Hot Work Permits
The conduction of heat from a working area by metal components or sparks created by tools can easily ignite adjacent materials - this, if not supervised properly, can prove costly.
Construction work on sites can often introduce a number of fire hazards to a building, including:
- flammable liquids, adhesives, paints, thinners or preservatives,
- gas/electric welding and cutting apparatus,
- flammable gases - LPG's (liquefied petroleum gases) and acetylene,
- cutting, welding and use of blow lamps,
- burning of waste,
- bitumen/tar boilers,
- temporary heating appliances,
- inadequately trained operatives, etc.
In addition to the increased level of fire risk, contractors are generally unfamiliar with the layout of the building the building procedures affecting others in the building and in particular the means of escape routes from the working area. It is therefore essential that adequate information and instruction on the building's fire precautions and evacuation procedures are supplied to the contractors, both to ensure that means of escape routes do not become obstructed due to the works, but also to ensure that the contractors themselves can evacuate in an emergency.
Supervision of hot works is strongly advised to reduce the risk of fire and accidents. Building managers should therefore consider the implementation of a permit to work system including a hot work procedure for such works.
Experience has shown that a satisfactory standard of care and supervision are far more likely to be achieved where a formalised written permit system is in force. Any works being undertaken which are subject to this written permit system will need to be approved by a competent person, with the authority to ensure compliance with the procedures in place. This could for example be the Client or Contractor's health and safety officer.
The Permit System
The permit system is essentially a document which sets out the work that is to be carried out and the precautions that are to be taken to reduce the chances of a fire taking place. It predetermines a safe working procedure and is a record that all foreseeable hazards have been considered in advance and all appropriate precautions are defined and taken in the correct sequence as work proceeds. On its own a permit system does not make the work any less hazardous, but it will tend to make the persons carrying out the work more aware and careful.
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 primary intent of the hot work permit can be summarised as:
- Ensuring that the intended hot work is necessary by consideration of alternative means to achieve the work,
- Identifying the times at which the hot work is intended,
- Undertaking a risk assessment of the process,
- Ensuring that all necessary precautions are considered and in place,
- Ensuring that the works are properly supervised through to ultimate safety.
The following is an example of the type of information that should be included in such a permit:
- The location of the works,
- The equipment to be used to carry out the work,
- Clear demonstration that the operative is adequately trained to carry out the work,
- The time of the works - day, weekend or out of normal working hours,
- Total period of the works - including start and finish times,
- Specific identified risks or hazards,
- Specific or general precautions to be taken,
- Record of final inspections,
ï,· Any shut down of services required to execute the works.
Of course this list is not exhaustive but gives an indication of the information that should be considered.
Procedure
Contractors should be made aware of the hot work permit system and it should be made part of contract conditions to comply with the procedure. The procedure should stipulate that applications to undertake hot works will only be granted where no alternative methods can be found. The client should also insist that requests for permits to undertake hot work be lodged with the client project supervisor by a set period, say 5 working days before proposed commencement of that element of work. This would allow the client's representative sufficient time to assess alternative options and to arrange supervision as necessary.
The permit should be issued for a specific task and only that task, and it should only be undertaken in a clearly identified location.
Before work commences, the work area should be inspected to check that the precautions stated on the permit have been undertaken. These include:
- removal of flammable materials and rubbish from the work area,
- adequate and appropriate fire fighting equipment close at hand,
- fire equipment such as sprinkler heads, hydrants, extinguishers, and call points should be free of obstruction,
- satisfactory means of escape from the work area.
There should be a check list on each permit proforma to ensure that these items have been carried out before the work starts. If necessary 'tick-boxes' with the items to be checked next to them should be set out clearly on the sheet, this can ensure that all possibilities that need to be checked, will be.
General Precautions
Contractors' personnel may be unfamiliar with the layout of the premises and the procedure in the event of a fire. Before starting any work they should be instructed on the building evacuation procedure,location of call points, etc.
Other precautions that can be undertaken are:
- Safeguarding that the hot work is only be carried out by trained and competent personnel.
- When hot work is being carried out in a building with an automatic fire detection system, only the devices in the immediate area where the work is being carried out should be isolated. These devices should be reinstated as soon as the works have been completed. The area should not be left unattended during the isolation period and alternative means of raising an alarm should be employed following a fire risk assessment.
- A trained person, not necessarily involved with the works, should provide a continuous watch during and for at least 1 hour following each period of hot work, to detect and extinguish any ignition in the work and surrounding areas.
- Limiting the commencement of hot work so that it does not take place later than 2 hours before the end of the working day.
Following Completion of the Hot Work
When the work is completed, hot welding rods and other hot waste materials should be removed and disposed of safely away from the building. All of the equipment used in the hot work process, including gas cylinders, should be removed to a secure area at the end of each work period and immediately when the task is finished. To ensure that a fire does not occur after the area has been cleared, supervision should continue for at least one hour after work is completed.
Lawrence Webster Forrest Limited
Lawrence Webster Forrest Limited is a fire safety engineering consultancy with over twenty years experience in the development of fire engineering technology and the application of fire safety standards.
As the UK's leading independent fire consultants. LWF specializes in helping businesses meet the requirements of fire safety legislation through cost effective fire safety consultancy services.
For further information please contact
Peter Gyere Marketing Manager on 020 8668 8663
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