What type of fire is primarily extinguished with water?

Water is the most effective extinguishing agent for Class A fires, which include ordinary combustibles such as wood, paper, fabric, and some types of plastics. These materials typically have a high water content and are capable of being cooled down effectively by water, which helps to suppress flames and prevent re-ignition.

In addition to cooling, water works by soaking into the burning material, which reduces the temperature below the ignition point. This physical and thermal method of extinguishment is particularly suited for materials classified under Class A.

When it comes to other classes of fires, water is not the preferred extinguishing agent due to the risk of spreading fire or causing hazardous situations. For instance, using water on Class B fires involving flammable liquids can cause the liquid to spread and worsen the fire. In Class C fires, which involve energized electrical equipment, water can conduct electricity and pose severe safety risks. Class K fires, which involve cooking oils and fats, require specialized extinguishing agents that can effectively smother the fire without spreading it.

Thus, the effectiveness of water as an extinguishing agent is specifically aligned with Class A fires, making it the ideal choice for this type of fire situation.