HI,

I have to do analysis for a surface laid pipeline as per ASME B31.4 code. I am using CAESAR II Determine option for selecting restrained/unrestrained criteria. In the output result, Caesar does calculate operating stress but allowable are zero. This is in line with the code. However, my question is if allowable stresses for operating case for unrestrained pipe is not provided by the code, then why Caesar is calculating the stresses in operating case? My client says if Caesar is calculating operating stresses, then we should compare it with 0.9*Sy same as in case of restrained pipeline. Can we do this while still following code?