The nature of fire
Generally, for a fire to occur, three elements are needed: fuel, oxygen and an ignition source.
The aim of fire prevention is to avoid these three coming into contact - and fires can be extinguished by removing one of the three from the equation.
There are substances that will burn without oxygen - and certain chemicals and preparations can react to oxygen in the air or other chemicals to produce their own 'internal' source of ignition.
But these are specialised areas outside of the scope of this guidance. If your workplace or work processes involve such items, please contact PCS Equality Health & Safety Department, who can supply additional information on these hazards.
It is almost impossible, in most working environments to avoid oxygen and fuel coming together - to prevent fires, the quantities and locations of the fuels must be controlled and kept away from possible sources of ignition.
So, the first step in a fire risk assessment is to identify the possible sources of fuel and ignition.
Sources of ignition
Common sources of ignition include:
- smoking materials;
- heat from processes (e.g. welding or grinding);
- electrical apparatus - either in normal use and in cases of overload or failure;
- ventilation outlets from heat-producing machinery;
- deliberate ignition - arson attacks etc.
All possible ignition sources should be identified as part of the risk assessment. Wherever possible, these should be controlled and kept out of the workplace or well away from combustible materials.
Everyday materials in workplaces, such as paper, furnishings etc., provide a ready source of fuel. Bulk supplies of such materials should be stored away from main work areas, in store cupboards, not left in a corner of the room on the floor.
Some materials - flammable liquids, gases, paint and varnish - ignite readily and burn with high heat or lots of smoke. Ideally such materials should be isolated from the workplace.
Where this is not possible, simple precautions such as fire-resistant store cupboards and keeping lids and covers on containers will help to minimise the risks.
Waste materials should never be allowed to accumulate in the workplace - good housekeeping is particularly important in minimising fire risks.
'Dangerous when burnt'
Some everyday products which are relatively harmless in normal use can change into lethal materials if they come into contact with the extreme heat of a fire.
Whilst it is not possible to list them all here, COSHH assessments and Product Hazard Data Sheets should be checked to ensure that precautions are adequate - especially if staff would be expected to undertake post-fire clean-up operations.
Means of escape
In the event of fire, people must be able to escape from the workplace in safety. Modern Building Regulations go a long way to ensuring adequate means of escape, but the following points should be borne in mind:
- with the possible exception of very small workplaces, people should be able to turn away from the point of the fire to escape. If they may have to pass a fire, in a corridor for example, the route may need additional protection by fire-resistant partitioning and/or self-closing fire doors.
- fire travels up natural chimneys, such as stairways. These will need adequate protection.
- doors should open in the direction of travel, whenever possible - and particularly if they lead from areas of high risk of fire, if they may be used by large numbers of people or if they are situated at the foot of stairways, creating a risk of crushing.
- all doors on escape routes must be capable of being easily and immediately opened from the direction of escape - including those to the outside. There are a variety of fixtures available to balance security with ease of escape. Advice can be obtained from the Fire Authority.
- escape routes should be short and lead to the outside or to a 'place of safety' - that is, a place which is adequately protected from the risk of fire by partitions/doors. Generally, two to three minutes is considered a maximum safe time. People with mobility impairments will need to be considered here. (See section on disabled people)
- escape routes must not be obstructed and should be regularly checked to ensure that they are free from clutter.
- adequate lighting is vital on escape routes - including alternative means of illumination should the electricity fail in the fire. Don't rely on natural light, the fire could occur in the winter, when it is usually dark by 4pm.
- if necessary, signs should be provided on doors and escape routes, clearly pointing the way out. These must comply with standard legislation on type, size and design.
Further detailed guidance on factors to consider in means of escape is contained on the fire guidance pages of the Communities website.
Fire fighting equipment
Most premises are provided with some means of fighting a fire. Unless staff are properly trained, however, they can put themselves and others at risk in using this equipment.
It is vital that all staff are aware of who is trained and when it is safe to attempt to control or extinguish a fire themselves, rather than evacuate the area and rely on the skills of the fire brigade.
As a general rule, fire fighting equipment should only be used to limit the spread of fire to enable safe evacuation. Before tackling any fire, it is vital that the alarm is raised and the fire brigade are called.
The most common form of fire fighting equipment are extinguishers.
Fires are broken into 4 classes, depending on the fuels involves:
- Class A Fires involving ordinary combustible materials
- Class B Fires involving flammable liquids or liquefiable solids
- Class C Fires involving gases.
- Class D Fires involving burning metals.
Different extinguishers are appropriate for different classes of fires:
Water (Colour Code: Red)
Suitable for Class A fires. Must not be used on live electrical fires, though can be safely used on burning electrical equipment once the electrical supply has been isolated.
