The Design and Organization of Data Centers/Layout Considerations
Consider where network and power comes into the building and where it will enter the data center, and how this will affect location of main edge routers, where cross connections will take place, placement of power transformers switches and UPS units. You may have multiple electrical entrance facilities for redundancy.
Space for wiring
Determine use of raised floor and/or overhead cable trays.
Some rack-to-rack cable organization will be necessary.
It is crucial to lay out your racks, shelving, and stand-alone systems with accuracy of a few inches when considering location over raised floor access ports.
You should have a minimum of three feet between rack front and back to allow for opening of doors.
A 6' rack spacing interval is recommended as floor tiles come in 2'x2'.
The location of the wheels and/or feet at the bottom of a rack are critical to being able to lift floor panels.
Space for other necessities
You may want to have space for a desk with monitor, if you don't have a formal office or NOC on the premise. You will want to have storage units for copious documentation and spare parts, unless you just use an empty rack, and possibly a place to drop old hard drives for secure disposal.
Phones and switches
Place light, power, and fire switches in an easy to reach place. If you have two entrances, have light switches at both entrances especially if main lighting is normally kept off.
Make sure phone is in easy reach of fire suppression cut off switch, NOT the other way around.
Consider putting "non-computer" assets in separate rooms. You can contain leaks easier, as well as keep service technicians away from servers, increasing security, and reducing the need for supervision.