TinnerFlow
Dampers, Penetrations & Life Safety · Dampers & Life Safety

Backdraft damper

Exhaust/intake

ConnectionFlanged/slip connection
SupportIndependent support

Before you start

  • Confirm airflow direction, damper orientation, mounting plane, manufacturer angle limit, pressure condition, and service access.
  • Inspect blades, pivots, seals, frame, weights, and stops.
  • Verify gravity-operated blades can move freely in the installed plane.
  • Check for wind, fan, or negative-pressure conditions requiring a specific model.

Tools and materials

Approved backdraft damper, flanged or slip connection components, gasket or sealant, fasteners, independent supports, level, square, and manufacturer instructions.

Lay it out

  1. Mark airflow direction and top.
  2. Confirm the frame is in the permitted plane.
  3. Reserve blade-swing and service clearance.

Set and support it

  1. Support the damper independently.
  2. Keep the frame square and level.
  3. Support adjoining duct so it cannot rack the frame.

Make the connection

  1. 1

    Set the damper in the approved airflow orientation.

  2. 2

    Connect one side while maintaining frame square.

  3. 3

    Recheck blade movement.

  4. 4

    Connect the second side.

  5. 5

    Seal the perimeter as permitted.

  6. 6

    Move the blades through full travel.

  7. 7

    Verify the installed angle remains within the manufacturer limit.

Check the install

  • The blades swing freely.
  • The orientation and plane are correct.
  • The frame is square.
  • No blade rub or obstruction is present.
  • The damper is independently supported.

Common mistakes

  • Installing the damper backward.
  • Mounting it at an unapproved angle.
  • Racking the frame with duct weight.
  • Sealing the blade edges.

Stop and ask

Stop if the installed angle, airflow orientation, pressure condition, or model does not match the manufacturer requirements.