The answer to your question here,
"does the length of the equipment comes into consideration when hit by an earthquake or a wind?"
is Yes.
However you should ask a Civil Engineer for the details of what effect wind or an earthquake will have on any object:
- size
- shape
- weight
- type of support
- distance supported above grade
- action of contents when full
- action of contents when partial fill
- etc
Any action on the vessel caused by wind or earthquake will also be transferred to the piping connected to this vessel so you bust make sure the piping is properly designed to be flexible but reasonably restrained.