More on Access Flooring

More on Access Flooring

Having participated in the original “Access Flooring” article [

EBNVol. 7, No. 1, January 1998] and followed the subsequent commentaries, I found it interesting that the discussion focused on floor-to-floor heights and somewhat overlooked the impact of displacement ventilation.

From our experience, Mr. Browning is correct in his remarks that a 12” raised floor is the typical nominal, 10” to 14” being the general range, depending on power and teledata requirements. The basic design guideline is to add 4” of net cavity height for supply air to the general office power, voice, and data distribution needs of traditionally 6” to 8”.

Within North America, it has now been successfully demonstrated that underfloor supply air can be as economical as traditional overhead design on a first-cost basis, and that the operational savings can be significant. The ventilation effectiveness of underfloor air per ASHRAE-62 and 62R also addresses the inadequacies inherent in overhead approaches.

If the raised access floor technology becomes the platform to undertake the design intents, underflow supply air is the next natural evolution within the office whereby displacement ventilation is taken to its modular potential. In any modern environment, we find the spot heat loads created at the workstation now exceed those traditionally zoned for lighting and should consider a “slab-up” versus “ceiling-down” approach to address the “I’m too hot” or “I’m too cold” complaints.

John Doris, V.P. Technical Services

Interface Architectural Resources

Grand Rapids, Michigan