Permit-to-Work Systems

In plants and refineries, high-risk jobs need a written permit before work starts. The permit makes operations and maintenance agree on the hazards, the controls, and exactly what work is allowed.

• General Industry
• Refineries & Plants

Common permit types

• Hot work: welding, cutting, grinding, open flames. See Hot Work Permits.
• Confined space entry. See Confined Spaces.
• Line break / equipment opening: opening pipes, vessels or equipment that held hazardous material.
• Lockout / energy isolation.
• Excavation: digging within the plant.
• Critical lifts and work over live process equipment.
• Working at heights and on roofs.

How permits work

1. The job is planned and hazards are identified.
2. Operations prepares the equipment: drained, purged, isolated and locked out, and tested.
3. The permit lists required PPE, gas testing, isolations and special precautions.
4. Both the issuer and the crew sign. Everyone on the crew reviews it.
5. The permit is posted at the job and valid only for the stated time and scope.
6. When work ends or conditions change, the permit is closed or reissued.

Last updated: October 1, 2026