No Sprinkler in Bathroom of Wood Construction?

8/4/2025

Per the 2019 edition NFPA 13, Section 9.2.4.1.1, you can omit fire sprinklers within a small bathroom not exceeding 55 square feet that have walls and ceilings of noncombustible or limited-combustible materials with a 15-minute thermal barrier rating.

Now, if you read further down in section 9.2.4.2 relating to closets and pantries, it states, "surfaced with noncombustible or limited-combustible materials.

So in section 9.2.4.1.1, are we talking about the sheetrock walls and ceiling or the construction of the walls and ceiling?

If the bathroom walls and ceiling are constructed of wood but are covered with sheetrock, are the sprinklers still allowed to be omitted?

I think it's confusing when they specify "surfaced with" when they are talking about the closets and pantries. Thanks in advance.

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

6 Comments

Pete H

8/4/2025 07:44:02 am

Let's check it out.

From NFPA 13 (2019 Ed.)

9.2. Allowable Sprinkler Omission Locations
9.2.4. Dwelling Units
9.2.4.1 Bathrooms
9.2.4.1.1* Unless sprinklers are required by 9.2.4.1.2 or 9.2.4.1.3, sprinklers shall not be required in bathrooms that are located within dwelling units, that do not exceed 55 sq. ft. in area, and have walls and ceilings of noncombustible or limited combustible materials with a 15 minute thermal barrier rating, including the walls and ceilings behind any shower enclosure or tub.
9.2.4.1.2 Sprinklers shall be required in bathrooms of limited care facilities and nursing homes, as defined in NFPA 101.
9.2.4.1.3 Sprinklers shall be required in bathrooms opening directly onto public corridors or exitways.
9.2.4.2* Closets and Pantries. Sprinkelrs are not required in clothes closets, linen closets, and pantries within dwelling units in hotels and motels where the area of the space does not exceed 24 sq. ft and the walls and ceilings are surfaced with noncombustible or limited-combustible materials.

A.9.2.4.1.1 A door is not required to omit sprinklers as long as the bathroom complies with the definition for compartment.
A9.2.4.2 Portable wardrobe units, such as those typically used in nursing homes and mounted to the wall, do not require sprinklers to be installed in them. Although the units are attached to the finished structure, this standard views those units as pieces of furniture rather than as a apart of the structure, sprinklers are not required.

--

Okay, so first thing: 9.2.4.2 does not apply to bathrooms. It only applies to closets and pantries in hotels and motels of less than 24 square feet.

So yeah, in your example where

9.2.4.2 is for closets and pantries. It does not apply to bathrooms.

So if the sheet rock provides a 15 minute thermal barrier and completely encapsulates the room (covers the walls and ceilings to a point that there is a 15 minute thermal barrier between the room and any combustible structural elements) and the room is a dwelling unit less than 55 square feet, you may omit. Otherwise, due to the wood structural construction (or the square footage or the fact it's not in a dwelling units), you need sprinklers.

Brett

8/4/2025 08:10:14 am

9.2.4.1.1 is not referring to the actual construction materials of the wood structure, but is referring to the surface material (drywall) that's providing the 15 minute thermal barrier.

The reason those two sections are written differently is because of bathtubs. You can build a bathroom that is surfaced with noncombustible or limited-combustible materials and not carry the drywall all the way around the backsides of the tub. This should always be coordinated prior to construction if you're planning on omitting sprinklers in bathrooms.

A closet or pantry won't have that issue, so it just says "surfaced".

Anthony

8/4/2025 08:46:34 am

Great call on the surround backing here! Many instillations call for a surround to be glued to OSB and then she rock to the lip of the top of the surround. This would NOT have a fire barrier as discussed. Check your arch details prior to omission.

Todd E Wyatt

8/4/2025 08:22:05 am

SUMMARY
IBC-2024
Chapter 9 Fire Protection and Life Safety Systems
Section 903 Automatic Sprinkler Systems
903.3.1 Standards
903.3.1.1 NFPA 13 Sprinkler Systems
903.3.1.1.2 BATHROOMS
In Group R occupancies sprinklers shall NOT BE REQUIRED in bathrooms that do NOT EXCEED 55 SQUARE FEET (5 m2) in area and are LOCATED WITHIN INDIVIDUAL DWELLING UNITS OR SLEEPING UNITS, provided that WALLS AND CEILINGS, including the walls and ceilings behind a shower enclosure or tub, are of NONCOMBUSTIBLE OR LIMITED-COMBUSTIBLE MATERIALS WITH A 15-MINUTE THERMAL BARRIER RATING.

EXPLANATION
The scoping Code (e.g. IBC-2024) determines WHERE an automatic sprinkler system (ASPS) is required ...

IBC-2024
Chapter 9 Fire Protection and Life Safety Systems
Section 903 Automatic Sprinkler Systems
903.2 the
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.

... based on Occupancy Classifications (OC) ...

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
903.2.9 Group S-1
903.2.10 Group S-2 Parking Garages

... and based on Specific Building Areas and Hazards ...

903.2.11 Specific Building Areas and Hazards
903.2.11.1 Stories Without Openings
903.2.11.2 Rubbish and Linen Chutes
903.2.11.3 Buildings 55 Feet or More in Height
903.2.11.4 Ducts Conveying Hazardous Exhausts
903.2.11.5 Commercial Cooking Operations
903.2.11.6 Other Required Fire Protection Systems

... and lastly during construction :

903.2.12 During Construction

The scoping Code references the ASPS standards (e.g. NFPA 13) that includes HOW the ASPS is to be designed & installed :

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
Automatic sprinkler systems shall be designed and installed in accordance with Section 903.3.1.1 unless otherwise permitted by Sections 903.3.1.2 and 903.3.1.3 and other chapters of this code, as applicable.
903.3.1.1 NFPA 13 Sprinkler Systems
903.3.1.2 NFPA 13R Sprinkler Systems
903.3.1.3 NFPA 13D Sprinkler Systems

Lastly, the scoping Code includes ASPS exemptions per the following, including BATHROOMS :

[F] 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
In Group R occupancies sprinklers shall not be required in bathrooms that do not exceed 55 square feet (5 m2) in area and are located within individual dwelling units or sleeping units, provided that walls and ceilings, including the walls and ceilings behind a shower enclosure or tub, are of noncombustible or limited-combustible materials with a 15-minute thermal barrier rating.

903.3.1.1.3 Lithium-Ion or Lithium Metal Batteries

Jack G

8/5/2025 11:06:37 pm

Not sure the question was answered above.
Bathrooms with rated specified construction and ceiling, can be omitted if there are combustibles above the rated ceiling when the ceiling is attached or within 6 inches of the wood/ combustible joists.

Muhammad Munir Malik

8/6/2025 10:50:36 pm

very nice Information thanks to all,,,,
one my question in record room important documents safe can we install the sprinklers system or other fire suppression system please guide me thanks

No Sprinkler in Bathroom of Wood Construction?

Leave a Reply.

ALL-ACCESS

SUBSCRIBE

COMMUNITY

YOUR POST

PE EXAM

FILTERS

ARCHIVES

PE PREP SERIES