Velocities in Relief Lines

[Traket]

I'm working on a project with the fluid being API 42 crude. I'm having a bunch of trouble finding a clear answer on allowable velocities for inlet and outlet lines for the relief. For inlets, I've found the general rule for <3% pressure drop but I'm expecting fluid velocity to matter prior to that for a liquid line.

Key in this question also is the velocity through the valves on the upstream and downstream side.

Thanks for the help. This is all for a 31.4 system.

 

[BigInch]

Velocities should probably be kept below 10m/s in any case, but that may cause too much pressure loss. Relief lines with too great of a pressure drop don't work all that well. So it really depends on how much pressure you have at the inlet and the length of the relief line. Relief valves must have enough capacity for your relief flow rate, without losing too much pressure across the valve itself. They must be sized exactly right.

you must get smarter than the software you're using.