Hello flexMen,

Please explain what the temperature of the piping system has to do with Occasional Load stresses.

Temperature is all about expansion (displacement) stresses (please look at B31.1, paragraph 104.8.3) and those are secondary stresses. Sustained (additive) loads (please look at B31.1, paragraph 104.8.1) result in primary stresses and Occasional loads (please look at B31.1, paragraph 104.8.2) also result in primary stresses. When you look at Occasional loading cases you do not use load combinations that include expansion/contraction (temperature).

Please provide a listing of all the load cases and combinations that you are running. That will be necessary if someone is to help you sort out your problem.

Regards, John.