Florida Fire State Practice Exam

What is the function of Class B foam?

1. Separates and cools

2. Smothers and extinguishes

3. Binds and stabilizes

4. Absorbs and retains

The correct answer is: Separates and cools

The function of Class B foam primarily lies in its ability to smother and extinguish flammable liquid fires, which makes it effective for use on fires involving substances like gasoline, oil, and other hydrocarbons. This type of foam works by forming a blanket over the surface of the burning liquid, thus cutting off the oxygen supply and suppressing vapor release. While the other options describe different properties, they do not capture the primary purpose of Class B foam effectively. The concept of separating and cooling does apply to certain firefighting methods, but it is not the main action of Class B foam. Additionally, smothering and extinguishing encompasses the complete process that Class B foam engages in during a firefighting operation involving flammable liquids.