Do I need to consider the expansion loadcase under Maximum Design Temperature for ASME B31.4? I am talking about pipeline with loop (vertical). Thank you in advance.

Sincerely,
marchie

Hi Marchie,

Thermal stress shall be calculated for the range of minimum and maximum operating temperatures. Temperature of the pipe at installation or completion of final tie-in, shall be used as T1. Refer to 402.5 of the B31.4 code.

Farhad,

Just a slight correction.

You are entirely right for un-restrained pipeline (typically AG pipeline, or UG pipeline treated as un-restrained / FAC = 0.001 in CII). As per para. 402.5.2 "NOTE", the "thermal stress should be calculated for the range of minimum and maximum operating temperatures".

However, for fully restrained pipeline (UG pipeline), as per para. 402.5.1, thermal expansion stress should be assessed between Installation and Operating Temperatures. The designer IS NOT OBLIGED to use the Maximum Range between Minimum and Maximum Operating Temperatures.

Regards,

Dorin,

You are right. Extreme cold and hot range is used for fatigue analysis. Extreme cold may happen during shut down in winter.