The airflows delivered into the plenum were measured with the
airflow-meter and their values were compared with the sums of
airflows through the diffusers. The difference between these two
values is the plenum air leakage. As reported in [13] uncontrolled
air leakage from the pressurized underfloor plenums (through gaps
between panels, electrical floor outlets, etc.) that enters the room
has a typical range for ‘‘well sealed’’ raised floors (carpet, tape,
etc.) of 0.254 103 to 0.508 103 m3 s1/m2 and a typical value
for ‘‘not well sealed’’ raised floors of 0.0127 m3 s1/m2 or greater.
Uncontrolled air leakage for configuration #1 is in the range of a
well-sealed raised floor (see Table 2), while for configuration #2,
it is in the range of a less well-sealed raised floor. The cause of
the difference between configuration #1 and #2 is related to a concentrated
leakage formed in a plastic edge of the plenum located in
the perimeter. This phenomenon was modeled in the CFD plenum
model because of its influence on the plenum air behavior.