DNV Greenlights HHI's Type B VLGC Tank Design
DNV has awarded an Approval in Principle (AiP) to HD Hyundai Heavy Industries (HHI) for an independent Type B LPG cargo tank design for very large gas carriers (VLGCs).
The approval covers HHI's design for a 90,000-cubic-metre independent Type B containment system for LPG carriers.
According to DNV, the use of Type B tanks in VLGCs is intended to improve operational safety and maintenance accessibility throughout a vessel's service life, while providing greater flexibility in the selection of inner hull materials during the design stage.
The design incorporates crack propagation and fatigue analyses in addition to the buckling and sloshing assessments typically carried out for Type A tanks.
The design is intended to maximize structural reliability by preventing the propagation of surface defects through the tank wall over its design life.
Safety features include a partial secondary barrier in the form of a leak path acting as a spray shield over welded areas, as well as four dedicated drip trays per tank designed to contain leakages and protect the surrounding hull structure.
“With our first LPG carrier design incorporating an independent Type B cargo tank, we are advancing safer and more adaptable gas carrier solutions. DNV’s AiP builds confidence as we move toward practical application,” said Hongryeul Ryu HHI Chief Technology Officer.
