Permit to Work System
Seven types of permit, one principle: no hazardous work on board begins without a documented authorisation that genuinely verifies safety conditions, not just a signature.
Operational Explanation
The Permit to Work (PTW) is the operational mechanism that translates ISM Code requirements into controlled, documented execution of hazardous work on board. The system typically covers seven permit categories: hot work, cold work, confined space entry, work at height, electrical isolation, pressurised systems, and diving operations — each with control requirements specific to its type of risk.
The hot work permit (welding, cutting, any activity generating flame or heat) is typically limited to a maximum of 12 hours' validity and requires: testing the atmosphere of the work area (below 1% of the Lower Explosive Limit, LEL), removal of flammable materials from the area, a dedicated fire watch, and verification of ventilation. The cold work permit covers activities without planned ignition sources (e.g. painting, cleaning in hazardous areas near cargo or fuel systems), but remains controlled work under the PTW system nonetheless.
Every permit has a maximum validity of 24 hours. The Master or the responsible officer must maintain awareness of all permits active at the same time and check their possible interactions before authorising a new one — hot work and a bunkering operation in progress, for example, cannot coexist in the same area.
Regulatory Reference
The Permit to Work is an operational requirement of the Safety Management System (SMS) required by ISM Code, paragraph 7 (Plans for shipboard operations), applied in practice to all high-risk activities also governed by SOLAS (e.g. confined space entry work, Chapter III Reg. 19.3.5).
Scope of Application
Every shipboard activity classified as hazardous work under the SMS procedure: hot work, cold work in a hazardous area, confined space entry, work at height, electrical isolation, pressurised systems, diving operations.
Procedure / How to Complete It
- Identify the type of permit required based on the nature of the planned work.
- Verify the safety conditions specific to the permit type (atmosphere test for hot work, isolation for electrical work, etc.).
- Check for interaction with other permits active at the same time before authorising the new work.
- Obtain authorisation from the responsible personnel (typically the ship's top four officers).
- Monitor the work for the entire duration of the permit, formally closing it on completion or expiry (maximum 24 hours).
Practical Example
Example of application: before welding work on deck, the responsible officer verifies that no bunkering operation is under way nearby, tests the area's atmosphere (confirming it is below 1% LEL), arranges a dedicated fire watch, and authorises the permit with 8 hours' validity, to be renewed if the work is not completed.
Real Cases
Common Mistakes Mistake Library
| Mistake | Consequence | How to avoid it |
|---|---|---|
| Hot work permit renewed without a new atmosphere test if the work extends beyond the initial validity | Risk conditions not updated, possible accident with an atmosphere that has changed in the meantime | Always repeat the atmosphere test when renewing a hot work permit |
| Multiple permits active at the same time without checking their mutual interactions | Unforeseen risk combinations (e.g. hot work and bunkering in the same area) | Always check all active permits before authorising a new one |
| Cold work treated as non-hazardous and therefore not subject to a formal permit | Activities with real risks (e.g. painting in a confined space) carried out without adequate controls | Apply the PTW system to cold work in hazardous areas too, not only to hot work |
PSC Observations
Operational Tips
- Always repeat the atmosphere test when renewing a hot work permit, don't rely on the initial test.
- Always check the interaction between all active permits before authorising a new one.
- Apply the PTW system to cold work in hazardous areas too, don't automatically treat it as low risk.
Checklist
- Permit type correctly identified based on the planned work
- Specific safety conditions verified (atmosphere, isolation, ventilation)
- Interaction with other active permits checked before authorisation
- Permit validity respected (maximum 12 hours for hot work, 24 hours in general)
- Formal closure of the permit on completion or expiry