OSH Security Practice Test

How do you put out a Class B fire?

1. Water

2. Dry chemical and halon extinguishing agents

3. Foam

4. B and C

The correct answer is: B and C

To effectively put out a Class B fire, which typically involves flammable liquids such as gasoline, oil, or solvents, the best methods include specific extinguishing agents that can suffocate the fire or break the chemical reaction. Using dry chemical and halon extinguishing agents is effective because they disrupt the chemical chain reaction of the fire. Dry chemical extinguishers, such as those containing monoammonium phosphate, can be particularly effective by smothering the flames and preventing re-ignition. Halon is another excellent option as it removes heat and interrupts the combustion process with minimal damage to equipment. Foam extinguishers can also be utilized on Class B fires. They work by forming a barrier between the fuel and the fire, effectively smothering the flames and preventing vapors from igniting. The foam also cools the burning liquid, further mitigating the risk of re-ignition. Water is not a suitable option for Class B fires, as it can spread the burning liquid and exacerbate the situation. Therefore, the combination of dry chemical or halon agents along with foam is the correct approach to safely extinguishing a Class B fire. Thus, the provided answer captures this essential information about effective fire suppression techniques.