Originally Posted By: sam

But, I have noted many using various operating pressures listed in line designation table in slp computation; aren't they wrong in approach ?

regards,

sam


I'd like to share you bout this one, those DESIGN Pressure and temperature are set for coincidental pressure and any other 'surprising' stress which come into system while OPERATING ones are usually used to nozzle check at equipment nozzle which intact to piping system. I suggest you to stick with Design Pressure when you arrange your piping system.

second, i have no idea why you use PD/4t in order to find wall thickness, as i know there are 3 stresses according to axis coordinate (correct me if i'm wrong):
1. Longitudinal Stress f:{PD/4t;F/A;Mb/Z}
2. Circumferential/Tangential Stress f:{PD/2t}
3. Shear stress f:{Mt/Z;VQ/A) this VQ/A is negligible
4. Radial Stress is negligible
and wall thickness design come from tangential stress checking PD/2t (hoop stress)


regards