Which agent is typically associated with Class K extinguishers used on cooking fats and oils?

• A. Dry chemical powder
• B. CO2
• C. Wet chemical agent
• D. Foam concentrate

Answer: (C)

Fires involving cooking fats and oils require a wet chemical extinguishing agent designed specifically for Class K. This agent, usually a potassium acetate solution, doesn't just cool the fire; it chemically reacts with fats to saponify them, forming a soapy, viscous layer on the oil surface. That layer cools and creates a barrier between the fuel and the air, slowing or stopping the release of flammable vapors and preventing reignition. This targeted action is why the wet chemical agent is best for cooking-oil fires. Other extinguishing agents don’t provide this combination of cooling and a stable soapy barrier on greasy surfaces, making them less effective for these fires.