Which extinguishers are suitable for Class K fires?

• A. Wet chemical extinguishers
• B. Water-based extinguishers
• C. Foam extinguishers
• D. CO2 extinguishers

Answer: (A)

Class K fires involve cooking oils and fats, so the extinguishing method must rapidly neutralize the oil and cool it to stop reignition. Wet chemical extinguishers do this with a potassium acetate–based agent that saponifies fats, creating a soapy layer that cools and smothers the fire. This targeted action makes them the best choice for Class K fires, especially in commercial kitchens. Water-based extinguishers are unsafe for grease fires because water can cause the oil to splatter and spread and can generate dangerous steam. Foam extinguishers may spread the oil or fail to cool it effectively. CO2 extinguishers displace oxygen but don’t cool the fuel surface or prevent re-ignition in a greasy fire, so they aren’t suitable for Class K.