ClassNK has granted Approval in Principle to a new ammonia-fuelled LPG and ammonia carrier developed by Kawasaki Heavy Industries and MITSUI E&S. The move marks another step in the shipping industry’s efforts to bring zero-carbon fuels into practical use.
Tokyo-based classification society ClassNK has issued an Approval in Principle (AiP) for an ammonia-fuelled LPG and ammonia carrier developed by Kawasaki Heavy Industries and MITSUI E&S. The approval confirms the vessel’s feasibility from both regulatory and safety perspectives.
Ammonia is gaining attention as a potential zero-carbon marine fuel since it does not emit CO₂ during combustion. However, its use introduces safety challenges, including toxicity and corrosiveness, which require new rules and design safeguards before vessels can be deployed commercially.
ClassNK has been active in developing guidance for alternative fuels. In 2021, before international standards for ammonia as a ship fuel were in place, the society released its “Guidelines for Ships Using Alternative Fuels” to help industry players advance their projects. The guidelines cover installation, controls and safety devices to reduce risks to ships, crew and the environment. In December 2024, the International Maritime Organization approved the “Interim Guidelines for the Safety of Ships Using Ammonia as Fuel,” based on a proposal submitted by ClassNK through the Japanese government.
For the latest AiP, ClassNK reviewed the vessel’s design concept against its guidelines, specifically Part C-2 on safety for liquefied gas carriers using ammonia fuel and Part C-3 on additional safety measures for engine rooms. The society also conducted a hazard identification (HAZID) risk assessment. After confirming the requirements were met, the AiP was granted.
“ClassNK will continue to contribute to new technology development and social implementation, including safety assessments,” the society said in its announcement.
An Approval in Principle is granted at an early stage of ship design or before a specific vessel project begins. It provides proof that the design complies with existing international conventions and classification rules. By doing so, it helps avoid regulatory rework later, shortens examination time during class registration, and gives shipbuilders and owners a technical basis for promoting their designs externally.
The new certification underlines growing momentum in Japan and internationally to bring ammonia-fuelled ships into service. Kawasaki Heavy Industries and MITSUI E&S are among several shipyards working on ammonia-ready or ammonia-fuelled designs as the shipping industry searches for viable options to meet long-term decarbonisation targets.
