Hazard: Fire

Hazard: Fire

Fire prevention is important in every workplace.

The specific hazards linked to fire are:

• heat and flames
• smoke and toxic fumes
• reduced oxygen
• collapse of buildings

Fires can start from any source of heat or flame – for example:

• sparks from cutting/grinding equipment
• electrical equipment overheating
• overloaded sockets
• hot surfaces, such as lighting and heating equipment
• tools or equipment with a naked flame such as welding/blow torches
• hot liquids such as fat in fryers
• smoking – if cigarettes or matches are not disposed of correctly
• arson (when someone starts a fire with the intent of causing damage)

Control: Fire

Once a fire has started, it may spread very quickly, producing smoke and toxic fumes. The main aim must always be to prevent a fire from starting in the first place.

Because fires need three elements, as the above fire triangle

if one of the elements of the fire triangle is missing, the fire cannot carry on burning.

Control of heat

Sources of ignition should be kept away from fuels for example, equipment that could produce a spark. Excessive heat and naked flames may start fires. These may be produced by friction in machines, hot surfaces, gas cookers and open fires.

Control of fuel

Material that could become fuel, either intentionally or by accident, must be kept to a minimum – for example, waste and rubbish should be removed regularly, the storage of flammable substances should be avoided or restricted and dusty atmospheres (such as bakeries and joinery workshops) must be well ventilated. Fuel must be kept away – and protected – from sources of ignition (for example, flammable substances must be kept in properly designed and selected fireproof stores or enclosures).

Control of oxygen

Oxygen is in the air around us and so is difficult to control. In the event of a fire, closing outside windows (where possible) and keeping fire doors shut will restrict the spread of fire.

It is always better to prevent a fire from starting in the first place, but if one does start you need to make sure you know how to get out of the building as soon as possible. For this reason, it is important to keep fire exit routes clear.

A further control is a Hot work permit.

A hot work permit is used to prevent fire or explosion and will specifically detail the work to be carried out, how and when it is to be done and the precautions to be taken.

The use of a permit system does not, by itself, make the job safe. It supports the safe system, providing a ready means of recording findings and authorisations required to undertake hot work.

Fire responses

Detection systems are available which, when linked to a warning device, give early warning of a fire.

The systems may detect high temperatures, rapid changes in temperature, smoke, radiation or certain gases produced by a fire.

Manual or automatic fire alarms normally give the warning of danger by a loud sound, such as a ringing bell or siren. Fire alarms must be checked regularly to make sure that they are working properly and everybody can hear them. Workers and regular users of a building should be made familiar with the sound of the fire alarm and the alarm signal should be explained to visitors on their arrival.

All buildings must have a safe exit in case of fire.

Emergency exits help people to get out of a building and away from a fire.

Escape routes in large buildings need to be planned carefully so that they are as simple as possible.

Some of the safety measures used in the building to protect escape routes include fire doors, emergency exits and fire-resistant staircases. Emergency exit doors must open outward to outdoors. They must not be locked unless strictly necessary. If they are locked, then there must be a safe emergency opening system, for example a push bar, which is labelled and explained.

There must be permanent signposting that clearly shows the way out in an emergency. Escape routes and fire doors must be kept clear at all times. Internal fire doors must be kept closed as they help to prevent flames and smoke from spreading and limit the oxygen supply to the fire.

There should also be an emergency lighting system that is checked regularly and maintained. Lifts must not be used as part of an evacuation route or during a fire because of the risk of people becoming trapped.

Managers need to know who is in a building, so workers, visitors and others should be asked to sign in and out. A register should be taken after evacuation to make sure that everyone has escaped.

Once the building is evacuated, everyone should remain at the chosen assembly point until told by a person in authority that it is safe to re-enter.

Regular fire drills should be carried out to check that evacuation procedures are effective.

Fire responses: Fire fighting

It is more important to evacuate a building and get people out safely than to fight a fire. However, there are occasions when simple fire-fighting techniques can eliminate a fire before it takes hold.

Fire-fighting techniques, which may be automatic or manual, eliminate one of the elements in the fire triangle, such as:

• cooling the heat
• starving the fire of fuel
• restricting oxygen – for example by using a fire blanket to smother flames from burning fat in a fryer

Automatic sprinkler systems detect and control a fire at an early stage.

They need to be permanently connected to a water supply and must be properly designed and maintained.

It is important that any fire extinguisher used is of the correct type, as wrong fire extinguisher can make things worse.  Extinguishers are colour coded and contain one of a number of substances that can put out fires:

• water – paper, wood and textile fires – red
• foam – flammable liquids, paper and wood – cream
• dry powder – most types of fire – blue
• wet chemical – deep-fat cooking fires – yellow
• CO2 – electrical fires – black

When operated, pressure releases the substance that can be directed onto the fire.

Portable fire extinguishers should be fixed in suitable, accessible position – usually by doors along exit routes – and must be clearly indicated by specific safety signs.

There should be enough of them for the type of premises and risks involved in the work activities. Extinguishers must be regularly checked and maintained.