Fire Classes and OSHA Fire Extinguisher Location Requirements

fire extinguisher location requirements

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.

Class A

Cause of Fire

Ordinary Combustibles: paper, fabric, wood, certain plastics, and more

Fire Extinguisher Symbol

Green triangle with the letter A

Location Requirements

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:

  • OSHA 29 CFR 1910.158 (Standpipe and hose systems)
  • OSHA 29 CFR 1910.159 (Automatic sprinkler systems)

Class B

Cause of Fire

Flammable Liquids: gasoline, oil, paint, turpentine, and more

Fire Extinguisher Symbol

Red square with the letter B

Location 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.

Class C

Cause of Fire

Live Electrical Equipment: electrical panels, wiring, motors, and more

Fire Extinguisher Symbol

Blue circle with the letter C

Location 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.

Class D

Cause of Fire

Combustible Metals: magnesium, sodium, aluminum, and more

Fire Extinguisher Symbol

Yellow star with the letter D

Location 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.

Class K

Cause of Fire

Combustible cooking components

Fire Extinguisher Symbol

Black hexagon with the letter K

Location 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.

Maximum Travel Area

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:

  • The time it would take for a person to get to an extinguisher and back to a fire
  • The actual distance a person would have to travel to get to an extinguisher and back to a fire

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.

The material provided in this article is for general information purposes only. It is not intended to replace professional/legal advice or substitute government regulations, industry standards, or other requirements specific to any business/activity. While we made sure to provide accurate and reliable information, we make no representation that the details or sources are up-to-date, complete or remain available. Readers should consult with an industrial safety expert, qualified professional, or attorney for any specific concerns and questions.


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Author: Herbert Post

Born in the Philadelphia area and raised in Houston by a family who was predominately employed in heavy manufacturing. Herb took a liking to factory processes and later safety compliance where he has spent the last 13 years facilitating best practices and teaching updated regulations. He is married with two children and a St Bernard named Jose. Herb is a self-described compliance geek. When he isn’t studying safety reports and regulatory interpretations he enjoys racquetball and watching his favorite football team, the Dallas Cowboys.