Lloyds Registry

The notice advises about the failure of CO2 cylinder valves that were manufactured by NK Co. Ltd, Korea prior to 2016.

It was found that the total number of empty or partially empty fixed CO2 system cylinders represented a loss of more than 50% of the ship’s available supply. The root cause analysis determined that the variable environmental conditions and fluctuating air cylinder pressures led to a material failure of the copper bursting discs in the cylinder valves.

In 2016, the cylinder valve’s manufacturer changed the material in the bursting discs from copper to nickel, which is more resistant to changing environmental conditions. Although NK Co. Ltd, Korea did not issue a service bulletin or similar notice recommending the replacement of copper bursting discs with nickel bursting discs in cylinder valves, they have since updated their User Manual.

https://www.lr.org/en/knowledge/class-news/19-23/