What does a U.L.C. rating of 10A 20BC indicate for a multipurpose fire extinguisher?

• A. The extinguisher is equivalent to 45 liters of water and has been tested for electrical non-conductivity
• B. The extinguisher can extinguish all classes of fire without limitation
• C. The extinguisher works only on flammable liquid fires
• D. The extinguisher is only effective for small fires under controlled conditions

Answer: (A)

A U.L.C. rating of 10A 20BC for a multipurpose fire extinguisher provides crucial information about its fire-fighting capabilities. The "10A" rating indicates that the extinguisher is equivalent to 45 liters of water in terms of its effectiveness on Class A fires, which typically involve ordinary combustible materials like wood, paper, and cloth. This rating signifies that the extinguisher can handle such fires effectively when deployed properly.

The "20BC" rating means that the extinguisher is capable of extinguishing Class B fires (involving flammable liquids such as gasoline or oil) and Class C fires (involving electrical equipment). Specifically, the "B" rating of 20 suggests that it is suited for larger flammable liquid fires compared to lower-rated extinguishers. However, the rating does not imply effectiveness for all fire types, particularly those classified as Class D (combustible metals) or potentially combinations involving other hazards.

The distinction of being "tested for electrical non-conductivity" is fundamental to extinguishers used in electrical fire scenarios, denoting that it can be safely used on live electrical equipment without the risk of creating a conductive path that could result in electric shock.

This understanding emphasizes