The APW

Air-pressurized water (APW) fire extinguishers can be identified by their silver casing. APW fire extinguishers weigh roughly 25 lbs. and stand 2-feet tall. These types of extinguishers contain two-thirds tap water and are pressurized with air. APW extinguishers are designed to battle wood, paper and cloth fires, also known as Class A fires. APW fire extinguishers should not be used to put out flammable liquid fires. Using this type of extinguisher on a flammable liquid fire will only spread the flames around.

Carbon Dioxide

Carbon dioxide fire extinguishers are designed to battle flammable liquid fires and electrical fires, also known as Class B and Class C fires. The size of these extinguishers can range as can the weight. Carbon dioxide extinguishers are filled with pressurized nonflammable carbon dioxide gas. A hard horn, or spout, can be located on carbon dioxide extinguishers. The horn will be attached to a hose on larger versions of the extinguisher. When activated, this type of extinguisher displaces the oxygen from the fire. Seeing bits of dry ice fly out of the horn when this extinguisher is in use is not uncommon. The casing for this extinguisher is red, and it should not be used on Class A fires.

Dry Chemical

Dry chemical fire extinguishers, also known as DC fire extinguishers, are designed to put out either Class B and Class C fires, or Class A, B and C fires. Those intended to put out all three classes of fires will be labeled as such and spray fine yellow powder. The main element within the powder is monoammonium phosphate. These fire extinguishers are pressurized by nitrogen. Dry chemical extinguishers that are intended only for Class B and C fires will also be labeled as such and should not be used to put out Class A fires. Dry chemical fire extinguishers have a red case and can weigh between 5 and 20 lbs.

Usage

Before using any type of fire extinguisher, you need to know what materials are burning, which will allow you to choose the right extinguisher for the job. The best time to use a fire extinguisher of any type is right when the fire starts. If the fire has begun to spread, evacuate the premises. If you opt to fight the fire with an extinguisher, take note of the smoke involved. All fires will produce smoke and carbon monoxide; however, some fires can also produce toxic gases, such as acrolein, ammonia, and hydrogen cyanide. These toxic gases can form from burning nylon in a carpet, foam padding, and other such materials. Even in small doses, the gases can be fatal.