Volume Control Damper is a Valve or Plate that regulates the Airflow inside a Duct, Chimney, VAV Box, or other Air Handling equipment; they are designed to provide positive control of the Airflow within Ventilation systems.

Manual dampers are turned by a handle on the outside of a duct.
Automatic dampers regulate Airflow constantly, operated by Electric or Pneumatic Motors.

Standard Types of DVAC VCDs:
     -VCD
     -VCD-FC
     -VCD-SC
     -VCD-RSC
     -VCD-FOSC
     -ALVCD
Construction of DVAC VCDs complies with SMACNA Standards