A class B fire extinguisher should be used for which type of fire?

A class B fire extinguisher is specifically designed to tackle fires that involve flammable liquids, such as grease, oil, and other liquids stored under pressure. These types of fires require extinguishing agents that can effectively smother the flames and prevent the burning liquid from reigniting.

When dealing with grease or oil fires, it's crucial to use the appropriate extinguisher, as using water can actually cause the fire to spread due to the oil floating on top. Class B extinguishers often contain substances like foam, dry chemical, or carbon dioxide, which help to suffocate the fire or inhibit the chemical reaction occurring in a flammable liquid fire.

The other options listed do not align with the specific applications of a class B extinguisher. Electrical fires, for example, require a different approach to avoid the risk of electrocution, while wood and paper fires usually necessitate a class A extinguisher. Flammable gases may also require specific precautions and extinguisher types depending on the nature of the gas. Thus, the focus on flammable liquids makes the class B extinguisher ideal for grease, oil, or liquids stored under pressure.