TinnerFlow
Elbows & Offsets ยท Elbows & Offsets

Rectangular radius elbow

90-degree radius turn

ConnectionTDC/TDF, S-drive or angle
SupportDedicated support near elbow

Before you start

  • Confirm the elbow radius, throat and heel orientation, joint type, airflow direction, turning-vane requirement, access requirement, and fitting support against the approved drawing.
  • Inspect the heel, throat, cheeks, seams, flanges, and any vane assembly for shipping damage or distortion.
  • Field-check both inlet and outlet centerlines before lifting the fitting.
  • Stage the correct corners, cleats, gasket, approved fasteners, sealant, clamps, drift pins, level, and dedicated support.

Tools and materials

Rectangular radius elbow, approved TDC/TDF, S-and-drive, or angle-joint components, gasket, corners, cleats, approved fasteners, sealant, clamps, drift pins, level, laser, and dedicated fitting support.

Lay it out

  1. Mark the inlet and outlet centerlines and the intended elbow plane.
  2. Confirm the throat and heel face the correct direction and the radius clears structure and access zones.
  3. Locate the support so the elbow body is carried independently instead of hanging from either adjoining run.

Set and support it

  1. Install the fitting support before closing both joints.
  2. Set the elbow at the correct elevation and hold it against roll.
  3. Support both adjoining duct sections so the elbow is not used to pull either run into line.

Make the connection

  1. 1

    Bring the upstream section to the same elevation and align the first tangent.

  2. 2

    Complete the first mechanical joint without forcing the fitting out of square.

  3. 3

    Recheck elbow rotation, throat and heel orientation, and the downstream centerline.

  4. 4

    Bring the downstream section to the outlet tangent.

  5. 5

    Complete the second mechanical joint.

  6. 6

    Install or verify turning vanes and access components where specified.

  7. 7

    Seal required seams and joints after the mechanical connections are complete.

  8. 8

    Load the supports and confirm the elbow does not roll or twist.

Check the install

  • The throat and heel are undamaged and smooth.
  • Both tangents align cleanly with the straight runs.
  • The elbow is square, supported, and not rolled.
  • Required vanes are secure and correctly oriented.
  • Both joints are fully seated and sealed.

Common mistakes

  • Connecting one end before checking the outlet centerline.
  • Using the elbow to hide a route error.
  • Letting the fitting hang from a flange joint.
  • Installing the wrong radius or wrong throat-and-heel orientation.

Stop and ask

Stop if the elbow radius, fitting type, vane requirement, orientation, or centerline differs from the approved fitting or cannot be installed without distortion.