For one of above ground pipeline project for oil lines & gas line in bahrain we are doing stress analysis as per ASME B31.4 & ASME B31.8 code, could you please clear us what code design factor has to be considered for stress analysis , as per ASME B31.4 it is mentioned as 0.72.

in the line we have some road crossing where we are considering the default value as F = 0.001 and the rest of the above ground portion as 0.72

is this the value to be considered for analysis. as the Caesar input page F value is empty should we put this value and analyse the model.is my understanding correct for analysis.

please guide in the matter ,

your earliest response appreciated.

That value of 0.72 is a factor for B31.4 Chapter IX - Offshore piping. For on-shore piping (B3.14) that field for "F" indicates the amount the pipeline may be considered under complete axial restraint. If you use the "Buried Pipe Modeler", CAESAR II fills this in for you.

B31.4 and B31.4 Ch IX are treated as two different Piping Codes in CAESAR II. Likewise, B31.8 and B31.8 Ch VIII are treated as two different Piping Codes.

Richard,

Thanks for the reply, as our pipeline are not buried pipes only few sections of the pipeline are buried that is only for road crossing that caesar model will take default value.

what input value should be put in the F factor place, is it we have to input 0.72 or we have to leave it empty.

please advice.

regards

ahmed

You would only use the 0.72 if you're offshore. Leave it blank.