Link to .pdf
Link to Seveso Inspection Series Home Page
CIC - The Permit-to-Work System
Definition
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 achieved.
Purpose of the Permit to Work
The need for a permit to a work should be assessed for any work that may be conducted in an area where dangerous substances are present and for which no existing procedure has been established. Where proposed work is identified as having a high risk, strict controls are required.
All company employees or contractors should be authorised by a responsible company person (normally, the supervisor) for the execution of the work required with the issue of a permit-to-work. In this document both the functional role and risks of the installation are described along with the risks associated with the execution of the work itself. It can be defined and written either following a risk analysis performed by the HSE unit or (in the case of complex works) following a joint on-site examination, carried out by the supervisor and the staff responsible for the execution of the work.In general, the preventive safety measures to be taken during execution and when work is completed can be established and documented either following the completion of a risk analysis performed by the HSE unit or, in the case of complex works, following a joint onsite examination, conducted by the supervisor and the staff responsible for execution of work.
When a permit to work may be needed
An effective system of permits-to-work cannot be achieved exclusively with the provision of a permit for the authorisation to work in dangerous areas, but it is an essential part of the SMS which is realized through specific procedures, instructions and authorizations. According to this principle the work shall be carried out against previously agreed safety procedures, a ‘permit-to-work' system. The adoption of a permit-to-work system for authorising, managing and documenting the execution of works and modifications, including testing, surveillance, inspection, maintenance, construction and/or assembly and finally dismantling of parts or components within an operating plant can minimize the occupational and process safety risks potentially associated with these activities.
Works concerning construction, maintenance, modification, etc. should be carried out in a planned and controlled manner through:
- Procedures or instructions including all information necessary to prevent a major accident and to ensure the safety of workers, in particular, preliminary inspection, cleaning operations, shutdown procedures, when necessary, and testing of associated safety systems. The effectiveness of these operations should then be fully verified prior to proceeding with the activity to ensure that all foreseeable risk has been removed;
- Control procedures specifying, at least, the initial job authorization required, the preliminary verification of operability, and the final checks necessary before the equipment or operational unit is placed back into operation;
- Procedures specifying what to do in case that an unsafe or abnormal situation arises and who to inform, and also what to do in an emergency including measures to be followed as outlined in the internal emergency plan;
- Instructions for cleaning the equipment before the operation and how to take charge of the equipment from the unit responsible for its control under normal operating conditions;
- A mechanism (e.g., daily observation and feedback) for verifying that the safety requirements are being followed and, where required, ongoing or spotcheck monitoring of working conditions and the performance of the employee during the execution of the activity (i.e., in confined spaces);
- Procedures to be followed to perform the non-routine activities (repair, replacement, inspection, etc.), including any procedure for uninstalling/re-installing the component;
- Specific criteria for inspections, tests, or whatever else is necessary to verify that the equipment is in perfect order prior to returning it to service;
- Instructions explaining the sequence of operations to be followed for recommissioning of equipment, including prestart- up, inspections and testing, e.g., verifying the absence of leaks, alignment of rotating parts, removal of trips and locks, etc.;
- Procedures for formal delivery of the equipment to the unit responsible for its control under normal operating conditions;
- Written authorisation specifying among other responsibilities, the means, timing, interfaces with other operations, operating limits, precautions, and signals.
Application and types of permits to work
The permit should be applied in all work areas in which these activities are carried out by internal personnel or contractors, except, generally:
- Normal operations already subjected to specific procedures;
- Works carried out in authorised workshops for which it is assumed that all the necessary precautions have been taken to carry out maintenance and repair activities at the workbench.
From a general point of view one can identify the following examples of permits-to-work:
- Work in which a flame or spark is prohibited;
- Hot” work, e.g., work involving the use of flame, heat, gases, flammable liquids or materials;
- Work in confined spaces;
- Working at heights;
- Construction and modifications, including excavation;
- Maintenance works;
- Work on electrical installations, utilities and other equipment (live or dead environments);
- Generic work (any work that does not fall within the previous categories of specific risks but, however, requires the safe management of works carried out by internal or external personnel).
Contents of the permit-to-work
To carry out non-routine activities, work orders, permits-to-work and other instructions (in agreement with what is described in paragraph “permit-to-work system”) should specify:
- The interested parties, the type of permit, the work area;
- Specifications of the work required and the time frame for execution. Actions that are specifically NOT authorized should also be specified. This latter measure is particularly important for avoiding ad hoc changes that could increase accident risks during temporary shut down or maintenance work.
