What Is a Permit to Work? When You Need One and How It Works

A permit to work is a formal written (or electronic) system that authorises named people to carry out specific high-risk work, at a specific place and time, and records the precautions that must be in place first. But a permit is not permission to do a dangerous job, and issuing one does not make the job safe. HSE’s own guidance says exactly that. Outside offshore installations, no law says every workplace must use permits. Instead, a permit to work is how many employers meet their legal duty to provide a safe system of work for jobs such as hot work, confined space entry and work on isolated plant.

At a glance: Nexis CPD’s £9 Permit to Work course explains how permit systems control high-risk work, from isolation to hand-back. It is CPD accredited and 100% online with a verifiable e-certificate, and any three courses cost £18. It is awareness training, not a regulated qualification, and does not authorise anyone to issue permits on a particular site.

What is a permit to work?

HSE’s permits to work page describes it as “a documented procedure that authorises certain people to carry out specific work within a specified time frame. It sets out the precautions required to complete the work safely, based on a risk assessment.”

HSE’s main guidance on the subject is HSG250, Guidance on permit-to-work systems. It is written for the petroleum, chemical and allied industries but says it applies to “other industries where permit-to-work systems are used”. It defines a permit-to-work system as “a formal recorded process used to control work which is identified as potentially hazardous”, and also as “a means of communication between site/installation management, plant supervisors and operators and those who carry out the hazardous work”.

So the permit is the form, but the system is the whole process around it: who can authorise work, what checks are made, how work is supervised and how plant is handed back. Its main job is communication — many permit failures happen because one group did not know what another group had done.

HSG250 is blunt about what a permit is not: “A permit-to-work is not simply permission to carry out a dangerous job.” It adds: “The issue of a permit does not, by itself, make a job safe — that can only be achieved by those preparing for the work, those supervising the work and those carrying it out.”

Is a permit to work a legal requirement?

For most workplaces, there is no regulation that says “you must use a permit-to-work system”. The duty is broader. Section 2(2)(a) of the Health and Safety at Work etc. Act 1974 requires employers to provide “plant and systems of work that are, so far as is reasonably practicable, safe and without risks to health”. Regulation 3 of the Management of Health and Safety at Work Regulations 1999 requires a “suitable and sufficient assessment” of the risks. Where that risk assessment shows a job is high-risk, non-routine or involves several groups working together, a permit to work is often the way to make the system of work safe and to prove it.

There are places where the law or an Approved Code of Practice (ACOP) points much more directly to permits:

• Offshore installations. Regulation 10 of the Offshore Installations and Pipeline Works (Management and Administration) Regulations 1995 is headed “Permits to work”. Where it is necessary for health or safety, the duty holder must make sure people do not do such work “save in accordance with the terms of a permit in writing, given by a competent person”.
• Confined spaces. The ACOP to the Confined Spaces Regulations 1997 (L101, third edition 2014) says a permit-to-work system “is usually required where there is a reasonably foreseeable risk of serious injury in entering or working in the confined space”. It also says that a decision not to use one “should be taken by a competent person”. See our guide to what counts as a confined space.

The ACOP point matters legally. L101 explains that an ACOP “has a special legal status”: if you are prosecuted and did not follow the relevant provisions of the Code, “you will need to show that you have complied with the law in some other way or a court will find you at fault”.

HSG250 itself is ordinary guidance, not an ACOP. It says following it “is not compulsory”, but that if you do, “you will normally be doing enough to comply with the law”, and inspectors may refer to it “as illustrating good practice”.

When do you need a permit to work?

HSG250 says permit-to-work systems “should be considered whenever it is intended to carry out work which may adversely affect the safety of personnel, plant or the environment”. It says they are normally most appropriate for:

• non-production work — maintenance, repair, inspection, testing, alteration, construction, dismantling, modification and cleaning;
• non-routine operations;
• jobs where two or more people or groups need to coordinate activities to complete the job safely;
• jobs where work and responsibilities transfer from one group to another.

