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What Is a Permit to Work in Construction?

Last updated: 5 March 2026

A permit to work (PTW) is a formal written system used to control high-risk activities on construction sites. It authorises specific people to carry out specific work at a specific time, ensuring all necessary precautions are in place before work begins.

Unlike a method statement which describes how to do work safely, a permit to work controls when and where high-risk work can take place. It is a management tool that ensures communication between different trades and prevents dangerous clashes of activities.

When Is a Permit to Work Required?

Permits to work are required for activities where the risk is high enough that normal method statements and risk assessments are not sufficient control on their own:

• Hot works: Welding, cutting, grinding, brazing — any work producing heat, sparks, or flames
• Confined space entry: Tanks, chambers, manholes, excavations deeper than 1.2m
• Electrical isolation: Work on or near live electrical systems
• Working at height: When standard edge protection or scaffold is not available
• Excavation near services: Digging near gas, electric, water, or telecoms utilities
• Breaking into live systems: Plumbing, HVAC, or fire suppression systems
• Crane lifts over occupied areas: When lifting operations cannot avoid occupied zones

What Should a Permit to Work Include?

• Description of the work and its exact location
• Start and finish times (permits must not be open-ended)
• Identified hazards and required precautions
• PPE requirements beyond standard site PPE
• Emergency procedures specific to the activity
• Isolation details (what has been isolated and how)
• Name and signature of the permit issuer
• Name and signature of the person carrying out the work
• Confirmation that the area has been made safe (permit closure)

The Permit to Work Process

1. Request: The contractor requests a permit, providing RAMS for the proposed work
2. Assessment: The site manager or PTW coordinator assesses the work against site conditions
3. Issue: The permit is issued with specific conditions, signed by both parties
4. Work: The work is carried out within the permit conditions
5. Monitoring: The site manager checks that conditions are being followed
6. Closure: On completion, the area is checked, made safe, and the permit is formally closed

Common Permit to Work Mistakes

• Leaving permits open overnight without renewal
• Issuing permits without physically checking the work area
• Workers starting before the permit is fully signed
• Not communicating permit conditions to all affected trades
• Failing to close permits and confirm the area is safe after work completion

A well-managed permit to work system is one of the most effective safety controls on a construction site. It forces communication, creates a formal record, and ensures that high-risk work only happens when proper precautions are in place.