French technology provider GTT has won two key approvals for its newest LNG membrane-type cargo containment system version named GTT NEXT1.

Bureau Veritas issued design approval for the new system while Lloyd’s Register handed out a general approval for ship application during Posidonia 2024 in Greece.

GTT described the two approvals as marking a “major milestone” and said GTT NEXT1 technology is now ready for commercial development.

The new system is the latest design evolution from GTT, whose membrane systems are dominating the LNG carrier building market.

The company said GTT NEXT1 — which has been described as a revamped version of its Mark V system — uses two metallic barriers and aims to provide a thermal level of performance equivalent to its Mark III Flex+ system.

The new design uses prefabricated reinforced polyurethane foam panels to support the primary and secondary membranes.

GTT said this provides “the best compromise” between thermal and mechanical performance.

The primary barrier, which is in contact with the cargo, is made from corrugated stainless steel — similar to that of the company’s other Mark membrane technologies — while the secondary barrier is made of the alloy Invar.

GTT said: “It is possible to deliver significant performance improvements, while using proven materials and components.”

Company chairman and chief executive Philippe Berterottiere described GTT NEXT1 as a “cutting-edge solution” and said it combines the best of the company’s proven technologies with new advancements which he said would ensure “optimal performance and improved reliability” for the transportation of LNG.

While GTT’s membrane cargo containment systems have been widely adopted there have been problems with the Mark III systems, largely relating to the glueing of a triplex layer, which have resulted in repairs and intense discussions about what testing shows up.

GTT’s other main offering — the NO96 system — uses two metallic barriers. But Mark III and its versions have offered better cargo boil-off rates and so have become the preferred choice.

GTT NEXT1 is designed to appeal to those LNG newbuilding buyers who prefer a design with two metallic barriers, effectively cutting out the possibility of any glueing problems.