Round duct joints need the required fasteners placed evenly around the joint. Too few fasteners means the joint can rotate, open, or leak, especially when the pipe is large or under load.
Ask when finish/exposed spiral, connection type, seal method, support, or fitting orientation is unclear.
Watch out
Do not seal a round joint that does not have the required mechanical fastening. Sealant does not replace fasteners.
Check
Check the approved detail, project spec, manufacturer direction, or shop standard for the required fastening pattern on this duct size and system.
Look at where the existing fasteners are placed
they need to catch both layers of metal, not just the outer pipe.
If fasteners are missing, add the required fasteners before sealing when the detail allows it.
Check that existing fasteners are snug and not stripped out in loose holes.
Seal only after the joint is mechanically fastened correctly.
Steps
Check the approved detail, project spec, manufacturer direction, or shop standard for the required fastening pattern on this duct size and system.
Look at where the existing fasteners are placed
they need to catch both layers of metal, not just the outer pipe.
If fasteners are missing, add the required fasteners before sealing when the detail allows it.
Check that existing fasteners are snug and not stripped out in loose holes.
Seal only after the joint is mechanically fastened correctly.
Say this to your foreman
This round joint has [number] fasteners installed. Is that enough for this duct size/system per the job standard, or do I need to add more before sealing?