Depressurize, mark the failed seam, and identify whether the duct/seam type matches the system pressure class and approved materials. Do not smear sealant over a popped structural seam and call it fixed.
Do not hide a popped seam with mastic, tape, or extra screws if the seam itself is not structurally right for the system.
Check
Stop/depressurize the test setup before handling the failed section.
Mark the exact seam, joint, fitting, or connector that failed.
Check duct type, gauge, seam style, connector type, pressure class, and whether the section was approved for that system.
Inspect for unsupported duct, damaged pipe, bad connector alignment, missing reinforcement, or overpressurized test condition.
Repair/replace per approved detail and retest only after the structural issue is corrected.
Steps
Stop/depressurize the test setup before handling the failed section.
Mark the exact seam, joint, fitting, or connector that failed.
Check duct type, gauge, seam style, connector type, pressure class, and whether the section was approved for that system.
Inspect for unsupported duct, damaged pipe, bad connector alignment, missing reinforcement, or overpressurized test condition.
Repair/replace per approved detail and retest only after the structural issue is corrected.
Say this to your foreman
The seam at [location] opened during the pressure/leak test. I depressurized, marked it, and checked the duct/seam type. Do you want this section replaced, reinforced, or sent back to the shop/detailer before retest?