When Does An Area Serve a Dwelling Unit?

4/20/2026

NFPA 13R, Section 6.6.5.1 (2019 Edition) requires sprinklers to be installed to protect balconies, decks, etc, that serve dwelling units.

What constitutes the definition of "serving dwelling units?"

If we have a landing over a stair in an exterior corridor, would that landing over the stair "serve a dwelling unit?"

This is a situation that the inspector is now bringing up at the end of the project and is requiring protection, even though the plans were approved, stating that this area was not to be protected per sections 6.6.5 and 6.6.5.1.

Please see the attached picture and let me know your thoughts.

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

6 Comments

Brett

4/20/2026 07:13:52 am

In my opinion 6.6.5.1 does not apply here. That section is in 13R because of IBC (2021) section 903.3.1.2.1 which says "balconies, decks, and ground floor patios of dwelling units and sleeping units". It doesn't say anything about "serving" dwelling units.

I would also argue that what the picture shows is not a balcony, deck, or patio.

Sprinkler coverage may be required in that location if the corridor shown is an open-ended corridor. See the 2021 IBC sections 903.3.1.2.2 and 1027.6.

Todd E Wyatt

4/20/2026 08:28:45 am

I agree with Brett ... start with the scoping Code (e.g. IBC-2024) to determine WHERE an automatic sprinkler system (ASPS) is required (see IBC 903.2 Where Required in REFERENCES below), then determine WHICH ASPS system is permitted (see 903.3.1.2 NFPA 13R Sprinkler Systems), and then determine HOW the ASAP is to be designed, installed, and inspected per the referenced Standards (e.g. NFPA 13R - 2022 per IBC-2024).

Todd E Wyatt

4/20/2026 08:29:36 am

REFERENCES
IBC-2024
Chapter 9 Fire Protection and Life Safety Systems
Section 903 Automatic Sprinkler Systems

903.2 Where Required
Approved automatic sprinkler systems in new buildings and structures shall be provided in the locations described in Sections 903.2.1 through 903.2.12.
903.2.1 Group A
903.2.2 Group B
903.2.3 Group E
903.2.4 Group F-1
903.2.5 Group H
903.2.6 Group I
903.2.7 Group M
903.2.8 Group R
An automatic sprinkler system installed in accordance with Section 903.3 shall be provided throughout all buildings with a Group R fire area.
903.2.8.1 Group R-3
903.2.8.2 Group R-4, Condition 1
903.2.8.3 Care Facilities
903.2.9 Group S-1
903.2.10 Group S-2 Parking Garages
903.2.11 Specific Building Areas and Hazards
903.2.12 During Construction

903.3 Installation Requirements
Automatic sprinkler systems shall be designed and installed in accordance with Sections 903.3.1 through 903.3.8.
903.3.1 Standards
903.3.1.1 NFPA 13 Sprinkler Systems
Where the provisions of this code require that a building or portion thereof be equipped throughout with an automatic sprinkler system in accordance with this section, sprinklers shall be installed throughout in accordance with NFPA 13 except as provided in Sections 903.3.1.1.1 through 903.3.1.1.3.
903.3.1.1.1 Exempt Locations
Automatic sprinklers shall not be required in the following rooms or areas where such rooms or areas are protected with an approved automatic fire detection system in accordance with Section 907.2 that will respond to visible or invisible particles of combustion. Sprinklers shall not be omitted from a room merely because it is damp, of fire-resistance-rated construction or contains electrical equipment.
1. A room or space where sprinklers constitute a serious life or fire hazard because of the nature of the contents, where approved by the fire code official.
2. Generator and transformer rooms separated from the remainder of the building by walls and floor/ceiling or roof/ceiling assemblies having a fire-resistance rating of not less than 2 hours.
3. Rooms or areas that are of noncombustible construction with wholly noncombustible contents.
4. Fire service access elevator machine rooms and machinery spaces.
5. Machine rooms, machinery spaces, control rooms and control spaces associated with occupant evacuation elevators designed in accordance with Section 3008.
903.3.1.1.2 Bathrooms
903.3.1.1.3 Lithium-Ion or Lithium Metal Batteries

