8 May 2006

8 May 2006

Raised Floors – Still Relevant?


Category: Uncategorized

With the widespread use of serves installed in racks instead of legacy mainframe configurations, the use of ethernet cable in cable trays located above server racks instead of legacy wiring types beetween mainframe boxes, and finally the use of in-line cooling equipment and/or overhead cooling with ducted returns for cold aisle/hot aisle configurations, is the installation of an access floor a wise use of money when developing a computer room?


Comments (5)

  1. Pete Sacco on 8th May 2006

    The moving of much of the power and data cabling overhead of the server cabinets greatly reduces the congestion under the raised floor. This in-turn allows for better cooling performance due to more efficient air distribution.

    Furthermore, the use of InRow cooling systems, such as APC’s RC series, also allows for cooling improvements without the need for a raised floor.

    However, it is my opinion that neither mitigates completely the need for a raised floor. There will still always be some cabling and or a concealed pathway needed for other distributed items such as temporary power cabling, large conductor power cables, some bulk data distribution in wire baskets, and cooling and/or water lines as part of the CRAC system.

  2. Pete Sacco on 8th May 2006

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  3. Webwonk on 14th Jun 2006

    Many data centers seem to be using higher raised floors to expand their air conditioning capacity. Some folks are using four-foot plenums. You still need lots of AC, even if design can help direct the chilled air more efficiently through your data center and get it to the hot spots. To increase the volume, you need capacity under the floor. The headroom matters, which is why it’s harder to lease/sell older data centers with lower clear ceiling heights.

  4. Pete Sacco on 14th Jun 2006

    The reasons it is hard to move a data center space with a low ceiling are as follows:

    1. In traditional perimeter CRAC design where the supply air is delivered into the raised floor, the heat must migrate back to the tops of the CRAC units to be rejected. If the migration path along the ceiling is constricted or if obstacled are encountered the heat is not effectively rejected. Thats not to say the CRAC units won’t continue to draw air in from any source, including cold air if necessary. This air mixing is the problem.

    2. Since a clear sub-floor cold air delivery path is so important it is wise to relocate cable pathway and management to an overhead strategy. If the ceiling height is too low, you are presented with the situation previously described.

    PTS offers a couple of cooling solutions to help mitigate low ceiling data centers.

    I hope this helps.

  5. matt_stansberry on 22nd Sep 2006

    Great blog Pete! From what I’ve heard, you still are going to need raised floors for maintaining balanced humidity and pressure levels as well.

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