CVS Pressure Relief Dampers are backdraft dampers with an adjustable start-open pressure that allows excess air escape to lower indoor pressure. Barometric relief dampers are used for gravity ventilation and low-velocity systems. CVS Pressure Relief Dampers are suitable for installation in round ductwork and comply with the requirements of SMACNA, DW144 and AMCA relating to these dampers. Available in various materials including Extruded Aluminum, Galvanized Steel, and Stainless-Steel construction. CVS control dampers are AMCA certified for Air Performance & Leakage.