When aiming a Class K extinguisher, where should you direct the discharge?

• A. At the surface of the burning oil/fat to coat it with the wet chemical
• B. At the source of the flame
• C. At the ceiling
• D. At the area around the fire

Answer: (A)

Directing the discharge at the surface of the burning oil or fat to coat it with the wet chemical is the essential action for Class K fires. The wet chemical (potassium acetate) reacts with fats to form a soapy, cooling layer on the surface. This saponified coating isolates the fuel from air, cools the oil, and helps prevent reignition. Aiming at the flame or at the ceiling won’t create that protective surface layer and can allow the fire to continue or spread. Similarly, spraying around the fire misses the fuel surface and doesn’t establish the coating needed to stop the burn. Coating the surface is what actually stops the fire effectively.