WHAT IS FIRE?

In order to have a fire, there must be three elements:

Fuel -- something which will burn

Heat -- enough to make the fuel burn

Oxygen -- air

Usually these three elements are expressed as a triangle, called the
Fire Triangle.

All three elements must be present at the same time to have a fire. Fire will burn until one or more of the elements is removed, then will go out.

FIGHTING SMALL FIRES

Used properly, portable fire extinguishers can save lives and property by putting out a small fire or containing one until the fire department arrives. It is essential that everyone be familiar with the proper use of portable extinguishers and know when and when not to use them. 

FIRE EXTINGUISHERS HAVE LIMITS

• Portable extinguishers are not designed to fight large or spreading fires.  Even against small fires, they are useful only under certain conditions.

• The operator must know how to use the extinguisher

• The extinguisher must be within easy reach, in working order, and fully charged

• The operator must have a clear escape route that will not be blocked by fire

• The extinguisher must match the type of fire being fought.  (Extinguishers containing water are unsuitable for use on grease or electrical fires.) 

• The extinguisher must be large enough to put out the fire. Many portable fire extinguishers discharge completely in as few as eight to ten seconds.

And remember, always be sure the fire department inspects the fire site, even if you think you've extinguished the fire.

FIRE EXTINGUISHER LOCATION

Fire extinguishers should be placed conspicuously and within easy reach so they can be accessed quickly while a fire is still small.

THE PROPER  FIRE EXTINGUISHER

Select only fire extinguishers that have been tested by an independent laboratory and labeled for the type and size of fire they can extinguish.  Use the labels below as a guide to purchase the kind of extinguisher that suits your needs.

CLASSES OF FIRES:

There are four classes of fires.   All fire extinguishers are labeled, using standard symbols, for the classes of fires on which they can be used.  A red slash through any of the symbols tells you the extinguisher cannot be used on that class of fire.  A missing symbol tells you only that the extinguisher has not been tested for a given class of fire, but may be used if an extinguisher labeled for that class of fire is not available.

Remember that the extinguisher must be appropriate for the type of fire being fought.  Multipurpose fire extinguishers, labeled ABC, may be used on all three classes of fire.  If you use the wrong type of extinguisher, you can endanger yourself and make the fire worse.  It is also very dangerous to use water or an extinguisher labeled only for Class A fires on a cooking-grease or electrical fire.

Fire Extinguisher Sizes:

Portable extinguishers are also rated for the size of fire they can handle.  This rating is expressed as a number from 1 to 40 for Class A fires and from 1 to 640 for Class B fires.   This rating will appear on the label --- 2A:10B:C, for example.  The larger the numbers, the larger the fire of a specific class on which the extinguisher can be used (but higher-rated models are often heavier - make sure you can hold and operate an extinguisher before you buy it).  No number accompanies an extinguisher's Class C rating.  The C on the label indicates only that the extinguisher is safe to use on electrical fires. Extinguishers for Class D fires must match the type of metal that is burning.  These extinguishers do not use numerical ratings.   Extinguishers for Class D fires are labeled with a list detailing the metals that match the unit's extinguishing agent.

Types of Fire Extinguishers:

Depending on their intended use, portable extinguishers store specific "extinguishing agents," which are expelled onto the fire.

• Pressurized water models are appropriate for use on Class A fires only.  These must never be used on electrical or flammable-liquid fires.
• Carbon dioxide extinguishers contain pressurized liquid carbon dioxide, which turns to a gas when expelled.  These models are rated for use on Class B and C fires, but can be used on a Class A fire.  Carbon dioxide does not leave a residue.
• Dry-chemical extinguishers are either stored-pressure models or cartridge-operated models.  The stored-pressure models have a lever above the handle for operation.  The cartridge-operated models require two steps:  Depress the cartridge lever, and then squeeze the nozzle at the end of the hose.  The dry chemicals leave a residue that must be cleaned up after use.
• Ammonium phosphate dry chemical can be used on Class A, B, and C fires, but should never be used on a fire in a commercial grease fryer because of the possibility of reflash and because it will render the fryer's automatic fire-protection system less effective.
• Sodium bicarbonate dry chemical, suitable for fighting Class B and C fires, is preferred over other dry-chemical extinguishers for fighting grease fires.  Where provided, always use the extinguishing system first.  This also shuts off the heat to the appliance.
• Potassium bicarbonate, urea-base potassium bicarbonate, and potassium chloride dry chemical are more effective and use less agent than sodium bicarbonate on the same fire.
• Foam (or AFFF and FFFP) extinguishers coat the surface of a burning flammable liquid with a chemical foam.  When using a foam extinguisher, blanket the entire surface of the liquid to exclude the air.

REMEMBER THE PASS-WORD

Keep your back to an unobstructed exit and stand six to eight feet away from the fire. 

Follow the four-step procedure:

Pull, Aim, Squeeze, and Sweep

PULL the pin:  This unlocks the operating lever and allows you to discharge the extinguisher. Some extinguishers may have other lever-release mechanisms.
AIM low:  Point the extinguisher nozzle (or hose) at the base of the fire.
SQUEEZE the lever above the handle:   This discharges the extinguishing agent.  Releasing the lever will stop the discharge.  (Some extinguishers have a button instead of a lever.)
SWEEP from side to side:  Moving carefully toward the fire, keep the extinguisher aimed at the base of the fire and sweep back and forth until the flames appear to be out.  Watch the fire area.  If the fire re-ignites, repeat the process.

SHOULD YOU FIGHT THE FIRE?

BEFORE you consider fighting a fire . . . .

• Call the Fire Department (Dial 911).

• Make sure the building is being evacuated.

• Determine whether the fire is small and is not spreading.

• Confirm you have a safe path to an exit not threatened by the fire.

• Know how to use a fire extinguisher.

NEVER fight a fire if even one of the following is true:

• The fire is spreading beyond the immediate area in which it started or is already a large fire.

• The fire could block your escape route.

• You are unsure of the proper operation of the extinguisher.

• You doubt that the extinguisher you are holding is designed for the type of fire at hand or is large enough to fight the fire.