Sure, the extra precautions can be expensive. But they’re simply part of the cost of building a secure facility that also can keep humming through disasters.
Suggestions:
Build on the right spot.
Have redundant utilities.
Pay attention to walls.
Avoid windows.
Keep a 100-foot buffer zone around the site.
Use retractable crash barriers at vehicle entry points.
Limit entry points.
Make fire doors exit only.
Protect the building’s machinery.
Plan for secure air handling.
Ensure nothing can hide in the walls and ceilings.
Use two-factor authentication.
Harden the core with security layers.
Prohibit food in the computer rooms.
Install visitor rest rooms.
http://www.csoonline.com/read/110105/datacenter.html
I would also advise that you don’t organize related systems in nice rows (hortiontal or vertical). It might be convienent but a localized incident could take out a whole critical business solution. So distribute related systems across a data center.