Join duct before insulation

Before you start

• Confirm the duct size, end construction, pressure class, seal class, and joint shown on the approved shop drawing.
• Inspect both duct ends for crushed corners, torn locks, bowed panels, loose reinforcement, or shop damage before lifting them into place.
• Make sure the supports are already installed or the sections are otherwise held so the joint is not carrying the weight of the run.
• Stage the correct S-cleats, drive cleats, sealant, hand tools, clamps, and access equipment before starting the joint.

Lay it out

1. Confirm insulation thickness, vapor-barrier requirements, support shields, and clearance to adjacent work.
2. Place the metal joint where it can be inspected before insulation is installed.
3. Ensure the support is sized for the insulated outside dimension.

Set and support it

1. Complete the permanent metal supports first.
2. Keep insulation materials away from the open joint until mechanical inspection is finished.
3. Provide shields or saddles so the future insulation will not be crushed.

Make the connection

1. 1

   Assemble the S-and-drive joint mechanically.

2. 2

   Inspect the full perimeter and correct any loose drive, damaged lock, or corner gap.

3. 3

   Apply the required duct seal and allow the specified condition or cure before covering.

4. 4

   Install insulation continuously across the joint.

5. 5

   Seal the outer jacket or vapor barrier without punctures or open seams.

6. 6

   Check that support hardware does not create a crushed or bare-metal path.