How can you tell which fires an extinguisher can effectively and safely put out?
Some fires may involve a combination of these classifications. Your fire extinguishers should have ABC ratings on them.
Water extinguishers or APW extinguishers air-pressurized water) are suitable for class A fires only.
Never use a water extinguisher on grease fires, electrical fires or class D fires -
the flames will spread and make the fire bigger!
Water extinguishers are filled with water and pressurized with oxygen.
Again - water extinguishers can be very dangerous in the wrong type of situation.
Only fight the fire if you're certain it contains ordinary combustible materials only.
Dry chemical extinguishers come in a variety of types and are suitable for a combination of class A, B and C fires. These are filled with foam or powder and pressurized with nitrogen.
BC This is the regular type of dry chemical extinguisher.
It is filled with sodium bicarbonate or potassium bicarbonate.
The BC variety leaves a mildly corrosive residue which must be cleaned immediately to prevent any damage to materials.
ABC This is the multipurpose dry chemical extinguisher.
The ABC type is filled with monoammonium phosphate, a yellow powder that leaves a sticky residue
that may be damaging to electrical appliances such as a computer.
Dry chemical extinguishers have an advantage over CO2 extinguishers since they leave a non-flammable substance on the extinguished material,
reducing the likelihood of re-ignition.
Carbon Dioxide (CO2) extinguishers are used for class B and C fires. CO2 extinguishers contain carbon dioxide,
a non-flammable gas, and are highly pressurized.
The pressure is so great that it is not uncommon for bits of dry ice to shoot out the nozzle.
They don't work very well on class A fires because they may not be able to displace enough oxygen to put the fire out,
causing it to re-ignite.
CO2 extinguishers have an advantage over dry chemical extinguishers since they don't leave a harmful residue - a good choice for an electrical
fire on a computer or other favorite electronic device such as a stereo or TV.
It is vital to know what type of extinguisher you are using.
Using the wrong type of extinguisher for the wrong type of fire can be life-threatening.
Look for the fire class symbols.
Every manufacturer use symbols that tell you at a glance which classes of fire the extinguisher is rated for.
They appear on the label as either the class letter inside an icon —
A in a green triangle,B in a red square and C in a blue circle — or as small pictorials that show the type
of fire on which the extinguisher is effective.
Which class should I pick?
Most residential extinguishers are BC- or ABC- rated.
For most homeowners, ABC extinguishers are the best choice. Here's why:
BC extinguishers use carbon dioxide or sodium bicarbonate as the extinguishing agent and are most effective on B and C fires,
though they can have some effect on an A fire. ABC extinguishers, however, work on all three fire classes.
Often referred to as "multipurpose," ABC units use ammonium phosphate. The downside to this chemical:
it leaves behind a fine, yellowish powder that can coat floors, furniture, and appliances, and wreak havoc on electrical
and electronic equipment if not quickly cleaned up.
What size do I need?
There are several considerations here. The primary ones are size and heft.
A unit that's too bulky and heavy is useless. Choose a unit that the smallest adult in your home can handle.
But you also need to consider the size of fire the extinguisher is rated to put out.
UL determines the latter qualifier. After using an extinguisher on fires of various sizes,
an examiner translates the results into a numerical code that accompanies the rated class.
The numbers range from 1 to 40 for a Class A rating, and 1 to 640 for Class B.
Class C fires get no numerical rating, because they're caused by an electrically energized A or B fuel.
The higher the number, the larger the fire the unit can handle.
Unfortunately, the more fire an extinguisher can put out, the bigger and heavier it is.
Your best bet: Buy an extinguisher that's rated highly, yet light enough for all adults in the house to handle.
As a rule extinguishers with a 5-A: 21-B:C rating. That means it will put out a Class A fire that it should put
out a Class B fire and that it works on electrical fires.
Should I choose a disposable or rechargeable model?
There's no easy answer; it depends on your habits and values.
Disposable models last about 12 years before they lose pressure and must be discarded. They weigh and cost the least.
Rechargeable models can be refilled and pressurized after use and if they lose pressure.
They're usually made of more durable materials, with metal head and discharge parts instead of the plastic found in most disposables.
On the downside, rechargeables should receive a yearly check by a certified technician for pressure and defects.
Servicing rates vary, so compare companies. And if you buy a rechargeable extinguisher from a store without on-site service,
be sure it can be serviced locally. Rechargeable models cost more than disposables.
Which should you buy?
Compare short- and long-term costs. And consider whether the durability of a rechargeable and the
reassurance of having it checked annually by a professional are worth its added expense. Remember, too, that whichever fire
extinguisher you decide on, only adults should use it!
