Stored-pressure water extinguishers are used on what type of fires?

Stored-pressure water extinguishers are specifically designed for extinguishing Class A fires, which involve ordinary combustible materials like wood, paper, cloth, and some plastics. The effectiveness of water extinguishers comes from their ability to cool the burning materials and reduce the temperature below the ignition point, thus extinguishing the fire.

Class A fires create ash when they burn and do not involve flammable liquids, gases, or metals, making water a suitable extinguishing agent. This type of extinguishing system relies on the physical property of water to absorb heat.

Using water extinguishers on Class B or Class C fires is inappropriate; Class B fires involve flammable liquids and gases, and using water can spread the fire. Class C fires include energized electrical equipment, where water presents a risk of electric shock. Class D fires involve combustible metals that react with water, presenting further hazards. Therefore, the application of water extinguishers is strictly confined to Class A situations for effective and safe fire suppression.