Flat-oval duct on Gripple trapeze

Before you start

• Confirm the flat-oval size, major and minor axis orientation, material, pressure class, joint type, and support detail against the approved drawing.
• Inspect the duct for sidewall dents, flattened ends, twisted axes, damaged beads, split seams, and shipping damage before lifting it.
• Check that the mating pieces use the same oval profile. A round-looking end and a truly matched flat-oval end are not the same thing.
• Stage the correct fittings, joint hardware, approved fasteners, sealant or gasket system, supports, lifting equipment, and hand tools before starting.
• Confirm the cable-trapeze system, load rating, attachment method, cable angle, support spacing, and approved hardware are specifically allowed for the duct size and project.

Lay it out

1. Lay out support points from approved structure and keep them clear of joints and weak fitting bodies.
2. Set cable drops so the trapeze will remain level and centered under the broad duct face.
3. Check that cable angles and attachment locations match the approved support detail.

Set and support it

1. Install and proof-check the approved anchors and cable hardware before lifting duct.
2. Use a wide cross member or saddle that supports the flat face without pinching the sides.
3. Keep both cable legs balanced so the duct cannot roll.

Make the connection

1. 1

   Set the cable trapezes to approximate elevation before lifting the first section.

2. 2

   Land the flat-oval duct on the broad support surface.

3. 3

   Level the support from side to side and along the run.

4. 4

   Connect the adjoining duct while both pieces are supported.

5. 5

   Complete the mechanical joint and seal.

6. 6

   Fine-adjust the cable system evenly without twisting the duct.

7. 7

   Lock and inspect all cable hardware.