Originally Posted By: Dee
Dear All,

I just want to see your opinion about this subject, i have followed many discussion about this topic, in Eng-Tips.com, Cheresources.com, and offcourse COADE CAESAR Forum, and still i am agree wit Mariog on the thread of "PSV Reaction Force" when he said:

Quote:
You have this force exactly where there is a FREE jet.
That means:
- in an open system, where really the free fluid jet is released into atmosphere
- in a closed system, at the header connection, presuming your PSV is not pressurizing the header- that is the header is counted as a large volume receiving the jet rather than a path for flow…
Quote:


This is also inline with LC Peng opinion on his book "Pipe Stress Engineering" about this subject.

But recently i have seen a method that quite conservative, and with this method i think when we are doing detailed engineering with static analysis, we only need to apply the reaction force on vertical and horizontal direction in PSV Body (as seen in figure below) as long as the good support/restraint applied in the system (also as seen in figure below), with stopper in approriate location after discherge valve, it will minimize the effect of reaction load downstream.

I want to hear opinion about this, please..

Regards

D



Hi Dee,

Providing line line-stop really helpfull to reduce stress due to PSV pop up. My recent project however client not allowed to have restrained close to the PSV (right before PSV outlet). Hence, in this case we should figure out case by case basis in which part the stress occured.

Force in vertical from the inlet of PSV normally can be negligible and only PSV reaction force from outlet of PSV that is having significant impact for calculating PSV case. DLF for coservative result can consider 2 times.

just my two cents
-wan-