Multipurpose dry chemical extinguishers are rated for which fire classes?

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

Answer: (B)

Fire extinguisher ratings show which types of fires the agent is effective against. Multipurpose dry chemical extinguishers carry an ABC rating, meaning they are suitable for Class A (ordinary combustibles), Class B (flammable liquids), and Class C (energized electrical equipment) fires. The dry chemical powder works by interrupting the chemical reactions occurring in the flame and by forming a barrier between the fuel and the air, plus it can help cool and smother the fire. Because of these properties, a single extinguisher with ABC rating can be used on common everyday fires, liquids, and electrical equipment, making it versatile for many occupancies. It is not intended for all fire types (for example, some metal or kitchen fires require specialized agents), but for these three classes it is appropriate.