Fire Extinguishers

Departments / Public Safety / Fire Prevention

Smoke alarms and escape plans are two of the most important components of your overall fire safety plan for your home or business. A third component of the your plan may include fire suppression equipment such as a fire extinguisher.

We are all familiar with what a fire extinguisher looks like as we see them almost everyday in our place of work, schools and in shopping areas.

The question is, do we know what to do in the event of fire and if you are using the correct type of fire extinguisher for the type of fire you encounter? Do you know how to safely and effectively use a fire extinguisher?

First, we must understand that fire extinguishers are tools. A fire extinguisher is no substitute for a trained, properly equipped fire fighter. Fire extinguishers are small tools for a small fire. If you feel your safety is in danger – do not attempt to use a fire extinguisher. Instead, evacuate the area closing doors behind you to stop the spread of smoke, toxic gases, heat and fire.

Fire Extinguisher Ratings

Fires extinguishers are rated by the type or class and size of fire they are capable of extinguishing. Newer extinguishers use a picture or symbol of the type or class of fire they can by used to fight.

	Class A Extinguishers will put out fires in ordinary combustibles, such as wood and paper. The numerical rating for this class of fire extinguisher refers to the amount of water the fire extinguisher holds and the amount of fire it will extinguish. The symbol you may see to designate the extinguisher may be used on a Class A fire is a green triangle with the letter A in the middle.
	Class B Extinguishers should be used on fires involving flammable liquids, such as grease, gasoline, oil, etc. The numerical rating for this class of fire extinguisher states the approximate number of square feet of a flammable liquid fire that a non-expert person can expect to extinguish. The symbol you may see to designate the extinguisher may be used on a Class B fire is a red square with the letter B in the middle.
	Class C Extinguishers are suitable for use on electrically energized fires. This class of fire extinguishers does not have a numerical rating. The presence of the letter “C” indicates that the extinguishing agent is non-conductive. The symbol you may see to designate the extinguisher may be used on a Class C fire is a blue circle with the letter C in the middle.
	Class D Extinguishers are suitable for use on combustible metal fires. Because combustible metals are found generally in specialized processing areas, the class D rating is found only on extinguishers designed for combustible metal fires and rarely will a household fire involve these types of materials. There is no picture designator for Class D extinguishers. These extinguishers generally have no rating nor are they given a multi-purpose rating for use on other types of fires.
A-B / B-C / A-B-C	Multi Class Extinguishers are extinguishers available today can be used on different types of fires and will be labeled with more than one designator, e.g. A-B, B-C, or A-B-C. Make sure that if you have a multi-purpose extinguisher it is properly labeled.
Old & New Label This is the old style of labeling indicating suitability for use on Class A, B, and C fires. This is the new labeling style with a diagonal red line drawn through the picture to indicate what type of fire this extinguisher is NOT suitable for. In this example, the fire extinguisher could be used on Ordinary Combustibles and Flammable Liquids fires, but not for Electrical Equipment fires.

Types of Fire Extinguishers

	Dry Chemical extinguishers are usually rated for multiple purpose use. They contain an extinguishing agent and use a compressed, non-flammable gas as a propellant.
	Halon extinguishers contain a gas that interrupts the chemical reaction that takes place when fuels burn. These types of extinguishers are often used to protect valuable electrical equipment since them leave no residue to clean up. Halon extinguishers have a limited range, usually 4 to 6 feet. The initial application of Halon should be made at the base of the fire, even after the flames have been extinguished.
	Water Extinguisher contain water and compressed gas and should only be used on Class A (ordinary combustibles) fires.
	Carbon Dioxide (CO2) extinguishers are most effective on Class B and C (liquids and electrical) fires. Since the gas disperses quickly, these extinguishers are only effective from 3 to 8 feet. The carbon dioxide is stored as a compressed liquid in the extinguisher; as it expands, it cools the surrounding air. The cooling will often cause ice to form around the “horn” where the gas is expelled from the extinguisher. Since the fire could re-ignite, continue to apply the agent even after the fire appears to be out.

How to use a fire extinguisher.

Even though extinguishers come in a number of shapes and sizes, they all operate in a similar manner. Here’s an easy acronym for fire extinguisher use:
P-A-S-S (Pull, Aim, Squeeze & Sweep)

	Pull the pin at the top of the extinguisher that keeps the handle from being accidentally pressed.
	Aim the nozzle toward the base of the fire.
	Stand approximately 8 feet away from the fire and squeeze the handle to discharge the extinguisher. If you release the handle, the discharge will stop.
Sweep the nozzle back and forth at the base of the fire. After the fire appears to be out, watch it carefully since it may re-ignite!

Fire Extinguishers