It then lists examples of work where permits or supporting certificates should be considered, including:

• work where heat is used or generated, such as welding, flame cutting or grinding;
• work which may generate sparks or other sources of ignition;
• work which may involve breaking containment of a flammable, toxic or other dangerous substance or a pressure system;
• work on high-voltage electrical equipment, or other electrical work which may give rise to danger;
• entry and work within tanks and other confined spaces;
• work involving hazardous substances, including radioactive materials and explosives;
• pressure testing;
• work affecting evacuation, escape or rescue systems;
• work involving temporary equipment such as generators or welding equipment;
• work at height;
• any operation which needs extra precautions or personal protective equipment;
• “any other potentially high-risk operation”.

Your own risk assessment should decide which jobs on your site need a permit. HSG250 describes permits as “an essential part of the task risk assessment process”: you identify the task and its hazards, then the controls, and “the extent of the controls required will depend on the level of risk associated with the task and may include the need for a permit-to-work”.

When is a permit to work not needed?

This is the part people often get wrong in the other direction. HSG250 warns that permit-to-work systems “should not be applied to all activities, as experience has shown that their overall effectiveness may be weakened”. It says permits “are not normally required for controlling general visitors to site or routine maintenance tasks in non-hazardous areas”.

The confined spaces guidance is similar. L101 says a permit is unlikely to be needed where the assessed risks can be controlled easily, the system of work is very simple, and you know other work activities cannot affect safe working in the space.

The reason is human. If every small job needs a permit, people start treating permits as paperwork. They fill in forms without reading them, sign without checking, and the permit stops telling anyone anything. HSG250 includes a case where a permit system for entering a vessel “had fallen into disuse” and a cleaner was overcome by fumes. A permit system that is used for everything can end up protecting nothing.

What are the different types of permit to work?

Sites use different names, and HSG250 warns that “similar terminology may be used at different sites for types of permits which are fundamentally different”. Its Appendix 2 describes the common types:

• Hot work permit — for work involving actual or potential sources of ignition in an area where there may be a risk of fire or explosion, such as welding, flame cutting and spark-producing tools.
• Cold work permit — for other potentially hazardous activities not covered by a hot work permit. Each site should define clearly which jobs it covers.
• Electrical work permit — “primarily a statement that a circuit or item of equipment is safe to work on”. HSG250 says “a permit should not be issued on equipment that is live”.
• Breaking containment permit (or equipment disjointing certificate) — for disconnecting equipment or pipework that contains, or has contained, hazardous or high-pressure fluids.
• Confined space entry certificate — sets out the precautions to remove dangerous fumes or oxygen-depleted air before anyone enters, and confirms the atmosphere has been tested.

HSG250 also suggests colours to help travelling workers recognise permits at a glance: red or red-edged for hot work, blue for cold work, green for confined space entry, black-edged for breaking containment, and yellow for high-voltage electrical isolation. These are suggestions for consistency, not legal requirements.

What should a permit-to-work form include?

HSG250 sets out the essential elements of a permit form and says “if the permit you use does not cover these areas it is unlikely to be fully achieving its purpose”. In summary, a permit should record:

1. the permit title;
2. a permit reference number, and references to any related permits or isolation certificates;
3. the job location;
4. identification of the plant or equipment;
5. a description of the work and its limitations;
6. the hazards, including residual hazards and hazards created by the work;
7. the precautions needed and what to do in an emergency, signed by those who carried out the precautions;
8. the protective equipment needed;
9. issue — signed by the issuing authority to confirm isolations and precautions are in place, with the date, time and duration of the permit;
10. acceptance — signed to confirm the work, hazards and precautions are understood and explained to everyone working under the permit;
11. extension and shift handover — signatures confirming the plant is still safe and new people have been briefed;
12. hand-back — signed to certify the work is complete and the plant is ready for testing and recommissioning;
13. cancellation — certifying the plant has been tested and successfully recommissioned.

HSG250 says signatures “should be dated and timed”. It also asks that forms be clear and usable: short sentences, a clear statement of “who does what and when”, items in the order they are done, and actual limits (“provide actual quantitative values and limits”) rather than vague wording.

Permits can be electronic, but HSG250 says electronic systems must prevent unauthorised issue, must not allow permits to be issued remotely without a site visit, and must be able to print paper permits for display at the job.

Who does what in a permit-to-work system?

