Dear Sirs,

I'm calculating seismic factor(for inserting in UNIFORM LOADS in CAESAR II) according to formula (32-2) of UBC97. The calculated seismic factor is 0.67g. I think this value is very big and is not reasonable. I have a question:
Does the mentioned formula is appropriate for considering effect of seismic?

My data:
Ip=1.5(4th column of table 16-K)
Ca=0.36
hx/hr=0.9
Zone 3
SOil SD

No idea?

my idea: basically, your piping is in Zone 3 (by 4 as defined in UBC 97), with a mapped ground acceleration 0.36g. Your soil is "moderately consolidated". You attach the piping to a structure almost on top of it. And you choose to have 50% margin because of importance of your piping,

To be more specific to your title "UBC 97 importance factor".
You attach a pipe to a structure. That structure can be a building or non-building, can belong to an "essential facility", to a "hazardous facility", to a "standard facility" etc. Based on this classification, the importance factor is intended to increase the design horizontal acceleration of that structure.
Your piping is not a structural part of that structure and I would consider that it is not necessary subject to the same "importance factor" as the structure; rather the importance factor would be related to the classification of the importance/hazard evaluated for that piping. But you would study the Code to understand you have the freedom to apply such approach.