Standard Design and Manufacture: BS1873 or ASME B16.34 Inspection and Test: API 598 End flange dimension: ASME B16.5,ASME B16.47(API 605 ,MSS SP44) Butt weld end dimension: ASME B16.25(BW) Face to face,end to end: ASME B16.10 Pressure-temperature ratings: ASME B16.34 NACE: NACE 0175