ClassNK will award the world’s first accreditation for “Machinery Room Safety for Ammonia” (MRS) to an ammonia-fueled medium gas carrier (AFMGC) currently being developed by a consortium that includes Nippon Yusen Kabushiki Kaisha (NYK) and Nihon Shipyard Co., Ltd. (NSY). The MRS notation indicates that the ship is equipped with advanced ammonia safety measures in its machinery room and confirms that it meets the highest safety standards according to guidelines for ammonia-fueled vessels.
The consortium, which includes NYK and NSY, is working towards delivering the AFMGC by the end of November 2026. This development is part of the Green Innovation Fund Project led by Japan’s New Energy and Industrial Technology Development Organization (NEDO). A significant challenge in this project is addressing the toxicity risks in the machinery room. Ensuring crew safety requires comprehensive measures, including designs to prevent ammonia leakage from piping and tanks. To tackle this, the consortium has conducted a thorough risk assessment reviewed by ClassNK, with NYK’s engineers leading safety evaluations from a user perspective and refining the ship’s specifications to achieve the highest level of safety.
The ammonia-fueled ship guidelines issued by ClassNK outline the minimum design requirements for safely using ammonia on board. To obtain the MRS notation, ships must meet an additional functional requirement that minimises personal exposure to any potential ammonia leaks in the machinery room.
The consortium will continue developing the vessel, preparing operational manuals, and ensuring the delivery by November 2026. Additionally, they aim to further enhance safety for ammonia-fueled ships through the knowledge and achievements gained, including the MRS accreditation, in collaboration with consortium members.