Piping pressure thrust, PipePlus

[rch11]

We use Algor PipePlus to analyze piping to meet ASMEB31.3. The software allows the user to include or exclude pressure thrust in the alaysis. If there are no bellows in a piping system, should pressure thrust be included in the analysis? If pressure thrust is included, the analysis results show large piping displacements and it is very difficult to get stresses within Code limits. I have modeled existing piping systems in our plant, including pressure thrust in the analysis, and found that the actual piping displacements are much less than the calculated displacements. I can not find anything in the B31.3 code that says that pressure thrust should be included if there is no expansion joint in a piping system. Any help?

 

[ibrahimdemir]

rch11,

Your answer is in the fundamental. If there is an opening in the axial direction of the pipe that pressure forces can not be equalised by the pipe itself or vessel(s) or any other equipment, you need to take the pressure trust load into consideration.
If you have a continuous piping between two pressure vessels, and no bellow used, there is no need to consider pressure trust in your calculation.
I hope this very short answer is sufficient for your application.

Ibrahim Demir
Clyde Babcock-Hitachi