Rapid Gas Decompression testing per API 6A Annex F requires 10 cycles at 80% rated pressure and maximum temperature. Only FFKM, FEPM, and special HNBR grades achieve 0000 rating (no cracks) required for subsea and sour HPHT gate valve applications worldwide https://globalsealstech.com/product-category/oil-gas-seals/api-6a-gate-valve-seals/