Body seals between valve body halves or body-bonnet connections contain pressure within valve cavities while accommodating thermal contraction during cooldown to LNG temperatures. Gasket materials must maintain compression and sealing effectiveness despite dimensional changes from thermal cycling, preventing leakage paths that would compromise valve integrity and safety. https://globalsealstech.com/product-category/oil-gas-seals/api-6d-ball-valve-and-lng-seals/