TRG-TRC014-EN 39
period two
Components of a VAV System
notes
Other publications contain more complete details related to duct design, but
here are a few general recommendations:
n Keep the duct layout as simple and symmetrical as possible
n Place main duct runs and, when possible, branch runs and terminal units,
above hallways and other “unoccupied” areas to ease installation and
maintenance and to help attenuate the sound radiated to the occupied
spaces
n Limit the use of flexible ductwork upstream of the terminal unit
n Apply a duct lining or duct silencer to the first section of the duct system in
order to attenuate supply fan noise
n Add balancing dampers upstream of diffusers in all noncritical branches
n If needed, reducing transitions should be located several duct diameters
upstream of terminal units
Duct Design Recommendations
▲ Keep as simple and symmetrical as possible
▲ Locate main runs, branch runs, and terminal units
above hallways or unoccupied spaces
▲ Minimize use of flexible ductwork upstream of
terminal units
▲ Use duct lining or a duct silencer in first duct
section to attenuate supply fan noise
▲ Place balancing dampers upstream of diffusers in
all noncritical branches
▲ Reducing transitions should be several duct
diameters upstream of terminal units
Figure 54
