Ensuring safe gas transportation passage
IACS supports the revision of the IMO IGC Code
By Kathrine Ilje Nerland, Safety Panel Chair
Since its entry into force in 1986, the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code) has set mandatory safety standards for new gas carriers. Since then, the Code has undergone several significant amendments to address emerging challenges and incorporate advancements in technology.
Given the complexity and continuous development of technologies involved in transporting gases, and the multiple hazardous properties of these gases, such as:
A regularly updated regulatory framework is essential to stay in line with technological development and for the safe design and construction of gas carriers.
Drawing on its experience during design approval and surveys, IACS has developed around 40 Unified Interpretations (UIs) to the IGC Code since its inception to foster uniform and correct application of its requirements. A similar number of papers have been submitted to the IMO to contribute to the Code’s development.
IGC Code Review
Based on an initiative by IACS and other stakeholders, the IMO is now conducting a focused review of the IGC Code following the large number of UIs developed since the latest major review of the Code entered into force in 2016.
The primary objective of this review is to remove ambiguity and promote the consistent implementation of the IGC Code requirements.
Under this initiative, in 2023 IACS revisited its implemented UIs and suggested draft amendments to the IGC Code to incorporate guidance into the mandatory regulatory framework. The understanding of and approach to several technical topics in the IGC Code has also been discussed, leading to proposed new UIs.?
Several amendments have been drafted by the Safety Panel, for example, related to discharge tests of dry chemical powder fire-extinguishing systems, the consideration of weathertight ventilators in stability calculations, and design temperatures for piping fittings and related components within the cargo area.
The IGC Code covers a wide range of safety aspects and multiple IACS Panels are therefore involved in its review. These include those related to the:
Many of these were discussed and agreed upon by the 9th session of the IMO Sub-Committee on Carriage of Cargoes and Containers (CCC 9) in 2023.
Water Spray Systems
One of the major topics that IACS has suggested to incorporate into the IGC Code is the clarification of the requirements concerning water spray systems covering the boundaries of superstructures and manned deckhouses, lifeboats, life rafts, and muster areas facing the cargo area.
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Having an adequate supply of water for firefighting is essential. On ships carrying flammable and/or toxic products, a water spray system for cooling, fire prevention, and protection of the crew is also key.
The focus has been on redundancy and backup arrangements for the system, in particular interconnection between the water spray system and the fire main system.
In this respect, it has been agreed that the water supply should have sufficient capacity to connect water from the fire main to the deck spray system, and that the emergency fire pump should have the size and capacity to supply the required amount of water if the main fire pumps are disabled.?
Based on the principle of dealing with one single fire incident at a time, the emergency fire pumps could be sized to cover either the water spray system or the engine room fire extinguishing system, whichever is greater, in addition to two hydrants.
Safety of LNG bunkering ships
In September 2023, the International Association of Classification Societies (IACS) issued a new Unified Interpretation (UI GC39) related to cargo transfer areas on LNG bunkering ships, which are specifically designed to transfer LNG from one vessel to another.
Some of these ships are permanently equipped with additional cargo transfer equipment—such as loading arms, bunkering booms, and transfer hose reels—designed to handle the low temperatures and high pressures associated with LNG. This equipment can be installed in different locations around the ship.
UI GC39 interprets the International Gas Carrier (IGC) Code such that, when in use, these additional cargo transfer arrangements on LNG bunkering ships are considered as "cargo manifolds" for the purpose of several existing safety measures.
This brings these additional cargo transfer arrangements into the scope of the existing IGC Code, which requires protection of cargo manifolds by:
Additionally, the regulation requiring the emergency shutdown system—which is fitted to stop cargo flow in the event of an emergency—to be automatically activated upon detection of a fire on the weather deck of the cargo area, including the cargo manifolds, will also extend to the cargo transfer areas on LNG bunkering ships under UI GC39.
UI GC39 will be uniformly implemented by all IACS Members for vessels contracted for construction on or after 1 July 2024.
Going forward, the IACS Safety Panel will continue to be actively involved in the development of the future regulatory framework for transportation of gases by sea, including for alternatives to methane gas fuels, such as LPG and ammonia.
With the maritime industry shifting to alternative fuels, new technologies, and novel designs, IACS is committed to continuing to share its knowledge and experience to ensure that operational safety is retained.
Read more from IACS' 2023 Annual Review