TAB Journal Spring 2018 - 10
A simple review of the data would indicate duct
leakage, but the low-pressure sides had been leak
tested and had passed successfully and a visual
inspection indicated a tightly sealed system. The
next move was to traverse an individual ACB
and compare to plenum pressure. A traverse was
done of ACB-37, and a CFM of 339 was recorded
which was 86 CFM and 34% higher than had
been measured using the plenum pressure. The
data measured here had matched exactly what
the design team had stated in the preliminary
meeting, but the question was why the plenum
pressure where so inaccurate.
A closer look and some more testing revealed that
the chilled beams themselves were leaking at the
seams which had caused the plenum pressures to
read lower supply air than what was delivered.
Although the engineering team's procedure was
"slightly" correct it didn't identify or correct the
actual problem which had caused the inaccuracies.
Moving forward on projects with many chilled
beams, leak testing a sample of chilled beams will
TAB Journal Spring 2018