Fire-safe certification per API 6FA and API 607 requires LNG valve seals maintaining emergency sealing after soft seal material burns. Primary PTFE seals provide normal operational sealing. Backup metal seats engage when soft seals fail during fire. Testing subjects valves to standardized fire exposure then verifies sealing capability. https://globalsealstech.com/product-category/oil-gas-seals/api-6d-ball-valve-and-lng-seals/