First and foremost, it is not a rack with just oversize footplates. That does not make a seismic rack.
The following are most of the basics for determining a seismic rack job:
1. Floor thickness & reinforcement.
2. Soil compaction underneath slab.
3. Seismic zone the building is in.
4. Code requirements of the city: UBC or IBC and which version most cities are now IBC.
5. Rack layout and design
6. Number of beam levels and the spacing of those levels. The further the levels are apart the more that downrates the capacity of the frame.
7. Weight of the loaded pallets (Average Weight).
8. PSI and gauge of the rack to be used with column size.
9. Bolted structural, tubular or snap together roll formed.
10. An engineer licensed in the state the job is to be installed, once the engineer does the calcs and drawings, if everything checks out, the engineer stamps the calcs and drawings.
11. Brand has nothing to do with seismic calculations. Seismic rated rack is based on facts and conditions. Many salespeople and customers have little idea about the seismic rated conditions.
12. There are a few cities that have conditions beyond seismic.
As a side note, other considerations are OSHA, ADA and of course the local fire department.
These are the things it takes to have a seismic rated and approved rack job. Whoever gets the permit has to have all this information and sometimes even a little more.