IACS: UR on ammonia releases in ammonia fuelled vessels

The International Association of Classification Societies (IACS) has published a new unified requirement (UR H1) on control of ammonia releases in ammonia fuelled vessels.

This document was published on 1 January 2024.

It addresses the control of ammonia releases in vessels that use ammonia as fuel.

The requirements laid out in the document are applicable whenever the use of ammonia as fuel on ships is permitted by the National Administration.

The document distinguishes between normal operation, abnormal scenarios, and emergency scenarios, providing clear definitions for each. It establishes concentration thresholds for dangerous ammonia levels, with 300 ppm or more considered immediately dangerous for life and health (IDLH) and 25 ppm as the recommended exposure level (REL-TWA) for longer durations.

The implementation of these requirements is outlined, specifying that they are to be uniformly applied by IACS Societies for existing ships seeking approval for ammonia fuel system plans after January 1, 2025, and for new ships contracted for construction on or after the same date.

The key requirements include designing systems to prevent direct ammonia release to the atmosphere during normal operation, and if unavoidable, limiting the concentration to 25 ppm in areas accessible to individuals. The document also mandates the identification and documentation of ammonia releases during normal and abnormal scenarios in the risk assessment and ship design documentation.

For more information, please see the document below (available only to subscribers):