Fire Safety & Hot Work

April 23, 2013

According to British Standard BS 9999: Code of Practice for Fire Safety in the Design, Management and Use of Buildings, contractors and subcontractors can present an additional fire risk due to their unfamiliarity with the premises, its fire risks and associated fire precautions. This risk is increased even further when contractors and subcontractors carry out hazardous activities such as hot work.
Where processes involving hot work are unavoidable, a strict, safe system of work to control the risk of fire arising from the activity is required. A particularly effective method of ensuring a safe system of work is the use of a “hot work permit”.

Hot work and fire risks

Hot work is defined as “operations requiring the use of open flames or the local application of heat or friction”. There are many procedures that might involve or have the potential to generate sufficient heat, sparks or flame to cause a fire. This includes welding, flame cutting, soldering, brazing, grinding and the use of other equipment incorporating a flame, e.g. tar boilers, etc.
Hot work is clearly a known source of ignition and therefore has the potential to create a significant fire risk for the premises. As an example, sparks and molten material from hot work can be scattered more than 35 feet during welding, cutting and grinding. These sparks and slag are typically at a temperature above 1000°F when expelled from the hot work operations. At this temperature, materials such as paper, wood, flammable liquids, vapours, and many other combustibles can be easily ignited if they are in the vicinity of the hot work activities.

As well as the initial risks of ignition, hot work can be a cause of rapid fire spread. Reasons for this include:

Work being undertaken in areas with limited fire stopping (e.g. roof voids)
Sparks and slag falling through cracks and other floor openings, starting fires in hidden locations
Work being undertaken by persons with little knowledge and awareness of fire risks and precautions
Work being undertaken in higher risk environments (e.g. confined spaces)
Pipes or other metal with conductive heat igniting combustible walls, partitions, ceilings, roofs or other combustibles
Containers and piping containing flammable vapours or fumes with the possibility of explosions and fire.

Risk control

Clearly the need to undertake hot work will be very much dependent on the work activities to be completed and it may not be possible to detail in the premises fire risk assessment specific issues. However, in general terms, hot work can be addressed and management control measures adopted. This will be linked in with the wider contractor management arrangements that the organisation should be employing, including:

Identifying all aspects of the work that the contractor will be required to do
Identifying any risks associated with the work (including hot work)
Ensuring that sufficient rules and control measures are in place when the work is undertaken.

BS 9999 recommends that hot work should only be undertaken if no satisfactory alternative method is feasible. The person responsible for fire safety should therefore evaluate the need to perform hot work. He/she should determine whether the hazard can be avoided or minimised, taking into account the following hierarchy.

Avoid the undertaking of hot work by adopting alternative work methods
Relocate the hot work outdoors or to specially designated areas that have been designed and constructed to minimise fire risk
Schedule hot work during shutdowns/out-of-hours if it cannot be avoided or relocated
Undertake the hot work in the area necessary using safe systems.

BS 9999 recommends that a “hot work permit procedure” should be followed before any hot work is allowed in or near a building so as to “ensure that correct actions are taken before hot work commences, during the operation and afterwards”.

Hot work permit

The use of a hot work permit is appropriate in circumstances where work will involve flames or sparks, where flammable materials are close by and when work is to be completed in environments where such activities are not normally carried out. Such a permit can:

Ensure that there is a formal check confirming that safe systems of work are being followed
Co-ordinate the work activities with other persons or other work processes
Provide time limits when it is safe to work
Provide specialised PPE or methods of communication
Ensure that the works are properly supervised through to ultimate safety.

When contractors are employed to perform hot work on the premises two options for hot work permits are available:

The host organisation employs its own hot work procedure that includes a hot work permit. All people, including contractors and internal employees, are required to use this procedure for all hot work carried out on the premises.
Contractors use a suitable hot work procedure of their own. In this case, the employer must be certain that the contractor is using a suitable hot work procedure and that the procedure is used in appropriate cases.

To be effective, the permit scheme should be implemented and supervised by competent staff. Everyone on the premises must be aware of the situations for which a permit is required and there must be regular checks to see that procedures are being followed.

In terms of control procedures, a hot work permit should only be issued:

If the person responsible for fire safety is satisfied that an adequate fire risk assessment and method statement have been prepared
By those competent and authorised to do so
When preparation work is complete and necessary precautions are in place
If the hot work is to be carried out by those competent in the particular activity.

Permit design

Any hot work permit system that is adopted should be tailored to the particular needs and risks found within the specific premises in question. Different areas within a building may contain varying levels of risk, and the permit should be designed to cope with all the risk potential. The permit should be designed to give as much information as possible in terms of the proposed works.

The hot work permit identifies the work to be done, the person who is to do the work, the length of time likely to be taken, the hazards associated with the work and the control measures used. The permit must be as simple as possible and should not take too long to complete, otherwise the person with responsibility for issuing them may fail to check properly that isolations, etc have been carried out before signing.

The layout of the document will depend on the work to be done and the managerial arrangements for responsibilities within the organisation. Typically, the permit will include:

Administrative details (permit title, number, job location, etc)
Description of the work to be undertaken
Hazards identified and precautions required
Fire-fighting equipment available
Time limits for work duration
Specific work methods required
Sections for authorisation, acceptance, hand-back and cancellation signatures.

Further information

BS 9999: Code of Practice for Fire Safety in the Design, Management and Use of Buildings is available from BSI.