Permit to Work System Explained: A Practical Guide for UK Contractors

A permit to work (PTW) system is one of the most effective tools for controlling high-risk work activities on site. Yet it is also one of the most misunderstood — often reduced to a signature on a form when it should be a live, managed process. This guide explains what a permit to work actually is, when you need one, and how to run it properly.

What Is a Permit to Work?

A permit to work is a formal written document that authorises specific people to carry out defined high-hazard tasks in a controlled way, at a specific time and place. It is not a general risk assessment or method statement — it sits on top of your RAMS as an additional layer of control for tasks where normal precautions are insufficient and a mistake could be fatal.

The permit records:

• exactly what work is authorised
• the hazards involved and controls required before work starts
• who has checked and confirmed those controls are in place
• the time window the permit is valid for
• what to do if conditions change
• a formal sign-off when work is complete

When Is a Permit to Work Required?

There is no single regulation that mandates PTW for a fixed list of tasks, but several pieces of legislation create duties that a PTW system helps discharge:

• Management of Health and Safety at Work Regulations 1999 (reg 3) — requires suitable and sufficient risk assessment; for certain hazards, a PTW is the appropriate control.
• COSHH Regulations 2002 — relevant where work in confined spaces or on plant involves hazardous substances.
• Work at Height Regulations 2005 — for complex or fragile-roof access work, a PTW provides additional authorisation control.
• Electricity at Work Regulations 1989 — effectively require permit to work arrangements for live or potentially live electrical work.

In practice, PTW systems are typically used for:

If your risk assessment identifies a task where a single failure in controls could cause a fatality, a PTW is almost certainly warranted.

The Key Roles in a PTW System

A PTW only works when roles are clearly defined and understood by everyone involved.

Issuing authority — typically a site manager, responsible engineer, or facilities manager. They confirm all precautions are in place before signing the permit and bear responsibility for the authorisation.

Performing authority — the person (or team leader) carrying out the work. They countersign to confirm they understand the permit conditions.

Competent person — for specialist tasks such as confined space entry or electrical work, an independently assessed competent person must be involved.

These roles must be genuinely separate. The person doing the job should never also be the person issuing their own permit.

The Permit to Work Process Step by Step

1. Identify the need — your risk assessment flags that standard controls are not enough.
2. Prepare the permit — the issuing authority documents the work scope, hazards, isolation requirements, atmospheric testing, PPE, emergency arrangements and time limits.
3. Implement precautions — isolations made, atmosphere tested, barriers erected, emergency equipment in place. Crucially, this happens before the permit is signed.
4. Issue and brief — the issuing authority briefs the performing authority face to face. Both sign. The performing authority keeps a copy at the workface.
5. Carry out the work — within the exact scope, location, and time stated. Any change in conditions must trigger a suspension.
6. Suspension — if conditions change (shift handover, change of task, deteriorating atmosphere), the permit is suspended and reissued fresh.
7. Clearance and close-out — when work is complete, the performing authority signs off. The issuing authority inspects, confirms the area is safe, and closes the permit. Isolations are only removed at this stage.

Common Failures That Cause Accidents

The HSE's investigation records repeatedly identify the same weaknesses:

• Permits issued by someone who has not physically checked precautions are in place
• Work scope creep — tasks expanding beyond what the permit covers
• Time limits ignored — permits used days after expiry
• Simultaneous operations not considered (two permits active that interact)
• Verbal "re-authorisation" without a new written permit
• No emergency plan specific to the permitted task

How a PTW Relates to Your RAMS

Your Risk Assessment and Method Statement sets out how a task is to be done. The permit to work is the real-time check that the conditions described in the RAMS actually exist on the day, at the time, with the right people in place. One does not replace the other — both are needed.

Setting Up a PTW System

For a PTW system to be legally defensible and practically effective, you need:

• Written PTW procedures specific to your site or business type
• Trained, competent issuing and performing authorities (training should be documented)
• Numbered, controlled permit forms with clear retention periods (commonly 12 months)
• A register of live permits to manage simultaneous operations
• Regular audits of how permits are being used in practice, not just on paper

A PTW system is only as strong as the discipline applied to it. The form is not the safety — the checks behind it are.