Liquefied Gases Handling

The main purpose of the present guide is to provide a thorough reference which might be useful to various port authorities as well as operating management of LNG carriers and terminals in reviewing or developing their planning in order to avoid the accidents or at lease reduce their possibility. The publication would also be quite helpful in controlling the possible consequences of such accidents happening within the port limits.

This second (revised) edition takes into account the STCW Convention and SOLAS IX as well as the ISM Code. It covers ships in transit and operation, ships alongside, public relations and periodic review. Note, however, that the present publication shall not be treated as a comprehensive technical manual on contingency planning since the authors have confined this document to the aspect directly relating to the carriage and handling of gases.

The circumstances influencing the contingency planning may vary from port to ports in the matters such as nautical/weather considerations, types of cargo being handled, authorities etc. When preparing this document, broader interpretation of the term "contingency planning" was taken, including considerations related to the accident prevention and control of possible consequences. 

The present Guide would mostly be applicable to all liquid gas carriers both at sea and approaches to the ports; it has been released by the working group with the assistance from members of OCIMF, ICS, SIGTTO and ISU aiming to provide a thorough reference that would be useful to the operating managements of gas ships in reviewing or developing their contingency planning.

The contingency plans supplement the SOPEP required for all ships >400 GT as per the Annex I to MARPOL. Regardless of how the liquefied gas is carried (pressure/temperature being meant), the cargo containment shall not be treated as part of the vessel's structure. Such containments are in all cases located inboard of the vessel's side plus above the bottom. The big portion of this booklet has been taken from the CPD (contingency planning document) that have been formulated by the managing teams of a number of companies within the shipping industry.

The present guide is mainly addressed at the ship operating companies  and assumes some general understanding of the cargo characteristics as well as of the design, construction and, of course, operation of the gas carrying ships. Definitely useful publication not only to the managerial stuff but also all personnel.

The purpose of the present SIGTTO publication is to provide a proper explanation of how insulation flanges protect from ignition caused by arcing. It contains information on the inductive circuits, electrical characteristics of the cargo transfer hoses together with the supporting calculations, some examples of the effects of hose inductance and resistance, information on the effect of capacitance, testing of the flanges and multiple loading arms and parallel circuits, all supplemented with the list of definitions and conclusions and recommendations.

The insulation flanges have been used for several decades; their effectiveness is sometimes seriously challenged, though there have been no reported fire incidents on the manifolds installed on board of tankers or gas carriers. This shall be taken into consideration by the ship operators having a background of road tanker operations, supplying the LNG as fuel oil.

Since this document mainly concentrates on the protection from arcing-caused fires, we would definitely consider it very important and recommended to everyone involved in such sort of operations as the info provided in the booklet might help in improving the operational safety.

This is a commemorative publication released in connection with the fortieth anniversary of one of the industry grands.

The core function of the cargo ESD system is to stop the flow of the cargo liquid/vapor in case of an emergency in order to bring the whole cargo handling system to a safe static condition. The present document released by SIGTTO was prepared to cover the emergency shutdown system arrangements for the gas carriers.

The book has been arranged in three parts; the first part of the booklet covers the philosophy and some general requirements. the second part addresses the functions of the emergency shutdown system and associated safety systems. Finally, the last part of the book deals with the linked ESD systems. There are several appendices at the end of the book providing some useful supplementary information such as one on ESD processing, pneumatic ESD links, IGC Code requirements applicable to the ESD systems, and others.

The publication was released due to the numerous concerns raised by the members of the organization about the interpretations of the functional requirements and is intended to encourage and promote the use of the linked systems; however, note that it shall not be treated as the technical specification for the ESD system design, it rather sets out the most important requirements to such systems...

In the last 35 years a high number of serious casualties have occurred involving fires in the cargo containment system of liquefied gas carriers, whilst the vessels have been in shipyards. Many of these have resulted in multiple fatalities, environmental damage and serious financial loss to the ship-owner.

It should also be borne in mind that it is not unknown for ships to be arrested and owners superintendents, or representatives, to be held in custody for lengthy periods whilst accidents are investigated. In 1995, the SIGTTO Secretariat undertook research into the subject and published the results at the Balikpapan Panel Meeting in September 1995. At the time this was thought to be sufficient to alert the industry to the problem, but a recent enquiry has shown that since September 1995 there have been 7 reported incidents resulting in 7 fatalities and the constructive total loss of a vessel undergoing repair.

This guide has been prepared by SIGTTO in order to draw attention to the problem and propose risk mitigation measures to those responsible for managing these activities. Whilst this safety guide was being prepared, in July 2001, a fire occurred on a 3200 m3 semi-pressurised LPGC at a repair yard in Slovenia. The fire, which burned for over 2 hours, damaged the structure and insulation of No.1 cargo tank and was caused by hot work during steel-work renewal in the double bottoms. There were no fatalities or injuries.

The first three decades of the LNG industry, i.e. until the end of the 1990s, were dominated by base load projects with long-term sale and purchase and associated shipping contracts, typically of 20 years duration. With such arrangements the project partners had an equity share or knowledge in all facets of the project, from gas gathering to gas distribution, including shipping.

Furthermore, their technical staff had a detailed knowledge and familiarity with all the individual sections of the contractual chain. By the end of the 20th century, however, a short-term or "spot" market was starting to develop within the industry. In this market LNG vessels are hired on "spot" and "short-term" charters, with the charterer often having little or no knowledge of the history of such vessels. This has led to charterers and buyers and sellers of the cargoes drawing upon their oil industry experience and insisting on vetting these vessels prior to accepting them.

This has occasionally raised questions about aspects of the vessels' operation and maintenance that partners in the original long-term projects had previously understood and accepted. One area, unique to the LNG trade, in which this has occurred is the maximum, operationally acceptable, gas concentration to be found in the insulation spaces of the cargo containment system of the membrane-type liquefied natural gas carriers, particularly those of older design.

The present document is mainly intended to provide all members of the Organization with the guidelines of the requirements that are applicable to the testing the LNG cargo handling systems. The scope of the publication shall be considered applicable to the designs featuring established membranes, SPB and spherical tanks.

Note that the content shall not be extended to the prototypes and novel ship designs since they will most probably require some specific approach, for example additional testing. Moreover, this paper shall not be treated as a sort of operational procedures; it is rather an aid to preparation of a specification to be used during the gas trials. The authors have tried to address all items that have to be tested before the vessel is handed-over as well as the testing done after the delivery, at the time of loading of the first cargo.

The figures there in the text of the document are indicative and it would be better to refer to the shipbuilder's/manufacturer's recommendations for figures for the particular ship. It is assumed that the trials are done by the shipbuilder before delivery, which is actually the common practice. The trials themselves are conducted to confirm the correct operation of the handling systems...