Section 717.1/Ducts and Air Transfer Openings in Fire-Rated Assemblies
IBC 717 covers fire damper and smoke damper requirements at duct penetrations through fire barriers, fire walls, fire partitions, smoke barriers, and shaft enclosures.
Section 717.2 requires fire dampers at duct penetrations through fire barriers, fire walls, and shaft enclosures with a fire- resistance rating. Fire dampers must have a fire resistance rating of at least 1.5 hours where the assembly has a fire- resistance rating of less than 3 hours, and 3 hours where the assembly has a 3-hour or greater rating. Section 717.3 requires smoke dampers at duct penetrations through smoke barriers and at air transfer openings in smoke barriers. Combination fire/smoke dampers are required where ducts penetrate assemblies that are both fire barriers and smoke barriers. Section 717.4 covers the installation requirements: dampers must be installed per the manufacturer's instructions, must be accessible for inspection and maintenance, and must be listed per UL 555 (fire dampers) or UL 555S (smoke dampers). Damper locations must be shown on both the mechanical drawings and the fire protection or architectural drawings for coordination.
Why this section exists
Ducts create passages through fire-rated and smoke-rated assemblies that can allow fire and smoke to spread between compartments. A fire damper closes when its fusible link melts (typically at 165 degrees F), blocking the duct opening and maintaining the fire- resistance rating of the assembly. A smoke damper closes automatically upon detection of smoke by the fire alarm system, blocking smoke migration before temperatures are high enough to melt a fusible link. Without dampers, the duct system becomes a pathway for fire and smoke to bypass rated barriers, defeating the compartmentation strategy. Missing fire and smoke dampers are among the most commonly cited deficiencies in penetration protection during plan review and field inspection.
What plan reviewers look for
Plan reviewers overlay the mechanical duct layout on the architectural floor plan to identify every duct penetration through a rated assembly. They verify a fire damper is shown at each penetration through a fire barrier, fire wall, or shaft enclosure. They verify smoke dampers at penetrations through smoke barriers. They check for combination fire/smoke dampers where assemblies carry both ratings. They verify the damper rating matches the assembly rating. They check that access panels are shown adjacent to each damper for inspection and reset. For NFPA 101 fire barriers, they confirm the same damper requirements are met.