Taps & Takeoffs · Taps & Takeoffs
Tap into lined duct
Internally lined rectangular main
ConnectionFlanged collar with liner treatment
SupportBranch support
Before you start
- Confirm liner type, condition, repair method, tap location, and branch route.
- Inspect the liner for moisture, delamination, or loose edges.
- Plan how the exposed liner edge will be sealed.
- Control liner debris and the cookie.
Tools and materials
Tap, approved cutting tools, liner knife, clamps, fasteners, compatible sealant, liner edge treatment, branch support, PPE, and cleaning tools.
Lay it out
- Mark the opening through metal and liner.
- Keep clear of liner seams and reinforcement.
- Plan edge treatment around the full opening.
Set and support it
- Support the main as needed.
- Clamp the tap without tearing the liner.
- Prepare independent branch support.
Make the connection
- 1
Cut the metal and liner cleanly.
- 2
Remove the cookie and liner debris.
- 3
Seal exposed liner edges.
- 4
Set and square the tap.
- 5
Fasten without pulling or tearing liner.
- 6
Seal the air barrier.
- 7
Connect and support the branch.
Check the install
- No loose liner remains.
- Exposed edges are sealed.
- The opening is clear.
- The tap sits flat and the branch is supported.
Common mistakes
- Leaving liner debris inside.
- Fastening through loose liner.
- Using incompatible sealant.
- Cutting wet or delaminated liner.
Stop and ask
Stop if the liner is wet, delaminated, loose, or cannot be repaired with the approved method.