Bending Stress for Sustained Case at Pipe Elbow

[MELEED]

I have a question on how Caesar II calculates the bending stress at pipe elbow. I am running a pipe system with 870 F temperature and 320 psi pressure. The expansion case passed without problem, but the sustained case couldn't pass. The failed area is around the elbow and the reported bending stress is really high. Can anyone help me?

 

[DSB123]

MeLeed,
Caesar II calculates the stresses in a bend in accordance with the relevant Code so depending on which Code is applicable to your piping review the Code equations for bends to establish the stress calculation. If the expansion case passed then either the bend thickness is insufficient or you have a poorly supported system since the sustained case is due to weight and pressure loads only. I suppose you are not using the full SIF's for the sustained case and are using 0.75xSIF? Have you checked the pressure stresses in the bend manually? deducting the longitudinal pressure stress from the allowable how much have you left for weight stresses?