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Size, Pressure & Special Routing · Size, Pressure & Special Routing

Shallow wide rectangular duct

Pancake duct

ConnectionTDC/TDF
SupportBroad trapeze

Before you start

  • Confirm shallow-wide dimensions, gauge, reinforcement, joint type, support density, and acceptable panel condition.
  • Inspect for severe bellies, dishes, creases, and damaged flanges.
  • Plan broad trapezes and spreader handling.
  • Do not expect the joint to flatten a badly bellied face.

Tools and materials

Shallow-wide rectangular duct, TDC/TDF components, gasket, corners, cleats, broad trapezes, spreader, clamps, drift pins, level, and sealant.

Lay it out

  1. Set the visible bottom plane.
  2. Use closer support planning where approved.
  3. Keep joints and fittings clear of support.

Set and support it

  1. Install broad trapezes before lifting.
  2. Use a spreader or multiple control points.
  3. Support fittings separately.

Make the connection

  1. 1

    Set the first section on support.

  2. 2

    Align the second section to the bottom plane.

  3. 3

    Install gasket and align flanges.

  4. 4

    Clamp square without forcing the panel.

  5. 5

    Complete all joint components.

  6. 6

    Seal the connection.

  7. 7

    Release lift and inspect for permanent dish or buckle.

Check the install

  • The duct has no severe permanent dish.
  • Reinforcement is complete.
  • The joint is square.
  • The broad support carries the panel.
  • The bottom plane remains stable.

Common mistakes

  • Trying to fix a bellied panel with cleats.
  • Lifting from the middle only.
  • Using narrow support.
  • Skipping reinforcement because the duct is shallow.

Stop and ask

Stop if the duct face is severely bellied, creased, or buckled, or if reinforcement and broad support are not complete.