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

Volume damper in round branch

Round branch

ConnectionSlip-fit damper collar
SupportAdjacent supports

Before you start

  • Confirm damper size, blade orientation, handle side, branch route, ceiling access, and insulation thickness.
  • Inspect the blade, shaft, quadrant, collar, and stops.
  • Verify the handle remains reachable after insulation and ceiling closure.
  • Check that the damper can rotate fully without hitting screws.

Tools and materials

Round volume damper, adjoining round duct, approved slip or gasketed components, fasteners, sealant, branch supports, level, marker, and access-label materials.

Lay it out

  1. Orient the shaft and handle toward the accessible side.
  2. Keep the damper clear of elbows and joints where practical.
  3. Mark the final handle position before connecting.

Set and support it

  1. Support both duct sections.
  2. Hold the damper centered and round.
  3. Keep branch weight off the damper collar.

Make the connection

  1. 1

    Seat the first duct connection fully.

  2. 2

    Orient the handle and blade.

  3. 3

    Connect the second side without rolling the damper.

  4. 4

    Install approved fasteners clear of the blade path.

  5. 5

    Seal both joints.

  6. 6

    Operate the blade through full travel.

  7. 7

    Label the access location where needed.

Check the install

  • The blade rotates fully.
  • The handle and quadrant remain accessible.
  • The damper stays round and aligned.
  • No screw interferes with blade travel.
  • Both joints are sealed and supported.

Common mistakes

  • Burying the handle above a closed ceiling.
  • Putting a screw into the blade path.
  • Using the damper to support the branch.
  • Installing the handle against a wall.

Stop and ask

Stop if ceiling or wall closure removes access, the blade cannot travel fully, or the branch arrangement forces the damper out of round.