a-practical-guide-to-noise-and-vibration-control-for-hvac-systems-second-edition-pdf

Figure A shows a typical air-handling unit (AHU) mechanical room in which
some of the most common system-related acoustical faults are noted. Of the 12
faults noted, very few have to do with the specific equipment or materials used.
Most of the faults are system related; that is, the individual components are not
designed and installed as if they were part of a whole system.
Airflow through the
AHU/ductwork layout shown in the figure would generate excessive turbulence,
noise, and rumble. The small mechanical room would have restricted airflow in
places, resulting in locally turbulent airflow and unexpected noise and rumble in the
tenant space. The vibration isolators would not perform as expected because they
are resting on a flexible floor structure. The designers of this hypothetical system
did not consider all of the system (interactive) effects of the various components
and how they would control the amount of noise and vibration that enters the building’s occupied spaces.