How to Extinguish Different Types of Fires

 

The fire classification system created by the National Fire Protection Association (NFPA) indicates the type of material fueling a fire, as well as the appropriate extinguishing agent. Specific types of fires should be handled in certain ways to prevent further damage and possible injury. If you are trying to earn a firefighter badge or fire investigator patches, you will have to learn this system. Even regular citizens can benefit from knowing the NFPA system, although if you are ever in a situation where a fire of any type is present, it's best to call your local fire department for professional assistance.

The five classes of the NFPA are A, B, C, D, and K. Each class has its own letter, color-coded symbol, and pictograph. This article briefly describes each class of fire, and explains how best to extinguish each.

A "Class A" fire is fueled by ordinary combustible materials such as wood, paper, trash, cloth, and most types of plastics. The Class A letter symbol is a green triangle with an "A" inside, and the pictograph features a trash can and a wood pile on fire. Class A fires can easily be extinguished with water or with a dry chemical fire extinguisher.

A "Class B" fire involves flammable or combustible liquids and/or gases. Common examples of Class B materials are gasoline, alcohol, kerosene, and oil-based paints. The Class B letter symbol is a red box with a "B" inside. A flaming gasoline can serves as the Class B pictograph. Class B fires should be extinguished with dry chemical or carbon dioxide fire extinguishers. Anyone who has earned his fire investigator patches will tell you, you should never try to extinguish a Class B fire with water.

"Class C" fires are fueled by electricity or energized electrical equipment. The Class C letter symbol is a blue circle with a "C" inside; the pictograph shows an electrical outlet. Extinguishing agents specially crafted for Class C fires do not include any conductive ingredients. Dry chemical extinguishers, carbon dioxide extinguishers, and halon extinguishers are acceptable methods of fighting Class C fires.

A "Class D" fire involves combustible metals such as magnesium, potassium, and titanium. Class D fires typically occur in chemical laboratory environments. The only symbol used to indicate a Class D fire is a yellow star with a "D" inside. Class D fires require a specialized type of extinguishing agent called dry powder. Dry powder is not to be confused with the dry chemical extinguisher. Even if you are not trying to get your firefighter badge or fire investigator patches, it's important to know the difference. Dry powder should be scooped or shoveled onto a Class D fire to smother out flames.

Finally, a "Class K" fire is one that involves vegetable oils, animal oils, grease, or fats; ingredients commonly found in a kitchen fire. The Class K designation is fairly new, so it does not yet have a generally accepted symbol. Kitchen fires should be extinguished with wet chemical extinguishing agents made to combat fats and oils.

~Jeff Burkman, 2010

How to Extinguish Different Types of Fires