Lloyd's Register has approved new prismatic IMO Type B independent cargo tanks, so called ACTIB (Aluminium Cargo Tank Independent Type B). The initial approval is for use in a DSME-developed 210,000 m3  STD LNG-RV design in accordance with LR's Guidance notes for liquefied gas carriers and floating offshore installations adopting IMO Type B independent tanks primarily constructed of plane surfaces.

The approval in principal (AiP) follows a one year period of development and collaboration between DSME and Lloyd's Register. An evaluation for the next step - General Approval - has also been completed by Lloyd's Register.

The ACTIB tanks, constructed of insulated aluminium 5083, will have the world's largest storage capacity in an independent, insulated LNG tank system. The volume capacity in the initial design will be nearly three times larger than comparable types currently in operation.

One of the leading benefits of ACTIB is the potential for safe and more flexible operations in part filled conditions as the structural arrangement can be designed to withstand sloshing. So, as well as application in the DSME designed 210,000 m3 volume LNG carrier, the tank will be of particular interest for wider use in LNG shuttle tankers, LNG FPSOs as well as LNG-as-fuel tanks where partial fill is a critical operational issue.

Through continued collaboration, Lloyd's Register and DSME become aware of the importance of further technical issues requiring examination, such as sloshing and fatigue calculations, and which are dealt with in the Particular Ship Application Approval (PSApp) stage, which takes place, typically, once a newbuilding contract has been signed.

"We are very pleased to continue our good relationship with Lloyd's Register, which has enabled such an excellent achievement by good cooperation. This new IMO type B independent cargo tank with insulation system developed with our own technology for extremely low temperature LNG containment system can be immediately incorporated into very large LNG carriers and/or LNG-FPSOs while enabling DSME to become greatly competitive in the market." said Mr. Man Soo Kim, Vice President and head of hull design of DSME.

"This is a very important achievement and a significant milestone for Lloyd's Register and DSME to drive the practical application of new technology enabling partial filling during operations; it also provides another option to the gas industry for cargo containment systems in LNG carriers, LNG FPSOs, and the like." said Luis Benito, Global Strategic Marketing Manager, Marine of Lloyd's Register.

DSME also plans to apply the ACTIB system to the fuel tank design of LNG-fuelled ships such as DSME's next-generation 'green ship' powered by LNG.

Source: LR