The 9th session of the International Maritime Organization (IMO) Sub-Committee on Carriage of Cargoes and Containers (CCC), discussed various issues and moved on with the finalisation of amendments to the IGF Code.

According to Lloyd’s Register (LR), recognising that there is an urgent need to develop safety provisions for alternative fuels to further promote the decarbonisation of shipping, CCC worked on the next phase of development of the International Code of Safety for Ships Using Gases or Other Low-Flashpoint Fuels (IGF Code). Key outcomes of the session are presented by LR as follows:

Draft Interim guidelines for the safety of ships using hydrogen as fuel

The draft interim guidelines have been further developed. They are goal-based and provide provisions for the arrangement, installation, control and monitoring of machinery, equipment and systems using hydrogen as fuel in order to minimise the risk to the ship, its crew and the environment.

They are non-mandatory and are intended to be read in conjunction with the International Code of Safety for Ship Using Gases or Other Low-flashpoint Fuels (IGF Code). They will apply to those ships to which SOLAS Chapter II-1, Part G – Ships using low flashpoint fuels applies. The following IGF Code chapters have been further developed:

  • Ch 2 General – definitions and abbreviations
  • Ch 4 General requirements – Risk assessment
  • Ch 5 Ship design and arrangement
  • Ch 6 Fuel containment system
  • Ch 7 Material and general pipe design
  • Ch 8 Bunkering

Hydrogen is notoriously difficult to contain and research around leakages poses many challenging questions. Much discussion is focusing on risks of leaks. Seeing how even small leakages may form hydrogen pockets and coupled with hydrogen’s lower explosion limit and that it is impossible to de-energise electrical equipment in time, Emergency Shut-Down (ESD) principles have been removed from the current draft Guidelines.


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To further progress the development of the Guidelines, a correspondence group has been established with the aim to further develop the following draft chapters (subject to amendments):

  • Ch 9 Fuel Supply to Consumer
  • Ch 10 Power generation including propulsion and other fuel consumers
  • Ch 11 Fire Safety
  • Ch 12 Explosion prevention
  • Ch 13 Ventilation
  • Ch 14 Electrical Installations
  • Ch 15 Control, Monitoring and Safety Systems

The correspondence group is expected to submit their report and proposed amendments to CCC 10.

Safety provisions for ships using low-flashpoint oil fuels

In order to provide an international standard for ships using oil-based fossil fuels, synthetic fuels, or biofuels with a flashpoint between 52°C and 60°, the IMO is developing Draft interim guidelines for the safety of ships using low flashpoint oil fuels. They are applicable to ships which have to comply with SOLAS Chapter II-1 Part G and are to be read in conjunction with the IGF code. It is expected that this work will be completed by the end of 2024.

An intersessional correspondence group developed the guidelines further. New inclusions have addressed the increased fire and explosion hazards by introducing provisions on ambient air temperature control, setting the upper limit to 45 °C, and having ventilation available where the temperature exceeds the limit. This means that the ventilation rate will need to be increased to 30 air changes per hour.

Further discussion will happen intersessionally through a correspondence group around mitigating the risk of leakages of low flashpoint diesel fuels into conventional engine-rooms which will result in dangerous increased concentrations of ignitable fuel vapour (double barrier principle, cooling sea water etc.).

Draft Interim guidelines for ships using ammonia as fuel

The interim guidelines are applicable to ships which have to comply with SOLAS Chapter II-1 Part G and are to be read in conjunction with the IGF Code as they add specific hazards and fuel properties to it. It is expected that this work will be completed between the end of 2024 and by the end of 2025.


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Given that ammonia constitutes a different risk profile to LNG, careful consideration of safety provisions that addressed its toxicity and corrosivity were discussed and are now included in the provisional draft text.

A correspondence group will further advance the development of these Guidelines and will be focusing on:

  • provisions for holistic risk assessment of the entire fuel system;
  • inclusion of semi-refrigerated ammonia and pressurised ammonia systems in the interim guidelines, and the use of pressurised ammonia systems through the alternative design process;
  • requirements for machinery in machinery spaces to be gas safe and with the need for ESD arrangements to be considered under the alternative design process;
  • safe haven/refuge on board ships using ammonia as fuel in case of ammonia contamination/leaks, taking into account the ship type and number of people on board. In this regard, it may be that the application of the interim guidelines could exclude specific ship types;
  • provisions for personnel safety and PPE as a last line of defence; and
  • mitigating measures for release of ammonia when considered necessary for safety (e.g. system shut-down scenario), but not emergency situations, – may include ammonia scrubbers and consequentially the disposal of residues should also be considered.

The correspondence group will report its developments to CCC 10.

Interim Guidelines for the Safety of Ships Using Fuel Cell Power Installations (MSC.1/Circ.1647)

These guidelines are applicable to ships which have to comply with SOLAS Chapter II-1 Part G. They were approved in 2022 but don’t cover storage of reformed fuels. Fuels which are already covered by either the IGF Code part A or by their own specific Guidelines will need to have this circular applied additionally.

Comments were presented based on the experience gained through the application of the interim guidelines and presented possible amendments:

  • Clarification of terminology (e.g. Fuel cell module, Power conditioning system).
  • Further elaborating the requirements for an alternative design by introducing the need for a specific risk assessment of fuel cell power installations which will need to be carried out for each onboard installation.
  • Provisions for Fuel cell modules already supplied in metallic enclosures.
  • Better clarity around Fuel cell spaces and arrangements and addition of Fire safety provisions.
  • Addition of a means for monitoring exhaust temperature and flammable gas detection.
  • Provision for Testing of the fuel cell power system.
  • Risks to persons and the environment.

Due to time constraints at CCC 9, it was not possible to consider these amendments. Therefore the work will be undertaken by a correspondence group.

Technical considerations when transposing the Interim guidelines for the safety of ships using methyl/ethyl alcohol as fuel (MSC.1/Circ.1621) into mandatory instruments under the IGF Code

These interim guidelines are applicable to ships which have to comply with SOLAS Chapter II-1 Part G. CCC 8 updated the work plan for the development of the IGF Code and safety provisions on alternative fuels. CCC 9 was not able to discuss the development of mandatory instruments regarding methyl/ethyl alcohols at this session.

Their development is expected to continue until late 2025 and they could enter into force by 2028.


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Issue 87 of Robban Assafina

(Sept./ Oct. 2023)


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