ClassNK has issued an approval in principle (AiP) for an ammonia-fuelled LPG/NH₃ carrier design developed jointly by Kawasaki Heavy Industries and MITSUI E&S Co.

The Japanese classification society said it reviewed the design concept based on its 'Guidelines for Ships Using Alternative Fuels (Edition 3.0),' specifically Part C-2 covering safety requirements for liquefied gas carriers using ammonia as fuel and Part C-3 addressing additional safety measures for engine rooms.

ClassNK explained that it examined the risk assessment through hazard identification (HAZID) studies before confirming that prescribed requirements had been met and issuing the AiP.

ClassNK originally released its alternative fuels guidelines in 2021, prior to the establishment of specific international standards for ammonia use as ship fuel. The guidelines stipulate requirements for installation, controls, and safety devices, aiming to minimize risks to ships, seafarers, and the environment.

In December 2024, the International Maritime Organization approved 'Interim Guidelines for the Safety of Ships Using Ammonia as Fuel' at MSC 109, following a proposal for safety requirements submitted by ClassNK through the Government of Japan.

ClassNK stated that it will continue to contribute to new technology development and social implementation, including safety assessments for alternative fuel systems.