Press Release

8 September 2025

Tokyo - ClassNK has issued an approval in principle (AiP) for ammonia fuelled LPG/NH₃ carrier, applied for jointly by Kawasaki Heavy Industries, Ltd. and MITSUI E&S Co., Ltd. The certification demonstrates its feasibility from regulatory and safety perspectives.

Ammonia, which does not emit CO₂ during combustion, is expected to see wider use as a zero-carbon fuel for ships. At present, various studies and development efforts are underway to bring ammonia fuelled ships into practical use.

In 2021, prior to the establishment of specific international standards for the use of ammonia as fuel for ships, ClassNK released the “Guidelines for Ships Using Alternative Fuels” to support pioneering initiatives in this field. The guidelines stipulate requirements for installation, controls, safety devices, etc., aiming to minimize the risks to ships, seafarers, and the environment associated with the use of ammonia fuelled ships. Furthermore, in December 2024, the “Interim Guidelines for the Safety of Ships Using Ammonia as Fuel”, which ClassNK had submitted a proposal for safety requirements to the IMO through the Government of Japan, were approved at MSC 109.

ClassNK reviewed the design concept of the vessel based on “Part C-2: Guidelines for the Safety of Liquefied Gas Carriers Using Ammonia as Fuel (Edition 3.0.2) ” and “Part C-3: Additional Safety Measures for Engine Rooms (Edition 3.0.2)” of the “Guidelines for Ships Using Alternative Fuels (Edition 3.0)”, and examined the risk assessment through HAZID. Upon confirming that the prescribed requirements had been met, ClassNK issued AiP.

ClassNK will continue to contribute to new technology development and social implementation, including safety assessments.

Image of ammonia fuelled LPG/ammonia carrier
(courtesy: Kawasaki Heavy Industries, Ltd.)


Approval in Principle (AiP):
At the initial stage of designing or before the specific target ship to be implemented is decided, the design is examined based on the existing regulations such as international conventions and ship classification rules, and an Approval in Principle (AiP) is issued as proof of conformity with requirements. It also prevents rework of regulatory aspects in the post-process, shortens the examination time at the time of class registration, and can be used as a technical basis for external appeal of the design status. For more information, visit our website.

For inquiries about this press release:
ClassNK Technical Solution Department
Tel: +81-3-5226-2042
E-mail: tsd@classnk.or.jp

For media-related inquiries:
ClassNK Public Relations Team
4-7 Kioi-Cho, Chiyoda-Ku, Tokyo 102-8567 Japan
E-mail: eod@classnk.or.jp

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