For automatic on-off valve(ball valve), should I test seat leakage according to standard ANSI FCI 70-2(similar with Globe control valve) or API-598 (similar to all type manual valves)
I have some problem with new on-off butterfly valve which provide zero leake(API598) by metal to metal sealing but this mention valve fail acceptance test in my workshop hence I contact valve's supervisor to solve this issue. He disassembly the valve and check all things such as alinement...