- Risks associated with the activity, including hazardous substances present and their properties
- Important characteristics of the area in which the work is located interfaces with other operations, other works covered by other permit-to-work and operating limits necessary for safe and efficient execution of the work;
- All those activities that need to be concluded before the start of the work described in the permit to work;
- Measures in place to control the risks and alarms or other warning signs that could indicate a potentially unsafe situation;
- Safety systems and procedures to protect workers from hazards such as disconnection, isolation and the preparation of locks and trips (Lockout-Tagout);
- The personal protective equipment to be worn;
- The confirmation of the supervisor indicating the possibility of starting the work under the conditions specified in the permit-to-work;
- The acknowledgment and acceptance of the performing unit (personnel or contractors) of the conditions and requirements specified in the permit-to-work;
- If there is an extension of the validity of the permit, there should be a special space for renewals. For renewal should be foreseen further authorization and acceptance;
- Formal confirmation that the maintenance work has been completed according to specification, including immediate communication to the relevant supervisor and/or shift manager that work has been completed;
- Confirmation by the supervisor that the work has been correctly executed and tested, closed the permit and authorized the recommissioning.
The communication of these requirements and the effectiveness of the operations stipulated in the permit should then be fully verified prior to proceeding with the activity to ensure that all foreseeable risk has been removed.
Fig 1 Example of a flow chart for a structure of a permit-to-work
Information, training and qualification
The following principles should also be embedded in the safety management system:
- All personnel who are in charge of critical operations for safety, including maintenance activities, (internal workers or contractors and sub-contractor employees, or in general whoever supplies products or services) should receive adequate training and information about the risks, the correct procedures to be followed, and the permit to work required to perform them.
- In case of special activities, for which the national legislation requires specific qualifications (e.g., electrical work, maintenance of ATEX equipment, works in confined spaces), the operator should set up specific procedures to take into account those instructions both for their employees (through a specific qualification) and contractor employees (verifying the qualifications of the external personnel).
- Those responsible for issuing work permits should be involved in risk analysis and accident investigation in order to gain the appropriate risk awareness and knowledge of the specific hazards inherent in the activities that they are required to authorize. As with other operational aspects, employees should be involved in establishing procedures for safe working.
- There should be explicit procedures for supervision, monitoring and auditing of contractors and suppliers to verify that the external company performs the work safely and in compliance with established requirements including a job performance evaluation against specific criteria based on the job requirements.
Case studies illustrating the importance of permit to Work Systems
Source: UK Health and Safety Executive (http://www.hse.gov.uk/techmeaspermit.htm) and Wikipedia
Hickson Welch Ltd Fire(22/9/1992)
Five persons were killed after a severe fire erupted in a batch processing plant following an attempt to clean 30 years of sludge from a vessel without a permit to work, or any prior analysis of the risks and associated safety precautions.
Pasadena - Phillips 66 (23/10/1989)
Failure to follow isolation procedures during routine maintenance of a reactor in the polyethylene plant led to the release of a flammable vapour cloud that eventually ignited, launching a devastating series of explosions. The incident resulted in 23 deaths and 314 injured.
San Francisco Natural Gas Pipeline Puncture (25/8/1981)
A 16-inch natural gas pipeline was punctured by an excavation contractor who, in violation of permit conditions, failed to verify the location of underground utilities. The gas did not ignite and was naturally dispersed. The PCB-mist spread over a busydistrict of the city, requiring the evacuation of 30,000 people.
Checklick questions and tips for inspecting permit to work
*Work permit procedures could cover any work - carried out by internal or external parties -that may be conducted in an area where dangerous substances are present.
**In this question list the term „performer” refers to the person(s) that will perform the work and covers the internal staff and contractors also.
General questions on permit-to-work related procedures
- Has it been determined, i.e., are there fixed criteria for, when the operator shall issue a work permit*?
- What types of work permits does the operator use for internal and external parties (what are the types of works assumed to be a safety risk at the particular site)?
- Does the operator have an overview (up-to-date records) of all ongoing work in the plant (including those with work permits)?
- Does the permit-to-work procedure describe how the risk analyse should be performed? Does the permit-to-work procedure describe who should be involved in doing the risk assessment? Do they involve the performer** in this process?Is there a procedure to ensure that all equipment, materials, vehicles used by performers meet relevant rules and standards and are only used by competent – and where relevant certified – individuals?
