The International Association of Classification Societies (IACS) has developed a Unified Requirement (URH1) overlaying the discharge of ammonia from the onboard techniques for bunkering, storing, getting ready and utilizing ammonia as gasoline.
IACS URH1 aligns with the Recommendations from U.S. National Institute for Occupational Safety and Health (NIOSH) and establishes that an ammonia focus of 300 ppm or extra is instantly harmful, and a focus of 25 ppm or extra is harmful if the publicity is longer than eight hours.
Additionally, it requires the system coping with ammonia be designed to forestall a direct launch of ammonia to the ambiance throughout regular operation and likewise, when doable, throughout any fairly foreseeable irregular state of affairs.
In conditions the place a direct launch is unavoidable underneath both a traditional or irregular state of affairs (such because the activation of a tank stress reduction valve), the factors the place ammonia is anticipated to be launched are required to be recognized by the designer in a threat evaluation and to be listed within the ship design documentation.
The focus ensuing from such releases should not exceed a secure focus (25 ppm) at areas of the ship accessible to the crew and that is to be demonstrated by fuel dispersion evaluation. This requirement is anticipated to consequence within the institution of “toxic areas” (just like hazardous areas on tankers) with entry restrictions and different precautions, such because the absence of air intakes in that space.
URH1 additional requires the purpose at which ammonia is launched to the ambiance, (e.g. outlet of vent mast) to be supplied with audible and visible alarms, that are to be activated when the discharged fuel has an ammonia focus of 300 ppm or extra, to warn folks to promptly depart the world and search refuge.
Gas dispersion analyses are required to be carried out for irregular and emergency situations recognized by the use of a threat evaluation. Depending on the outcomes of those analyses, measures should be taken to stop the crew onboard from being uncovered to harmful concentrations of ammonia. The areas the place all fairly foreseeable ammonia leaks might happen (e.g. secondary enclosure, gasoline preparation room), even when not usually manned, are to be monitored and the supply of the discharge needs to be shut down when a focus exceeding 300 ppm is detected.
In different work regarding using ammonia as a gasoline, IACS is engaged on Requirements for ammonia therapy techniques (gear meant to scale back the focus and/or amount of launched ammonia) and necessities for fuel dispersion evaluation.
Other secure decarbonisation-related work underway in IACS contains creating necessities for the choice and testing of supplies and gear, together with transportable tanks, for using hydrogen as gasoline, and necessities on electrical power storage techniques, together with a Type Approval normal for Lithium-based batteries.
IACS Secretary General Robert Ashdown mentioned: “URH1 on the control of ammonia releases on ammonia fuelled vessels is a first, but significant, step in providing industry with enhanced levels of assurance for this new fuel type and will be supplemented with further complementary guidance in due course. This work, together with the other work-streams underway within our Safe Decarbonisation Panel, demonstrates IACS’ strong commitment to ensuring that safety remains at the forefront of the maritime industry’s efforts to meet its decarbonisation targets.”
