What type of fire requires the use of water to be extinguished?

The correct choice is related to A-class fires, which involve ordinary combustible materials such as wood, paper, and cloth. These materials are generally suited for extinguishment by water because water can effectively absorb the heat and reduce the temperature of the burning materials below the ignition point, thereby extinguishing the fire.

Using water on A-class fires is effective because water cools the material and removes the heat required for combustion. It can also help to dampen the surrounding area to prevent re-ignition. For instance, when water is applied to a fire involving wood or paper, it can quickly reduce the flames and stop the burning process.

In contrast, flammable liquids, electrical equipment, and certain reactive metals require different types of extinguishing agents that do not involve water. Flammable liquids are better handled using foam or dry powder to avoid spreading the flames or causing an explosion. Electrical fires require non-conductive agents to prevent electrocution, and metal fires often need specific dry powders that can react safely to suppress the fire. Understanding the characteristics of different classes of fires is essential to utilizing the appropriate firefighting methods and materials effectively.