What Is a Permit To Work and When Is It Required

A permit to work is a formal written authorisation to carry out a specific high-risk task, in a defined location, for a defined period, under stated conditions. It is issued by an authorised person, accepted by the person in charge of the work, and cancelled when the work is complete and the area has been checked.

The document is the smallest part of it. What makes a permit system work is that it forces a conversation before the work starts and a check after it finishes, between two people who both have to put their names to it.

When one is required

There is no single regulation requiring permits for construction generally. The requirement comes from three directions: specific regulations for specific activities, the general duty to have a safe system of work, and the site rules set out in the construction phase plan.

The Confined Spaces Regulations 1997 are the clearest statutory case: entry requires a safe system of work and suitable emergency arrangements, and a permit is the standard way of demonstrating both. Beyond that, permits are conventional for:

• Hot works — welding, cutting, grinding, brazing, bitumen boilers, anything producing a flame, spark or hot surface.
• Confined space entry — tanks, chambers, deep excavations, ducts, voids, sewers.
• Excavation and ground penetration, tied to the service search and the permit to dig.
• Work on or near live electrical systems, and any isolation and lock-off.
• Roof work and work on or near fragile surfaces.
• Lifting operations, particularly over occupied areas or the public highway.
• Work affecting fire systems — sprinkler or alarm isolation.
• Work near or on live services: gas, high-voltage, pressurised systems.
• Work in occupied premises, and any work affecting an existing building's means of escape.

Your RAMS must state which permits the work needs, who obtains them and at what point in the sequence. A method statement that describes welding without mentioning a hot work permit is one of the routine findings described in what a principal contractor looks for.

The five stages

1. Application: the contractor requests the permit, describing the work, the location, the timing and the controls, normally attaching the RAMS.
2. Assessment and issue: the authorised person checks the work against the site's other activities, specifies conditions — isolations, atmospheric testing, fire watch, exclusion zones, standby person — and signs.
3. Acceptance: the person in charge of the work signs to confirm they understand the conditions and will work within them, and briefs the operatives. The permit is displayed at the workplace.
4. Work, within the stated limits of scope, area and time. Anything outside them requires a new permit, not a verbal extension.
5. Hand-back and cancellation: the work is confirmed complete or suspended, the area is checked, isolations are removed in a controlled order, and both parties sign it off. The cancelled permit is retained.

Stage five is the one that gets skipped, and it is the one that catches fires. A hot work permit that is not handed back means nobody checked the area afterwards.

The hot work permit in particular

Fires starting from hot work typically ignite well after the work stops, from smouldering material out of sight. A hot work permit should therefore specify combustible material removed or protected within a stated radius, openings and voids covered, a suitable extinguisher to hand, a fire watch maintained during the work and — critically — for a stated period after it ends, commonly at least sixty minutes with a further check later. It should also state whether the fire alarm or sprinkler system is affected, who authorised any isolation, and when it will be restored.

Confined space permits

A confined space permit needs to name the space, the specified risks assessed, the atmospheric testing regime and the gas monitor to be used with its alarm levels, the ventilation arrangements, the entrants and the standby person outside, the communication method, the rescue plan and the rescue equipment on site, and the time limits on entry.

The rescue arrangements are the part that must be in place before anybody enters, and they must not depend solely on calling the fire and rescue service. A significant proportion of confined space deaths are would-be rescuers who entered without equipment.

Why permit systems fail

• Blanket permits covering a week and a whole floor, which defeat the definition of a specific task in a defined place for a defined period.
• Issue by someone who never visits the location, so the conditions are generic.
• Acceptance signed by a supervisor who then never briefs the operatives.
• Conditions written as "as per RAMS", which passes the assessment back to a document the issuer may not have read.
• Scope creep during the shift, with the same permit used for work it never described.
• Permits not displayed at the workplace, so nobody doing the work can see the conditions.
• No hand-back, and no post-work check.
• So many permits required that the system becomes a queue and people work around it — the most dangerous failure mode of all, because it drives high-risk work underground.

Getting the proportion right

Permits should be reserved for work where the consequences of getting it wrong are severe and where coordination with others genuinely matters. Requiring a permit for every task devalues the ones that count. The construction phase plan should say clearly which activities need which permits, who the authorised persons are and how to reach them, and how long issue takes — see construction phase plan versus RAMS for where those rules belong.

Retain cancelled permits with the project records. They are requested during investigations and audits, and a complete set showing issue, acceptance and hand-back for every high-risk task is strong evidence that the system was operated rather than printed. If you submit the permit alongside the RAMS for review, the document types that can be reviewed together covers how the pair is read, and the cross-check between the two — permit conditions against the method statement sequence — is worth running every time. The excavation permit sits in the same family; the excavation RAMS guide covers the service search that a permit to dig depends on.

This article is general guidance on UK construction documentation practice. It is not legal advice, a compliance certification or a substitute for review by your own qualified health and safety personnel, who remain responsible for deciding whether any particular document is adequate. See our disclaimer.