Isolation of fuel tanks
IMCA has been advised of a near-miss accident that occurred during a fuel transfer operation. Whilst the vessel was in dry dock, fuel was accidentally transferred into a tank in which hot work was planned. As a result, around 7mâ³ of marine diesel oil was spilled onto the dock via an opening in the tank and the hull of the vessel. No people were working on the dock at the time, nor were there personnel inside or in the vicinity of the tank.
The situation occurred with a lock-out/tag-out procedure and a permit to work both in place. Such systems should have functioned as barriers against the unintended flow of fuel in an open tank.
After investigation of the incident, the company decided to change the isolation requirements for entry into a fuel tank. It made the following recommendations:
- When access to a fuel tank is required for maintenance or cleaning activities, all fuel inlets should be blind flanged;
- Isolation by means of blind flanges should be reflected on the permit to work;
- Isolation tags should be logged, using the drawings of the fuel system as guidance;
- Information on the status of open tanks should be known in the engine control room and on the bridge;
- All isolation points for each tank should be identified and known.
Safety Event
Published: 30 April 2006
Download: 
IMCA SF 05/06
IMCA Safety Flashes
Submit a Report
IMCA Safety Flashes summarise key safety matters and incidents, allowing lessons to be more easily learnt for the benefit of all. The effectiveness of the IMCA Safety Flash system depends on Members sharing information and so avoiding repeat incidents. Please consider adding safetyreports@imca-int.com to your internal distribution list for safety alerts or manually submitting information on incidents you consider may be relevant. All information is anonymised or sanitised, as appropriate.
IMCA’s store terms and conditions (https://www.imca-int.com/legal-notices/terms/) apply to all downloads from IMCA’s website, including this document.
IMCA makes every effort to ensure the accuracy and reliability of the data contained in the documents it publishes, but IMCA shall not be liable for any guidance and/or recommendation and/or statement herein contained. The information contained in this document does not fulfil or replace any individual’s or Member's legal, regulatory or other duties or obligations in respect of their operations. Individuals and Members remain solely responsible for the safe, lawful and proper conduct of their operations.