ABC Extinguisher Types

Fire is a day-to-day necessity in many homes. Water heaters, stoves, ovens, fireplaces--many use or require fire to work. But fire is also very dangerous. According to the U.S. Fire Administration, in 2008, 3,320 people died and nearly 17,000 were injured from fires, and 118 firefighters died in the line of duty. Property loss was estimated to be $15.5 billion in 2008, and 84 percent of the civilian fire deaths happened inside homes. Properly maintained fire extinguishers may have reduced that percentage.

Class A extinguishers

• A class A type of fire extinguisher is for the average combustible type of materials, such as paper, cardboard, wood and the majority of plastics. The rating on extinguishers of this type indicate how much water it holds, and how much fire it can extinguish.

Class B extinguishers

• A class B fire extinguisher is for use in fires that are fueled by combustible fluids like gasoline, grease, kerosene or oil. The numeric rating on class B extinguishers is an indicator of roughly how many square feet of fire can be extinguished.

Class C extinguishers

• A class C type fire extinguisher is meant for use on electrical fires, or fires started by appliances, circuit breakers, wiring, or electrical outlets. Water should never be used to put out an electrical-based fire, because while you might put out the fire, you risk electric shock. Class C fire extinguishers do not have a numeric rating. The C in the classification indicates that the extinguisher is non-conductive.

Class D extinguishers

• Class D fire extinguishers are most commonly found in chemical laboratories, as they are intended for use on fires involving combustible metals like magnesium, potassium, titanium, or sodium. These extinguishers, like class C extinguishers, have no numeric rating. No extinguisher will have a D class along with others; the D rating is for D class fires only.

Types of extinguishers

• Water extinguishers, also known as APW (air pressurized water), are for class A fires only. Use of an APW extinguisher on an electrical fire can result in shock, and will spread around a oil/gasoline/kerosene/grease-based fire and make things worse.

  Dry chemical extinguishers are much more versatile, and can be for Class A, B, C, or even multi-class in nature. They are generally filled with a powder or foam and are pressurized with nitrogen. A class BC extinguisher is a regular dry chemical type extinguisher. it will be filled with sodium or potassium bicarbonate. This type of extinguisher can leave a slightly corrosive residue that will have to be cleaned immediately to prevent damage. A class ABC extinguisher is a multi-purpose extinguisher. These extinguishers are commonly filled with monoammonium phosphate, which is a yellow powder. it leaves a sticky residue that can be damaging to electrical appliances. The benefit to these dry chemical extinguishers is that they leave a nonflammable substance covering the extinguished material, which greatly reduces the change of re-ignition.

  Carbon dioxide (CO2) extinguishers are used for B and C class extinguishers. This is because while CO2 is nonflammable, as well as cold as it expands, it is not guaranteed to displace enough oxygen to prevent re-ignition of a fire once put out.