Question

Which of the following fire extinguisher is not used for quenching of fires involving electrical equipment

• A. CTC Fire extinguisher
• B. CO\(_2\) Type extinguisher
• C. BCF Fire extinguisher
• D. Foam type extinguisher

Hint:

A simple safety rule for fires: NEVER use water or water-based extinguishers (like foam) on electrical fires.
Also, never use water on flammable liquid fires (Class B), as it can spread the burning liquid.
CO\(_2\) and Dry Chemical Powder (DCP) extinguishers are the most common multipurpose types safe for electrical fires.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
We need to identify which type of fire extinguisher is unsafe for use on fires involving live electrical equipment (Class C or Class E fires).

Step 2: Detailed Explanation:
The primary danger with electrical fires is the risk of electrocution.
Therefore, the extinguishing agent used must be

non-conductive.
Let's analyze the options:
-

CTC (Carbon Tetrachloride) and BCF (Halon/Bromochlorodifluoromethane): These are halogenated hydrocarbons.
They are non-conductive and were historically used for electrical fires.
However, they are now largely phased out due to their high toxicity (CTC) and ozone-depleting properties (BCF/Halon).
But they are technically usable on electrical fires.
-

CO\(_2\) Type extinguisher: This extinguisher releases carbon dioxide gas, which smothers the fire by displacing oxygen.
CO\(_2\) is non-conductive and leaves no residue, making it an excellent choice for electrical fires.
-

Foam type extinguisher: This extinguisher releases a foam that is primarily composed of water mixed with a foaming agent.
Since water is a conductor of electricity, using a foam extinguisher on live electrical equipment poses a severe risk of electric shock to the operator.

Step 3: Final Answer:
The foam type extinguisher is not used for fires involving electrical equipment due to the risk of electrocution.
This corresponds to option (D).