How do I choose a Fire Extinguisher?
Choosing the right extinguisher is very important. Every extinguisher should be tested and labeled by an independent
testing laboratory. It should also be large enough to put out a small fire. A 2 1/2-pound extinguisher empties in only
10 seconds; a 5-pound extinguisher in 15-20 seconds; and a 10-pound extinguisher in about 30 seconds. The
Lombard Fire Department will guide you in selecting the proper fire extinguisher for your home or business. In
addition to size, every portable fire extinguisher should be labeled:
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Class A fires are ordinary solid materials like burning paper, wood, cardboard, clothes, plastics etc. Symbol
A in a green triangle.
Class B fires involve flammable or combustible liquids and gases such as gasoline, kerosene, LPG and
common organic solvents like toluene, xylene. Symbol B in a red square.
Class C fires involve energized electrical equipment, such as appliances, switches, panel boxes, power
tools, hot plates and stirrers. Water is a particularly dangerous extinguishing medium for class C fires
because of the risk of electrical shock. Symbol C in a blue circle.
Class D fires involve combustible metals, such as magnesium, titanium, potassium and sodium as well as
organometallic reagents. These materials burn at high temperatures and will react violently with water or other
chemicals. Handle with care.
Some fires may be a combination of these! Your fire extinguishers should have ABC ratings on them. These ratings
will often have numbers on them that look something like "3-A:40-B:C". Higher numbers mean more firefighting
power. In this example, the extinguisher has a good firefighting capacity for Class A, B and C fires.
Q: What are the typical Fire Extinguishers?
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Water extinguishers are suitable for class A (paper etc.) fires, but not for class B, C and D such as burning
liquids, electrical fires or reactive metal fires. In these cases, the flames will be spread or the hazard made
greater!
Dry chemical extinguishers are useful for class ABC fires and are your best all-around choice. They have an
advantage over CO2 extinguishers in that they leave a blanket of non-flammable material on the
extinguished material which reduces the likelihood of reigniting. They also make a terrible mess -- but if the
choice is a fire or a mess, take the mess! Note that there are two kinds of dry chemical extinguishers!
Type BC fire extinguishers contain sodium or potassium bicarbonate.
Type ABC fire extinguishers contain ammonium phosphate.
CO2 extinguishers are for class B and C fires. They don't work very well on class A fires because the
material usually reignites. CO2 extinguishers have an advantage over dry chemical in that they leave behind
no harmful residue -- a good choice for an electrical fire on a computer or other delicate instrument. Note
that CO2 is a bad choice for flammable metal fires. CO2 extinguishers are not approved for class D fires!
Metal/Sand Extinguishers are for flammable metals (class D fires) and work by simply smothering the fire.
You should have an approved class D unit if you are working with flammable metals.
Q: Should You Fight The Fire Or Not?
When you are dealing with a fire, even a small one, you are in danger. Don't try to be a hero.
Fire doubles in size every minute it burns. That means that what is a small, contained fire one moment could
easily engulf an entire room in a matter of seconds! Smoke and gases can be even more deadly than
flames. In less than two minutes you can pass out or even die from poisonous gases and smoke.
It is much better to not even attempt to fight a fire unless you are certain that all occupants are moving to a
safe area, that the fire department has been called and that you have at least one unobstructed exit behind
you. Never fight a fire between you and the exit. If you are unsure of the danger or if there is any chance of
the fire spreading to you, leave immediately! Close all doors behind you as you leave. Wait outside so that
you can tell firefighters where the fire is located.
If the flames are as tall as you, if the room is getting smoky, if the heat from the fire is so hot that you can't
get within five feet of it, or if you feel uneasy, you should not try to fight the fire, but should leave the building
immediately.
Q: How many types of fire extinguishers are there?
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There are basically four different types or classes of fire extinguishers, each of which extinguishes specific
types of fire.
Q: How are fire extinguishers labeled?
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Newer fire extinguishers use a picture/labeling system to designate which types of fires they are to be used
on. Older fire extinguishers are labeled with colored geometrical shapes with letter designations. Both of
these types of labels are shown below with the description of the different classes of extinguishers.
Additionally, Class A and Class B fire extinguishers have a numerical rating which is based on tests
conducted by Underwriter's Laboratories that are designed to determine the extinguishing potential for each
size and type of extinguisher.
Q: What are the single class ratings?
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
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.
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.
Class D Extinguishers are designed for use on flammable metals and are
often specific for the type of metal in question. 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.
Q: What are the multi-class ratings?
Many 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.
This is the old style of labeling indicating suitability for use on Class A,
B, and C fires.
This is the new style of labeling that shows this extinguisher may be
used on Ordinary Combustibles, Flammable Liquids, or Electrical
Equipment 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
Q: What are the different 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 These extinguishers 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.
Q: What is the proper use of a fire extinguisher?
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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, and 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!
Congratulations You are Done!