What the permit evidences
A permit is not a formality but the evidence of a check made before work started. It shows three things:
- The atmosphere was measured — flammable gas concentration and, where needed, oxygen level, at the point of work and immediately before it.
- Ignition sources are controlled — isolation and lockout, equipment emptied and purged, earthing against static, the surrounding area cleared.
- Responsibility is named — the issuer, the person doing the work, the attendant, and the person authorised to stop it, all in writing.
Measurement is not a one-off
In long tasks the atmosphere changes while work proceeds. The permit therefore states the measurement frequency; where continuous monitoring is required, the instrument stays on site for the duration. “We measured this morning” does not cover an afternoon job.
Hot work is a separate threshold
Welding, cutting, grinding and any open-flame work is done in a zone only as a last resort. First: can the work be moved outside the zone, can the equipment be removed and worked on in a safe area? If it goes ahead, the surroundings are cleaned, combustible surfaces covered, a fire watch posted, and the area kept under observation for a period after work ends — smouldering usually shows itself once everyone has left.
Closing matters as much as issuing
On closure it is verified that the area is back to normal: guards refitted, temporary connections removed, energy safely restored, area clean. An unclosed permit is a hazard left open in the system, and the next shift does not know about it.