Question

Which of the following extinguishing agents is intended for use in incipient stage fires where water is ineffective?

a) Water
b) Foam
c) Dry chemical
d) Carbon dioxide

Answer 1

The correct extinguishing agent for incipient stage fires where water is ineffective is Carbon dioxide (d). It's used for electrical and flammable liquid fires, unlike carbon tetrachloride which was discontinued due to toxicity issues.

Step-by-step explanation:

The extinguishing agent intended for use in incipient stage fires where water is ineffective is d) Carbon dioxide. Carbon dioxide extinguishers are particularly effective on fires involving electrical equipment and flammable liquids, as they leave no residue and do not conduct electricity. Organic fires often involve flammable liquids, and a fluorinated solution in the form of foam can spread across the burning surface to extinguish the fire. Although carbon tetrachloride was historically used in fire extinguishers for electrical fires, it has been phased out due to the formation of the toxic gas phosgene. Instead, more modern fire extinguishing materials, like carbon dioxide and foaming agents, are now used to address different types of fires effectively.

Answer 2

For incipient stage fires where water is ineffective, the intended extinguishing agent is c) Dry chemical.

Step-by-step explanation:

In firefighting, the choice of extinguishing agent depends on the type of fire. For incipient stage fires where water might be ineffective or even dangerous (such as in electrical or grease fires), dry chemical agents (Option C) are often preferred. Dry chemical extinguishers contain powder that disrupts the chemical reaction of the fire, suppressing flames and preventing re-ignition.

While foam (Option B) is effective for flammable liquid fires, it might not be suitable for all incipient stage scenarios. Carbon dioxide (Option D) is effective for electrical fires but may not be as versatile as dry chemical for different fire types. Water (Option A) can exacerbate certain fires, making it unsuitable for all situations.

Option C is the answer.