I might be a few days late on my reply to this thread, but have a few things I would like to add.

I'm not sure what your budget is with your DC, but what most DC's implement in their DC to help with the cold/hot thing is the following.

Every Isle is the servers back to back

So when your walking an isle on your left and right side are the back sides of the server. At the end of that isle you have a Air Cooling unit that sucks air into it then cools it and shoots it back out. This will help getting air away from your servers.

This means you will have air conditioners basically in your Server room, however getting a water detection cable and strategically placing it around the perimiter of the DC floor and by the AC units will help you to guard against water.



As far as a Fire suppresion system, I recommend a Gas called FM 200..read more about it here
http://www.fireline.com/fl_fm200firesuppression.html

Its odorless, leaves no residue, and you can be in the same room if it goes off.


Also, one other suggestion.

On your wire racks for the Fiber and Ethernet cables, you will be far happier if you puti n wireing racks that have holes in them..that will allow you to run a cable out of the rack to a server anywhere rather than having to wait to a hole thats cut in the rack at a pre-determined point by the manafacturer.