Thanks Michael Fletcher,
You confirmed what I have been thinking and what I have used in a recent project.
Could you please shed some light on Elbows. The actual fitting thickness is used in SIF for elbows in B31.3. However we generally do not input the value of fitting in elbow input spreadsheet in CAESAR. So if we use a thicker elbow (Sch 80) with s Sch 40 pipe, do we have to input the thickness in the input spreadsheet or use element Sch 80 thickness for the the elbow element?

Thanks for your help

M. Waheed