Flat-oval acoustic double-wall

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 double-wall construction, inner liner or perforated core, insulation thickness, outer shell joint, inner slip connection, and acoustic/thermal requirements.

Lay it out

1. Confirm the inner and outer profiles, airflow direction, and required insertion depth.
2. Plan the joint so the inner liner or core can be inspected before the outer shell is closed.
3. Check support width for the larger outside dimension.

Set and support it

1. Use wide supports that carry the outer shell without crushing the insulated assembly.
2. Handle with soft slings and keep water, dirt, and metal debris out of the open double-wall ends.
3. Support both sections so the inner connection is not forced by the outer shell.

Make the connection

1. 1

   Inspect the inner liner, insulation, and outer shell at both ends.

2. 2

   Align and seat the inner connection first without tearing or folding the liner.

3. 3

   Restore or place the specified insulation or acoustic material at the joint.

4. 4

   Bring the outer shells together while keeping the inner connection centered.

5. 5

   Complete the approved outer joint and fastener pattern.

6. 6

   Seal the required inner and outer locations.

7. 7

   Inspect the inside with a light and remove all loose debris before closing access.