Standard spacing for server rack?
 

Does anyone know what the standard square foot spacing is for a single server rack? I could have sworn I have seen this number before in a white paper, but I cannot find it again for the life of me; and I need to find this number to give an estimate for how many racks I can fit in a given data center.

That depends on your tile layout (if you are using a RAF), are you planning to use a 7 or 8 tile span? A rule of thumb for a 7 tile layout is 19 - 23 (this includes all the Data Center white space).

I am somewhat new to data centers and especially the building and planning process. You mentioned RAF in the previous post, could you please explain to me what this exactly means?

Sorry for the week late response, but I unfortunately don't know what the tile spacing will be. I've been asked to gather a lot of data center calculations for an unknown data center of unknown specs and just wanted to see if there was a general spacing rule to follow. I ended up giving them a 18 sq ft spacing rule per server rack, 2' x 9', for the time being.

I unfortunatley don't have a square foot figure as we generally look at the overall site in terms of power and square footage to figure out density, and whether to shrink down or make big depending on what we get.

In respect of our row configurations, lets take two rows, running a hot aisle in the middle with 600mm x 1000mm racks. We have 5 x (600mm x 600mm) tiles for two rows (let's call this R). You would then require at least 2 tiles for working in front of those, so we add another 4 x (600mm x 600mm) to the calculations (lets call this FB).

We also need space to work round the outside as well, for lets add another 2 tiles to the outsides of the row so we can walk all the way round; so we would need 4 x (FB + R).

PS: This is very rough, and should not be taken as gospel as it does not take into account dealing with any plant equipment, H&S, fire exit routes and all that stuff - oh, and I may have made a mistake in my maths somewhere which I probably have :)

Sorry about the delay (missed this one):o

RAF is Raised Access Floor or Raised Floor.

Tate Access Floors, Raised Floor Systems

Before I forget, I do want to thank you all for the help. Like I said, I'm having to make a lot of calculations based off of many unknowns; but I think with the responses I have gotten so far, I was able to make the most accurate calculations for the time being. Thanks again for the help.

Technical questions
 

Hi Amattson,

In order to properly answer your question you need to think of a couple of things?

1) What is the intended density/rack of your comptuer room?
2) How tight for space are you?
3) Will you be using inrow cooling or end of row?
4) Will you be using a raised floor?

I ask you these questions because a typical server rack receiving 100 CFM of air at a standard delta T of 5.5 degrees Celsius will have 5.3 kW heat dissipated from the rack. A 56% open perf tile will allow anywhere between 200 and 400cfm pass through it depending on the pressure differential above and below the floor. This being said, this air would be divided between two racks (one on each side of the perftile) and maybe only half of the air would actually enter the servers (some would go around the servers and some over the tops of the racks). So we would be doing well to get 50cfm actually through the server meaning you are looking at a density of 2.5kW/rack if your cold aisle is one tile wide (6 tile pitch) or two tiles wide 5kW/rack if your cold aisle is two tiles wide(7 tile pitch). If you are looking to increase densities further I strongly suggest using a 32" wide cabinet and 42" to 48" deep cabinet.

On another note if your design group is asking for a sqft estimation per rack they have absolutely no clue what they are doing. I see it all the time. Regular engineering groups think they can design a data center and try and use basic building principles like w/sqft and sqft/rack to do it. Those parameters worked 10 years ago but with the densities we are seeing today you will end up with an inoperable data center.

Hopefully this helps and hopefully I didn't scare you too much with that last statement. If you want to reach me directly for any additional questions please feel free to contact me directly through my corporate IT infrastructure consulting website. www.planus.ca/contact

Best of luck,

datacenter geek

Nice posts here. Thanks for sharing.