The duct system, which carries air from the fan system to terminal units, is a very important part of
any air conditioning, heating and/or ventilation system. Since ducts have to be designed, fabricated and
installed to suit specific project needs, this activity almost always falls on the critical path of the HVAC
project.
Important performance parameters are: amount of leakage, vibration and noise, efficiency and turbulence
of the airflow, dimensional accuracy, physical appearance, goodness of fit with other building services,
speed of assembly and installation and, most importantly, pressure drop offered by the system which
translates into energy consumed for operation of the system.