Assemble an S-and-drive offset

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 required rise, offset, travel, and plane from approved field dimensions.
2. Mark each fitting piece so the offset is assembled in the intended direction.
3. Verify the assembled offset will clear the obstruction and still reach the downstream centerline.

Set and support it

1. Preassemble on the floor when size and access allow.
2. Support each elbow or transition portion so the assembly does not fold at a joint.
3. Use a level, square, or laser to keep both changes in the same plane.

Make the connection

1. 1

   Dry-fit the two offset pieces and verify overall rise and travel.

2. 2

   Install S-cleats and drives at the internal joint while the assembly is square.

3. 3

   Lift the assembly with enough support points to prevent racking.

4. 4

   Connect the upstream end, then recheck the downstream centerline.

5. 5

   Connect the downstream end without stretching or compressing the offset.

6. 6

   Finish, seal, and install supports at both ends and at heavy fitting bodies as required.