Fires and Extinguishers (2020 Update)
This update incorporates OSHA Regulations and NFPA Guidelines which are enforceable by OSHA.
So there I was, at the local home improvement store, looking for a new fire extinguisher for the car. I was looking for a compact size that would fit in the onboard compartment. I happened to notice a gentleman who was quite perplexed by the variety and classes of extinguishers. There were large and small, multi-purpose, single purpose. He asked me if I understood the different labels. I replied in the affirmative, and briefly described the different types of fires and extinguishers. Several other people passing by stopped to listen, as they were also curious, thus leading to the creation of this article. Fires are classified by the combustion agent, these are:
Alpha – Combustible solids such as paper, and cloth
Class A fire extinguishers must be within 75 feet of the material. Also, for every 3,000 square feet, there must be one fire extinguisher. For example, if a building is 9,000 square feet, there must be three separate fire extinguishers. CFR 1910.157(d)(2)
Bravo – Liquids such as gasoline, kerosene, Boiled Linseed Oil, and others
Class B fire extinguisher must be within 50 feet of the material. CFR 1910.157(d)(4)
Charlie – Gasses such as oxygen, hydrogen, methane, butane to name a few
1910.157(d)(5) states The employer shall distribute portable fire extinguishers used for Class C hazards on the basis of the appropriate pattern for the existing Class A or Class B hazards, current best practice is to follow the 50 feet guidance.
Delta – Metals like aluminum, magnesium, potassium, sodium, and lithium
Class D fire extinguishers must be 75 feet from the hazard. CFR 1910.157(d)(6)
Echo – Live electrical equipment. For de-energized equipment, treat as Alpha
Kilo/Foxtrot – Cooking oils such as canola, sunflower, olive, and peanut
Class K/F fire extinguisher must be within 30 feet from the hazard.
Mounting: Depending on the weight of the fire extinguisher will determine where it is placed on the wall. The height can vary between 3 ½ to 5 feet. A fire extinguisher that weighs 40 pounds or less can be no more than five feet high and no less than 4 inches off the ground. A fire extinguisher that is over 40 pounds can be no more than 3 ½ feet high and at least 4 inches off the ground. It is important to identify every substance that is being used throughout the workplace.
Where the employer has established and implemented a written fire safety policy which requires the immediate and total evacuation of employees from the workplace upon the sounding of a fire alarm signal and which includes an emergency action plan and a fire prevention plan which meet the requirements of 29 CFR 1910.38 and 29 CFR 1910.39 respectively, and when extinguishers are not available in the workplace, the employer is exempt from all requirements of this section unless a specific standard in part 1910 requires that a portable fire extinguisher be provided.
The methods of fighting these fires are often mutually exclusive. For example, you DO NOT use water to fight an electrical fire with energized equipment, this creates a potential for electrical shock. Using water on flammable liquids and cooking oils will only spread the fire as oil floats.
Often, the best method for fighting a fire is simply smothering it. Once you remove one of the legs of the fire triangle, the fire is out.
Most fire extinguishers are multiple purpose, such as A-B-C, or B-C. Commercial food preparation regulations specify a K-type extinguisher. Common fire suppressants are carbon dioxide (CO2), potassium bicarbonate (PKP, or Purple K, which actually is purple to visually identify the agent), sodium bicarbonate, water, Halon and its replacements (H3R, FE-13TM).
I personally advise clients to have a PKP extinguisher in the kitchen, as this agent suppresses flammable liquids, electrical fires, and cooking oils with low toxicity, easy clean-up, and no electric shock hazard.
This article is not a substitute for professional advice, but is meant to be a guide to educate the average consumer in fire types and suppression methods.