Dear Flarenuf
what is your calculated size for the tailpipe and what is your size for the header?
Calculated tail pipe size is 14'' and header size is 10''
normally the tailpipe is sized for rated flow but once it reaches the main header you should be using design flow.
what are you sizing the TP on , backpressure or velocity ? I am considering Backpressure.
the built up back pressure from the tie in to header back to the PSV outlet flange shouldn't be that large surely ? Back pressure is increasing largely.
is this PSV flowing individually or part of a scenario ? PSV is flowing in blocked oulet case.individually and collectively in fire scenario.
are you saying you have to have a large diameter TP in order to meet BP limits on valve ? YES
conventional PSV ?YES