Cooking fires are classified as which class?

• A. Class A
• B. Class B
• C. Class C
• D. Class K

Answer: (D)

Cooking fires are classified as Class K because they involve fats and oils used in cooking. Oils burn differently from ordinary combustibles and from other flammable liquids, and water can cause the oil to splatter or flash, making the fire worse. The Class K extinguishing agent is a wet chemical (typically potassium acetate) that reacts with fats to saponify them, creating a soapy, cooling layer on the surface. This prevents re-ignition and helps smother the fire by separating the oil from the air. In contrast, Class A covers ordinary combustibles like wood and paper, Class B covers flammable liquids, Class C covers electrical fires, and Class D covers certain metal fires, none of which are the specific hazards of cooking-oil fires.