Permits to Work · Best Practice · Construction

Permit to Work — Generic

The Generic Permit to Work provides a formal written system for controlling high-risk activities on construction sites. It ensures that authorised personnel have assessed the hazards, implemented controls, and communicated the safe system of work before an activity begins. The permit must be signed by both the issuer and the permit holder and displayed at the work location.

Last reviewed: 29 March 2026 — This guide reflects UK law as of this date. MHSWR 1999 / HSE Guidance remains current with no amendments enacted as of 29 March 2026. Next scheduled review: 29 March 2027.

What a PTW is	A formal written document that authorises specific work at a specific location for a specific period, forming part of a safe system of work
When required	High-risk activities, interface risks between trades, non-routine tasks, and any work where the normal controls are insufficient without additional formal authorisation
PTW lifecycle	Five stages: Request, Authorise, Issue, Monitor/Work, Handback/Close
Self-issue rule	NEVER — the person carrying out the work must never issue their own permit
Duration	Time-limited — every permit must state a defined validity period, typically a single shift or less

1. Purpose and Legal Basis

A permit to work (PTW) is a formal written safe system of work. It is not a risk assessment, not a method statement, and not a standalone authorisation to carry out work. It is a documented control mechanism that ensures specific preconditions have been met before high-risk work begins, and that those conditions are maintained throughout the work, and that the workplace is returned to a safe state when the work is complete.

The legal basis for permits to work derives from the Management of Health and Safety at Work Regulations 1999, Regulation 3 (risk assessment) and Regulation 4 (principles of prevention), the Health and Safety at Work etc. Act 1974, Section 2 (general duty to ensure safe systems of work), and CDM 2015, Regulation 13 (duties of contractors). While no single regulation explicitly mandates a permit to work by name, the permit system is the recognised and expected method of controlling high-risk work where the consequences of failure are severe. HSE guidance across multiple industries identifies the PTW as the standard of good practice.

A PTW is required whenever the normal workplace controls are insufficient to manage the risks of a particular activity. Typical triggers include hot works, confined space entry, electrical isolation, excavation near underground services, work on pressurised systems, work at height where additional controls are needed beyond the standard plan, and any activity where interface risks between trades could lead to a serious incident.

A PTW does not replace a risk assessment or method statement

A common misconception is that a permit to work covers all the documentation for a particular task. It does not. The risk assessment identifies the hazards and evaluates the risks. The method statement sets out how the work will be done and what controls will be applied. The permit to work confirms that all those preconditions have been met at a specific time and place, and formally authorises the work to proceed. All three documents are required — one does not substitute for another.

2. Five Stages of the PTW Lifecycle

Every permit to work follows a defined lifecycle. Each stage must be completed in sequence, documented, and signed by the responsible person. Skipping a stage, or combining stages informally, defeats the purpose of the system and creates the conditions for a serious incident. The five stages are set out below.

Stage	Action	Responsible person	Key requirements
1. Request	The person requiring the work submits a formal request describing the task, location, duration, and hazards	Requesting person (supervisor or contractor)	Must reference the supporting RAMS; must identify the specific permit type required
2. Authorise	A competent authorising person reviews the request, assesses whether preconditions can be met, and approves or rejects the permit	Permit authoriser (site manager, PC representative, or designated competent person)	Must verify that the RAMS is adequate; must confirm preconditions are achievable; must never authorise a permit for their own work
3. Issue	The permit is formally issued at the point of work after a physical check that all preconditions are in place	Permit issuer (may be the same as the authoriser on smaller sites)	On-site verification that isolations, barriers, PPE, fire watch, and all other preconditions are physically in place — not just documented
4. Monitor / Work	The permitted work is carried out within the stated scope, location, and time period; conditions are monitored throughout	Permit holder (the person in charge of the work) and issuer	Work must stop immediately if conditions change; permit holder must be on site at all times; no deviation from the permitted scope without a new or amended permit
5. Handback / Close	The work area is returned to a safe state, the permit holder confirms completion, and the permit is formally closed	Permit holder (handback) and issuer/authoriser (close)	Work area inspected; temporary isolations removed or confirmed permanent; fire watch completed (for hot works); all copies of the permit collected and filed

Suspension and revalidation

If conditions change during the work — for example, an unexpected service is discovered during excavation, weather conditions deteriorate, or another trade needs to work in the same area — the permit must be suspended immediately. Work must stop and the area made safe. The permit can only be revalidated after the issuer has revisited the work area, confirmed that all preconditions are restored, and signed the permit back into force. A suspended permit that is resumed without formal revalidation provides no protection.

