Elbows & Offsets ยท Elbows & Offsets
Rectangular mitered elbow without vanes
Low-velocity/specified turn
ConnectionTDC/TDF or S-drive
SupportFitting support
Before you start
- Confirm the design specifically permits a mitered elbow without turning vanes.
- Verify pressure, velocity, noise, and system requirements do not call for a different elbow.
- Inspect the miter line, seams, flanges, and interior for damage or obstruction.
- Field-check both centerlines and support locations.
Tools and materials
Mitered rectangular elbow, approved TDC/TDF or S-and-drive components, gasket, corners, cleats, fasteners, sealant, clamps, level, laser, and fitting support.
Lay it out
- Mark inlet, outlet, airflow direction, and elbow plane.
- Confirm the fitting clears structure and service access.
- Locate support under the elbow body.
Set and support it
- Install the dedicated support before closing both joints.
- Hold the elbow square and prevent roll.
- Support both adjoining sections independently.
Make the connection
- 1
Set the elbow on its support and align the inlet.
- 2
Complete the first mechanical joint.
- 3
Recheck outlet centerline and fitting square.
- 4
Bring the downstream run into alignment without twisting the elbow.
- 5
Complete the second joint.
- 6
Seal required seams and joint corners.
- 7
Inspect the inside for loose metal or obstruction.
Check the install
- The no-vane application matches the approved design.
- The elbow is not twisted or racked.
- Both runs align cleanly.
- Seams and corners are sealed.
- No internal obstruction or loose metal remains.
Common mistakes
- Using a no-vane elbow where the design requires vanes.
- Forcing the second run into a twisted fitting.
- Supporting the elbow from one joint.
- Treating a low-cost fitting as interchangeable with a radius or vaned elbow.
Stop and ask
Stop if the velocity, pressure, noise, or project specification may require turning vanes or a different elbow type.