Relief valve inlet/outlet lines
Relief valve inlet/outlet lines
(OP)
Hi,
A basic questions:
What should be the design pressure of the inlet and outlet lines of a PSV:
1/ Inlet: the set pressure or the relieving pressure?
2/ outlet: The same pressure?
Thanks in advance
A basic questions:
What should be the design pressure of the inlet and outlet lines of a PSV:
1/ Inlet: the set pressure or the relieving pressure?
2/ outlet: The same pressure?
Thanks in advance
"We don't believe things because they are true, things are true because we believe them."
"Small people talk about others, average people talk about things, smart people talk about ideas and legends never talk."





RE: Relief valve inlet/outlet lines
1) Inlet, design pressure is the same as the design pressure of the equipment that is protected (often same as set pres, and less than relieving pres).
2) Outlet, design pressure based on margin above maximum operating pres or standard value for relief system (many clients use 50 psig).
RE: Relief valve inlet/outlet lines
"We don't believe things because they are true, things are true because we believe them."
"Small people talk about others, average people talk about things, smart people talk about ideas and legends never talk."
RE: Relief valve inlet/outlet lines
RE: Relief valve inlet/outlet lines
The more you learn, the less you are certain of.
RE: Relief valve inlet/outlet lines
RE: Relief valve inlet/outlet lines
RE: Relief valve inlet/outlet lines
Good point, yes I agree sometimes it is the destination of the discharge line that determines flange rating. Ultimately of course the engineer has to determine the max operating pressures for pipe sections and where the pipe code breaks need to occur.
One other point on a discharge on a pump suction connection. This is not the preferred choice -its better to go to a storage tank where possible. Also, for the example you mentioned , even a 600# flange matching the 600# pump suction may not be adequate if the pump discharge is a higher rating (say 900# for example) and you have a closed discharge valve by accident.
The more you learn, the less you are certain of.