maximum travel distance of 30 feet.

To learn more about Fire Extinguishers visit our Portable Fire Extinguishers Online Training web page.