Model BD-84

Adjustable Counterbalanced Backdraft Damper
Triple-V Blade

The BD-84 backdraft damper employs counterbalanced gravity operated triple-V style blades and a rugged channel frame to restrict reverse airflow and to permit the forward flow of air in the intended direction. Adjustable counterbalances attached to the blades axles permit field adjustment to regulate start-to-open and full blade operation. The BD-84 damper is intended to be mounted vertically in either exhaust or intake installations for medium to high velocity and pressure applications.

Standard Construction

Frame: 8" x 2" X 14 ga. (203 x 51 x 2.0) galvanized steel channel.
Blades: 6" x 16 ga. (152 x 1.5) galvanized steel - triple-V
Axles: 1/2" (13) diameter plated steel.
Linkage: Concealed in frame.
Bearings: Steel ball bearing, press fit into frame.
Counterbalances: On-blade axle, crankarm and weights - adjustable.
Minimum Size: 6" x 6" (152 x 152)
Maximum Size: 48" x 96" (1219 x 2438)

Ratings

Leakage: 70 cfm/ft² @ 4 in. wg. (0.36 m³/s/m² @ 1.00 kPa) with no seals.
                 40 cfm/ft² @ 1 in. wg. (0.21 m³/s/m² @ 0.25 kPa) with no seals.

Temperature: -25^oF to 250^oF (-32^oC to 121^oC) with no seals.
                       -15^oF to 150^oF (-23^oC to 66^oC) with seals.