3. Common Mistakes

Self-issuing permits

The person carrying out the work must never issue their own permit. The entire purpose of the PTW system is independent verification — a second competent person confirms that the preconditions are in place before the work is authorised. Self-issuing removes this check entirely and reduces the permit to a piece of paper with no safety value.

Permit left open beyond its validity period

Every permit must have a defined expiry time. A permit issued at 08:00 for a single shift is not valid the following morning. Work that continues beyond the stated validity period is unpermitted work. If the task is not complete by the expiry time, the permit must be closed and a new one issued after re-verification of all preconditions.

No physical check at the point of work before issue

A permit signed in the site office without a visit to the work area is worthless. The issuer must physically attend the work location and verify that every stated precondition — isolations locked off, fire extinguishers in place, barriers erected, atmospheric testing completed — is actually in place. A desk-based permit is a paper exercise, not a safe system of work.

Treating the PTW as a substitute for RAMS

A PTW does not replace the need for a risk assessment and method statement. The RAMS identifies the hazards, assesses the risks, and sets out the controls. The PTW confirms that those controls are in place at a specific time and location. Issuing a permit without an underlying RAMS means the hazards have not been properly assessed and the controls have not been thought through.

No formal handback or close-out

A permit that is never formally closed leaves the system in an ambiguous state. The issuer does not know whether the work is complete, whether temporary isolations are still in place, or whether the area is safe for other trades to enter. Every permit must be formally handed back by the permit holder and closed by the issuer, with a documented confirmation that the work area has been returned to a safe condition.

4. Related Documents

The generic PTW provides the overarching framework for all permit types. The following documents are directly related and should be cross-referenced when establishing or operating a permit-to-work system.

Document	Relationship
E2 — Hot Works PTW	Specific permit type for any process producing open flames, sparks, or significant heat. Includes mandatory fire watch requirements and post-work inspection periods that go beyond the generic PTW framework.
E3 — Confined Space Entry PTW	Specific permit type for entry into any substantially enclosed space where specified risks are present. Requires atmospheric testing, standby person, and rescue arrangements that are unique to confined space work.
E5 — Electrical Isolation PTW	Specific permit type for work on or near electrical systems requiring isolation. Incorporates lock-out/tag-out procedures and the GS38 three-step proving dead test.
E14 — Handback Certificate	The formal record of permit close-out and area handback. Confirms that the work area has been returned to a safe state and that all temporary measures have been removed or made permanent.
B1 — Generic Site Risk Assessment	The site-wide risk assessment that identifies the activities requiring a PTW. The PTW system should be referenced in the generic RA as a control measure for high-risk activities.

5. Frequently Asked Questions

Is a permit to work legally required?▾

No single regulation mandates a permit to work by name. However, the Management of Health and Safety at Work Regulations 1999 require a suitable and sufficient risk assessment and the implementation of appropriate control measures. For high-risk activities such as hot works, confined space entry, and electrical isolation, a permit-to-work system is the recognised standard of good practice and the expected control mechanism. In any investigation or prosecution following a serious incident, the absence of a PTW system for high-risk work would be treated as a significant failure in the safe system of work.

Who can issue a permit to work?▾

A permit must be issued by a competent person who is independent of the work being carried out. The issuer must have the authority to stop the work, the knowledge to assess whether preconditions are met, and the training to understand the specific hazards involved. On most construction sites, permit issuers are site managers, principal contractor representatives, or designated competent persons who have received formal PTW training. The person carrying out the work must never issue their own permit.

Can a permit cover multiple days?▾

In general, no. A permit to work should be time-limited to a single shift or a defined working period. At the end of each shift, the permit must be closed and the area made safe. If the work continues the next day, a new permit must be issued after all preconditions are re-verified. Some organisations operate a shift-handover system where a permit can be extended across shifts, but this requires a formal re-check and re-signature by the incoming shift issuer. An open-ended permit that runs indefinitely provides no ongoing assurance that conditions remain safe.

What happens if conditions change during permitted work?▾

The permit must be suspended immediately. Work must stop and the area must be made safe. The permit holder must notify the issuer, who must revisit the work location and assess whether the preconditions can be restored. If they can, the permit is revalidated with a new signature and the work resumes. If conditions have changed materially, the original permit must be cancelled and a new permit issued that reflects the changed circumstances. Continuing to work under a permit whose preconditions are no longer met is unpermitted work.

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