Dear experts
I am new in crude oil pipeline stress analysis as per ASME 31.4 design code. We need some clarification from stress analysis experts.
Here my doubt is the Fac should be 1.0, 0.0, or 0.001. This value should be one for pipe under complete axial restraint. This value should be one when the pipe is fully restrained, such as buried for a long distance. The default value for Fac is 0.0. When Fac is 0.001, this indicates to CAESAR II that the pipe is buried but that the soil supports have been modeled. This causes the hoop stress component, rather than the longitudinal stress, to be added to the operating stresses if the axial stress is compressive.
B31.4 Chapter IX - F1, hoop stress design factor, according to Table A402.3.5(a) of B31.4. Appropriate values are 0.72 for pipelines or 0.60 for platform piping and risers.
As per 31.4 the design factor value is 0.72 and CAESAR II default value 0.001 for underground pipelines.
I have attached marked CAESAR II input entered location.
Kindly advise me which value (0.72 or 0.001) is applicable for crude oil pipeline stress analysis as per ASME 31.4 design code.
by
rajiv

First, FAC is used differently for B31.4 and B31.4 Chapter IX.

For the Offshore Chapter (IX), FAC should be either .72 or .60. This is something you have to decide.

For the main body of B31.4, FAC can be 0.0 or 1.0, indicating unrestrained, or restrained piping respectively. In addition, if you utilize the Buried Pipe Modeler and let CAESAR II re-mesh the model and apply soil restraints, then FAC is set internally to 0.001. In this case, CAESAR II determines the restrained/unrestrained state of the pipe based on whether the axial stress is tensile or compressive.