Hello everyone (especially Richard Ay),

I am confused with the "Relief Load Synthesis" result which is the force of "thrust at valve pipe/vent pipe interface"&"thrust at vent pipe exit".

My input data are as follows: line tem. 500C,design pressure 7460Kpa,orivice ID 30mm,relief valve piping 96mm,vent stack length 6700mm, ratio of gas specific heats 1.3,gas constant 461.5 N.m./Kg./deg.K

I got the result which showed the interface force:9237N and the ventpipe exit force:4714N.

However, I check the result using the method of ASME B31.1 nonmandatory appendice II, which I got the F1 result:
5186N. This data is more nearly to the vent pipe exit force caculated by CAESAR II.
The input data of caculation by 31.1 is as the same as CAESAR II, which W = 12.4 lbm/sec (from caesar ii), A1=15.23in^2,h0=1463.37btu/lbm

How can I select for the piping stress caculation?

Thank first!

There is nothing to select. You decide which load you want to analyze with, and specify this value in the dynamic (force set) analysis.