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Note: Extinguishers provided for the protection of cooking grease fires shall only be of the sodium bicarbonate or potassium
bicarbonate dry chemical type (Class B-C). Cooking grease fires are a special hazard requiring agents suitable for this application. Sodium bicarbonate and potassium bicarbonate dry chemicals are considered suitable
for the special nature of heated grease fires, others may not be due to agent characteristics. Additionally, the residues of multipurpose dry chemical extinguishers (Class A-B-C) can cause corrosion when left in
contact with metal surfaces. NFPA 10 and 96 standards.
Multi-Class Ratings
This is the new style of labeling that shows this extinguisher may be used on Ordinary Combustibles, Flammable Liquids, or Electrical
Equipment fires.
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 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.
Household Extinguishers:
Most household portable fire extinguishers on the market use a "dry-chemical" extinguishing agent. Depending on the type of dry-chemical extinguishing agent used, these will be label BC
(meaning they are rated for fighting Class B and C fires) or "multipurpose" ABC (rated for fighting all three classes of fires).
Extinguisher Size:
A–rated and B–rated portable fire extinguishers are rated for the size of fire they can extinguish.
When selecting a fire extinguisher, the rule of thumb, of course, is the bigger the better. Larger extinguishers, however, can be heavy and therefore difficult to operate.
It is important for safety reasons that you have some idea of a portable extinguisher's capacity before you attempt to
fight a fire. Many people are unaware that the majority of portable extinguishers are best suited for fighting very
small fires (in wastebasket or toaster oven, for example). Some discharge completely in as few as 8 seconds.
The "size" of an extinguisher is determined by standard tests during which experienced laboratory technicians
attempt to put out fires in a controlled setting. All extinguishers rated for Class A or B fires are labeled with a
number: from 1 to 40 for an A rating, and from 1 to 640 for a B rating. This number is a relative indication of the
extinguisher's "size" or fire-fighting effectiveness. The larger the number, the larger the fire that extinguisher can put
out. Most extinguishers sold for uses in the home have 1-A, 2-A, or 3-A ratings for Class A fires and 5-B, 10-B, 20-B, or 40-B ratings for B fires.
A typical rating for an ABC household model might be "2-A: 10-B: C." A typical rating for a BC extinguisher might
be "10-BC." There is no number to indicate size attached to the C rating. The C rating is included to tell you only
that the extinguisher can be used on fires involving energized electrical equipment. Such a fire will always involve either Class A combustible or Class B Flammables, hence the multi-rating combinations.
Parts of Portable Fire Extinguisher: Most portable extinguisher for home use consists of six basic parts.
- The cylinder: The body of the stored pressure extinguisher holds some combination of extinguishing agent and expellant gas.
- The handle: The handle is nothing more than a grip for carrying and for holding the extinguisher when you
use it. Handle design will vary widely depending on an extinguisher's make and model, but all portable
extinguishers weighing more then 3 pounds are required to have handles. (Note: Lifting an extinguisher by the handle will not discharge the unit.)
- The trigger: This is usually a short lever mounted above the handle at the top of the extinguisher, although
some models may differ. Squeezing the trigger releases the extinguishing agent through the nozzle.
- The nozzle or horn: Depending on the type and model, the extinguishing agent is expelled from the top of the
extinguisher through a fixed nozzle, or a nozzle or cone attaches to the extinguisher by a short hose.
- The pressure gauge or pressure indicator: Over time, the pressure stored in a portable fire extinguisher may
dissipate. An extinguisher that has lost too much pressure will not operate properly. Therefore, stored-pressure extinguishers are designed with a built-in pressure gauge or pressure indicator so you can check
the extinguisher's operating pressure. (A pressure check should be done at least once a month.)
- The locking mechanism: To prevent accidental discharge, all portable extinguishers come with some sort of
locking mechanism that must be removed or released before the extinguisher will work. In most modern home
fire extinguishers, there is a pin, with a large loop at one end, located below the trigger. You must pull the pin
out before you can squeeze the trigger to discharge the extinguisher. See the following illustration.
How to Operate a Portable Fire Extinguisher:
There are four basic steps to operating a portable fire extinguisher. An easy way to remember the procedure is to think of the word "PASS."
