What does an extinguisher labeled 10A 100B C indicate about its capabilities?

• A. It is a water-based extinguisher suitable for all types of fires.
• B. It can extinguish Class A fires up to 100 units, Class B fires up to 10 units, and is not suitable for electrical fires.
• C. It can extinguish Class A fires up to 10 units, Class B fires up to 100 units, and is suitable for Class C electrical fires.
• D. It is only suitable for Class C fires and cannot be used on Class A or B fires.

Answer: (C)

Verified step by step guidance

1. Understand that fire extinguisher labels use letters and numbers to indicate the types of fires they can extinguish and their effectiveness. The letters A, B, and C correspond to different fire classes: Class A for ordinary combustibles, Class B for flammable liquids, and Class C for electrical fires.
2. Recognize that the number before the letter indicates the extinguisher's effectiveness rating for that class of fire. For Class A fires, the number represents the approximate amount of wood the extinguisher can put out, measured in units. For Class B fires, the number corresponds to the approximate square footage of flammable liquid fire it can extinguish.
3. Interpret the label '10A 100B C' as follows: the extinguisher can handle Class A fires up to 10 units, Class B fires up to 100 units, and the presence of 'C' means it is safe to use on electrical fires (Class C).
4. Note that the label does not provide a numerical rating for Class C fires because the main concern is whether the extinguisher is non-conductive and safe to use on electrical equipment, which the 'C' indicates.
5. Conclude that the extinguisher is suitable for Class A fires up to 10 units, Class B fires up to 100 units, and is safe for use on Class C electrical fires, matching the correct interpretation of the label.