A Class K fire extinguisher is used for fires involving cooking oils.

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

Answer: (D)

Cooking oil fires involve fats that burn at very high temperatures and can spread quickly. Water-based extinguishing methods are dangerous here because they can cause the oil to splash and the fire to flare up. A Class K extinguisher is designed specifically for these fires in kitchens. It uses a wet chemical agent (potassium acetate) that saponifies fats—turning the oil into a soapy layer—and cools the surface. This creates a barrier between the oil and air, helping to smother the flames and prevent reignition. It’s tailored to cooking oils and fats, whereas extinguishers for ordinary combustibles, flammable liquids, or electrical fires wouldn’t address the unique properties of oil fires effectively.