Dryer Duct Rated Assembly Membrane Penetrations

2024 International Building and Mechanical Code

The requirements of 2024 IBC Section 714 – Penetrations must be met.
Dryer ducts may be addressed per the guidance below with a detail signed and sealed by the engineer of record.

Code Reference

2024 IBC Building Code Section: 714 – Penetrations

Approved Methods for Dryer Duct Penetrations

1. Duct Wrap Method (Section A)
   The duct can be wrapped with a rated duct wrap from the point it enters the rated assembly to the point where it exits.
   • Must be listed and labeled for intended use
   • Rating must match the assembly (floor/ceiling, roof/ceiling, or wall)
   • Penetrations must be sealed to prevent smoke or flame passage
2. Tested Assembly Method
   If the assembly test report allows membrane penetrations by ducts, the dryer duct may pass through as specified.
   • Follow test report requirements
   • Dampers are NOT allowed
3. Engineering Judgment
   A letter from:
   • A Utah-registered engineer (passive fire protection expertise), OR
   • An IAS-approved testing agency
4. Relocate Membrane (Section B)
   Move the rated membrane so the duct is not within the assembly.
5. Chase/Soffit Method
   Enclose dryer duct in a chase/soffit enclosed in final wall finish that is completely outside the rated floor ceiling assembly and all dryer duct is within the same residential unit and where the fire chase terminates flush to the back of the exterior wall sheathing and the duct runs flush to the exterior of the wall sheathing to the outside and is terminated at least 3 feet away from any operable openings or air inlet.
6. IMC Compliance
   Dryer ducts must meet IMC Section 504 – Clothes Dryer Exhaust.

Details & Diagrams

Section A – Duct Wrap Detail

Includes:

• Fire-resistant-rated assembly
• Rated membrane
• Duct wrap at penetration
• Sealant at membrane interface

Section B – Membrane Relocation Detail

Includes:

• Continuous blocking
• Rated membrane above duct
• Unrated ceiling membrane below
• Duct fully outside rated assembly

Keywords

Horizontal assembly, fire-resistance-rated, fire resistant-rated assemblies