Installing flange joint with unsupported duct weight hanging on it

Take the duct weight off the flange joint before assembly. Both sections need temporary or permanent support so the gasket and flange faces meet level, square, and evenly.

Stop if

• Ask when connector type, gasket, cleat/bolt schedule, pressure class, or manufacturer detail is unclear.

Watch out

• Do not let unsupported duct weight hang on the flange or use bolts, corners, drift pins, or clamps to pull the run into place.

Check

• Add or adjust support so neither duct section hangs from the joint.
• Put gasket on one flange face only and bring the joining duct in at matching elevation.
• Install corners on the joining duct and align close holes with drift pins if needed.
• Hold aligned flange faces with protected C-clamps/locking clamps while hardware starts.
• Recheck level, square, and support before final tightening.

Steps

• Add or adjust support so neither duct section hangs from the joint.
• Put gasket on one flange face only and bring the joining duct in at matching elevation.
• Install corners on the joining duct and align close holes with drift pins if needed.
• Hold aligned flange faces with protected C-clamps/locking clamps while hardware starts.
• Recheck level, square, and support before final tightening.

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