Design Standard : IS 9890-1981Pressure Testing : BS 6755 Part I/API 598/IS 6157-1981Flange Dimensions : ANSI B 16.5Face to Face : ANSI B 16.10/IS 9884-1981Screwed Dimensions : ANSI B 1.20.1/BS 21/IS 554Socket Weld Dimensions : ANSI B 16.11/BS 5351/ IS 4712Butt Weld Dimensions : ANSI B 16.25/BS 5351/ IS