Permit to Work System in Construction

A permit to work is not just another form to fill in. It is a formal safety control that verifies all necessary precautions are in place before high-risk work begins. When the system works properly, it prevents disasters. When it is treated as a paperwork exercise, it gives a false sense of security that can be worse than having no system at all. Here is how to make it work on your site.

What Is a Permit to Work System

A permit to work (PTW) is a formal documented procedure that authorises certain people to carry out specific work at a specific time. It is a final check, carried out at the point of work, that confirms all the identified hazards have been addressed and the controls described in the risk assessment and method statement are actually in place.

The HSE describes a permit to work as "a formal recorded document which authorises specific work to be performed within a defined period of time. It sets out the precautions required to complete the work safely."

A PTW system is not a substitute for risk assessment or method statements. It sits on top of them. The risk assessment identifies the hazards and controls. The method statement describes the safe system of work. The permit confirms that everything is ready before work starts.

When Permits Are Needed

The activities that require permits should be defined in your site rules and communicated during induction. Common permit-controlled activities on UK construction sites include:

• Hot works: Any work involving open flames, sparks, or high temperatures. Welding, brazing, soldering, grinding, disc cutting, use of blow torches, hot bitumen application.
• Confined space entry: Entry into any space that meets the definition under the Confined Spaces Regulations 1997. Tanks, manholes, deep excavations, voids, ducts, and some roof spaces.
• Excavation: Digging near known or suspected underground services (gas, electricity, water, telecoms). Often called a "permit to dig" or "dig permit."
• Electrical work: Work on or near live electrical systems. Isolation and lock-off procedures.
• Temporary works: Loading and dismantling of falsework, formwork, and other temporary works.
• Roof work: Work on or near fragile roofs, or at roof level where specific fall protection is needed.
• Breaking into live systems: Cutting into operational pipework, ductwork, or cable routes.
• Crane operations: Particularly complex lifts, tandem lifts, or lifts near overhead power lines.

The Permit Process Step by Step

1. Request: The person who wants to carry out the work requests a permit from the permit issuer. They provide details of the work, location, duration, and the team involved.
2. Assessment: The permit issuer reviews the request against the risk assessment and method statement. They visit the work location to verify conditions.
3. Precautions check: The issuer confirms that all required precautions are in place: isolations complete, atmospheric testing done, fire extinguishers positioned, exclusion zones established, emergency procedures in place.
4. Issue: If satisfied, the issuer completes the permit, signs it, and the person doing the work counter-signs to confirm they understand the conditions. Both retain a copy.
5. Monitor: The work proceeds under the permit conditions. The permit issuer or their delegate should check that conditions are being maintained during the work.
6. Close out: When the work is complete (or the permit period expires), the work area is inspected, any fire watch period is completed, and the permit is formally closed. Both parties sign the closure.
7. Record: Completed permits are filed as part of the project safety records. They should be kept for the duration of the project and typically for 3-5 years after completion.

Hot Works Permits

Hot works permits are the most frequently issued type on most construction sites. The key elements are:

• Before the work: Remove or protect combustible materials within the hazard zone (typically 10 metres for welding, less for grinding depending on spark trajectory). Check the area above, below, and behind the work point. Cover or seal any openings where sparks could travel. Position a suitable fire extinguisher within reach.
• During the work: Maintain a dedicated fire watch. The fire watcher does nothing else -- they watch for fire. They must be trained in the use of extinguishers and know the emergency procedures.
• After the work: The fire watch continues for a defined period after the work stops (60 minutes is the industry standard, though some insurers require longer). The area is inspected before the fire watch ends. The permit is not closed until the fire watch period is complete.

Hot works are one of the leading causes of fire on construction sites. The London Fire Brigade has identified hot works as the cause of numerous major construction site fires. Proper permit controls are essential. For more on this topic, see our fire safety plan guide.

Confined Space Permits

Confined space permits are the most safety-critical permits on any site. Entry into confined spaces without proper controls has resulted in multiple fatalities, often including would-be rescuers.

The permit must confirm:

• The space has been identified as a confined space and the specific hazards assessed
• Atmospheric testing has been carried out with a calibrated multi-gas detector (oxygen, flammable gas, hydrogen sulphide, carbon monoxide as a minimum)
• The space has been ventilated if required
• All services into the space have been isolated and locked off
• The entrant has the required PPE including breathing apparatus if needed
• A trained standby person is positioned at the entry point throughout the work
• Emergency rescue arrangements are in place and tested
• Communication systems are established between the entrant and standby person

Making the System Work in Practice

A PTW system only works if everyone takes it seriously. Here is how to make that happen:

• Keep permits simple: A four-page permit form discourages use. Keep it to one side of A4, with clear checkboxes and space for specific notes. The detail belongs in the risk assessment, not the permit.
• Train everyone: Permit issuers need formal training. Workers need to understand that work cannot start without a permit and that violating permit conditions is a disciplinary matter.
• Display permits: The permit should be displayed at the point of work so that anyone can see that the work is authorised and check the conditions.
• Audit regularly: Check that permits are being issued, conditions are being maintained, and closure procedures are followed. Random checks build confidence in the system.
• React to breaches: If someone is caught working without a permit or violating permit conditions, the response must be proportionate but firm. Ignoring breaches destroys the system.

Common Failures

• Permits issued without site visits: The issuer signs the permit in the office without checking the actual conditions at the point of work.
• Open-ended permits: Permits that are issued on Monday and never closed. Permits must have a defined time limit and must be reissued for each shift.
• Fire watch not maintained: The fire watcher wanders off to do other work, or the post-work fire watch period is skipped because everyone wants to go home.
• Permits treated as a formality: Ticking boxes without actually checking that controls are in place. If the permit says "area cleared of combustibles" but the area has not been cleared, the permit is a lie.
• No system for subcontractors: Subcontractors doing hot works or confined space entry without going through the main contractor's permit system. All high-risk work on site should go through the same system regardless of who is doing it.

Site Manager AI can help you create permit templates, track active permits, and maintain a complete audit trail of all permit-controlled work on your site.

Related Reading

• Temporary Works Coordinator Responsibilities
• Fire Safety Plan for Construction Sites
• Toolbox Talk Topics for Construction
• Compliance Checklist for HSE Visits