OHS practices - Work environment

Fire

Generally, fire occurs because of poor industrial housekeeping or unsafe work practices. Workplaces are often likely to contain many fire hazards.

Following safe working practices will dramatically reduce or eliminate the risk.

When a fire occurs, evacuation of all people in the building or general area is the highest priority.

What is fire?

A chemical reaction that creates a fire may occur whenever the following three elements exist:

oxygen
heat
fuel.

These elements may be represented in a diagram known as a 'fire triangle'. To prevent a fire from starting, keep the fuel sources and ignition sources separate. Extinguishing a fire involves removing one of the elements.

A fire extinguisher is used to remove heat or oxygen.

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Equipment

Virtually all fires begin on a small scale and can easily be extinguished if the correct equipment or fire extinguisher is readily available and properly used.

Portable extinguishers are designed to extinguish small fires before they develop into large uncontrollable fires. The type of fire extinguisher to use depends on the type of fire you are fighting.

Fire extinguishers
Fire extinguisher	What it is
	Water type Red with no coloured band. Effective against: Class A fires – Ordinary combustible (wood, paper, cloth, plastics, rubber). How it works: Mainly by cooling burning material. Caution: Do not use on flammable liquids or electrical appliances. You need to be careful using this type of extinguisher. If used on an electrical fire, electrocution will most likely occur. Using a water type extinguisher can spread a burning fluid, causing the fire to spread.
	Foam type Red with blue coloured band. Effective against: Class A fires – Ordinary combustibles (wood, paper, cloth, plastics, rubber). Class B fires – Flammable liquids (oil, paint, petrol). How it works: Foam blankets a burning liquid, excluding oxygen and cools the material. Caution: Do not use on electrical or metal fires. This type of extinguisher is very handy for flammable liquids. It can extinguish solid materials as well as burning liquids. Don't use it on electrical fires (class E fires).
	Dry chemical powder (ABE) or (BE) Red with white coloured band. ABE effective against: Class A fires – Ordinary combustibles (wood, paper, cloth, plastics). Class B fires – Flammable liquids (oil, paint, petrol). Class C fires – Flammable gasses (LPG, CNG, acetylene). Class E fires – Live electrical equipment (computers, switchboards, power tools) BE effective against: Class B fires – Flammable liquids (oil, paint, petrol). Class C fires – Flammable gasses (LPG, CNG, acetylene). Class E fires – Live electrical equipment (computers, switchboards, power tools). How it works: Absorbs fuel molecules into the surface, diminishing the ability of the fire to continue. Caution: Does not cool the fire very well, fire may flare up again. Be careful when using this type of extinguisher, the fine powder discharged from the extinguisher may restrict vision for a short time and also infiltrate nearby equipment.
	Wet chemical Red with oatmeal coloured band. Effective against: Class A fires – Ordinary combustible (wood, paper, cloth, plastics, rubber). Class F fires – Cooking oils or fats. How it works: Smothers the fire. Caution: Dangerous if used on live electrical equipment. This is definitely the type of extinguisher to have in a kitchen which uses cooking oils or fats. As the solution from this extinguisher is usually alkaline, it is advised to clean and remove all residues within a reasonable time period.
	Carbon dioxide Red with black coloured band. Effective against: Class E fires – Live electrical equipment (computers, switchboards, power tools) Limited effectiveness for: Class A fires – Ordinary combustible (wood, paper, cloth, plastics, rubber). Class B fires – Flammable liquids (oil, paint, petrol). How it works: Reduces oxygen available to the fire, diminishing the ability of the fire to continue. Caution: Suitable for small fire only, not very effective on class A and B fires.
	Vaporising liquid Red with yellow coloured band. Effective against: Class A fires – Ordinary combustible (wood, paper, cloth, plastics, rubber). Class E fires – Live electrical equipment (computers, switchboards, power tools). How it works: Smothers the fire. Caution: Check the characteristics of the specific extinguisher. Some older types of these extinguishers contain halon, an ozone depleting gas. To protect the environment these are banned and should be replaced.
	Fire blanket Effective against: Class F fires – Cooking oils or fats. How it works: Smothers the fire. Caution: Do not lift or remove the fire blanket until the fire has cooled. A fire blanket can also be used to extinguish a fire on a person’s clothing. To do this wrap the blanket around the victim and roll them on the ground.