The International Association of Classification Societies (IACS) has published a new Unified Requirement (UR H2) establishing a comprehensive safety framework for ammonia release mitigation systems (ARMS) on ammonia-fuelled ships.
The UR provides harmonised requirements for the design, testing and certification of ARMS intended to manage ammonia releases during normal operations and foreseeable abnormal scenarios.
Key features of UR H2 include:
- Enabling the Safe uptake of ammonia as a marine fuel: It aligns with MSC.1/Circ.1687 and provides clarity on how ammonia release mitigation systems should be implemented, assessed, and approved by Classification Societies.
- Facilitating the application of ARMS: Achieved through setting out a clear framework for evaluating ammonia release scenarios and corresponding mitigation measures. This approach supports the development of tailored technical solutions while maintaining a consistent safety objective.
- Recognising multiple technical solutions while ensuring consistent safety outcomes: It covers a range of mitigation concepts—including dissolution tanks, scrubbers, combustion units, and dilution systems—without constraining innovation, provided that defined safety objectives and exposure limits are met.
- Establishing clear expectations for testing, certification, and onboard readiness: The UR defines workshop and onboard testing regimes, certification requirements, and operational readiness criteria to ensure that ARMS remain effective in mitigating the hazards connected with operational ammonia fuel releases.
As the industry accelerates its transition toward alternative fuels, the need for harmonised standards becomes increasingly important in meeting decarbonisation objectives. IACS UR H2 is considered a welcome contribution to the global efforts to transition to zero-carbon fuels.
IACS Safe Decarbonisation Panel Chair, Eva Peno Jimenez, said: “This publication represents an important step towards harmonised global standards for ammonia-fuelled ships. By providing a common technical reference, the UR supports designers, shipowners, equipment manufacturers and regulators, and facilitates consistent implementation across the IACS membership.”
