Report by TAIC into fatal burst nitrogen cylinder published

February 2017, on board the passenger cruise ship Emerald Princess, a nitrogen cylinder burst resulting in one fatality.
February 2017, on board the passenger cruise ship Emerald Princess, a nitrogen cylinder burst resulting in one fatality.

New Zealand’s Transport Accident Investigation Commission (TAIC) has published its report on the accident in Port Chalmers, Dunedin in February 2017, on board the passenger cruise ship Emerald Princess. A nitrogen cylinder burst resulting in one fatality. The core of the report highlights a lack of global minimum standards for inspection, testing and rejecting pressure cylinders for stored energy systems on lifeboat launching installations, a common system on cruise ships.

On February 9, 2017, while the Bermuda-flagged passenger vessel ‘Emerald Princess’ was berthed at Port Chalmers in Dunedin, its crew was conducting maintenance procedures on one of the lifeboat launching systems.

As the maintenance was completed the crew was putting pressure on a bank of high-pressure nitrogen-gas cylinders that were a part of the launching davit ‘stored energy’ system. Additionally, one of the nitrogen bottles burst resulting in the death of one crew member who was standing close by.

After the incident, TAIC investigated the vessel and discovered that:
– The nitrogen cylinder burst out at below its normal working pressure because severe external corrosion had reduced the wall thickness to about 30% of its original thickness;
– The failed nitrogen cylinder and several other pressure cylinders within the stored energy system, despite having been surveyed about two weeks earlier, were not fit for purpose and should not have been left in service;
– There is an immediate need for consistent and proper standards to be developed at a global level for maintaining, inspecting, testing and, where necessary, replacing high-pressure cylinders associated with stored energy systems on board ships;
– The crew were following the approved and appropriate procedure for re-pressurising the stored energy system.

After the results of the investigation, the operator wrote down many immediate safety actions to prevent a recurrence of the accident on any of its vessels.

Recommendations

TAIC has made two recommendations:
1. For the manufacturer to improve training for its surveyors;
2. For Maritime New Zealand to raise, through the appropriate IMO safety committee for its consideration, the implications for maritime safety of not having adequate minimum standards for the inspection, testing and rejection of pressure vessels that are part of stored energy systems.

Lessons Learned

Any sign of corrosion on high-pressure cylinders should be fully investigated by a person competent in examining high-pressure cylinders before any remedial work is undertaken and the cylinders are allowed back into service.

The TAIC issued an interim report with early recommendations to the equipment manufacturer, the International Society of Classification Societies, the Cruise Lines International Association and Maritime New Zealand to alert their members and surveyors as appropriate to the circumstances of the accident and to have the condition of similar installations checked.

Read the report in full: TAIC-Burst-nitrogen-cylinder

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