Backdraft and Pressure-Relief Dampers
Backdraft and pressure-relief dampers are crucial components in ventilation systems, ensuring airflow is properly managed. These dampers help maintain efficient and safe air movement in various HVAC applications.
Backdraft Damper
A backdraft damper, also known as a gravity damper, allows air to flow in one direction while preventing reverse airflow. These dampers are essential for exhaust or intake systems. They can operate using gravity, where the air pressure or velocity opens and closes the damper, or they can be motorized to open and close as needed.
Pressure Relief Damper
A pressure relief damper is a type of backdraft damper with an adjustable start-open pressure. This allows it to maintain a consistent pressure at various airflows. The damper closes when the differential pressure decreases. Pressure relief dampers do not open fully right away when the set pressure is reached, making them useful for safety and control purposes.
Selecting the Right Damper
When choosing backdraft and pressure-relief dampers, consider the following factors:
- System velocity and back pressure requirements
- Mounting direction and airflow
- Installation method (inserted into the duct or flange-mounted)
- Operation type (gravity or motorized)
- Start-open pressure
Specifications:
- Mounting Position: Vertical or Horizontal
- Airflow Direction: Vertically Up, Vertically Down, and Horizontal
- Velocity (m/s): 1500 (7) to 6400 (33)
- Maximum back pressure in. wg (kPa): 1 (0.25) to 20 (5)
- Motorized: Optional, Standard
- Material: galvanized steel, painted steel, 304 or 316 stainless steel
- Spring-Assisted: Standard or Non-Standard
- Frame Construction: • No flange; • Flange on discharge; • Flange on intake
Suggested Applications:
- Exhaust
- Roof ventilation
- In-duct ventilation
- Air intake
- Sidewall ventilation
- Blower outlets
- Branch duct isolation
- Industrial process isolation
- Emergency generator radiator outlets
Standards and Certifications:
- IECC
- ASHRAE
- AMCA 500D
