Safety & information: Using fire extinguishers

Safety & information:

Using fire extinguishers

Part 1. Preparation and safety

Objective

• Locate workplace fire extinguishers and identify applications and operating procedures.

Personal safety
Whenever you perform a task in the workshop you must use personal protective clothing and equipment that is appropriate for the task and which conforms to your local safety regulations and policies. Among other items, this may include:

• Work clothing - such as coveralls and steel-capped footwear
• Eye protection - such as safety glasses and face masks
• Ear protection - such as earmuffs and earplugs
• Hand protection – such as rubber gloves and barrier cream
• Respiratory equipment – such as face masks and valved respirators

If you are not certain what is appropriate or required, ask your supervisor.
Safety check

• Do not attempt to fight a fire unless you have a fire extinguisher large enough to extinguish the fire. Many small extinguishers empty in 8 to 10 seconds.
• Never try to extinguish a fire that is spreading rapidly.
• Do not try to put out a fire unless you know what type of fire is burning. Using the wrong fire extinguisher will make the fire worse.
• Test the fire extinguisher before you attempt to extinguish a fire.
• Do not inhale any fumes from a fire. Fire gives off toxic gases.
• Do not use water on grease fires, electrical fires or fires where electrical wiring is present.
• If you cannot fight the fire, leave the area and call the fire department.
• See your local fire department for a demonstration of the appropriate procedure in your jurisdiction.
• Make sure that you understand and observe all legislative and personal safety procedures when carrying out the following tasks. If you are unsure of what these are, ask your supervisor.

Points to note

• Each workshop will have a firefighting procedure. There should be a workshop fire warden and fire officers. Understand clearly the firefighting policy for your workshop.
• Fire extinguishers will be located in easily accessible places. Do not block access to fire extinguishers with workshop equipment and clutter.
• Fire extinguishers either smother or quench a fire. A fire extinguisher that smothers a fire does not remove heat. Keep a watch over the fire. Even though the fire may seem to be out, it may restart.
• Workshops will have various firefighting tools: fire hoses, fire buckets, fire blankets and fire extinguishers. Each has a specific application and method of use. Familiarize yourself with each of these tools.
• Fire blankets are manufactured from fire retardant material and have multiple uses. They can be used to smother a fire in a cleaning station or wrap around clothing that has caught on fire. They may be used to shield people from fire when evacuating a building or be used as a stretcher to carry injured or unconscious people.
• Never use water on a fuel-based fire. The fuel will float on the water and spread further.
• The only exception to this is in the case of a fire fuelled by methanol. Methanol is heavier than water and burns with an invisible flame. Use a water extinguisher on a methanol fire.
• Fire buckets contain sand that can be thrown over a fire to smother it. Do not be too quick to empty all the sand in one throw. You may not completely cover the fire the first time.

Fighting a fire

• Three elements must be present at the same time for a fire to occur: fuel, oxygen and heat. These three elements are demonstrated by the fire triangle. The secret of firefighting involves the removal of one of these elements, usually the oxygen or the heat.

• Know how to operate the extinguisher. Read the instructions when you purchase the extinguisher. You will not have time to read them once a fire has started.
• Never turn your back on a fire or allow a fire to get between you and a means of escape. If you are fighting a fire outside, always have the wind at your back.
• If possible, get an assistant to guide you and inform you of the fire's progress.
• If a fire occurs in your work area, remember the PASS word:
  • Pull, Aim, Squeeze, Sweep
• PULL out the pin that locks the handle at the top of the extinguisher to prevent accidental use.
• Carry the fire extinguisher in one hand, and use your other hand to AIM the nozzle at the base, or seat, of the fire. Some fire extinguishers need to be turned upside down to operate. Check which way to hold the extinguisher you've chosen.
• Stand about 2.8 m (8 ft) away from the fire and SQUEEZE the handle to discharge the fire extinguisher.
• Remember that if you release the handle on the extinguisher, it will stop discharging.
• SWEEP the nozzle from side to side at the base of the fire. Watch the fire. Although it may appear to have gone out, it may re-ignite.
• If the fire is indoors, you should be standing between the fire and the nearest safe exit. If the fire is outdoors, you should be standing facing the fire with the wind on your back, so that the smoke and heat are being blown away from you. Again, make sure that you have a means of escape, should the fire get out of control.
• When you are quite sure that the fire is out, report it to your supervisor. Also report what actions you took to put out the fire.
• Once the circumstances of the fire have been investigated, and your supervisor or the fire brigade has given you the all clear, clean up the debris and submit the used fire extinguishers for inspection and re-filling.

Fire classifications

• There are 5 classes of fire.
  • "A" class fires involve wood, paper, cloth, rubber and trash.
  • "B" class fires involve flammable liquids, such as oil, paint, gasoline, grease, and tar.
  • "C" class fires involve flammable gases, such as LPG, Natural Gas, Acetylene, etc.
  • "D" class fire is fuelled by combustible metals - magnesium, potassium turnings and metal shavings. They are not as common as "A", "B", or "C" class fires.
  • "E" class fires need electricity to feed the fire. This class includes wiring, damaged appliances, circuit breakers and fuse boxes. Once the electrical supply has been disconnected, the fire changes to the class of fuel it is burning.

Fire extinguisher types

• There are four types of fire extinguisher. Each type can be used for one or more classes of fire.
  • Water extinguishers contain water pressurized by an inert gas or compressed air. The water quenches the heat from the fire to below its vaporization point. They should only be used on class "A" fires.
  • Carbon dioxide fire extinguishers are most effective when used against "B", "C" and "E" class fires. The gas is heavier than air and provides an inert blanket that smothers the fire. A carbon dioxide fire extinguisher will spray small ice particles with the gas. This is normal.
  • Dry Powder fire extinguishers contain a fine powder, usually sodium bicarbonate, held under pressure by an inert gas. The extinguisher smothers the fire with a fine powder. These extinguishers are good to fight any fuel or liquid fire.
  • Foam fire extinguishers contain a chemical that forms a soft foam that floats over the target area and smothers the fire. These are effective fighting liquid, gaseous, paper or wood fires.

Fire extinguisher suitability

• You will often see more than one symbol on a fire extinguisher. This identifies the extinguisher as suitable for more than one class of fire.
• Class "A", "B" and "C" fire extinguishers have a numerical rating. These are used to determine the extinguisher's potential to fight a fire. This rating is expressed as a number from 1 to 40 for Class "A" fires and from 1 to 640 for Class "B" and "C" fires. It will appear on the extinguisher, e.g. 1A or 20B or 4A: 20B:C. A larger number means a larger fire extinguisher.