ClassNK has granted Approval in Principle for a spray form insulation system designed for IMO Type B tanks used in LNG and ammonia-fuelled vessels, marking regulatory validation for technology developed by Nihon Shipyard and Hankuk Carbon.

The Japanese classification society issued the AiP following safety reviews based on its Rules and Guidance for the Survey and Construction of Steel Ships, which incorporates both the IGC Code and IGF Code requirements. The certification confirms the design concept and demonstration mock-up test results comply with prescribed regulatory standards.

The development addresses growing demand for alternative fuel storage solutions as the maritime industry pursues decarbonization. While IMO Type C tanks have been the conventional choice for LNG-fuelled ships due to productivity and cost advantages, Type B tanks are gaining attention for large-capacity applications, particularly on container ships and ammonia-fuelled vessels, according to ClassNK.

Type B tanks offer improved cargo efficiency and greater outfitting flexibility compared to Type C designs, making them suitable for vessels requiring substantial fuel storage capacity.

The AiP was presented during a handover ceremony attended by Moon-soo Cho, CEO of Hankuk Carbon; Tomoaki Takahira, Director and Chief of Design Division at Nihon Shipyard; and Masaki Matsunaga, Executive Vice President of ClassNK.

Nihon Shipyard was established in 2021 as a joint venture between Imabari Shipbuilding and Japan Marine United Corporation, focusing on sales and design of commercial ships and offshore structures excluding LNG carriers. Hankuk Carbon, founded in 1984, manufactures composite materials including carbon fiber and glass fiber prepregs for various industries.

The Approval in Principle process allows designs to be examined against international conventions and classification rules before specific vessel implementation is determined, potentially reducing regulatory rework and examination time during class registration.