I do have a hard time believing in the validity of applying a Building Code to the seismic analysis of piping. The building code approach is really aimed at determining base shear reactions and anchorage forces for structural design associated with piping or other mechanical attachments. This approach is not intended to predict associated bending stresses in piping.

However, having said that, I do use criteria in the NBC (Canadian equivalent of UBC) for seismic evaluation of piping using uniform load factors. Calculation of these load factors requires a certain amount of interpretation of the code (i.e., how flexible a system is) and this interpretation may not be uniform for all users.

As a final note, ASME B31.3 does make reference to ASCE-7. Chapter nine of this reference provides quite a thorough treatment of pipe seismic reactions but probably in the same vain as the UBC, which I've only partially glimpsed.

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B. Harrington
brian.harrington@veco.com
Burnaby, BC
Phone: (604) 659-3335
Fax: (604) 659-3345