TinnerFlow™3rd YearYELLOW · Check FirstFlat-Oval / Thermal Expansion
Thermal movement needs somewhere to go. Replace the damaged section and add the approved expansion/flexible detail if the run is growing under heat.
Warm discharge air can make long metal runs move. If the run is locked solid, wide flat-oval seams may take the stress and split.
Check temperature, run length, fixed points, supports, and whether an expansion coupling/flex connector is required. Replace split seam sections that cannot be restored mechanically.
Do not smear sealant over a split structural seam and keep the run locked solid.
Thermal seam failure can keep reopening, leak air, and damage supports if movement is not handled.
Final direction belongs to the foreman, approved drawings/specs, manufacturer instructions, pressure/material schedule, employer policy, and AHJ/code requirements.