How to Treat Storage Room in 13R Apartment?

11/2/2023

We have an NFPA 13R (2019), 4-story apartment. It's Group R-2, Class V-A construction, with open interior breezeways hallways in "garden style". Combined, all floor levels are ~60,000 sqft (~15,000 sqft per floor).

The design includes one 320 sqft storage room and about four 55 sqft storage closets in the interior breezeway per floor that tenants can rent if they choose.

All storage rooms and closets have gypsum ceilings.

From what I can tell, NFPA 13R-2019 doesn't really address storage like this, so I'd assume to revert back to NFPA 13 in order to protect? Is that a correct approach?

Due to the combustible construction - would that trigger coverage above and below ceilings in these spaces?

And then - am I permitted to tie into an NFPA 13R system, or would this even need a separate riser?

We could have two scenarios - one with rooms 2-hour fire resistance rated from the R-2, and another where it's incidental and not separated.

Thanks in advance for your input.

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8 Comments

Pete H

11/2/2023 07:18:12 am

Check NFPA 13R (2022 edition referenced)

Sections 7.2.3.1:

For compartments 500 sq. ft. or less that meet all of the following conditions and are protected with quick response sprinklers, the design area shall be permitted to be limited to the number of sprinklers in the compartment but not shall not exceed four sprinklers:

1) The area is protected with 30 minute-rated construction,
2) The sprinklers are spaced at 225 sq ft max for light hazard, 130 sq ft max for OH, or in accordance with their listing
3) Openings have a lintel depth at least 8 in. in depth
4) The total area of openings, excluding any overhead doors that open to the exterior, does not exceed 50 sq. ft.
5) Discharge Densities are in accordance with NFPA 13

[Due to #5, you may need to throw on an additional calc to justify the density]

Also worth consideration:

7.2.4: Where residential sprinklrs are used outside the dwelling unit as allowed by 6.2.2.2, the discharge criteria shall be in accordance with Section 7,.1, except as modified by 7.2.4.1,
7.2.4.1 Residential sprinklers shall be permitted to be used in ordinary hazard areas that meet the following conditions:

1) The area is compartmented into 5000 square feet or less by 30 minute fire rated construction
2) the sprinklers are spaced at 130 sq. ft. per sprinkler
3) Openings have a lintel depth at least 8 in. in depth
4) The total area of openings, excluding any overhead doors that open to the exterior, does not exceed 50 sq. ft. per compartment
5) Discharge Densities are in accordance with NFPA 13 for ordinary hazard.

---

Additionally consider that garages, which are also ordinary hazard, are listed to also have protection in accordance with Section 7.2 if they are accessible by people from more than 1 dwelling unit.

--

I believe you're still in NFPA 13R, so the above and below in combustible construction is still not required as per Section 6.6.6.

But obviously, check the references yourself and make your own judgments on whether you agree or not.

Todd Wyatt

11/2/2023 08:58:43 am

SUMMARY
The limited areas of the storage on each story constitutes an “Accessory Occupancy”. These storage areas can be assigned to the primary Occupancy Classification (OC) of Group R-2. They are permitted to be protected by the same automatic sprinkler system (ASPS) that protects the Group R-2 spaces.

EXPLANATION
The scoping Code (e.g. IBC-2021) determines WHERE an automatic sprinkler system (ASPS) is required to be provide based on either the Occupancy Classification(s) (OC) (Sections 903.2.1 through 903.2.10) and/or "Specific Building Areas and Hazards" (903.2.11).

A Group R-2 Residential OC is required to be “provided throughout all buildings with a Group R fire area” with an ASPS per 903.2.8 Group R.
The type of ASPS (NFPA 13, NFPA 13R, & NFPA 13D) for a Group R is determined by 903.3.1.2 based on the floor level of the highest/lowest story(s) and the number of stories. If it meets all of the conditions, then NFPA 13R is permitted to be installed versus NFPA 13.

