Types of Fire Extinguishers


Different types of fire extinguishers are designed to fight different classes of fire.

The 3 most common types of fire extinguishers are:

1. Water (APW)
2. Carbon Dioxide (CO2)
3. Dry Chemical (ABC, BC, DC)

 

1. Water (APW) Fire Extinguishers

APW Fire ExtinguisherAPW stands for "Air-Pressurized Water."

They are large silver fire extinguishers that stand about 2 feet tall and weigh about 25 pounds when full. Filled with ordinary tap water and pressurized air, they are essentially large squirt guns.

Fire Triangle

APW’s extinguish fire by taking away the heat element of the Fire Triangle.

 

Class A LabelAPW’s are designed for Class A fires only: Wood, paper, cloth.

 

• Using water on a flammable liquid fire could cause the fire to spread.

• Using water on an electrical fire increases the risk of electrocution.  If you have no choice but to use an APW on an electrical fire, make sure the electrical equipment is unplugged or de-energized.

 

2. Carbon Dioxide Fire Extinguishers

CO2 Fire ExtinguisherThe pressure in a CO2 extinguisher is so great, bits of dry ice may shoot out of the horn.

CO2 cylinders are red.  They range in size from 5 lbs to 100 lbs or larger.  On larger sizes, the horn will be at the end of a long, flexible hose.

Class BC LabelCO2’s are designed for Class B and C (Flammable Liquids and Electrical Sources) fires only.


In accordance with regulations (and manufacturers’ recommendations), CO2 extinguishers should undergo hydrostatic testing and recharge every 5 years.

Fire TriangleCarbon dioxide is a non-flammable gas that takes away the oxygen element of the fire triangle. Without oxygen, there is no fire.

CO2 is very cold as it comes out of the extinguisher, so it cools the fuel as well.

A CO2 may be ineffective in extinguishing a Class A fire because it may not be able to displace enough oxygen to successfully put the fire out. Class A materials may also smolder and re-ignite.

 

3. Dry Chemical (ABC) Fire Extinguishers

Fire TriangleDry chemical extinguishers put out fire by coating the fuel with a thin layer of dust.  This separates the fuel from the oxygen in the air.

The powder also works to interrupt the chemical reaction of fire.  These extinguishers are very effective at putting out fire.

ABC extinguishers are red. They range in size from 5 to 20 lbs.

"ABC" fire extinguishers are filled with a fine yellow powder.  The greatest portion of this powder is composed of monoammonium phosphate.  The extinguishers are pressurized with nitrogen.

ABC Fire ExtinguisherDry chemical extinguishers come in a variety of types.

You may see them labeled:
• DC (for "Dry Chemical")
• ABC (can be used on Class A, B, or C fires)
• BC (designed for use on Class B and C fires)

It is extremely important to identify which types of dry chemical extinguishers are located in your area.

Class ABC LabelAn "ABC" extinguisher will have a label like this, indicating it may be used on Class A, B and C fires. You don't want to mistakenly use a "BC" extinguisher on a Class A fire thinking that it was an “ABC” extinguisher.