Effectiveness of mechanical ventilation in mitigating ammonia leaks: a safety assessment for ammonia-fuelled ships

Lin Yang; Binteng Gu; M.P. Mujeeb-Ahmed; Peilin Zhou; Byongug Jeong; Haibin Wang; Ana Mesbahi; Injun Yang

doi:10.1016/j.ijhydene.2025.151568

Effectiveness of mechanical ventilation in mitigating ammonia leaks: a safety assessment for ammonia-fuelled ships

Lin Yang, Binteng Gu, M.P. Mujeeb-Ahmed^*, Peilin Zhou, Byongug Jeong, Haibin Wang, Ana Mesbahi, Injun Yang

^*Corresponding author for this work

Naval Architecture, Ocean And Marine Engineering

Research output: Contribution to journal › Article › peer-review

Abstract

This study assesses the effectiveness of mechanical ventilation systems in mitigating ammonia leaks onboard ships, with a focus on crew safety. Numerical simulations are conducted for two case vessels – a container ship and a RoPax ship – under various leak scenarios in storage spaces. The analysis evaluates ammonia concentration levels against the occupational safety threshold of 30 ppm and the lower flammability limit. Sensitivity analysis considers vent position, number of vents, ventilation rate, and ambient temperature. Results show that optimal vent configurations and higher air-change rates (ACH) significantly reduce ammonia concentrations and decay times, thereby enhancing ventilation efficiency. The minimum ventilation durations for safe crew access to the storage areas following a leak were determined as 20 min for the Container ship and 15 min for the RoPax ship. These findings provide practical guidance for ship designers and operators, supporting the safe adoption of ammonia as a marine fuel while addressing the risk associated with its toxicity and handling.

Original language	English
Article number	151568
Number of pages	27
Journal	International Journal of Hydrogen Energy
Volume	178
Early online date	24 Sept 2025
DOIs	https://doi.org/10.1016/j.ijhydene.2025.151568
Publication status	Published - 13 Oct 2025

Funding

The work presented in this paper has been carried out within the UKRI HORIZON-CL5-2021-D5-01 NH3CRAFT project, co-funded by the European Commission (Project Number: 101056831 (HE), 10105683 (IUK)). The authors would like to express sincere gratitude to all the partners in the project, including designers, class societies, industries, and academia, for their critical review and constructive feedback during the course of this study. The views and opinions presented in this paper are those of the authors alone.

Keywords

ammonia as a marine fuel
ammonia toxicity
mechanical ventilation
safety assessment
sustainable shipping

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Yang-etal-IJHT-2025-Effectiveness-of-mechanical-ventilation-in-mitigating-ammonia-leaksFinal published version, 23.5 MBLicence: CC BY 4.0

Cite this

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title = "Effectiveness of mechanical ventilation in mitigating ammonia leaks: a safety assessment for ammonia-fuelled ships",

abstract = "This study assesses the effectiveness of mechanical ventilation systems in mitigating ammonia leaks onboard ships, with a focus on crew safety. Numerical simulations are conducted for two case vessels – a container ship and a RoPax ship – under various leak scenarios in storage spaces. The analysis evaluates ammonia concentration levels against the occupational safety threshold of 30 ppm and the lower flammability limit. Sensitivity analysis considers vent position, number of vents, ventilation rate, and ambient temperature. Results show that optimal vent configurations and higher air-change rates (ACH) significantly reduce ammonia concentrations and decay times, thereby enhancing ventilation efficiency. The minimum ventilation durations for safe crew access to the storage areas following a leak were determined as 20 min for the Container ship and 15 min for the RoPax ship. These findings provide practical guidance for ship designers and operators, supporting the safe adoption of ammonia as a marine fuel while addressing the risk associated with its toxicity and handling.",

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author = "Lin Yang and Binteng Gu and M.P. Mujeeb-Ahmed and Peilin Zhou and Byongug Jeong and Haibin Wang and Ana Mesbahi and Injun Yang",

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T2 - a safety assessment for ammonia-fuelled ships

AU - Yang, Lin

AU - Gu, Binteng

AU - Mujeeb-Ahmed, M.P.

AU - Zhou, Peilin

AU - Jeong, Byongug

AU - Wang, Haibin

AU - Mesbahi, Ana

AU - Yang, Injun

PY - 2025/10/13

Y1 - 2025/10/13

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AB - This study assesses the effectiveness of mechanical ventilation systems in mitigating ammonia leaks onboard ships, with a focus on crew safety. Numerical simulations are conducted for two case vessels – a container ship and a RoPax ship – under various leak scenarios in storage spaces. The analysis evaluates ammonia concentration levels against the occupational safety threshold of 30 ppm and the lower flammability limit. Sensitivity analysis considers vent position, number of vents, ventilation rate, and ambient temperature. Results show that optimal vent configurations and higher air-change rates (ACH) significantly reduce ammonia concentrations and decay times, thereby enhancing ventilation efficiency. The minimum ventilation durations for safe crew access to the storage areas following a leak were determined as 20 min for the Container ship and 15 min for the RoPax ship. These findings provide practical guidance for ship designers and operators, supporting the safe adoption of ammonia as a marine fuel while addressing the risk associated with its toxicity and handling.

KW - ammonia as a marine fuel

KW - ammonia toxicity

KW - mechanical ventilation

KW - safety assessment

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JF - International Journal of Hydrogen Energy

M1 - 151568

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Effectiveness of mechanical ventilation in mitigating ammonia leaks: a safety assessment for ammonia-fuelled ships

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Keywords

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