Fire Extinguisher Ratings

There are three parts to look at when selecting a fire extinguisher.  The Capacity, Class of Fire and the UL Rating.

Capacity

The capacity or size of a fire extinguisher indicates the amount of extinguishing agent it is capable of holding usually measured in pounds.  Sizes and capacities can range from 2.5 lb. to 350 lb.  Extinguishers 30 lbs. and larger may come equipped with wheels since they may be to heavy to lift and maneuver to a fire.

UL Rating

Each rated fire extinguisher label has a UL rating.  Rated fire extinguishers are tested by the Underwriters Laboratory (UL) for safety and performance.  The alpha numerical ratings are the UL performance and  effectiveness designation, this is another way of saying how effective the extinguisher will be in different types of fires.

The number next to the letter A can range from 1 to 40, which is the water equivalency for extinguishers.  The number next to B and C is a measure of square feet of fire the extinguisher can extinguish.

Capacity	UL Rating	Suggested Model	Type
2-1/2 lbs.	1A-10B:C	JL Cosmic 2-1/2E Buckeye 13315 Strike First SF-ABC110ST	ABC
5 lbs.	2A-10B:C	JL Cosmic 5X	ABC
5 lbs.	3A-10B:C	Strike First SF-ABC310	ABC
5 lbs. or 6 lbs.	3A-40B:C	JL Cosmic 5E JL Cosmic 5B JL Cosmic 6E Strike First SF-ABC340 Buckeye 10914	ABC
10 lbs.	4A-60B:C	Buckeye 11310	ABC
10 lbs.	4A-80B:C	JL Cosmic 10E JL Orbit FE10V JL Orbit FE10VB Buckeye 11340	ABC
10 lbs.	6A-80B:C	Strike First SF-ABC680	ABC
20 lbs.	6A-120B:C 10A-120B:C	Buckeye 12120  JL Cosmic 20E	ABC
20 lbs.	120B:C	JL Industries FPK20C Buckeye 12620	Purple K
30 lb.	10A-160B:C	Buckeye 12905  JL Cosmic 30E	ABC

The Underwriters Laboratory (UL) rates fire extinguishers to be used on certain types of fires. It is vital that you use the correct fire extinguisher for the fire as using the wrong type of fire extinguisher could be life threatening.

FM Global approval is similar to UL Listing.  For this reason, fire extinguisher manufacturers no long seek FM Global approval.


Class of Fires

Class	Types of Fires	Type of Fire Extinguisher	Symbol
A	Wood, Paper, cloth, trash and other ordinary combustibles	Multipurpose ABC Fire Extinguisher, Type A Fire Extinguisher
B	Gasoline, Oil, Paint and  other Flammable Liquids	Multipurpose ABC Fire Extinguisher, C02 or Dry Chemical Agent (Purple K) Fire Extinguishers
C	Wirings, live electrical equipment	Multipurpose ABC Fire Extinguisher, C02 or Dry Chemical Agent (Purple K) Fire Extinguishers
D	Combustible Metals (such as magnesium,  titanium, potassium and sodium)	Specialty Type D Fire Extinguisher (usually made for specific metals)
K	Combustible Cooking Fluids like fats and oils	Type K Commercial kitchen Fire Extinguisher used in conjunction with a fire suppression system

Class A Fire Extinguisher is used for Class A Fires. These fires are considered Ordinary Combustibles. The fire includes paper, cloth, wood, rubber and plastics. An Air pressurized Water (APW) Fire Extinguisher is labeled a Class A Fire Extinguisher. Never use a Class A fire extinguisher on flammable liquids or electrical fires as the extinguisher will spread the fire or electrocution could occur.

Class B Fire Extinguisher is used for Class B Fires. These are flammable liquid fires including Oils, Gasolines, and paints. CO2 Carbon Dioxide Fire Extinguisher and Dry Chemical Fire Extinguishers are both labeled Class B Fire Extinguishers.

Class C Fire Extinguisher is used for Class C Fires. These are Electrical Fires such as appliances, wiring, circuit breakers and outlets. Never use water on an electrical fire due to the risk of electrocution. CO2 fire extinguishers and Dry Chemical Fire Extinguisher are both used for Electrical Equipment Fires.

Class D Fire Extinguisher is used for Class D Fires. These fires are comprised of powders, flakes or shavings of combustible metals (magnesium, titanium, potassium and sodium). The fire extinguishers contain a sodium chloride based dry powder. Many Class D extinguishers are geared to a specific metal.

Class K Fire Extinguisher is used for Class K Fires. These fires are combustible cooking fluid fires comprised of oils and fats. These are typically found in commercial kitchens. These extinguishers are used in conjunction with a built-in hood suppression system. Special Precautions should be taken around electrical equipment - make sure the power has been turned off.  This is not a Purple K type extinguisher (see below).

ABC Fire Extinguishers are considered a multipurpose fire extinguisher that can be used on Class A, B and C fires. ABC fire extinguishers use dry chemical fire retardant powder made up of mono ammonium phosphate. This is a yellow powder that will leave a sticky residue one the fire has been extinguished. These are the most popular style fire extinguisher and represent about 80% of the extinguishers sold.

Carbon Dioxide (CO2) Fire Extinguishers are used for Class B and Class C fires. These extinguishers contain carbon dioxide and are highly pressurized. Do not use on Class A fires as the combustible fire might be able to re-ignite. The CO2 Extinguishers have an advantage over dry chemical extinguishers as they do not leave a harmful residue which is a good choice for delicate electronic equipment.

Purple K Fire Extinguishers contains high performance extinguishing agent most effective for dealing with flammable liquid fires.  Suitable for use on Class B and Class C fires.  It is not recommended for use on sensitive electronic equipment.  This is not a Class K type extinguisher for use on cooking oils and grease (see above).