3.7 Permit-to-Work Systems

What a permit-to-work system is

A permit-to-work (PTW) system is a formal written system, forming part of a safe system of work, that controls certain types of potentially hazardous work. It makes sure that all necessary actions are taken before, during and after particularly high-risk work.

Why PTW systems are used

The purpose is simple: to make high-risk, non-routine tasks safer. On top of a risk assessment and method statement, a permit is issued to a particular person, for a specific time, authorising them to do the work under strict controls. A PTW system:

• helps ensure compliance with regulatory requirements
• gives written permission to carry out a task
• makes sure every aspect of the work is planned and checked
• puts risk assessments and method statements into action
• communicates health and safety information, meaning the hazards and controls of the job
• provides a procedure to make sure essential controls stay in place
• provides a procedure to return the area to a safe state when the work ends
• gives a means of communication
• is a written record

How PTW systems work

A permit is issued through the site system by an authorised competent person, not necessarily a senior manager. The system identifies the work, hazards, isolations, precautions and people responsible. Paper copies or electronic records must make current permit status available to the people who need it; one possible distribution is:

• one is carried by the workers holding the permit and displayed in the work area
• one is kept by the authorising manager
• one is displayed in a central location where all live permits are shown

The process normally has five stages.

Issue. The senior manager issuing the permit must be competent to do so. The authorising manager specifies:

• the type of work
• the place where it is to be done
• the workers who will do it
• the control measures to be in place before, during and after the work
• the date and time of the permit
• how long the permit is valid
• any other permits running at the same time
• a copy of the method statement or risk assessment, which may be attached
• the name and signature of the authorising manager

Receipt. The issuing authority hands the permit to the workers who will do the task. They read the control measures and sign to say they understand and agree to the requirements. Work can then begin under the conditions stated. The plant and equipment are under the control of the workers who hold the permit.

Clearance. The performing authority reports whether the work is complete, confirms people and tools are clear and records any outstanding hazards. Controls and isolations are removed only through the agreed release procedure, after checking linked permits and other exposed people. Clearance does not by itself authorise restart.

Cancellation. Follow the site system for closure, suspension or cancellation. Stop work if permit conditions are not met or change unexpectedly, keep necessary precautions in place and refer to the authorised issuer. An inspector is not automatically the site permit-cancelling authority.

Extension. Unfinished work needs formal revalidation, extension or a new permit according to the system. Verify conditions, isolations, responsibility and shift handover; do not simply carry on after expiry.

In some places permits are treated as unnecessary paperwork, filled in because someone at head office says so. HSE guidance HSG250 lists the essential elements of a permit form:

1. Permit title
2. Permit reference number, with reference to other relevant permits or isolation certificates
3. Job location
4. Plant or area identification
5. Description of the work to be done and its limits
6. Hazard identification, including residual hazards and hazards linked to the work
7. Precautions needed and actions in an emergency, with signatures from the people who carried out precautions (for example the isolating authority) to confirm they were taken
8. Protective equipment, including PPE
9. Issue: signature of the issuing authority confirming isolations have been made and precautions taken (except where they can only be taken during the work), with the date, time and duration of the permit. High-hazard work needs a further signature from the permit authoriser
10. Acceptance: signature confirming understanding of the work, hazards and precautions, and that the permit information has been explained to all permit users
11. Extension and shift handover: signatures confirming checks that the plant remains safe to work on, and that new performing authorities and permit users know the hazards and precautions, with a new expiry time
12. Hand-back: signed by the performing authority to certify the work is complete, and by the issuing authority to certify the work is complete and the plant ready for testing and recommissioning
13. Cancellation: certifying the work has been tested and the plant satisfactorily recommissioned

Summary notes for Element 3 · Cheat sheet · Glossary. A study aid, not published or endorsed by NEBOSH.