Forged Steel Check Valve Standard and specification: 1, Design and manufacture: API 6D, BS 1868, ASME B16.34 2, Connection ends: ASME B16.5, ASME B16.47 3, Face to face dimension: ASME B16.10 4, Testing and inspection: API 598, API 6D 5, Normal pressure or rating: class 150 ~ class 1500 6, Normal diameter: 1/2" ~ 2" 7, Major Material:A105,F304,F316, F11,F22,LF2