A permit to work (PTW) is a formal written system used to control high-risk, non-routine work such as hot work, confined space entry or work on energized equipment. The permit documents the hazards, required controls, authorized people and time limits, and it must be approved by a responsible person before work starts and closed when work ends.
A permit to work system is more than a form. It is a communication process between the people who own an area or system, the people doing the job and anyone else affected, so that nobody starts dangerous work until conditions are confirmed safe.
What Is a Permit to Work?
A permit to work is a documented authorization that allows a specific task to be done, at a specific location, by named people, for a limited time, under defined precautions. It forms part of a site's safety management system and is typically required for work that falls outside normal operating procedures or where a mistake could cause serious injury, fire, explosion or a toxic release.
OSHA does not have a single "permit to work" standard, but several OSHA standards require written permits for specific activities:
- Permit-required confined spaces (29 CFR 1910.146): OSHA defines an entry permit as the written or printed document provided by the employer to allow and control entry into a permit space, containing the information specified in paragraph (f) of the confined spaces standard.
- Process safety management (29 CFR 1910.119(k)): employers covered by process safety management must issue a hot work permit for hot work operations conducted on or near covered processes.
- Welding, cutting and brazing (29 CFR 1910.252): before cutting or welding is permitted, the area must be inspected by the person responsible for authorizing the work, who designates the precautions to follow, preferably in the form of a written permit.
Many organizations extend the same permit approach to other high-risk tasks, even where no specific standard requires it.
Common Types of Work Permits
Most PTW systems use different permit types for different hazards, each with its own checklist of controls.
Hot work permit
Covers welding, cutting, grinding, brazing and other spark- or flame-producing work. Typical controls include removing or shielding combustibles, gas testing where flammable atmospheres are possible, fire extinguishers on hand and a fire watch during and after the work. See hot work.
Confined space entry permit
Required before entry into a permit-required confined space. The permit records atmospheric testing results, isolation measures, entrants, attendants, the entry supervisor and rescue arrangements.
Electrical or energized work permit
Used when work must be performed on or near energized electrical equipment. It documents the justification for energized work, shock and arc flash risk assessments, PPE and approach boundaries.
Other common permits
- Isolation or line-breaking permits: for opening pipes, vessels or systems that contain or have contained hazardous materials, often linked to lockout/tagout.
- Excavation permits: for digging where buried utilities, cave-ins or ground stability are concerns.
- Working at height permits: for tasks requiring fall protection beyond routine access.
- Cold work permits: for non-routine maintenance that does not involve ignition sources but still carries significant risk.
What a Permit to Work Should Include
The exact content varies by permit type, but an effective permit typically records:
- The exact location, equipment and scope of work
- The date, start time and expiry time
- The names of the issuer, the person in charge of the work and the workers performing it
- The hazards identified, usually drawn from a job hazard analysis or risk assessment
- Isolation and lockout points, with verification
- Required testing, such as gas or atmospheric monitoring, with results, times and the tester's name
- Required PPE and equipment
- Emergency and rescue arrangements
- Cross-references to related permits active in the same area
- Signatures for issue, acceptance, any handover, and close-out
For confined spaces, OSHA's 1910.146(f) lists required content including the purpose of entry, authorized duration, authorized entrants, attendants and entry supervisor, hazards, isolation measures, acceptable entry conditions, test results, rescue services, communication procedures, equipment and any related permits such as hot work permits.
How a Permit to Work System Works: Step by Step
- Request. The person planning the work describes the task, location, timing and crew, and submits a permit request.
- Assess hazards. A competent person reviews the task using a job hazard analysis or risk assessment, considering nearby operations and simultaneous work.
- Specify controls. The issuer lists the required isolations, tests, PPE, barricades, fire watch or standby personnel.
- Prepare the area. Operations staff isolate energy sources, drain or purge systems, and complete testing. Each step is verified, not assumed.
- Issue and accept. The issuer and the person in charge of the work walk the job site together, confirm controls are in place, and sign the permit. The crew is briefed on hazards and precautions.
