API 6D ball valves in LNG vapor return lines manage pressure equalization. Seals handle gas-phase methane at low temperatures. The valve’s reduced bore minimizes inventory holdup. LNG seals use low-friction coatings for smooth operation. Testing includes vacuum conditions to simulate tank evacuation. https://globalsealstech.com/product-category/oil-gas-seals/api-6d-ball-valve-and-lng-seals/