- Pull the Pin: Holding the extinguisher with the nozzle pointing away from you, release the locking mechanism. In most cases, this means pulling out the pin located below the trigger.
- Aim low: Standing 6 to 8 feet away from the fire, point the extinguisher nozzle at the base of the fire – the
lowest point of the fire nearest you. Extinguishers are designed to be operated in an upright position. Always hold the extinguisher vertically. Never cradle it horizontally or at an angle in your arms.
- Squeeze the trigger: Squeeze the trigger slowly and evenly. This will release the extinguishing agent and expel it through the nozzle.
- Sweep side to side: As the extinguishing agent is expelled, sweep the nozzle from side to side – "driving the
fire back.." As the fire closest to you goes out, you may move closer to the fire and continue the sweeping
motion until the fire is extinguished. Remember, hold the extinguisher upright. If the fire does not diminish immediately, get out of the building!
Extinguishing Common Household Fires: Even a small fire should be treated with respect, and you should never
attempt to fight a fire unless it is safe to do so. Before fighting a fire, be sure the fire department has been called or is
being called and be sure you have an unobstructed exit route. If the fire you are fighting begins to spread or the
room fills with smoke, leave the area immediately. Remember: big fires start small, and portable fire extinguishers have
their limitations. In the City of Tucson it is the law that the fire department be notified of all fires.
- A grease fire in a frying pan: The safest and easiest way to extinguish a frying-pan fire is to smother it by
sliding a tight-fitting lid over the pan, and then turning off the burner. This will cut off the fire's supply of
oxygen. Do not remove the lid or attempt to move the pan until the pan has cooled completely. Never
attempt to carry the pan to a sink or outdoors. If you use a dry-chemical extinguisher remember to stay back at least 6 feet to avoid splashing burning grease out of the pan. Never use water on this type of fire
- A grease fire in an oven or broiler: Turn off your oven or broiler. Because kitchen ranges are vented, simply
keeping the oven door or broiler drawer shut will usually contain, but probably not smother, the fire.
However, opening the door or drawer will invariably cause the fire to flare up. When opening your oven door or drawer do it slowly and with extreme care. Have a BC or ABC rated extinguisher ready. Do not
attempt to move the pan or baking dish until the fire is out and the pan or dish has cooled completely.
- A wastebasket fire: A fire in a wastebasket usually involves burning paper. Staying back from flames as far
as possible, apply water to the fire until it is out. Or use a portable fire extinguisher rated for Class A fires.
You may also safely use a dry-chemical extinguisher that is rated only for Class B and C fires; however, because a BC extinguisher has no A rating it may not be fully effective.
- Fires involving furniture, drapes, or tablecloths: These are Class A fires and can be extinguished with water.
Unlike wastebasket fires, fires involving furniture, drapes, or tablecloths are not "contained" and can spread
rapidly. For this reason it is often best to fight them with a portable fire extinguisher rather than buckets of
water. Once the burning fabric is extinguished and completely cooled it should be removed from the house;
the potential for rekindling, especially with furniture, is very high. Be sure to protect yourself from burns when removing the item.
- A car fire: If a car fire involves only upholstery (for example, a fire in the back seat started by a cigarette), use
any fire extinguisher available. If the fire involves the engine or dashboard, however, the fire could quickly
become very dangerous. Always shut off your engine. Such car fires can be fought with a fire extinguisher
with a B:C or ABC rating. Do not open your hood; aim your extinguisher through the car's grill. If you cannot
extinguish the fire immediately, leave the area, keep everyone far way from the car, and wait for the fire department.
- A fire involving gas lines: The only safe way to fight a fire in a kitchen range, furnace, or space heater
involving natural gas or propane is to shut off the supply of gas. Know where gas-line shutoff valves are in
your home. The same is true for any fire involving heating oil under pressure (such as in a furnace burner).
Never attempt to extinguish a gas fire without shutting off the fuel supply. An open gas line is a potential explosion hazard.
Remember: Even if a fire appears to be out, it can re-ignite. After using your portable fire extinguisher, watch the fire
area until it is inspected by the fire department.
In the City of Tucson it is the law that the fire department be notified of all fires!
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