903.3.1.2 NFPA 13R Sprinkler Systems
Automatic sprinkler systems in Group R occupancies shall be permitted to be installed throughout in accordance with NFPA 13R where the Group R occupancy meets all of the following conditions:
1. Four stories or fewer above grade plane.
2. For other than Group R-2 occupancies, the floor level of the highest story is 30 feet (9144 mm) or less above the lowest level of fire department vehicle access.
For Group R-2 occupancies, the roof assembly is less than 45 feet (13 716 mm) above the lowest level of fire department vehicle access. The height of the roof assembly shall be determined by measuring the distance from the lowest required fire vehicle access road surface adjacent to the building to the eave of the highest pitched roof, the intersection of the highest roof to the exterior wall, or the top of the highest parapet, whichever yields the greatest distance.
3. The floor level of the lowest story is 30 feet (9144 mm) or less below the lowest level of fire department vehicle access.
The number of stories of Group R occupancies constructed in accordance with Sections 510.2 and 510.4 shall be measured from grade plane.

903.3.1.2.1 Balconies and Decks
Sprinkler protection shall be provided for exterior balconies, decks and ground floor patios of dwelling units and sleeping units where either of the following conditions exists:
1. The building is of Type V construction, provided that there is a roof or deck above.
2. Exterior balconies, decks and ground floor patios of dwelling units and sleeping units are constructed in accordance with Section 705.2.3.1, Exception 3.
Sidewall sprinklers that are used to protect such areas shall be permitted to be located such that their deflectors are within 1 inch (25 mm) to 6 inches (152 mm) below the structural members and a maximum distance of 14 inches (356 mm) below the deck of the exterior balconies and decks that are constructed of open wood joist construction.

903.3.1.2.2 Corridors and Balconies in the Means of Egress
903.3.1.2.3 Attics

903.3.2 Quick-Response and Residential Sprinklers
903.3.3 Obstructed Locations
903.3.4 Actuation
903.3.5 Water Supplies
903.3.6 Hose Threads
903.3.7 Fire Department Connections
903.3.8 Limited Area Sprinkler Systems

F Marvitz

4/20/2026 09:58:29 am

My comment is to remind designers, and contractors that just because a set of plans is approved, does not mean the design is free from missed items or code compliance.

The responsibility is ultimately the applicants. Under the 2024 IFC, (also in past editions) two sections address this specifically.

1. 106.2.3 It shall be the responsibility of the applicant to ensure that the construction documents include all of the fire protection requirements and the shop drawings are complete and in compliance with the applicable code and standards.

2. 106.2.4 Construction documents approved by the fire code official are approved with the intent that such construction documents comply in all respects with this code. Review and approval by the fire code official shall not relieve the applicant of the responsibility of compliance with this code.

Just a reminder to not hang your hat on an plan approval. All responsibility to get it right ultimately lies with the applicant/designer.

Todd E Wyatt

4/21/2026 08:43:07 am

Agreed!

AHJ's Plan Review response letters typically (always) include CYA statements that transfer the liability of Code compliance back to the Owner and/or the Design Professional and away from their Plan Review department ... an example :

The submittal described above has been reviewed for conformance with applicable Wisconsin Administrative Codes and Wisconsin Statutes. The submittal has been CONDITIONALLY APPROVED.

The owner, as defined in chapter 101.01(10), Wisconsin
Statutes, is responsible for compliance with all code requirements. Only those object types listed above have been approved; other submittals such as plumbing and those listed above under REQUIRED SUBMITTAL(S), may also be required.

Mark Harris

4/21/2026 09:30:59 am

Agree with comments that need to look at this if it is an egress that needs protection. My understanding is history of requiring sprinklers on decks, patios accessed from dwelling unit was from hazard people created from what they stored or did on the patio or deck.

Hopefully AHJ allowed a certificate of occupancy while this is being resolved.

When Does An Area Serve a Dwelling Unit?

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