Hot Work Permit: What the Permit Must Cover and When You Need One

A permit is required for hot work anywhere other than a designated hot work area, a workshop bay or welding booth designed and equipped for it. On a construction site that is almost everywhere: roof work, plant rooms, fit-out, pipework, steel erection and repairs in occupied buildings. Sites commonly also require one inside a designated area when flammable liquids, gases, dusts or combustible stock are present, when the work is within a set distance of them, usually 10 to 15 metres, or when a fire system is isolated. The site’s permit-to-work procedure says which; the permit form cannot answer the question on its own.

A hot work permit that will satisfy AS 1674.1 and a principal contractor records: the exact location and the work to be done; the issuer, the permit holder and the fire watch by name; the start and expiry time, usually a single shift; the combustible materials within the work radius and what was done with them, removed, covered with fire blankets or wet down; openings, drains, ducts and wall cavities that could carry sparks and how they were sealed; flammable atmosphere checks where gas or vapour could be present; the fire-fighting equipment at the work and who checked it; any fire detection or sprinkler isolation and the arrangement to reinstate it; the fire watch during the work and for the period after it, commonly 30 to 60 minutes; and the close-out signature once the area has been inspected cold. A permit with a tick box for each of these is doing the thinking the regulations require; one that says "hot work permit" with a signature line is not.

The fire watch is the control that distinguishes a real hot work permit from a formality. The person named must have no other duties during the work, must be equipped to put out an incipient fire and to raise the alarm, and must stay for the post-work watch period written on the permit, because most hot work fires start after the welder has packed up, from smouldering material or sparks that travelled through a gap. The permit records the watch period and the fire watch signs the close-out.

If smoke detectors or sprinklers in the area are isolated so that the work does not trigger them, the isolation is itself a permit condition: who authorised it, when it was done, the alternative fire watch arrangements while the system is down, and the reinstatement and test afterwards. Many building insurers require notification of fire system isolations and a limit on how long they may last. The hot work permit is where that is recorded.

The permit form is the visible part. Behind it a permit-to-work system defines who is authorised to issue hot work permits, what training they need, the areas and conditions that require a permit, how long a permit lives, how it is extended or suspended, and where completed permits are filed in the register. A contractor arriving with their own hot work permit still works under the site’s system: the site’s procedure says whose permit governs and who witnesses. Sites that buy a permit form without the procedure find out at the first audit that the auditor wants the procedure.

Welding and cutting on a construction site is usually high risk construction work, which means a SWMS is required as well. The two documents do different jobs: the SWMS describes how the welding task is done safely, the permit authorises this particular instance of it, in this place, today, with these fire controls. Both are kept with the job records.