A multipurpose dry chemical extinguisher would be rated for which classes?

• A. Class A
• B. Class A and B
• C. Class A, B, and C
• D. Class B and C

Answer: (C)

A multipurpose dry chemical extinguisher is designed to handle three kinds of fires: ordinary combustibles (A), flammable liquids (B), and energized electrical equipment (C). The ABC powder works by coating the fuel to interrupt the chemical reactions occurring in the flame and by forming a barrier that cools and smothers the fire. Because it covers all three classes, its rating includes A, B, and C. This is why the best answer reflects all three classes. The other options would miss one or more fire types that ABC extinguishers are capable of handling—so they’re not as complete a choice.