Thank you Ibrahim.

I have seen this information. According to this document design factors for ASME codes ar based on SMYS, but for API RP 1111 is equations based on Burst Pressure (Higher than design).

For this project the software to be used is CASESAR II, so i´m trying to figure out how can i make a stress analysis using CAESAR and an equivalent design factor between API RP 1111 and B31.8 (if possible)

Would it be reasonable to proceed as follows?
- First we perform the design pressure calculation applying the hoop stress eqquation as per API RP 1111 in order to obtain the minimum wall thickness for the riser.
- Then we analyze the longitudinal and combined stress as per ASME B31.8 chapter VIII using a stress analysis software.
- In order to avoid obtaining hoop “overstress” in the stress analysis as per B31.8, i propose to apply a “equivalent design factor” for hoop stress F1, based on the wall thickness obtained from API RP 1111