In September 2021, a fire broke out in the auxiliary engine room on board the Finnish-registered ro-ro cargo ship Finnmaster while leaving the port of Hull in the UK. The MAIB is investigating this accident with the support of the Finnish Safety Authority. Our lead investigating officer, Simon Graves, explains the key initial findings of the safety investigation, which are already having a major impact on the maritime industry:

The crew activated the on-board fixed fire extinguishing system to try to fill the engine rooms with carbon dioxide (CO2) put out the fire. The system was designed to empty 42 cylinders into the engine room, each holding 45 kg CO2. In the event, only 21 of the cylinders are activated and thus only half of the required number CO2 was introduced into space. Fortunately, the crew was able to extinguish the fire with no damage other than a partial failure CO2 the system could have far worse consequences.

In the early stages of the MAIB’s investigation, it became apparent that a fix had been made CO2 the fire extinguishing system partially failed due to clogging of some flexible hoses that provide CO2 to the valves on the cylinders to open them when the system is activated. A close inspection of the flexible hoses connected to the system revealed a manufacturing defect in some of the hose couplings that was impeding flow CO2 through the system. An investigation into the source of hose assemblies that were installed earlier this year found that more than 33,000 hose assemblies originated from the same supply chain and were likely installed on ships around the world, a small percentage of which may have same factory defect.

In early 2022, we published safety bulletin 1/2022 with a detailed statement of the identified problem with CO2 systems on Finnmaster and advises recipients of damaged hoses to check their systems to ensure they are fully functional should they be needed in an emergency. We have also requested that information on any findings be shared with us to determine the extent of the problem.

Since the release of the safety bulletin, the MAIB has received a number of positive reports of findings in fixed fire extinguishing systems affected by the same problem. In one case, a large drilling vessel certified to carry 200 people was found to have five damaged hoses. The fault has been fixed CO2 The fire-fighting system on board this vessel could have led to catastrophic consequences and loss of life.

We continue to receive responses to the safety bulletin and encourage all companies to respond to our recommendations in the bulletin to confirm that they have taken immediate corrective action to identify and correct any blocked pilot hoses on the affected CO2 fire extinguishing systems.

Graham Wilson, Chief Inspector of the investigation, notes:

A complex technical MAIB investigation into this accident is ongoing and will be published in due course. However, issuing urgent security bulletins such as this one to inform the industry of significant security issues as soon as they are identified and to advise organizations to take timely appropriate action is a key element of the MAIB’s role. The success of this particular bulletin in identifying and resolving a critical safety issue on other ships underscores the value and importance of these safety warnings. This really demonstrates the effectiveness of the MAIB in preventing future accidents.

Information request

If you are a service provider, owner or operator and have details of any blocked pilot system hoses that would assist this investigation, please follow the instructions below:

Email with the title “CO2 Pilot System Hose Problems’ and include the name of the vessel, the date and location of installation of the affected hose assemblies and details of the defects found.

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