- Display the permit. The permit is posted at the work location so anyone can see what work is authorized and under what conditions.
- Monitor the work. Conditions are rechecked as required, such as periodic gas testing. If conditions change, work stops and the permit is suspended.
- Hand over at shift change. If work extends across shifts, the outgoing and incoming permit holders formally hand over and sign.
- Close out. When work is complete, the crew confirms the area is safe, tools and people are clear, and isolations can be removed. The issuer inspects and signs the permit closed before equipment is returned to service.
- Retain and review. Completed permits are kept and periodically audited. For permit-required confined spaces, OSHA requires canceled entry permits to be retained for at least one year to support the annual program review.
Roles in a Permit to Work System
- Permit issuer or authorizer: usually from operations or the area owner. Confirms the work can be done safely in the context of the plant and signs to authorize it.
- Permit holder or performing authority: the person in charge of the crew who accepts the permit and ensures the listed controls are followed.
- Workers: understand the permit conditions before starting and stop work if conditions change.
- Specialists: gas testers, fire watches, attendants and electrical qualified persons who carry out specific permit requirements.
Everyone in the system should have stop work authority if conditions no longer match the permit.
Permit to Work vs. Lockout/Tagout
Lockout/tagout (LOTO) and a permit to work are complementary, not interchangeable. LOTO, governed by 29 CFR 1910.147, is a procedure for isolating hazardous energy so machines cannot start or release energy during servicing. A permit to work is the broader authorization that covers the whole task, including hazards that LOTO does not address, such as hot work, atmospheric hazards or simultaneous operations. In many PTW systems, the permit lists the required LOTO isolation points and is not issued until those isolations are verified.
Common Mistakes to Avoid
- Treating the permit as paperwork. Signing a permit without visiting the job site defeats its purpose.
- Vague scope. "Maintenance on Line 3" is not a scope. Work that grows beyond the permit needs a new or revised permit.
- Open-ended durations. Permits should expire, and confined space permits may not exceed the time needed to complete the task.
- Poor shift handovers. Critical information about isolations, test results and unfinished steps is easily lost between shifts without a formal handover.
- Ignoring simultaneous operations. Two permits in the same area, such as hot work next to line breaking, can create combined hazards.
- Skipping close-out. Returning equipment to service before the permit is formally closed can expose people still working.
- No auditing. Without regular checks of live and closed permits, gaps go unnoticed.
How SMS360 Helps
The SMS360 Work Permits module lets teams request, review, approve and close permits digitally, with records of who issued and accepted each permit and when. Active permits can be viewed on mobile devices and dashboards, which helps supervisors see what high-risk work is underway at each site. Completed permits are stored for audits and reviews, and reminders help keep expiring or open permits from being overlooked.
Frequently Asked Questions
What is a permit to work system?
A permit to work system is a formal, documented process for authorizing and controlling high-risk, non-routine work. It defines who can request, issue and accept permits, what hazards must be assessed, which controls must be in place before work begins, how permits are displayed, handed over and closed, and how completed permits are audited. It ensures everyone involved understands the hazards before work starts.
When is a permit to work required?
OSHA requires written permits for entry into permit-required confined spaces and for hot work on or near processes covered by process safety management. Beyond those requirements, most organizations require a permit for any task where failure of controls could cause serious harm, such as hot work, energized electrical work, line breaking, excavation and certain work at height.
How long is a work permit valid?
A permit is valid only for the duration written on it, which many sites limit to a single shift. For permit-required confined spaces, OSHA states the authorized duration may not exceed the time needed to complete the assigned task. If work continues past expiry, or conditions change, the permit must be revalidated or a new one issued.
Who can issue a permit to work?
Only people who are trained and formally authorized by the employer should issue permits. This is usually an operations supervisor or area owner who understands the process, equipment and surrounding activities. For confined spaces, the entry supervisor named on the permit must sign it before entry begins.
