Meaning of a permit-to-work system

Where proposed work is identified as high risk, strict controls are required. In these cases, the work must be carried out against previously agreed safety procedures, a ‘permit-to-work’ system.

The permit-to-work is a documented procedure that authorises certain people to carry out specific work within a specified time frame. It sets out the precautions required to complete the work safely based on a risk assessment. It describes what work will be done and how it will be done; the latter can be detailed in a safe system of work.

However, it should be emphasised that a ‘permit to work’ is not a replacement for robust risk assessment. But it can help bring the risk assessment ‘to life’ where it matters – at the sharp end.

Why permit-to-work systems are used

Instructions or procedures are adequate for most work activities, but some require extra care. A ‘permit to work’ is a more formal system stating what work is to be done and when and which parts are safe. A responsible person should assess the work and check safety at each stage. The people doing the job sign the permit to show that they understand the risks and precautions necessary.

Before introducing a PTW system, it is imperative that all affected workers and responsible signatories receive training and instruction in the issue, use and closure of permits.

Once the system is implemented, it must be monitored and audited to ensure that it works as intended.

Case Studies…

How permit-to-work systems work and are used

The permit-to-work requires declarations from the people authorising and carrying out the work. In addition, where necessary, it requires a declaration from those involved in shift handover procedures or extensions to the work.

Finally, before equipment or machinery is put back into service, the permit originator will require a declaration that it is ready for normal use.


A competent issuing authority sets the permit’s parameters and confirms that precautions are in place. 

A description and assessment of the task(s) to be performed (including the plant involved and the possible hazards). This will determine the need for, and nature of, other key elements — namely, the isolation of sources of energy and inlets, the additional precautions required (e.g. atmospheric monitoring, personal protective equipment, emergency equipment) and the permit duration. 


A competent worker (performing authority) confirms understanding of the work, hazards involved and corresponding precautions. Then, using signatures, the permit should be issued by an authorised person and accepted by the competent person responsible for the work. 


Of the PTW, by the performing authority, confirming that the work has been completed to plan. On completion of the work, the competent person would need to indicate on the permit that the area had been made safe for the permit to be cancelled by the authorised person, after which isolations could be removed.


Of the PTW by the issuing authority confirming the work has been tested and the work area returned to normal use.

When to use a permit-to-work system

A PTW is not simply permission to carry out a dangerous job. Instead, it is an essential part of a system that determines how that job can be carried out safely and helps communicate this to those doing it.