- Does the permit-to-work procedure specify who is allowed to issue a work permit
- Is there a procedure to check the medical fitness (e.g. blood pressure) – if possible by the operator’s own doctor - on-site just before starting the work? (This could be relevant in case the performers have to use autonomous breathing aparatus or work at heights.)
- Is there a designated person that the operator has charged with the responsiblity for follow-up of the performer to ensure that work is being carried out properly? Are there clear communication channels determined between the performer and the operator?
- Is there a procedure to train performers (to inform them about, e.g., the general hazards of the plant/workplace, the correct behaviour to be followed in case of a major accident, the alarm signs, assembly points, etc.) with a verification of knowledge acquired including a regular update of the training?
- Is there a special training for special work (e.g., ATEX related or electrical works)?
- Are the external contractors treated in the same way regarding safety as internal employees (e.g., the same safety procedures are applied to them)?
- Does the company have an internal control system to verify that the permit to work system functions as required?
- Is there a periodic inspection (e.g., daily observation and feedback) for verifying that the safety requirements are being followed by the contractor?
Questions on content of related documents (work permits, work orders, other instructions)
Do they include the following:
- Reference to the equipment to work on (e.g., tag number),
- The type of work to be carried out and the period in which the work permit is valid (if work is not finished the work permit has to be reissued or prolongued),
- The important characteristics of the area in which the work is located (including the dangerous substances that are/were in the installation and indication of their dangerous properties),
- Risks associated with the activity,
- How to take charge of the equipment from the personnel responsible for its operation (who/when from the opreator’s personnel will pass the equipment to the contractor) and approval (e.g., signature) of the person responsible for the installation,
- Instructions for cleaning the equipment before the operation (including the state of cleanness of the installation and the measures to ensure that the installation is safe to work),
- Safety systems/procedures to protect workers from hazards such as disconnection, isolation and the preparation of locks and trips (e.g., isolation on the basis of a documented blind list or opening the equipement after a documented isolation),
- The personal protective equipment to be worn and measures to ensure that the work can be performed safely,
- What kind of mobile fire extinguishing equipment must be present,
- What to do in cases when unsafe or abnormal situations arises (references to the internal emergency plan – warning signs, alarms, measures in place to control the risks, where to find emergency showers and evacuation routes)
- Inspections, tests, or whatever else is necessary to verify that the equipment is in perfect order prior to returning it to service,
- The sequence of operations to be followed for re-commissioning of equipment, including pre-start-up, inspections and testing (e.g., verifying the absence of leaks, alignment of rotating parts, removal of trips and locks),
- Procedures for formal delivery of the equipment to the unit responsible for its control under normal operating conditions including formal confirmation that the maintenance work has been completed according to specification,
- Confirmation (e.g., via authorized signatures, email, etc.) that each party to the contract has agreed to the contents of the work permit acknowledging both required actions as well as actions that are not permitted,
- Confirmation that the workplace has been checked by the operator's personnel a few hours after the finalisation of hot work?
Questions for the verification of work in progress
- Are all measures specified on the permit in place?
- Are these measures sufficient to guarantee the safety of the work in progress?
- For confined space entry without authonomous breathing equipement, is continous oxygen measurement in place and, where relevant, also measurement of harmful concentrations of hazardous substances and also measurement of LEL in case there is a risk of an explosive atmosphere?
- Is a manhole watch continuously present during entry of a confined space?
- Is continuous lower explosive limit (LEL) measurement provided for hot work in place?
- Is a fire watch present during work with open flames?
Tips for inspectors (what to check during the regular inspection)
- Check the operator’s register on ongoing and finished works carried out with work permit.
- Check and follow the permits through their life-cycle (compare with the related SMS procedure).
- Check the content of the current permits and related documents.
- Do spot checks of ongoing works (Are the conditions for the safe operation ensured on the workplace: e.g., closure of the working area, disconnection, isolation, cleanness of the installation, continous lower explosion limit measurement, the use of proper, safe work tools, the wearing of appropriate personal protective equipements; presence of mobil fire extinguishing equipement, etc.).
- Have interviews with the involved persons (performers and their supervisor, operator) in order to test their knowledge on the procedures, their own roles and tasks, the hazards of the current work, workplace and the surroundings of the workplace (hazardous materials presents in other installations nearby), to measure their awareness of safety, to listen to their safety related concerns.
PDF Version for Printing
Go back to the Common Inspection Criteria website
