What is the primary function of foam blankets in firefighting?

• A. To create a barrier against smoke
• B. To suppress vapors and cool hot surfaces
• C. To extinguish electrical fires
• D. To increase visibility in smoke

Answer: (B)

The primary function of foam blankets in firefighting is to suppress vapors and cool hot surfaces. Foam is particularly effective in combating flammable liquid fires, as it forms a blanket over the surface of the burning liquid, effectively cutting off the supply of oxygen and preventing the release of flammable vapors. This action reduces the risk of flashback and helps to stabilize the fire area, allowing for safer firefighting operations. Additionally, the cooling effect of the foam helps to lower the temperature of hot surfaces, which further diminishes the potential for re-ignition and helps in controlling the spread of the fire.

In contrast, creating a barrier against smoke is not the primary role of foam; while it may have some effect, its design and application focus on vapor suppression and cooling. Similarly, foam blankets are not intended for use on electrical fires, where specific extinguishing agents are recommended to avoid electrical hazards. Increasing visibility in smoke is also not a function of foam; instead, firefighting gear and tactics specifically geared toward visibility management are employed for that purpose.