Which type of fire extinguisher is most appropriate for class B fires?

• A. Water type
• B. D-type
• C. Foam type
• D. Chemical type

Answer: (C)

The foam type fire extinguisher is particularly well-suited for class B fires, which involve flammable liquids such as gasoline, oil, or paint. Foam extinguishers work by smothering the burning liquid, creating a barrier that prevents oxygen from sustaining the fire. The foam also separates the fuel from the air, which is essential for effectively putting out the fire.

Foam extinguishers are designed to cool the flames while simultaneously preventing re-ignition, making them a preferred choice for combating class B incidents. The careful formulation of the foam creates a lasting effect over the liquid's surface, which is advantageous in dealing with flammable liquids that can easily reignite if not adequately covered.

In contrast, water-type extinguishers can worsen class B fires because they can spread burning liquids, while the D-type and chemical type extinguishers are specialized for different classes of fire. The D-type is for combustible metals, and chemical types are often geared towards class A or some class C fires, making them less effective for the specific challenges posed by class B fires.