We consider ground seismic acceleration in static seismic analysis while our piping supports are taken from aboveground structures and equipments, quite tall!

Is it not against seismic codes in US and India as fire resulting from leakages post earthquake can result in loss of costly infrastructure?
I understand that east coast is not earthquake prone.But, amplified acceleration shall be considered as per seismic codes in India, I understand.
If I am wrong, please correct me.
Reg,
Sam
PS:I dislike ignoring axial tensile force in flange leak check by NC method which can hamper public safety while providing short term gain in productivity in piping stress analysis. By shortcuts, we gain in short term, but build a risky future. Often fire happens in piping flange leak due to this short cut!

If you believe your structure has a higher component of acceleration due to being on a tall structure, it makes sense to "elevate" your analysis.

However, it'll be up to the end user if they wish to pay for this analysis and installation. You should run some calculations and issue an opinion for review.

Some additional thoughts:

1) Is a static analysis sufficient at all? My opinion is that if you have 2 separate structures with 2 different natural frequencies, you run the risk of the structures swaying in opposite directions at some point.

2) If buildings can be designed to be "earthquake proof" that it should also be possible for piping structure, too. The question then becomes can we do so cost effectively, and with the structures fulfilling their intended purpose?

You are right that often enveloped or independent support response spectrum analysis and seismic anchor movement analysis is apt to use in nuke or power plant applications.

India has a very good IS-1893 and IS-875 code addressing seismic and other design loads on structures. But, apart from government projects, we seldom use them fully!
Reg,
Sam

As I understand things, these seismic displacements do more damage than the seismic inertial loads. Also, the B31E code provides a separate stress check (with yield as the limit) for this seismic anchor motion (SAM).