News

• Having demonstrated the safety equivalence of its reinforced design, GTT now offers its Mark III membrane technology at an effective pressure of 1 barg, above the current 0.7 barg standard, giving operators greater operational flexibility.
• Combined with the outstanding insulation performance of the Mark III membrane technology, the 1 barg tank design pressure will enable LNG dual-fuel vessels to comply with future port regulations requiring cold ironing at quayside.

Paris, 3 June 2025 – GTT announces that it has received an Approval in Principle (AiP) from DNV for its membrane tank design rated for 1 barg[1], suitable for LNG[2] dual-fuel vessels.

This approval extends the operating range of the Mark III technology, following the DNV’s AiP for a 2 barg design pressure on smaller-capacity tanks, notably suited to cruise-ships.

It offers ship-owners several key benefits, including:

• Extended pressure-holding time

Increasing the design pressure significantly lengthens the time before the tank reaches its maximum pressure, greatly reducing the need to burn boil-off gas during periods of low engine load.

• Warmer-temperature bunkering

Vessels fitted with these tanks can load LNG at warmer temperatures, giving operators access to a broader range of LNG suppliers.

• Cold-ironing compliance

The enhanced pressure capacity will enable LNG-powered vessels to comply with upcoming cold ironing regulations at the quayside (e.g., under the AFIR directive[3]) without compromising tank integrity, enhancing environmental performance while optimising LNG consumption
and supporting compliance with emerging carbon intensity standards.

DNV’s AiP confirms that GTT’s 1 barg solution achieves safety equivalence with conventional atmospheric-pressure tank designs. The approval is based on a comprehensive evaluation of containment integrity, fuel gas handling systems, tank domes, and hull structure under elevated pressure scenarios.

Philippe Berterottière, Chairman and CEO of GTT, declared: “We are pleased to secure DNV’s Approval in Principle. This innovation underlines our commitment to delivering practical, future-proof solutions that enhance operational flexibility, reduce emissions and support ship-owners in meeting evolving environmental regulations.”

Martin Cartwright, Global Business Director, Gas Carriers at DNV, stated: "We are thrilled to be working with GTT on this project and to award this AiP for this membrane tank development. This represents a significant step in enhancing LNG tank flexibility to meet evolving regulatory demands and is a good example of how technical advancement and regulatory foresight can go hand in hand to support the maritime energy transition. We look forward to continued collaboration.”