IBC 717.5.4

Fire dampers in fire partitions (IBC 717.5.4)

Fire partitions need fire dampers at ducts and air transfer openings, but several exceptions remove them, most often in sprinklered residential buildings.

Rated corridor walls are fire partitions too. Their extra exception for sprinklered buildings (717.5.4 Exception 1) and the corridor smoke damper rules are on the rated corridor page.

What counts as a fire partition (other than a corridor): Dwelling and sleeping unit separations, tenant separations in covered and open malls, elevator lobby separations and egress balcony separations. Since 2021 also some ambulatory care separations and vestibules.

Rules last reviewed October 12, 2026. How the rules are checked

Check your case in the tool (2024 IBC)Start the tool with the 2021 IBC · Start the tool with the 2018 IBC

When each damper is required

Every result the tool can give for a duct carrying heating, cooling or ventilation air, or an air transfer opening, through this assembly. Labels show where a result applies only to ducts, only to air transfer openings, or only in some editions.

Fire damper

Required
In Group H, none of the 717.5.4 exceptions apply, so ducts and air transfer openings through a fire partition need a listed fire damper.
IBC 717.5.4
Required
Ducts and air transfer openings through a fire partition need a listed fire damper, and none of the exceptions apply.
IBC 717.5.4
Not required
Tenant separation walls in mall buildings that need not extend to the deck above do not need fire dampers.
IBC 717.5.4 Exc. 2
Not requiredDucts only
The fire partition is rated 1 hour or less, the building is fully sprinklered, and the duct is a ducted steel HVAC system that is continuous from the equipment to the outlets.
IBC 717.5.4 Exc. 4
Not requiredDucts only
The duct is a small steel duct above the ceiling with the required steel sleeve detail.
IBC 717.5.4 Exc. 3

Also required

Flexible ducts and flexible air connectors may not pass through any fire-resistance-rated assembly, and flexible air connectors may not go through any wall, floor or ceiling at all. (ducts only) IBC 717.7
Where no damper is required, the duct penetration must still be firestopped so the wall keeps its rating (through-penetration or membrane-penetration protection). IBC 717.1.2, IBC 714.3 to 714.4.3

Common situations by edition

Common situations: the tool’s result in each edition
Situation	2024 IBC	2021 IBC	2018 IBC
Duct through a 1-hour dwelling unit separation, NFPA 13R sprinklers, continuous steel ductwork	No damper required	No damper required	No damper required
Duct through a 1-hour fire partition, building not sprinklered	Fire damper required	Fire damper required	Fire damper required
Small steel duct above the ceiling with the steel sleeve detail, building not sprinklered	No damper required	No damper required	No damper required
Air transfer opening through a 1-hour fire partition	Fire damper required	Fire damper required	Fire damper required
Duct through a mall tenant separation that is not required to reach the deck	No damper required	No damper required	No damper required
Duct through a fire partition next to a Group H area	Fire damper required	Fire damper required	Fire damper required

Select a result to open it in the tool with every answer filled in, including the conditions not listed here.

Exceptions and conditions the tool checks

These are the questions the tool asks, in order, with the explanation it gives. Section numbers are shown for each edition where they differ.

Is either side of this wall a Group H (high-hazard) area?

Group H covers buildings or areas that store or use hazardous materials above set quantities.

What is the required fire-resistance rating of the assembly?

Use the rating the code requires for this wall or floor, shown on the life safety plans.

Is this a tenant separation wall in a covered or open mall building that is not required to extend to the floor or roof deck above?

IBC 717.5.4 Exc. 2

Is the building fully protected by an automatic sprinkler system?

Yes, NFPA 13 throughout. IBC 903.3.1.1
Yes, NFPA 13R throughout. IBC 903.3.1.2, used in some residential buildings
No, partial or NFPA 13D only.

Does the HVAC duct system meet all of these?

The exception applies only when every item is met:

It is a ducted HVAC system carrying supply, return or exhaust air
The ducts are sheet steel, No. 26 gage or thicker
The steel ductwork is continuous from the air handling equipment to the air outlets and inlets

IBC 717.5.4 Exc. 4

Does the duct meet all of these?

This exception covers small steel ducts above a ceiling with a specific sleeve detail.

The exception applies only when every item is met:

The duct is made of materials approved by the mechanical code
The duct is no larger than 100 square inches
The duct is steel at least 0.0217 inch thick
The duct has no openings that connect the corridor with adjacent rooms or spaces
The duct is installed above a ceiling
The duct does not end at a wall register in the rated wall
A steel sleeve at least 12 inches long and 0.060 inch thick is centered in the opening
The sleeve is fastened on both sides of the wall and on all four sides of the sleeve with steel angles at least 1-1/2 by 1-1/2 by 0.060 inch, fastened to the sleeve and to the wall with No. 10 screws
Mineral wool batting fills the gap between the sleeve and the wall all the way around

IBC 717.5.4 Exc. 3

Code changes that affect this assembly

Static and dynamic fire dampers: Since 2021 the testing list no longer requires a dynamic label for fire dampers; a new section limits static-listed dampers to systems that shut down in a fire.
Damper access: Since 2021 dampers with fusible links or internal operators need a 12-inch access door or a removable duct section.

Questions

Does a duct through a dwelling unit separation need a fire damper?

Not where the wall is rated 1 hour or less, the building is fully sprinklered and the steel HVAC ductwork is continuous.

Fire damper: not requiredAll three editions

Fire damper: not required. The fire partition is rated 1 hour or less, the building is fully sprinklered, and the duct is a ducted steel HVAC system that is continuous from the equipment to the outlets. IBC 717.5.4 Exc. 4

Also: Where no damper is required, the duct penetration must still be firestopped so the wall keeps its rating (through-penetration or membrane-penetration protection). IBC 717.1.2, IBC 714.3 to 714.4.3

Full result in the tool: No damper required

Do air transfer openings in fire partitions need fire dampers?

Yes, unless the wall is a mall tenant separation that does not have to reach the deck above. The other exceptions cover ducts only.

Fire damper: requiredAll three editions

Fire damper: required. Ducts and air transfer openings through a fire partition need a listed fire damper, and none of the exceptions apply. IBC 717.5.4

Full result in the tool: Fire damper required

What is the small duct exception?

A small steel duct above the ceiling, with a steel sleeve fastened with steel angles, needs no fire damper. Every item in the checklist below must be met.

Fire damper: not requiredAll three editions

Fire damper: not required. The duct is a small steel duct above the ceiling with the required steel sleeve detail. IBC 717.5.4 Exc. 3