What's Inside a Fire Extinguisher?

7/12/2021 (Permalink)

In the United States, fires are characterized by five classifications, Classes A, B, C, D, and K. Fire extinguishers are rated based upon the specific fires they are meant to suppress. This is important to note when purchasing a fire extinguisher for your home or business. Which type of fire is most likely to occur at your property? Read the fire class classifications below to determine which fire extinguisher would be helpful in each specific situation. 

Class A Fires

• Involve common combustibles such as wood, paper, and cloth
• Should be extinguished with a dry chemical fire extinguisher or a Halotron extinguisher

Class B Fires

• Involve flammable liquid fuels such as oils, grease, gasoline, alcohols, and paint thinner
• Should be extinguished with a dry chemical fire extinguisher
• Do not use water to extinguish this type of fire

Class C Fires

• Electrical fires
• Should be extinguished with a dry chemical fire extinguisher
• Do not use water to extinguish this type of fire

Home fires are commonly Class A, B, or C.

Class A, B, and C dry chemical fire extinguishers are usually filled with either mono ammonium phosphate ( yellow powder) or sodium bicarbonate (white powder). Mono ammonium is corrosive and should be properly cleaned up as soon as possible. Sodium bicarbonate is nontoxic and noncorrosive.

Class D Fires

• Involve combustible metals like magnesium
• Mostly occur in manufacturing and industrial facilities   
• Class D fire extinguishers contain powdered metal such as copper, sodium chloride, sand, graphite, or sodium carbonate           

Class K Fires

• Cooking fires due to cooking oils or grease
• Should be extinguished with a wet chemicals fire extinguisher 
• Mostly occur in commercial kitchens
• Do not use water to extinguish this type of fire
• Class K wet chemical fire extinguishers contain a potassium acetate-based agent which suppresses the fire with soapy foam. 

Please read the color-coded label on your fire extinguisher prior to use and always air out a room after using a fire extinguisher. Consult the Safety Data Sheet(SDS) before attempting cleanup. The cleaning method varies for each type of fire extinguisher chemical. Depending on the type of fire extinguisher used and the amount of residue, you may want to leave the cleanup to our experienced fire restoration professionals. While dry chemical fire extinguishers are nontoxic, inhalation of mono ammonium phosphate or sodium bicarbonate can cause health effects. To learn more about fire extinguisher safety visit https://www.poison.org/articles/fire-extinguisher-safety-184.

Please contact our office if you need assistance with fire damage restoration or cleaning up after using a fire extinguisher.