IMC 607.5.1
What it means on the job
All duct penetrations through fire-rated walls and floors must have fire dampers rated to match the wall rating. This is a life-safety code requirement.
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Related IMC sections
IMC 603.6
Flexible air duct must be supported at intervals not exceeding the manufacturer’s spacing (typically 5 ft) with sag no more than 1/2 inch per foot of spacing. Excess sag chokes airflow and traps condensate.
IMC 605 (Air Filters)
Return air grille has no filter rack. All return air must be filtered before entering the air handler per mechanical code.
IMC 607 / NFPA 90A
This is a textbook-correct installation as taught in SMACNA apprenticeship programs. IMC 607 requires fire dampers at duct penetrations through fire-rated walls, and NFPA 90A requires smoke dampers at smoke barrier penetrations. Using a combination fire/smoke damper satisfies both requirements. The key elements are all present: UL listed assembly (matches the wall rating), proper sleeve (maintains the wall's fire rating), fire caulk (seals the annular space), and interlock to the fire alarm (ensures the smoke damper closes when smoke is detected). Union halls emphasize this installation because fire/smoke damper work is a high-liability specialty that commands premium wages.
CraftIQ explanations are original educational commentary written in trade language and verified against the cited standards. Always confirm requirements against the code edition adopted by your jurisdiction — this is training material, not a substitute for the code book or your AHJ.