Looking for opinions and experience here...

When doing seismic analyses, assuming the owner or code does not require otherwise, do you guys think it is good practice to consider an operating-basis earthquake ("OBE") load case, even though the B31 codes do not require it?  As you know the B31 codes require an occasional load case which (for the static equivalency analysis) consists of sustained load + seismic load (W+P±U, to use C2's nomenclature).

In addition to that I have also always considered an operating-basis earthquake, which would consist of W+P+T±U, in the somplest case, for a system operating at non-ambient temperature.  This is not a B31 load case (although I think it is in the nuke code - I don't have any nuke experience) but my opinion is that it's prudent to check this load, especially for deflections, leakage moments, and for equipment/vessel flange loads.  Opinions?

Thanks for your time and thoughts.

Thanks!
Pete