Foam (Colour Code: Cream)
Different foams can be suitable for different classes of fires. Some contain a water-based foam and are not suitable for use on live electrical equipment. Usually foam extinguishers can be used either on Class A or on Class A & B fires.
Powder (Colour Code: Blue)
Suitable for Class A fires - and some also suitable for Class B. Usually safe used on live electrical equipment, but not ideal because it does not always penetrate inside spaces and causes clogging of machinery which might otherwise be re-usable.
Special dry powders can be used on Class D fires.
Carbon Dioxide (Colour Code: Black)
Suitable for Class B fires and safe and clean if used on live electrical equipment. CO2 is an asphyxiant, and great care must be taken in its use.
Vaporising Liquids (Colour Code: Green)
Suitable for Class B fires and on live electrical equipment. Older extinguishers of this type may contain Halon gas, which is environmentally harmful.
Halon extinguishers should be replaced wherever possible. This type of extinguisher also produces asphyxiant gases and the same care is needed as for CO2.
From January, 1997, all new extinguishers are now colour-coded in accordance with a new British and European Standard (BS EN 3 Part 5), which states that all extinguishers should be coloured RED - with an area of not more than 5% of the body coloured to denote the type of extinguisher.
This only applies to new extinguishers - existing ones do not have to be replaced or repainted before the end of their useful life.
Other means of fire fighting
Hose reels may be available, and are longer lasting than water-based extinguishers. They should be used in the same way and have the same suitabilities and restrictions.
Fire Blankets are good for smothering both small quantities of burning fats or oils and for clothing which is on fire.
Sprinkler Systems are more often required by Insurance Companies, especially as a combined fire detection and fire fighting mechanism.
'Gas flood' systems operate by releasing large quantities of inert gas into a contained area and are very effective at protecting storage areas and electrical equipment rooms. There must be a failsafe method to override any automatic release mechanism when people are present in the area.
Siting of extinguishers
It is important that people can pick up extinguishers readily. If they are provided to control specific risks (e.g. CO2 extinguishers for VDUs), they need to be situated close to that risk - otherwise, the fire may well have taken a good hold before someone can go and collect the extinguisher.
Extinguishers provided for general protection need to be located close to exit points from work areas and on the escape routes.
Notices should be displayed to pinpoint the locations of fire fighting equipment, where this is not immediately obvious. The notices should also specify the type of extinguisher and its suitable uses.
Fire detection and warnings
The sooner a fire is detected, and a warning given to staff, the safer it is for everyone. In most workplaces, a fire would quickly be spotted by staff working in or moving around the premises. However, if there are parts of the workplace that are infrequently visited they may be better protected by installing a fire detection system, especially if a fire taking hold in that area could threaten the escape route.
In all but the very smallest workplaces, a mechanical system of raising the alarm in case of fire will be necessary. Any system must be easily operated and audible throughout the workplace.
Any workplaces including sleeping accommodation should be provided with an automatic system for detecting fire and sounding the alarm.
Testing and Maintenance
Extinguishers, alarm and fire detection systems and any emergency lighting all need to be frequently checked and tested, to ensure that everything will work in the event of a fire.
Fire escape routes should be checked to ensure that they are free of obstructions, preferably on a daily basis. similarly, a quick visual check to ensure that all fire extinguisher are in place, and not off somewhere else propping open a fire door, is a good idea.
A planned system of checks and maintenance, backed up a log-book, should be used, with regular frequent checks by a responsible person from within the premises supported by at least annual testing by competent servicing engineers.
It is vital that people know exactly what to do (and what not to do) in the event of fire.
Staff should be trained to ensure that:
- they are aware of how to raise the alarm if they discover a fire;
- they know what the fire alarm sounds like;
- they know who is responsible for calling the Fire Brigade;
- they can follow the shortest escape route from the premises;
- they know where to assemble outside of the premises - this should be at a near-by location but far enough away to allow unrestricted access to the premises for the emergency services.
- they are aware of how, when and whether to use fire fighting equipment.
In larger premises, it may be necessary to designate certain staff to carry out specific tasks in the event of fire - such as ensuring that a part of the building is clear of people. This may require additional training.
Regular visitors to the building may also benefit from training on the fire procedures. Staff should be made aware of how to deal with any visitors who may be present - it is preferable for them to be escorted by the person they are visiting, if this is practical.
Regular drills help to enforce the messages from the training. These can be held with or without prior warning. Drills should involve everyone.
Printed notices, at strategic points within the workplace, can help re-enforce the messages from training and remind staff of their actions to take in case of fire.