API 521 PSV sizing basis when using ARC valve
API 521 PSV sizing basis when using ARC valve
(OP)
http://www.eng-tips.com/viewthread.cfm?qid=82879
Have 2 x 100% multistage centrifugal pumps each with arc valves for min flow. Assuming operator error on both 2 x 100 pumps and blocked flow API states that no credit should be taken for instrumentation,should you assume both arc valves have also failed for the design basis of piping protection PSV?
It seems allot like multi-jeopardy to me. Also one consideration in my mind is the direct acting nature of the arc valves which makes their reliability much higher than a more indirect type of instrument.
Have 2 x 100% multistage centrifugal pumps each with arc valves for min flow. Assuming operator error on both 2 x 100 pumps and blocked flow API states that no credit should be taken for instrumentation,should you assume both arc valves have also failed for the design basis of piping protection PSV?
It seems allot like multi-jeopardy to me. Also one consideration in my mind is the direct acting nature of the arc valves which makes their reliability much higher than a more indirect type of instrument.





RE: API 521 PSV sizing basis when using ARC valve
RE: API 521 PSV sizing basis when using ARC valve
RE: API 521 PSV sizing basis when using ARC valve