Which of the following is NOT an extinguishing agent for Class B fires?

Class B fires involve flammable liquids, gases, and greases, and the types of extinguishing agents used for these kinds of fires are specifically effective at displacing oxygen or interrupting the chemical reaction of combustion.

Carbon dioxide is an effective agent for Class B fires because it works by displacing oxygen around the fire, thus suffocating it. Dry chemical extinguishers are also designed to combat Class B fires by forming a barrier between the fuel and the oxygen, effectively interrupting the combustion process. Halon types function similarly to both CO2 and dry chemicals by inhibiting the chemical reaction necessary for the fire to burn.

Water, on the other hand, is not suitable for extinguishing Class B fires because applying water can spread the flammable liquid, exacerbating the situation. In many cases, introducing water to a Class B fire can lead to an explosive reaction, particularly with certain flammable liquids. Therefore, among the listed agents, water is the only one that should not be used to extinguish Class B fires. Understanding the properties of each extinguishing agent is vital for effectively managing different types of fires and ensuring safety.