Which rating is required for fire extinguishers on mobile cranes? (alternate phrasing)

• A. 10BC
• B. 5BC
• C. 2A 10BC
• D. 4A 60BC

Answer: (A)

On mobile cranes the main fire hazards are flammable liquids such as hydraulic oil and diesel, and electrical equipment. The extinguisher you need must be able to handle those types of fires, which are Class B and Class C. A rating of 10BC indicates the extinguisher is sized and suitable for Class B and C fires, with enough capacity to tackle a small to moderate incident. An extinguisher with an A rating would address ordinary combustibles like wood or paper, which aren’t the primary crane hazard, so it isn’t the minimum requirement here. Larger or combined ratings (like including an A rating or greater BC capacity) are acceptable but not required—the minimum you need is 10BC.