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The world’s first accreditation for “Machinery Room Safety for Ammonia” (MRS) will be granted by ClassNK for the 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).

MRS is Class notation demonstrating a ship is equipped with excellent ammonia safety measures for the machinery room. MRS also confirms the vessel meets the highest safety measures under the guidelines for ammonia-fueled ships.

Risk assessment

The consortium to which NYK and NSY belong is aiming for AFMGC delivery by the end of November 2026. The vessel development is under the Green Innovation Fund Project by Japan’s New Energy and Industrial Technology Development Organisation (NEDO). One of the biggest challenges in the ship’s development is to overcome toxicity in the machinery room.

It is essential to have measures to keep the crew safe, such as a design to avoid ammonia leakage from piping and tanks. To overcome toxicity, the consortium has conducted a risk assessment reviewed by ClassNK, risk assessments and safety measures from a user’s point of view led by NYK’s engineers, and a study of the ship’s specifications to realise the world’s highest level of safety.

Overview of MRS notation

For an MRS notation, it is necessary to satisfy the optional functional requirement to minimise personal exposure

The minimum design requirements for using ammonia safely on board are regulated in the ammonia-fueled ship guidelines issued by ClassNK.

To receive an MRS notation, it is necessary to satisfy the optional functional requirement to minimise personal exposure to leaking ammonia in the machinery room. This notation shall be granted only to ships that meet the functional requirement and secure the highest level of safety.

Future developments

The consortium continues vessel development, the creation of operation manuals for actual operations, etc., aiming for delivery by November 2026.

Moreover, it aims to further improve safety for ammonia-fueled ships through technical know-how and achievements, including MRS accreditation, with the collaboration of consortium members.

Vessel overview

  • Type: 40,000 m3 type ammonia fueled ammonia gas carrier.
  • Planned delivery date: November 2026.
  • Shipbuilder: Japan Marine United Corporation, Ariake Shipyard.
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