Gas has been a major topic of discussion at International Maritime Organization (IMO) in recent years and the results of these deliberations are now coming to fruition. At one level, the gas shipping industry has revamped its standards governing the design, construction and equipment of gas carriers to take into account the numerous advances that have been made in liquefied gas transport technology.
On a second front the maritime sector in general has been working to develop a new set of international standards governing the use of gas as fuel on ships. Because vessels powered by liquefied natural gas (LNG) are expected to proliferate in the years ahead, as one way of enabling ship owners to comply with increasingly tight restrictions on ship atmospheric emissions, the primary focus has been on LNG. However, the new standards also make allowance for the use of alternative low flash point gaseous and liquid fuels in marine propulsion systems.
Work on the revision of the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code) began in 2007 when the IMO Secretariat agreed that, due to the technical nature of the project, the Code update work could best be undertaken by the gas shipping industry itself. The drafting of the revised provisions was carried out under the auspices of the Society of International Gas Tanker and Terminal Operators (SIGTTO) over a period of two years. The initiative represented the first time that IMO had delegated the revision of a major set of standards to an industry body.
SIGTTO brought together a wide cross section of the gas shipping world to participate in the IGC Code revision work. A total of 129 specialists from 18 countries and representing 48 different gas shipping sectors were organised into 10 working groups. After 39 working group and six steering group meetings the updating work was completed and a draft revised IGC Code was submitted to IMO in November 2010.
The revision was necessary due to the changes that have occurred in the gas shipping sector since the IGC Code was adopted in 1983. Although the Code has served the industry well, with just a few amendments, over the past 30 years, many in the industry believed that in some areas the standards for gas carriers were dropping below the requirements for conventional tankers, e.g. in the protective location of cargo tanks.
In addition the existing IGC Code provisions did not cover aspects such as the new propulsion systems that have been developed and the process plant and mooring systems on LNG regasification vessels. The carriage of LNG in Type C pressure vessel tanks was also deemed worthy of some further attention in the revised Code. To augment these major changes the SIGTTO working groups used the opportunity to implement a raft of minor amendments and clarifications to the Code, as well as new requirements for the carriage of carbon dioxide and mixed C4 cargoes.
The new provisions have been the subject of some fine-tuning at IMO over the past 12 months and at the 16th Session of IMOâ€™s Bulk Liquids and Gases Subcommittee (BLG 16) in February 2012 the contents of the revised Code were approved. The draft IGC Code now moves onto the next stage, in which its provisions will be considered by other IMO subcommittees over the coming year.
The intention is then to collate the feedback from the reviews carried out by the various sub-committees for discussion at BLG 17 early in 2013. Any amendments agreed at the session will then be incorporated in a final draft of the IGC Code for consideration at the 91st Session of the Maritime Safety Committee (MSC 91), BLGâ€™s parent body, which is scheduled for May 2013. SIGTTO is hoping that the text of the revised Code will be approved at MSC 91 to enable its entry into force in 2014.
The second gas code under consideration at IMO is the new International Code on Safety for Gas-Fuelled Ships (IGF Code). Following the introduction of the cross-fjord ferry Glutra in 2000, over 25 LNG-fueled vessels have been built for operation on Norwegian coastal routes and offshore service.
A similar number of LNG-fueled vessels are under construction, including several larger vessels and many for international trading. The use of LNG as marine fuel is set to escalate in the years ahead and the bunkering infrastructure that will support this development is beginning to take shape. The initial focus of the work to extend the LNG supply chain is in IMO emission control areas (ECAs) but several of the large new LNG import terminals now under construction worldwide are being configured with LNG coastal distribution and bunkering hub roles in mind.
The class rules developed by DNV for the pioneering LNG-fueled vessels in Norway have formed the basis of work on the new IGF Code regime. A key stepping stone between the DNV rules and the finalisation of the IGF Code has been the â€śInterim Guidelines on safety for gas fueled engine installations in shipsâ€ť which were adopted by IMO in 2009. These guidelines, in turn, are utilised as the starting point for the gas-fuelled ship rules that other class societies have now developed.
The introduction of gas-handling systems on board ships that are not gas carriers represents a quantum leap that has widespread implications for the shipping industry. The likelihood is that, amongst the gaseous options, LNG will be the fuel of choice and this means that a myriad of seagoing and port staff will have responsibility for handling this cryogenic liquid in future.
In recognition of the implications of this new regime IMO is taking pains with the drafting of the new IGF Code to ensure that issues such as training, emergency shutdown (ESD) arrangements, fuel tank location and alignment with the IGC Code are comprehensively covered for a range of ship types. The use of gaseous fuels on passenger ships is a special consideration that the Norwegians have already considered for their coastal vessels and is now being given further attention in the IGF Code drafting work.
As was the case with the IGC Code, substantial progress was made with the draft IGF Code at BLG 16. At the meeting it was decided that the Code should include provisions for ESD-protected machinery spaces, subject to certain conditions, and that locating bunker tanks under accommodation spaces should not be prohibited as long as adequate safeguards are in place.
The work at BLG 16 also included a review of the later chapters of the draft IGF Code. As a result of the review, the IGF working group identified a number of areas where additional input is required from other IMO subcommittees. The Standards of Training and Watchkeeping (STW) Sub-Committee has been asked whether the training requirements for gas and chemical tankers are suitable for officers and crew serving on ships fuelled by gas or low-flash point fuels or whether specific training is required.
The IMO Sub-Committee on Stability and Load Lines and on Fishing Vessels Safety (SLF) has been requested to consider a proposal on the distance from the ship side of bunker tanks while the Ship Design and Equipment (DE) Sub-Committee has been asked to consider lifesaving appliances. At present, the lifesaving equipment provisions for tankers are also applicable to LNG carriers and there are no additional requirements for IGF Code vessels other than those existing for cargo or passenger ships.
The IGF working group also discussed the installation of gas detectors at the inlets to accommodation and machinery spaces in order to cover situations involving an escape of gas, such as during bunkering operations. This proved to be a controversial issue which will require further study.
The IGF correspondence group will continue to work on the draft IGF Code prior to the BLG 17 meeting early next year. The primary focus in the new IGF Code will be on the use of natural gas as fuel but it has been decided that the possibility of using other low flash point fuels should also be specifically addressed in separate sections of the Code.
The complex technical nature of these final gas-fuelled ship deliberations means that the IGF Code is unlikely to achieve the same 2014 entry-into-force date as that targeted for the IGC Code. However, in overall terms the IGF Code is now in the finishing straight and its provisions are set to be in force by 2015, the same year that the allowable sulphur levels in ship fuel in ECAs are reduced from 1.0 to 0.1%.