How many classes of fire are recognized in the U.S.?

The United States recognizes five classes of fire, each designated for specific types of combustible materials. This classification system helps in understanding the nature of a fire and determining the appropriate firefighting measures to take.

The five classes are:

1. Class A: Fires involving ordinary combustible materials such as wood, paper, cloth, and some plastics. These are typically extinguished with water or foam.

2. Class B: Fires fueled by flammable liquids, gases, or greases, such as gasoline, oil, and solvents. Special extinguishing agents like foam, CO2, or dry chemical agents are necessary for these fires.

3. Class C: Fires that involve energized electrical equipment. The extinguishing agent must not conduct electricity, so CO2 or dry chemical extinguishers are preferred to avoid shock hazards.

4. Class D: Fires that involve combustible metals, such as magnesium, sodium, or potassium. These fires require specific dry powder agents that smother the flames and are safe for use on such metals.

5. Class K: Fires that involve cooking oils and greases, typically found in commercial kitchens. Specialized extinguishing agents are designed for these types of fires to control flare-ups.

Understanding these classes is crucial for safely addressing different fire scenarios, making