Valve Design: API 609, MSS SP-67
Face To Face: API 609, MSS SP-67, DIN3202, BS EN558-1
Pressure Test: API 598
Flange Drilling: ANSI B16.1 class125, BS4504 PN10/PN16, DIN2501 PN10/PN16
Top Flange: ISO5211
Bundor butterfly valve: https://www.bundorusa.com/