The ABCs of Fire Extinguishers

Division of Safety & Hygiene, Ohio Industrial Commission

We all use some form of fire almost every day of our lives, whether it is cooking on a gas range, heating a room with a cozy fire rom the fireplace, or lighting a cigarette.

But what would happen if an unexpected fire occurred? Many of you would panic because you don't know the proper fire fighting procedures.

You must first understand that there are four types of fires and using extinguisher improperly or using the wrong extinguisher could result in additional property damage and injury.

Class A fires consist of combustibles, such as wood, paper or cloth. This type of fire can be put out with water-filled extinguishers. When using these extinguishers, get as close to the fire as possible without endangering yourself, and aim the nozzle toward the base of the flames. Continue spraying until all smoldering material is wet down. Deep-seated fires, such as in baled materials, must be thoroughly soaked and may have to be pulled apart in order to reach the smoldering fire.

A multipurpose dry-chemical extinguisher can also be used on Class A fires. With this type of extinguisher the flames are attacked at the edge of the fire with the nozzle directed at the fire in a sweeping motion. The powdered chemical becomes sticky when heated, allowing it to form a film that clings to the heated material and smother the fire

Whenever you are in areas where flammable liquid are stored you must comply with the "no smoking". Just one lighted cigarette could ca.e a fire that could result in extensive damage.

Fires that burn flammable liquids, such as oil, gasoline, solvents and paints, their primary fuel, are Class B fires. Dry chemical extinguishers are usually used to fight this type of fire. When using this extinguisher stand approximately 10 feet away from the fire to apply the powder. Then gradually move in closer; applying the powder from side to side near the base of tie fire.

Carbon dioxide extinguishers are also effective on flammable liquid fires. You must use this type of extinguisher near the edge of the fire at close range in an enclosed area where no wind or draft exists. Since fires can spread with the presence of oxygen, carbon dioxide is used to decrease the amount of oxygen surrounding the fire until the air can no longer support the combustion.

Class C fires are electrical fires. If at all possible, turn off the power in the area before attempting to combat the fire. When electrical equipment is de- energized, extinguishers for Class A or B fire may be safely used; otherwise, the best extinguishers are carbon dioxide and dry chemical extinguishers. Carbon dioxide in on conductive and noncorrosive. Because dry chemical extinguisher leave sticky film, cleaning is easy.

Also included in Class C fires erases or liquified gas the form of liquid pillage, or liquid or gas leak, such as methane, propane or butane. Foam or dry-chemical powder can be used to control these fire. Class D fires involve combustible metal, such magnesium, sodium and potassium; The most reactive combustible metals are alkali metals. Water causes these metals to release hydrogen and a large amount of heat, causing the hydrogen to ignite and explode. Even the moisture on your hand may cause thee metal to react. Special dry-compound powders, such as powdered graphite and sodium chloride, powdered talc, soda ash and limestone, are made to extinguish these fire. In cases of emergency dry sand can be used.

Extinguishers should be placed in locations where they are easily seen and aren't apt to be damaged. They should be hung at an appropriate height above the floor within easy reach. These extinguishers come in sizes that allow for easy handling, and there should be an adequate number of them in the area they protect.

Most portable extinguishers are marked in order to classify the extinguisher.

Note to Discussion Leader:

Have a chart showing the classification symbol that appear on the four different extinguisher.

It is important to know the location of telephones, extinguisher and alarm boxes, since time wasted can increase the danger. Inadequately trained person have sometimes failed to see an alarm box or telephone.

Note to Discussion Leader:

Inform employee of area where phones, alarm boxes and extinguishers are located.

Even with a sprinkler system, extinguishers are useful, because they can control the spread of a fire.

If you see a fire and know from experience that it can be controlled by an extinguisher, a call for help can be postponed. But if after a few second the fire is increasing, immediately call for assistance.

Note to Discussion Leader:

You may want to demonstrate how to operate the extinguishers used il your area.

The operation of extinguishers becoming simpler. All extinguishers made in the United States and Canada operate by pulling the restraining pin and applying the extinguishing agent by squeezing the trigger that controls the application of the agent.

We must prevent and top unwanted fires that destroy lives, jobs and buildings. In order to achieve this goal, all personnel must cooperate. Take the time to put waste paper in the appropriate containers. And don't allow trash, such as oily rags or paper, to accumulate. Since we cannot do without fire, we must be careful about the ways we use things that could cause unwanted fires.