/ Field knowledge · IMC 607.5.1–607.5.2
A fire damper alone is not enough at a horizontal exit.
Fire walls, fire barriers, and horizontal exits are not interchangeable. A duct crossing a rated wall may need a fire damper, a smoke damper, both, or a named exception. A fire damper alone does not provide smoke control at a horizontal exit. Applying a fire-barrier exception to a fire wall is a code error — not a conservative choice.
Educational 2024 International Mechanical Code (IMC) 607.5–607.5.2.1 from Daily Code Talk. Confirm the adopted edition. Distinct from fire partitions (607.5.3) and floors (607.6). This is not a damper schedule.
- 607.5: FD, SD, combination FD/SD, CRD, and corridor dampers at the locations in 607.5.1 through 607.5.7. Where an assembly requires both fire and smoke protection, provide a combination FD/SD or both a FD and SD.
- 607.5.1 fire walls: ducts and transfer openings permitted through fire walls by IBC 706.11 protected with listed fire dampers. Fire walls are the most restrictive vertical assembly — penetrations are limited.
- 607.5.1.1 / 607.5.2.1 horizontal exits: where a fire wall or fire barrier serves as a horizontal exit, each duct or transfer opening also needs a listed smoke damper. The fire damper alone is not sufficient.
- 607.5.2 fire barriers: listed FD generally required. Ducts and transfer openings cannot penetrate interior exit stairways, ramps, or exit passageways except where permitted by IBC 1023.5 and 1024.6. Pair with 601.3.
- Fully ducted exception is not a blanket pass: 1-hour-or-less fire barriers, non-Group H, sprinklered building, and continuous minimum 26 gage sheet steel from equipment to terminals. All four at once. It is a fire-barrier path — do not apply it to a fire wall.
On the set: assembly type labeled to match the architectural life-safety plan, damper type with listing, exception and all conditions on M-001, FD and SD at horizontal exits.
Fire-barrier exception used on a fire wall
Or FD only at a horizontal exit. If the architectural drawings do not clearly label the assembly type, the damper callout is incomplete. Request written coordination before submittal.
Source: Daily Code Talk — IMC 607.5.1–607.5.2 · partitions: 607.5.3 · corridors: 607.5.4 · 607: name the assembly.
What to send
Life-safety plan with fire walls, fire barriers, and horizontal exits marked, and the damper callout at those openings.
If a fire-barrier exception was used on a fire wall
Send the rated plan. Masterbuild will say whether 607.5.1 still has no IBC 706.11 path — or a horizontal exit still has FD only.
Send Project Background+1 (786) 398-6940 · osmany.portal@masterbuildconsulting.com
Masterbuild provides engineering services under a written scope. Nothing on this page is project-specific engineering advice, a code interpretation for your project, or a representation about permit approval. Confirm the adopted edition. Fire wall vs fire barrier, horizontal-exit smoke dampers, and the four-condition fully ducted exception are 2024 IMC 607.5 education from Daily Code Talk — not a damper schedule. This page is not legal advice.