Dear Members.
We are conducting stress calculation for LNG pipeline. It Caries LNG from Jetty Unloading arm to LNG storage Tank total run of pipe is 1.5KM with expansion loops.
Now we have requested to study the case below.
During startup before LNG placed in to the pipeline to be cooled down to -160degC by using Nitrozen gas. This gas will be enter in to the pipeline at the jetty. during that time at the other end of the pipe is at ambient temperature 21degC.
Pipe size DN400, 4mm thick and 316L and insulation thickness is 170mm.

I am using thermal bowing delta T as 139deg (160-21) to calculate the support loads and thermal stresses in the pipeline.
Since I am i am doing first time may i Know is it the correct way to consider this case.

Can any one please advise me.

Best regards
KK