IMO's revised guidelines for alternative metallic materials in cryogenic service

Eda Zenic -

The International Maritime Organization issued a circular with revised guidelines for the acceptance of alternative metallic materials for cryogenic service in ships carrying liquefied gases in bulk and ships using gases or other low-flashpoint fuels.

  • The Maritime Safety Committee, at its 102nd session (4 to 11 November 2020), acknowledging a potential need for alternative metallic materials to be used for the construction and safe operation of low-temperature fuel and cargo-carrying ships and the need for guidance in this respect, approved the Guidelines for the Acceptance of Alternative Metallic Materials for Cryogenic Service in Ships Carrying Liquefied Gases in Bulk and Ships Using Gases or Other Low-Flashpoint Fuels (MSC.1/Circ.1622), prepared by the Sub-Committee on Carriage of Cargoes and Containers (CCC) at its sixth session (9 to 13 September 2019).
  • The Maritime Safety Committee, at its 105th session (20 to 29 April 2022), approved amendments to the Guidelines (MSC.1/Circ.1648), prepared by the Sub-Committee on Carriage of Cargoes and Containers (CCC) at its seventh session (6 to 10 September 2021).
  • The Maritime Safety Committee, at its 108th session (15 to 24 May 2024), having qualified high manganese austenitic steel for ammonia service, and in order to revise additional compatibility test requirements for ammonia service, approved the Revised Guidelines for the Acceptance of Alternative Metallic Materials for Cryogenic Service in Ships Carrying Liquefied Gases in Bulk and Ships Using Gases or Other Low-Flashpoint Fuels, as set out in the annex, prepared by the Sub-Committee on Carriage of Cargoes and Containers (CCC) at its ninth session (20 to 29 September 2023).
  • The Revised Guidelines incorporate the amendments in MSC.1/Circ.1648 and provide detailed guidance on how to document alternative metallic materials for their suitability and compliance with the IGC and IGF Codes, and a framework for evaluation and approval of alternative metallic materials for cryogenic service.
  • Member States are invited to bring the annexed Revised Guidelines to the attention of all parties concerned.
  • This circular supersedes MSC.1/Circ.1622 and revokes MSC.1/Circ.1648.