Job titles vary from site to site, so HSG250 suggests common names for the main roles:

• Originator — the person who needs the job done.
• Issuing authority — the person who issues the permit after checking that the precautions are in place.
• Permit authoriser — a second person who authorises higher-risk permits before issue.
• Performing authority — the person who accepts the permit on behalf of the people doing the work.
• Permit user — the people working under the terms of the permit.
• Area authority — the person in control of the location where the work is done.
• Isolating authority — the person responsible for making isolations.
• Site checker — for example, an authorised gas tester.

On a small site, one person may cover several roles. HSG250 accepts this, but sets one firm limit: “a person should not issue a permit to themself”. Where the potential for harm is particularly high, it says a second person should see the permit before it is issued.

HSG250 gives the employer or site occupier overall responsibility for the system, but says “everyone who carries out work of any kind on a site or installation — contractors, subcontractors, in fact all workers — has responsibilities and duties under a permit-to-work system”.

How does a permit to work work, step by step?

Every site’s procedure is different, but most follow the same life cycle that HSG250 describes:

1. Plan and assess. The job is identified, a task risk assessment is done and the precautions are decided, often with a method statement describing how the work will be done.
2. Prepare the plant. Isolations are made, lines drained or purged, and atmospheres tested, as the permit requires.
3. Issue. The issuing authority checks the precautions in person and signs the permit, including the time limits.
4. Accept and brief. The performing authority signs to confirm they understand the job and the hazards, and briefs the team.
5. Display. HSG250 says copies should be displayed at or near the work site and in the control room or permit coordination room, so operators can see what equipment is under maintenance.
6. Do and supervise the work. The issuing authority should visit the site — “as a minimum, at start and completion of the task”. Managers “should not rely solely on scrutinising forms”.
7. Suspend if needed. Work may stop for an alarm, a change of scope or while waiting for parts. HSG250 stresses that “a suspended permit remains live until it is cancelled”, so isolations may still be in place.
8. Hand over between shifts. The incoming shift must know about outstanding permit jobs, their status and the status of the plant. HSG250 recommends that the incoming issuing authority signs to allow the permit to continue.
9. Hand back. The performing authority confirms the work is complete. The issuing or area authority confirms that the plant is safe and isolations have been removed. The person in control of operations acknowledges the plant is back under their control.
10. Cancel. The permit is closed once the plant has been tested and recommissioned.

How do isolations fit into a permit to work?

Isolation is often the most important precaution a permit records. HSG250 says one function of a permit is “specifying the precautions to be taken, including safe isolation from potential risks such as hazardous substances, electricity and other energy forms”.

The permit does not replace the isolation itself. Regulation 19 of PUWER requires means to isolate work equipment from its energy sources (see our guide to PUWER). Regulation 13 of the Electricity at Work Regulations 1989 requires “adequate precautions” to stop equipment that has been made dead from becoming charged again while people are working on it. Physical locks and tags put those isolations in place, and the permit records and controls them. Our guide to lockout tagout explains how the two work together and when you need both.

HSG250 also warns about interacting jobs. Where one isolation protects more than one job, it should be “clearly detailed on the permit or a supporting cross-referenced isolation certificate”. In one HSG250 case study, two fitters were working on the same pipes under one permit. The first fitter returned the permit thinking the job was done, and the operator opened the steam valve while the second fitter had not finished his part of the work. A fitter was scalded by high-pressure steam escaping from the open pipe.

What goes wrong with permit-to-work systems?

HSG250 is built around real incidents. The pattern is consistent: the failures are rarely about the form itself and almost always about communication, checking and discipline. Examples it describes include:

• Piper Alpha, 1988. HSG250 summarises Lord Cullen’s findings. Permits were “commonly kept in the performing authority’s pocket” instead of being displayed. Suspended permits were kept in the safety office rather than the control room. A shift handover failed to pass on that a pressure safety valve had been removed for overhaul and not replaced, and that missing valve “was the source of the leak which subsequently ignited”.
• Hickson and Welch, Castleford, 1992. Five people were killed when a jet of flame erupted from a still being raked out. Permits had been issued for removing a lid and blanking an inlet, but “no permit was issued for the actual job to be done”.
• Pasadena, USA, 1989. A vapour cloud explosion killed 23 people during contractor maintenance. HSG250 says there was “no effective permit-to-work system in operation that applied to both company employees and contractors”.
• Hot work near hidden hazards. Welding on pipe supports ignited fumes in pipes leading to a tank. The permit “made no reference to the surrounding risks” because the pipes being welded did not themselves carry flammable material.

