TinnerFlow™3rd YearRated Wall PenetrationsYELLOW · Check First
A fire damper sleeve cannot be forced into a pinched opening. The sleeve/frame must sit without binding so the damper can operate and the rated assembly can be finished correctly.
If a core hole is oval, jagged, or tight, forcing the fire damper sleeve can distort the sleeve and bind the damper frame or blade track.
Stop before forcing it in. Mark the tight spots, verify the required opening/annular space against the damper installation instructions and rated assembly detail, then have the opening corrected before the sleeve is set and firestopped.
Use this as training guidance. The foreman, approved drawings, project specs, manufacturer installation instructions, employer safety policy, and AHJ/code requirements always control the final answer.