In general, there are four recognized fire classes: Class A, Class B, Class C, and Class D. These classifications are based on the materials or substances that can cause a fire. Fire extinguishers also have ratings that are based on these classifications, and it’s important to use the right type of fire extinguisher on the corresponding class of fire.
In addition, the Occupational Safety and Health Administration also has requirements on how fire extinguishers should be distributed in a workplace for employee use. These requirements can be found in OSHA 29 CFR 1910.157 (Portable fire extinguishers).
Different fire extinguisher ratings work with different fire classes. Find out below how to comply with OSHA requirements and ensure that your facility is properly protected from fires.
Cause of Fire
Ordinary Combustibles: paper, fabric, wood, certain plastics, and more
Fire Extinguisher Symbol
Green triangle with the letter A
According to OSHA Standard 1910.157(d)(2), employees should have a travel distance of 75 feet (22.9 m) or less to Class A fire extinguishers.
Employers can also choose to utilize a sprinkler system or standpipe system with hose stations instead of distributing Class A fire extinguishers. However, these systems have to be able to meet the requirements laid out in the following standards:
Sprinkler and standpipe systems also have to be able to:
Flammable Liquids: gasoline, oil, paint, turpentine, and moreFire Extinguisher Symbol
Red square with the letter BLocation Requirements
According to OSHA Standard 1910.157(d)(4), employees should have a travel distance of 50 feet (15.2 m) or less to Class B fire extinguishers.
Live Electrical Equipment: electrical panels, wiring, motors, and moreFire Extinguisher Symbol
Blue circle with the letter CLocation Requirements
According to OSHA Standard 1910.157(d)(5), employers must distribute Class C fire extinguishers based on Class A and Class B hazards.
Fire extinguishers get a Class C rating only if they already have a Class A or Class B rating. Additionally, Class C fire extinguishers are not able to conduct electricity, which makes them best suited for electrical hazards.
Combustible Metals: magnesium, sodium, aluminum, and moreFire Extinguisher Symbol
Yellow star with the letter DLocation Requirements
According to OSHA Standard 1910.157(d)(6), there should be a travel distance of 75 feet (22.9 m) or less from any area with combustible metals to Class D fire extinguishers.
If a working area generates flakes, powders, and shavings of combustible metals at least once every two weeks, then employees working in the area should have access to a Class D extinguisher.
Combustible cooking componentsFire Extinguisher Symbol
Black hexagon with the letter KLocation Requirements
While Class K fire extinguishers are not covered by OSHA fire extinguisher requirements in 29 CFR 1910.157, they are nonetheless worth having in certain facilities. According to National Fire Protection Association (NFPA) recommendations, there should be a travel distance of 30 ft (9.1 m) or less between a hazard and a Class K fire extinguisher.
One important thing to remember about fire extinguisher location requirements is that extinguishers should be spaced in such a way that they completely cover their protected area. Thus, calculating the distance between two extinguishers isn’t always simple or straightforward.
For example, a Class A fire extinguisher has a maximum travel area of 75 feet. This does not automatically mean that two Class A extinguishers can be 150 feet apart. A distribution like this can leave blind spots and may end up making employees take longer to respond to fires.
It’s also important to remember that while these extinguishers have a recommended maximum travel area, you should also take these two things into account:
For example, a Class A fire extinguisher has been placed at its maximum distance of 75 feet from a hazard. If a fire breaks out, an employee will have to travel the entire 75 feet toward the fire extinguisher, and the entire 75 feet once again to get back to the fire. Thus, the employee will actually have to travel 150 feet, not 75. Fires can grow and a lot can happen in the short time it takes for a person to run 150 feet.
With careful consideration of fire classes and fire extinguisher distribution, you’ll be able to ensure that your employees will be able to respond to fires in the most efficient manner possible. This can help prevent damage to property, injuries, and loss of life.