ClassNK has announced the issuance of a General Design Approval (GDA) for Mitsubishi Shipbuilding Co., Ltd.'s innovative Low-pressure LCO2 Cargo Tank.
This approval confirms the tank's adherence to relevant regulations at the detailed design level, marking a significant step forward in the field. Notably, it is the first time a GDA has been granted for a liquefied CO₂ cargo tank made of KF460 steel, utilising technology that bypasses post-weld heat treatment (PWHT).
Innovation in tank manufacturing
The approved design incorporates a safety assessment process based on Engineering Critical Assessment (ECA), a fracture mechanics method designed to omit PWHT, commonly deemed a bottleneck in the manufacturing process.
Mitsubishi Shipbuilding was given an Approval in Principle (AiP) for this ECA evaluation process in September 2024. This positions the company at the forefront of innovations aimed at optimising efficiency in tank production.
Focus on carbon-neutral advancements
Following proof of the tank's compliance with all defined needs absent PWHT, the GDA was officially granted
With detailed design evaluation by Mitsubishi Shipbuilding and a material property assessment of Nippon Steel Corporation's newly developed NK standard KF460 steel, the tank's structural integrity under designated temperature conditions has been validated using ECA.
In response, ClassNK undertook a thorough review in line with Part N of their 'Rules and Guidance for the Survey and Construction of Steel Ships'. Following confirmation of the tank's compliance with all prescribed requirements absent PWHT, the GDA was officially granted.
A milestone achievement
This issuance represents ClassNK's debut in granting a GDA for an LCO2 cargo tank, underscoring its commitment to supporting cutting-edge carbon-neutral efforts through rigorous safety assessments.
This move is expected to pave the way for further advancements in sustainable maritime technologies.
