Backdraft Damper

Model: BD3000

Backdraft Damper
  • BD3000 Leakage test
  • Operation Test Setup – Front View
  • Operation Test Setup – Side View
  • Operation Test

Backdraft Damper

Leakage Rating :

0.1 m3/s/m2 or 1% based on 10 m/s air approach velocity at 1000 Pa.

Pressure Rating : up to 2000 Pa (standard construction), >2000-7000 Pa (refer to factory)
Operating Velocity :  10m/s, (for higher velocity - refer to factory)
Temperature rating :  50 degrees C (for higher temperature - refer to factory)

Description        :

Due to space constraint, backdraft dampers are frequently installed closed to fan discharge in ventilation duct system causing rattling noise and damage to the blade, blade linkage and its bearings.  Our engineers at OLS have produced a completely new version of the backdraft damper that is fail-proof and does not cause rattling noise under turbulence flow.

The OLS BD3000 backdraft damper is a twin blade design that pivot on ball-bearing or bronze bushes and does not response to air turbulence like most backdraft dampers.  Opening of the damper blade take place with very low pressure and air velocity, 10 Pa and 4 m/s respectively.   And air leakage rate in closed position is less than 0.05 m3/s/m2 at 1000 Pa pressure differential not achievable with normal backdraft damper.  This damper can be constructed to handle high velocity and pressure ventilation system.


  • Low pressure required to open damper
  • Low pressure loss
  • No rattling noise due to air turbulence.
  • Low air leakage across closed damper
  • Ideal for installation in close proximity to fan
  • Trouble-free operation