Class A Fire Extinguisher - also called Type A Fire Extinguishers
A Class A fire extinguisher consists of a hand held cylindrical pressure vessel and an agent that can be used to extinguish an ordinary fire. For a Class A extinguisher, that agent is water, and a Class A Extinguisher is effective against ordinary combustible materials such as paper, wood, cardboard, and most plastics.
All fire extinguishers fight fire by utilizing an agent to act upon the chemistry of the fire by removing one or more of the three elements necessary to maintain fire—commonly referred to as the fire triangle. The three sides of the fire triangle are fuel, heat, and oxygen. The agent acts to remove the heat by cooling the fuel or to produce a barrier between the fuel and the oxygen supply in the surrounding air. Once the fire triangle is broken, the fire goes out. In the case of a Class A extinguisher, the agent cools the fuel and breaks the triangle.
The numerical rating on Class A extinguishers indicates the amount of water it holds and the amount of fire it can extinguish. Information on the numerical rating can be found on the label on the device
There are many types of fires, and there is no single type of fire extinguisher that can suppress all types of fires. While water has proven effective in extinguishers used against wood, paper and plastic fires (Class A), a Type A fire extinguisher should never be used on an electrical fire as it is an electrical conductor. For this reason, it is not safe as an agent to fight electrical fires where live circuits are present (Class C). In addition, Class A extinguishers should also not to be used to fight flammable liquid fires (Class B), especially in tanks or vessels. In this instance, water can cause an explosion due to flammable liquids floating on the water and continuing to burn. In addition, a powerful stream of water can splatter the burning liquid to other combustibles.Furthermore, Class A extinguishers should not be used to fight metal fires (Class D) where flaming metals such as magnesium and titanium.
In Class A or water fire extinguishers, the water can freeze inside the extinguisher at lower temperatures. If you plan on keeping your Type A fire extinguisher in areas subject to below freezing temperatures, anti-freeze water extinguisher are available, which uses a non-flamable anti-freeze to prevent the liquid in the extinguisher from freezing.
All Class A fire extinguishers must be monitored an maintained according to local, state and federal codes. Electronic monitoring of extinguishers, like that provided by the en-Gauge electronic monitoring system, is available for all Class A fire extinguishers