Dear,
When I use the FAC=0.6, according chapter IX (B31.4) ; CAESAR II shows an OPE stress... this is a unrestrained pipe and I didn't find that question in the code. Why CAESAR II shows it? Are there in the code anything about this "OPE STRESS"?,

Thank's!

For B31.4 Ch IX, FAC is the Hoop Stress Design Factor per Table A402.3.5(a) of the code. This then lowers the allowable stress for the OPE, SUS, and OCC cases for the hoop stress comparison. B31.4 Ch IX does not distinguish between restrained and unrestrained piping as B31.4 does. Instead, it performs code stress checks on Hoop Stress, Longitudinal Stress, and Equivalent Stress for Operating, Sustained, and Occasional load cases (not Expansion).

Thank's Loren!!!

But, I have another question... The allowable stress in B31.4 is estabilished as follow:
S=0,72*Sy*E...

*0,72 is the "FAC" on CII?

->In local standard (NBR 15280 - Brazil), this factor is estabilished by local instalation (similar B31.8) and for a SCRAPERS LAUNCHERS local this factor is 0,6. Can I put it in the "FAC" on the CII?

regards,