Allowabel Tail pipe back pressure - fire case
Allowabel Tail pipe back pressure - fire case
(OP)
In the event of a fire case the allowable pressure is 21% of set (psig). I am doing tail gas calculations and am not certain if the built up back pressure needs to be less than 21% or 10%. thanks





RE: Allowabel Tail pipe back pressure - fire case
The allowable backpressure depends on the type of PSV (conventional, bellows, remote pilot operated). No matter what type is selected, the backpressure cannot be so high as to reduce the capacity of the PSV below the requirement.
Good luck,
Latexman
RE: Allowabel Tail pipe back pressure - fire case
RE: Allowabel Tail pipe back pressure - fire case
There are at least three aspects a backpressure affecting a Pressure Relief Valve (PRV).
i) Maximum allowable accumulated pressure of protected vessel.
If allowable overpressure is 21% of set pressure, then allowable back pressure can be as high as 21% of set pressure
ii) PRV Capacity
Shall ensure PRV capacity is not affected by back pressure for any overpressure i.e. 10% or 21%
iii) PRV Stability
Shall ensure stability of PRV for back pressure exceeded 10%.
For conventional spring loaded PRV, you may read more in "Several Impact of Backpressure on Conventional PRV"
JoeWong
Chemical & Process Technology
RE: Allowabel Tail pipe back pressure - fire case
RE: Allowabel Tail pipe back pressure - fire case