A return plenum wall buckles inward at AHU startup
Large flat plenum panels can buckle under negative pressure when they are not stiff enough. Stabilize the casing with approved stiffeners or tie-rod reinforcement before the metal fatigues or tears.
The return plenum at [unit/location] is buckling inward on startup. I checked the panel, seams, and AHU connection. Do you want stiffeners/tie-rods added per detail or should we hold for detailer direction?
Watch out
Do not treat a buckling return plenum as only a noise problem
the casing can fatigue, split seams, or damage the equipment connection.
Check
Shut down or hold startup if the plenum is buckling hard or making loud metal pops.
Check whether the panel is deforming, cracking, pulling seams, or stressing the AHU connection.
Confirm plenum size, material, stiffener detail, and negative-pressure application against the approved drawings/specs.
Bring the foreman options such as external structural stiffeners, internal tie-rods, panel replacement, or detailer review.
Retest only after the casing is reinforced and fasteners/seals are checked.
Steps
Shut down or hold startup if the plenum is buckling hard or making loud metal pops.
Check whether the panel is deforming, cracking, pulling seams, or stressing the AHU connection.
Confirm plenum size, material, stiffener detail, and negative-pressure application against the approved drawings/specs.
Bring the foreman options such as external structural stiffeners, internal tie-rods, panel replacement, or detailer review.
Retest only after the casing is reinforced and fasteners/seals are checked.
Say this to your foreman
The return plenum at [unit/location] is buckling inward on startup. I checked the panel, seams, and AHU connection. Do you want stiffeners/tie-rods added per detail or should we hold for detailer direction?