Does 25% Opening Limit Affect Door in Fire Wall?

9/3/2026

I'm working on a church youth building in a rural area and trying not to sprinkler due to cost. Occupant load of each wing is under 300. Wings to be separated with a double fire wall between the lobby and the east wing.

NFPA 221 (2018) Section 6.10.1 requires the length of openings not to exceed 25% of the fire wall length.

Does that apply in this scenario? See image below for openings within the fire wall.

(Note: There are other emergency exits for the west wing not shown in the image for use in case of fire.) Thank you for your help.

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7 Comments

Pete H

9/3/2026 06:18:14 am

I'd check NFPA 80 to see if there's some exemption, but everything I'm seeing includes fire doors within "opening protectives"

Glenn Berger

9/3/2026 08:25:06 am

I need to see a complete code analysis -

Are you trying to indicate a double fire wall from the right side Assembly Space?

Do you really have a fire wall or just a (double) fire barrier?

In most jurisdictions, you can not use roll up doors in a means of egress.

Todd Wyatt

9/3/2026 08:36:58 am

Review the scoping Code (e.g. IBC-2024 and IEBC-2024) to see if the Addition is exempt from automatic sprinkler protection (ASPS) protection :

IBC-2024
Chapter 9 Fire Protection and Life Safety Systems
Section 903 Automatic Sprinkler Systems
903.2 Where Required
903.2.1 Group A
An automatic sprinkler system shall be provided throughout buildings and portions thereof used as Group A occupancies as provided in this section.
903.2.1.3 Group A-3
An automatic sprinkler system shall be provided throughout stories containing Group A-3 occupancies and throughout all stories from the Group A-3 occupancy to and including the levels of exit discharge serving that occupancy where ONE of the following conditions exists:
1. The FIRE AREA exceeds 12,000 square feet (1115 m2).
2. The FIRE AREA has an occupant load of 300 or more.
3. The FIRE AREA is located on a floor other than a level of exit discharge serving such occupancies.

A Fire Barrier (FB) vs a Fire Wall (FW) is permitted to separate the same building (Existing + Addition) into Fire Areas (FA) that may exempt them from being protected by an ASPS.

IBC-2024
Chapter 7 Fire and Smoke Protection Features
707.3.10 Fire Areas
The FIRE BARRIERS, fire walls, horizontal assemblies or combinations thereof separating a single occupancy into different fire areas shall have a fire-resistance rating of not less than that indicated in Table 707.3.10. The FIRE BARRIERS, fire walls, horizontal assemblies or combinations thereof separating fire areas of mixed occupancies shall have a fire-resistance rating of not less than the highest value indicated in Table 707.3.10 for the occupancies under consideration.

If a Fire Wall was used for other reasons (Allowables ... Building Area, Building Height, Number of Stories), the maximum opening in a FW in a non-sprinklered building is 156 square feet and the aggregate width of openings at any floor level shall not exceed 25 percent of the length of the wall :

IBC-2024
Chapter 7 Fire and Smoke Protection Features
Section 706 Fire Walls
706.8 Openings
Each opening through a fire wall shall be protected in accordance with Section 716 and shall not exceed 156 square feet (15 m2). The aggregate width of openings at any floor level shall not exceed 25 percent of the length of the wall.
Exceptions:
1. Openings are not permitted in party walls constructed in accordance with Section 706.1.1.
2. Openings shall not be limited to 156 square feet (15 m2) where both buildings are equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1.

Louie Lincoln

9/3/2026 08:45:00 am

I don't see why anyone would not want to utilize sprinklers. They work 24hours a day seven days a week. You don't get that with any other protection. I would use sprinklers first then look for any other protection.

Conrad

9/3/2026 01:27:15 pm

A few points to consider:

To count as separate buildings, the east wing must have an independent exit leading directly outside.

A 1-hour barrier is not enough. Separating buildings requires a structurally independent fire wall (typically 2 to 4 hours).

The 299 figure is a threshold workaround and will draw the plan examiner's scrutiny.

Jack G

9/3/2026 04:05:41 pm

I d like to see a code analysis and the entire 2 wings with fire walls windows and exits,,.....but how i see this per 1006.2.1,2.2thru 2.6 :
For 300 occupancy 2 exits are required, exit door 60 inches ( non sprinklers, 45 inches sprinklered. The wings exit thru the lobby, but there is only 1 exit door.
Now if you look at the 2 wings emptying into the lobby ,the requirement is 3 exits for 501 to 1000 occupants.
Need at least 2 exis more on each wing plus the common lobby one for a total of 3 exits.

Donnie Brewer

9/3/2026 05:16:20 pm

Must have a minimum number of 3 approved exits. The occupant load exceeds 300, so sprinklers are required. Have you done the cost analysis to determine the difference ? If you build non separated use sprinkled throughout theres is no need to separate the building using expensive fire rated assemblies, doors, dampers, etc. that are often not maintained properly.

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Does 25% Opening Limit Affect Door in Fire Wall?

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