ClassNK Publishes Onboard Ammonia Leak Estimates

ClassNK has published industry-first estimated leak frequencies for ammonia fuel from onboard components for ammonia-fueled ships. 

For new ammonia-fueled ship designs, risk assessments involve the consideration of the probability of ammonia leak from each component. However, statistical data of onboard ammonia leak have been extremely limited, making probability estimation difficult.

ClassNK, in collaboration with the Research Institute of Science for Safety and Sustainability (RISS), a department of the National Institute of Advanced Industrial Science and Technology (AIST), used the Bayesian method to estimate the probability of ammonia leak from each component based on:

• the onshore ammonia leak frequency data in Japan extracted from the database of the High Pressure Gas Safety Institute of Japan, and

• the LNG leak frequency data in LNG-fueled ships.

The estimated leak frequencies were added as an appendix of 'Part C of Guidelines for Ships Using Alternative Fuels (Edition 3.0)'.