Standards: Design and manufacture: ASME B16.34,API 600,API 6D
Face to face/end to end: ASME B16.10
Pressure temperature rating: ASME B16.34
End flange dimension: ASME B16.5(for NP ≤ 24); ASME B16.47 series B, API 605 or ASME B16.47 series A, MSS SP-44 (for NPS bigger than 24), ISO 7005-1, JIS B2238, BS 12627
Inspection and test: MSS SP-61,API 598