Dear All,

As I understand ASME B31.4 - 2012 defines two conditions of a pipeline, "Restrained" and "Unrestrained"

For "Restrained" pipelines the code requires an assessment for the operating load case (OPE) where it compares the longitudinal stress SL (computed for restrained case and including thermal stresses)to the allowable stress S=0.9*SMYS.

For "Unrestrained" pipelines the code requires an assessment for a sustained load case (SUS) where it compares the longitudinal stress SL (computed for unrestrained case from pressure and external loadings) to the allowable stress S=0.75*SMYS.
and also requires an assessment for an expansion load case (EXP) where it compares SE to SA.

So it somehow adopts the same philosophy of ASME B31.8
Is that true? Please correct me if I am wrong.

Also does CII follow this procedure (if it is true)? and starting from which version?

Regards