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5 Fire Extinguisher Classes & Uses

Most building owners and managers know they must equip their businesses with portable fire extinguishers. Many, however, aren’t aware that not all fire extinguishers are the same. For instance, water is excellent for putting out some fires but can make matters worse if used on an electrical fire.

Choosing the proper fire extinguishers to keep people and assets safe is essential to a successful fire and life safety program.

Types of Fires & Fire Extinguishers

Portable fire extinguishers are classified by the type of fire they’re designed to put out. There are five basic classifications, each labeled with either a letter-shaped symbol or picture.  

Class A

Designed for use on ordinary combustible fires, Class A fire extinguishers safely put out fires fueled by materials like paper, wood, cloth, rubber, and many plastics.

Because there are several ways you can extinguish a Class A fire, there are various Class A fire extinguishers available, with some using a clean agent and others a water mist to suffocate and cool fires. 

Class B 

A Class B fire involves flammable and combustible liquids like gasoline, oil, lacquers, alcohol, and grease.

Most Class B portable fire extinguishers safely suppress these fires using carbon dioxide or clean agents that suffocate and extinguish the flames. Class B extinguishers that use clean agents are a preferred option, as they don’t leave a residue or need cleanup.

When extinguishing a fire involving flammable gas, it’s critical to shut off the fuel source promptly. Otherwise, unburned gas can escape into the atmosphere and cause an explosion if exposed to an ignition source.

Class C

Class C fires involve energized electrical equipment. Like Class B models, most Class C portable fire extinguishers rely on carbon dioxide or another clean agent to suffocate the flames.

Class D

Class D fire extinguishers are needed when a fire involves combustible metals like titanium, magnesium, and sodium.

Because common extinguishing agents can react with a combustible metal fire and cause it to spread, most Class D fire extinguishers use a dry powder agent to suppress the fire and absorb heat.

Class K 

Class K fires involve cooking appliances that use animal or vegetable oils or fats. Class K fire extinguishers typically employ a wet chemical agent made with potassium to cool and suppress a kitchen fire simultaneously.

Multipurpose Fire Extinguishers

It’s also good to know that multipurpose fire extinguishers are electrically nonconductive and use a special chemical to smother fires.

For instance, multipurpose dry chemical or ABC fire extinguishers are safe for Class A, Class B, and Class C fires. 

Choosing the Right Type of Fire Extinguisher

The National Fire Protection Association recommends using portable fire extinguishers for non-growing fires confined to a small area or when the smoke has not filled the space.

Because there are so many different types of fire extinguishers, it’s essential to consult with a fire and life safety expert who can help you choose the right models and ensure your business is prepared for any fire emergency.

With over 35 years of experience in the fire protection industry, Kauffman Co. is your go-to source for fire extinguisher services, including:

To learn more about the different classifications of fire extinguishers and the fire safety services we offer, contact us online or call (713) 893-1090 today.

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