Join small square duct

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 the branch route, elevation, and final boot or terminal location before closing the joint.
2. Place the joint where it can be reached with normal hand tools instead of forcing a hammer into a tight ceiling corner.
3. Check that the next hanger is close enough to prevent the small branch from sagging.

Set and support it

1. Support the installed piece and hold the loose branch level with a lift, stand, or second worker.
2. Keep the branch centered on the route so the joint is not twisted to reach the next fitting.
3. Do not let a diffuser boot, flex connection, or tap carry the branch weight.

Make the connection

1. 1

   Pre-fit the S-cleats to the top and bottom hems.

2. 2

   Bring the small sections together by hand and verify all four corners are aligned.

3. 3

   Start the side drives square to the lock. Small duct edges tear quickly if the drive is started crooked.

4. 4

   Seat each drive fully using controlled blows.

5. 5

   Fold or secure the drive ends, remove sharp edges, and apply the required seal.

6. 6

   Install or verify the next branch support before releasing the section.