8 Types of Permit To Work (PTW)

Types of permit to work

In this article, we will be discussing on the “Types of Permit to Work“. There are several types of permit to work, but within the scope of this article, we will talk about eight (8) types.

Before we get into the types of work permit let us remind ourselves of what a Work Permit is.

What is a Work Permit

Work Permit or Permit To Work (PTW) is a safety program initiated for high risk activities. It is a core element of integrated safe system of work (ISSOW) systems, along with risk assessment and isolation planning. It enables as low as reasonably practicable (ALARP) reduction of unsafe activities in non-trivial work environments. Permit to work adherence is essential in process safety management.

Types of Permit To Work

Types of Permit to Work

There are several types of work permits. Permit to work are develop to suit the task is it meant to cover; this is where we derive the types which is based on its purpose.

  1. General Work Permit:

General work permit is the job or the work which doesn’t involve work that can be included in Hot work, height work, confined space are considered as cold work. This generally includes the work in which no heat or spark will generate. The Cold work permits, typically blue-edged or the colored blue

2. Hot Work Permit:

The Hot work is usually taken to apply to the operation that could include the application of the heat or the ignition sources to tanks, vessels, the pipelines etc., which may contain or have the contained flammable vapor, or in areas where the flammable atmospheres may be present. It is typically colored red or the red-edged.

3. Work at Height Permit:

Authorization to work on elevated spaces (2m from the ground) be it ladders, scaffolds, Mobile Elevated Work Platforms (MEWP) and other spaces that are off the ground.

4. Confined space permit:

A confined space entry also refer as vessel entry and OSHA defined the term permit-required confined space. Industries and some workplace have equipment and areas fall under Confined space which is not meant work person but has a provision for personnel entry to perform a certain task. They include any vessel, tank, container, pit, or any other similar space which has a very limited opening which is not suitable to work for a longer time and this enclosed system gives rise to the occurrence of an accident.

5. Excavation Work Permit:

This permit covers the Authorization for personnel to mine or dig land in order to build infrastructure, extract resources or unearth hidden artifacts. The risk involved in excavation includes falling, being trapped, explosions, airborne contaminants, etc.

6. Electrical Work Permit:

Electrical work is any work where the worker or the worker’s tools will intentionally be in contact with electrically energized circuits.  Testing and/or the use of testing equipment is not considered electrical work, unless the testing requires that the worker and/or the worker’s tools will intentionally be in contact with the electrically energized circuits.

7. Special Hazard Work Permit:

Special hazard work permit and industry and workplace specific, designed based on the hazard present in that particular organization. Link Nuclear power station where the potential hazard is nuclear waster and radiation. In those industries, special hazard work permit are issues which are designed to safeguard person from those hazards

8. Chemical Work Permit:

This covers the authorization to work with harmful chemical substances or in a chemically induced atmosphere that is either toxic or corrosive by nature. Chemical engineers that mostly work in chemical plants and labs.

READ: Mechanical Hazards And Common Mechanical Injuries

Content of a Permit to Work

There are necessary contents of every permit to work, these contents include:

  • The caption of the permit
  • The job to be done
  • Brief description of the job to be done
  • The inherent hazards in the job
  • Corrective measures in place
  • Location of the job
  • Time of the job; Start time and end time.
  • Responsible person
  • The equipment/ machinery involved
  • Emergency plan
  • Signatories (Permit supervisor and the plant/machinery supervisor), etc.

The aim of having a drawn-out permit to work check-list is to ensure that necessary controls are not omitted.

After a permit is designed, it can be easily implemented even with a less skilled professional; this is possible because almost all the necessities for the job has already been stipulated. What is needed is just to ensure that the stipulated conditions are met.

It is needful that the permit be followed through-out the task. At any point where any of the conditions stipulated in the permit changes, the permit has to be withdrawn and the task suspended. This withdrawal will be pending when all the conditions will be met.

Other Things to Note About PTW:

Suspended Work

There are situations where work being done with a Permit to Work must be suspended.  Some examples of when this may occur are:

  • High risk, hazardous situations occur and for safety reasons, the work must stop;
  • The work requires more time than is allowed on the Permit to Work (the work isn’t completed before the time when the Permit to Work expires);
  • An accident occurs while the work is being completed;
  • An emergency (e.g. fire alarm) occurs at the plant site (e.g. compressor station);
  • The work scope changes significantly from what was originally planned when the Permit to Work was prepared and authorized.

Whenever these and similar situations occur, the work must stop immediately; the work site must be made as safe and secure as possible; and a new Permit to Work must be prepared and authorized, following all of the steps required when making any Permit to Work.  In all cases, safety procedures must be implemented to make the work site safe before work starts again (eliminate the hazards or reduce the risks to acceptable levels).   Once the safety procedures have been implemented and a new Permit to Work has been issued, work can start again

READ: What Is Online Permit To Work System & Examples

Monitoring the Work

Work that is being completed with a Permit to Work must be regularly monitored by the Project Supervisor and/or the site HSE Supervisor to ensure that the specified safety procedures are being complied with.  The Project Supervisor must make a schedule for determining how often the work should be monitored.  For jobs where there are potentially high risks, the work should be monitored more frequently, particularly when critical tasks are being completed.  Whenever specified safety procedures are not being complied with, the work must be stopped until the Project Supervisor and/or the HSE Supervisor determines that the safety procedures are being complied with.

If the non-compliance is very serious, a written report, describing what the non-compliance was and why the non-compliance occurred, must be written and submitted to the HSE Manager.  A copy of the report should also be kept at the work site field office.  If a sub-contractor is responsible for the serious non-compliance, another copy of the report should be sent to the Contracts Administration Department and the copy should be kept in the sub-contractor’s file for future contract evaluation reference.

Completion of the Work

When the work has been completed, the job site must be left in a safe, operating condition with all locks, tags and isolations removed.   All rubbish, surplus materials, tools and equipment used for the work must be removed from the work site.  To the extent possible, the work site must be restored to its original condition before the work started, unless the work was intended to change the work site condition (e. g. construction of structures, permanent excavations, permanent landscaping).

READ: Confined Space Entry Permit Requirements – What You Need to Know


Permit to work is a safety procedure that tends to ensure that every safety measures/check boxes have been ticked to ensure safe job delivery. It is mostly used for high risked jobs and requires very close supervision. So this blog post “8 Types of Permit To Work (PTW)”, has explained what a Permit to Work (Work Permit) is and also move further to highlight some types of work permit and what the supposed content of the work permit are.

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