Britannia P&I Club, in their latest B!NSIGHT publication, explores the safety considerations of using ammonia as a fuel, regarding many aspects, including bunkering.
According to Britannia, an ammonia-fuelled ship is an IGF ship, and the bunkering process for ammonia will therefore be subject to strict controls. The management of BOG generated whilst bunkering may require the use of a second hose connection (vapour return line) to return the BOG back to the bunker supplier.
Given the highly toxic nature of ammonia, the correct PPE should be worn by operators involved with the connection/disconnection of the bunkering hose. Further points to consider are:
- Plan each bunkering operation individually, collaborating closely with the bunker supplier. This planning includes: a. Conducting a combined risk assessment b. Performing a compatibility assessment c. Developing a joint plan of operations d. Creating a separate plan and risk assessment for any simultaneous operations (SIMOPs) e. Confirming the methods of communication
- Install an Emergency Shutdown System (ESD) on the vessel, connecting it to the bunkering source’s ESD system during the bunkering operations.
- Test the ESD system after connecting the bunkering hose and before ammonia transfer.
- Fit a filter/strainer at the bunkering source to prevent the ingress of foreign objects.
- Purge bunker hoses and lines with nitrogen before starting bunkering, ensuring it is below the Lower Explosion Limit (LEL) of ammonia.
- Pressure test the manifold connection with nitrogen before commencing ammonia transfer to confirm there are no leaks.
- Agree on maximum transfer rates with the supplier.
- Continuously monitor the fuel tank levels and pressures, considering the tank pressure relief valve capacity.
- Drain and purge bunker hoses and lines upon completing bunkering and before disconnection.
- Constantly monitor the vessel’s moorings throughout the transfer operation to avoid a breakout situation.
- Use a dry break-away coupling/self-sealing quick release to stop ammonia transfer and safely disconnect bunker hoses in case the vessel and source start moving apart (breakout).
- Maintain positive pressure in accommodation areas to prevent toxic ammonia ingress.
The bunker station should also be fitted with the following:
- A proper mechanical shielding of all potential leakage points on the bunker manifold, including temporary mechanical shielding of the bunkering connection.
- Leakage detection with automatic closing of the bunker valve.
- A water spray system above the bunker manifold to reduce toxic vapours in the bunkering station.
- Suitable ventilation and gas detection systems, if the bunker station is enclosed.
- A spill tray fitted beneath the bunker connection to collect any leakages and to prevent the water/ammonia from washing overboard.
To remind, ABS recently published an advisory on ammonia bunkering safety which addresses essential aspects of bunkering ammonia as a fuel, providing the maritime industry with a comprehensive understanding of the challenges involved and strategies to effectively tackle them. The advisory covers a range of critical topics, including ammonia bunkering design, operational procedures, risk assessment, dispersion analysis, safety protocols, and training. By focusing on these areas, ABS aims to enhance the industry’s knowledge and readiness for the safe handling of ammonia as a fuel, ultimately supporting its integration into maritime operations.
