Principles of control
6.7 Permits to work
Principles of control
89 6.5.8 Monitoring safe systems
Safe systems of work should be monitored to ensure that they are effective in practice. This will involve:
➤ reviewing and revising the systems themselves, to ensure they stay up-to-date
➤ inspection to identify how fully they are being implemented.
In practice, these two things go together, since it is likely that a system that is out of date will not be fully imple- mented by the people who are intended to operate it.
All organizations are responsible for ensuring that their safe systems of work are reviewed and revised as appropriate. Monitoring of implementation is part of all line managers’ normal operating responsibilities, and should also take place during health and safety audits.
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➤ who is authorized to do the work
➤ the steps which have already been taken to make the plant safe
➤ potential hazards which remain, or which may arise as the work proceeds
➤ the precautions to be taken against these hazards
➤ for how long the permit is valid
➤ that the equipment is released to those who are to carry out the work.
In accepting the permit, the person in charge of doing the authorized work normally undertakes to take/main- tain whatever precautions are outlined in the permit. The permit will also include spaces for:
➤ signature certifying that the work is complete
➤ signature confi rming re-acceptance of the plant/
equipment.
6.7.3 Principles
Permit systems must adhere to the following eight principles:
1. wherever possible, and especially with routine jobs, hazards should be eliminated so that the work can be done safely without requiring a permit to work
2. although the Site Manager may delegate the responsibility for the operation of the permit system, the overall responsibility for ensuring safe operation rests with him/her
3. the permit must be recognized as the master instruction which, until it is cancelled, overrides all other instructions
4. the permit applies to everyone on site, including contractors
5. information given in a permit must be detailed and accurate. It must state:
(a) which plant/equipment has been made safe and the steps by which this has been achieved (b) what work may be done
(c) the time at which the permit comes into effect 6. the permit remains in force until the work has been
completed and the permit is cancelled by the per- son who issued it, or by the person nominated by management to take over the responsibility (e.g. at the end of a shift or during absence)
7. no work other than that specifi ed is authorized. If it is found that the planned work has to be changed, the existing permit should be cancelled and a new one issued
8. responsibility for the plant must be clearly defi ned at all stages.
6.7.4 Work requiring a permit
The main types of permit and the work to be covered by each are identifi ed below. Appendix 6.3 illustrates the essential elements of a permit form with supporting notes on its operation.
General permit
The general permit should be used for work such as:
➤ alterations to or overhaul of plant or machinery where mechanical, toxic or electrical hazards may arise
➤ work on or near overhead crane tracks
➤ work on pipelines with hazardous contents
➤ repairs to railway tracks, tippers, conveyors
➤ work with asbestos-based materials
➤ work involving ionising radiation
➤ roof work
➤ excavations to avoid underground services.
Confi ned space permit
Confi ned spaces include chambers, tanks (sealed and open-top), vessels, furnaces, ducts, sewers, manholes, pits, fl ues, excavations, boilers, reactors and ovens.
Many fatal accidents have occurred where inadequate precautions were taken before and during work involv- ing entry into confi ned spaces. The two main hazards Figure 6.8 Permit to work.
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Principles of control
91 are the potential presence of toxic or other dangerous
substances and the absence of adequate oxygen. In addition, there may be mechanical hazards (entangle- ment on agitators) ingress of fl uids, risk of engulfment in a free fl owing solid like grain or sugar, and raised tempera- tures. The work to be carried out may itself be especially hazardous when done in a confi ned space, for example, cleaning using solvents, cutting/welding work. Should the person working in a confi ned space get into diffi culties for whatever reason, getting help in and getting the individual out may prove diffi cult and dangerous.
Stringent preparation, isolation, air testing and other precautions are therefore essential and experience shows that the use of a confi ned space entry permit is essential to confi rm that all the appropriate precautions have been taken.
The Confi ned Spaces Regulations 1997 are summar- ized in Chapter 17. They detail the specifi c controls that are necessary when people enter confi ned spaces.
Work on high voltage apparatus (including testing) Work on high voltage apparatus (over about 600 volts) is potentially high risk. Hazards include:
➤ possibly fatal electric shock/burns to the people doing the work
➤ electrical fi res/explosions
➤ consequential danger from disruption of power sup- ply to safety-critical plant and equipment.
In view of the risk, this work must only be done by suit- ably trained and competent people acting under the terms of a high voltage permit.
Hot work
Hot work is potentially hazardous as:
➤ a source of ignition in any plant in which fl ammable materials are handled
➤ a cause of fi res in all processes, regardless of whether fl ammable materials are present.
Hot work includes cutting, welding, brazing, soldering and any process involving the application of a naked fl ame. Drilling and grinding should also be included where a fl ammable atmosphere is potentially present.
Hot work should therefore be done under the terms of a hot work permit, the only exception being where hot work is done in a designated maintenance area suitable for the purpose.
6.7.5 Responsibilities
The effective operation of the permit system requires the involvement of many people. The following specifi c responsibilities can be identifi ed:
(Note: all appointments, defi nitions of work requiring a permit etc. must be in writing. All the categories of people identifi ed below should receive training in the operation of the permit system as it affects them.)
Figure 6.9 Entering a confi ned space.
Figure 6.10 Hot work permit is usually essential except in designated areas.
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Site manager
➤ has overall responsibility for the operation and man- agement of the permit system
➤ appoints a senior manager (normally the chief engin- eer) to act as senior authorized person.
Senior authorized person
➤ is responsible to the site manager for the operation of the permit system
➤ defi nes the work on the site which requires a permit
➤ ensures that people responsible for this work are aware that it must only be done under the terms of a valid permit
➤ appoints all necessary authorized persons
➤ appoints a deputy to act in his/her absence.
Authorized persons
➤ issue permits to competent persons and retain copies
➤ personally inspect the site to ensure that the con- ditions and proposed precautions are adequate and that it is safe for the work to proceed
➤ accompany the competent person to the site to ensure that the plant/equipment is correctly identi- fi ed and that the competent person understands the permit
➤ cancel the permit on satisfactory completion of the work.
Competent persons
➤ receive permits from authorized persons
➤ read the permit and make sure they fully under- stand the work to be done and the precautions to be taken
➤ signify their acceptance of the permit by signing both copies
➤ comply with the permit and make sure those under their supervision similarly understand and implement the required precautions
➤ on completion of the work, return the permit to the authorized person who issued it.
Operatives
➤ read the permit and comply with its requirements, under the supervision of the competent person.
Specialists
A number of permits require the advice/skills of special- ists in order to operate effectively. Such specialists may include chemists, electrical engineers, health and safety advisers and fi re offi cers. Their role may involve:
➤ isolations within his/her discipline – e.g. electrical work
➤ using suitable techniques and equipment to moni- tor the working environment for toxic or fl ammable materials, or for lack of oxygen
➤ giving advice to managers on safe methods of working.
Specialists must not assume responsibility for the permit system. This lies with the site manager and the senior authorized person.
Engineers (and others responsible for work covered by permits)
➤ ensure that permits are raised as required.
Contractors
The permit system should be applied to contractors in the same way as to direct employees.
The contractor must be given adequate informa- tion and training on the permit system, the restrictions it imposes and the precautions it requires.