Full definition
Classification of the fuel type in a fire that determines the correct extinguisher and suppression strategy. Class A: ordinary combustibles (wood, paper, plastic). B: flammable/combustible liquids (gasoline, oil). C: energized electrical equipment — never use water. D: combustible metals (magnesium, titanium). K: cooking oils and fats. ABC dry chemical extinguishers cover classes A, B and C. Applying the wrong agent can spread or worsen the fire.