A volume damper is a manually or electronically adjustable valve installed in ductwork to control and balance airflow to different zones or areas of a building. Volume dampers allow technicians to precisely adjust cubic feet per minute (CFM) delivery to individual rooms or zones during system commissioning and operation. These devices range from simple butterfly dampers to complex opposed-blade designs with 0 to 90 degree adjustment range.
Types and Specifications
Butterfly dampers are most common for low-pressure applications below 2 inches of water column, while opposed-blade dampers provide better control in higher-pressure systems. Volume dampers are available in sizes from 3 to 60 inches diameter with manual handles or motorized actuators for automatic control. Standard damper leakage rates are typically 5 to 15 percent when fully closed.
Commissioning and Balance
Volume dampers are essential for proper system balancing, allowing technicians to achieve design airflow within 5 to 10 percent of calculated values. They are installed in each branch duct supplying individual zones or areas. Locking handles and position indicators help maintain proper damper settings throughout equipment life.