Pleas ID this IBM system....

Jay West jwest at
Tue May 21 12:43:25 CDT 2019

No modern datacenter that I have seen still uses a raised floor *OTHER THAN* about 3 inches for a ground plane. There is a reason for that... the old idea of forced cooling under the floor and mixing power & data cables there has been found to be a truly bad idea.

Power in most any modern datacenter is via "track lighting" rails directly over the row of racks. Ex:

HVAC units are generally not inside the datacenter any longer either, nor are UPS's. These cause access control issues with vendors doing maintenance and raises issues for publicly traded companies that must meet certain control & accountability standards. Not to mention locating them on the datacenter floor can cause issues with cool air routing. So these days the hot and cold aisles are alternating, with a windsock/tube above the racks for cold air delivery to the front and an 8 foot or so fan built in the hot aisle wall. This is the optimum place for particle (smoke) sensors as well. That design also lets in certain situations outside air to be used.

So to say you "definitely need a raised floor for a datacenter" is only true if you are trying to create a period replica. A modern datacenter built that way... well... not sure any self-respecting contractor would build one 'the old way' :)

-----Original Message-----
From: cctalk [mailto:cctalk-bounces at] On Behalf Of Adrian Stoness via cctalk
Sent: Tuesday, May 21, 2019 12:03 PM
To: Patrick Finnegan <pat at>; General Discussion: On-Topic and Off-Topic Posts <cctalk at>
Subject: Re: Pleas ID this IBM system....

all systems have their advantages disadvantages it all depends on what your doing and designs u choose. personaly i think raised floor and tray above are best then u keep all ur power below away from ur data lines plus but then ur setup is only as good as the lazyest tech u get comming in running stuff.

On Tue, May 21, 2019 at 11:38 AM Patrick Finnegan via cctalk < cctalk at> wrote:

> On Tue, May 21, 2019, 04:13 Christian Corti via cctalk < 
> cctalk at> wrote:
> > You definitely need a raised floor
> > for a data center. You need it for forced air cooling and for 
> > running the water and condensate pipes.
> Ductwork doesn't have to be below the floor. Modern co-lo facilities 
> that I have been in (such as Switch Supernap) don't have a raised floor.
> Plumbing (unless you're doing aisle containment or RDHx) shouldn't run 
> through the IT space in the data center.
> Cooling water to racks should be dewpoint adjusted, so you don't need 
> condensate drains inside the DC.
> And overhead trays are much more difficult to
> > work with if you want to lay new cables because you have to climb up 
> > and down the ladder all the time, moving the ladder from here to 
> > there and back to here...
> >
> I solved that by having multiple ladders. In my experience, it's a lot 
> easier than trying to reach through a cluttered raised floor under racks.
> The only good reason that I have seen in this thread for a raised 
> floor is to match older equipment that routes cables downwards.
> Pat
> >

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