HSG250 says incidents are often caused by “failure to implement procedures properly”, and that those failures often come back to “a lack of training, instruction, communication or understanding” of what permits are for.

What training do permit-to-work users need?

HSG250 says “effective training is essential” and that there should be “successive levels of training” for the people involved. Training should cover:

• the principles of a permit-to-work system;
• when permits are required;
• the types of permits, supporting certificates and other documents, such as risk assessments and method statements;
• the responsibilities and competence requirements of people who sign permits;
• the responsibilities of permit users;
• lessons from incidents and from audits.

It says training should happen at induction, before anyone works under a permit, and before anyone becomes authorised to sign permits. It also says “competence should be tested”, re-tested at appropriate intervals, and recorded. For issuers, it says competence should cover “practical and thinking skills as well as knowledge”, and that trainee issuers commonly have their permits countersigned by experienced issuers for a period.

That is the honest limit of any online course. HSG250 lists distance learning and e-learning among suitable training methods, and an awareness course is a good way to learn the principles, the vocabulary and the lessons from past incidents. But authority to issue or accept permits on a particular site comes from that employer, after site-specific training and a competence assessment. No certificate from any training provider authorises you to issue permits on someone else’s plant.

Which courses cover permit-to-work systems?

These three £9 courses work well together for maintenance staff, supervisors, contractors and anyone who works under or manages permits, each with a verifiable certificate:

• Permit to Work — how permit systems work, the main permit types, roles, handover and hand-back.
• Lockout Tagout (LOTO) — isolating energy sources safely before maintenance.
• Confined Space Awareness — recognising confined spaces and the precautions for entry.

Method Statement Awareness and Risk Assessment Awareness are useful alternatives for people who plan high-risk work. Any three courses cost £18 with the pay-for-2-get-3 offer — add them to the cart and the discount applies automatically. These are awareness courses: CPD accredited, but not regulated qualifications, and not a substitute for site-specific permit training and authorisation.

Frequently asked questions

What is a permit to work?

A formal written or electronic system that authorises named people to carry out specific high-risk work at a set place and time. It records the hazards, the precautions such as isolations, and the checks made before work starts. It also controls handover between shifts and hand-back when the work is finished.

Is a permit to work a legal requirement in the UK?

Not as a general rule. Employers must provide safe systems of work and assess risks, and a permit system is often how they do that for high-risk work. Offshore regulations expressly require permits where necessary, and the confined spaces Approved Code of Practice says a permit is usually required where there is a foreseeable risk of serious injury.

When is a permit to work required?

HSE guidance says to consider one for non-routine, non-production or high-risk work, especially hot work, confined space entry, breaking containment, dangerous electrical work and work where several groups need to coordinate. Permits are not normally needed for routine tasks in non-hazardous areas.

Who can issue a permit to work?

Only a person the employer has trained, assessed as competent and authorised as an issuing authority for that site. HSE guidance says a person should not issue a permit to themselves, and higher-risk permits should be seen by a second person before issue.

What is a hot work permit?

A permit for work that involves actual or potential sources of ignition in an area where there may be a risk of fire or explosion, such as welding, flame cutting and grinding. HSE guidance suggests hot work permits are red or red-edged so they are easy to recognise.

A permit is a conversation, not a signature

£9 per course. CPD accredited, 100% online, verifiable e-certificate. Pay for 2, get 3 — any 3 courses for £18.

This article is general information, not legal advice. It summarises HSE guidance (HSG250, published 2005, and the L101 Approved Code of Practice) and the legislation cited as it applies in Great Britain at the time of writing. HSG250 is aimed mainly at the petroleum and chemical industries, and some legislation listed in its appendix has since been replaced. Always follow your site’s own permit procedure and take competent advice for specific situations. A Nexis CPD awareness course is CPD accredited but is not a regulated qualification and does not authorise anyone to issue or accept permits.