Stem seals in API 6A gate valves consist of multiple V-ring packing sets with live-loaded Belleville springs. Materials like PTFE, PEEK, and graphite achieve fugitive emissions below 50 ppm per ISO 15848-1, essential for environmental compliance in California, Norway, and EU-regulated facilities. https://globalsealstech.com/product-category/oil-gas-seals/api-6a-gate-valve-seals/