The areas of the storage spaces on each story … 320 sf + 4(55) = 540 sf/story … and the area of each story … 15000 sf … constitutes an Accessory Occupancy since the storage areas are <10% of each story (540/15000 = 3.6% < 10%). For this reason, the building is not required to be classified as both Group R-2 and Group S Storage; just Group R-2 (per 311.1.1 Accessory Storage Spaces). No separation is required between accessory occupancies (storage) and the main occupancy (residential).

If the storage areas were >10% (>1500 sf) of each story’s area (15000 sf), then the storage areas would be required to be classified as Group S Storage and would need to meet the ASPS per Section 903 Automatic Sprinkler Systems. Depending on the hazardous nature of the stored items, it would be classified as Group S-1 Moderate-hazard Storage or Group S-2 Low-hazard Storage. Each have different thresholds for when an ASPS is required. If an ASPS is required, it is required to be NFPA 13; NFPA 13R is not permitted for Group S.

11/2/2023 08:59:18 am

REFERENCES
IBC-2012
Chapter 9 Fire Protection and Life Safety Systems
Section 903 Automatic Sprinkler Systems

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.
903.2.9 Group S-1
An automatic sprinkler system shall be provided throughout all buildings containing a Group S-1 occupancy where one of the following conditions exists:
1. A Group S-1 fire area exceeds 12,000 square feet (1115 m2).
2. A Group S-1 fire area is located more than three stories above grade plane.
3. The combined area of all Group S-1 fire areas on all floors, including any mezzanines, exceeds 24,000 square feet (2230 m2).
4. A Group S-1 fire area used for the storage of commercial motor vehicles where the fire area exceeds 5,000 square feet (464 m2).
903.2.10 Group S-2 Parking Garages

903.3 Installation Requirements
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:
Four stories or fewer above grade plane.
1. The floor level of the highest story is 30 feet (9144 mm) or less above the lowest level of fire department vehicle access.
2. The floor level of the lowest story is 30 feet (9144 mm) or less below the lowest level of fire department vehicle access.
3. 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
903.3.1.2.2 Corridors and Balconies in the Means of Egress
903.3.1.2.3 Attics

Chapter 3 Occupancy Classification and Use
Section 311 Storage Group S
311.1 Storage Group S
Storage Group S occupancy includes, among others, the use of a building or structure, or a portion thereof, for storage that is not classified as a hazardous occupancy.
311.1.1 Accessory Storage Spaces
A room or space used for storage purposes that is accessory to another occupancy shall be classified as part of that occupancy.

Chapter 5 General Building Heights and Areas
Section 508 Mixed Use and Occupancy
508.2 Accessory Occupancies
Accessory occupancies are those occupancies that are ancillary to the main occupancy of the building or portion thereof. Accessory occupancies shall comply with the provisions of Sections 508.2.1 through 508.2.4.
508.2.1 Occupancy Classification
508.2.2 Allowable Building Height
508.2.3 Allowable Building Area
The allowable area of the building shall be based on the applicable provisions of Section 506 for the main occupancy of the building. Aggregate accessory occupancies shall not occupy more than 10 percent of the floor area of the story in which they are located and shall not exceed the tabular values for nonsprinklered buildings in Table 506.2 for each such accessory occupancy. No separation is required between accessory occupancies and the main occupancy.
Exceptions:
1. Group H-2, H-3, H-4 and H-5 occupancies shall be separated from all other occupancies in accordance with Section 508.4.
2. Group I-1, R-1, R-2 and R-3 dwelling units and sleeping units shall be separated from other dwelling or sleeping units and from accessory occupancies contiguous to them in accordance with the requirements of Section 420.

Jack G

11/2/2023 09:26:17 am

In reading thru the question, about a storage room in a 4 story 13R apartment building, I question if 13R is applicable ( if building is subject to inc) as table 601 does not allow 13R in V-A construction. Please review.

Joe F

11/2/2023 10:45:21 am

If NFPA-13R is allowed for your project, then according to NFPA-13R (2019)
Δ 6.6.7 Sprinklers shall not be required in closets (regardless of size) on exterior balconies and exterior corridors, as long as
the closet does not have doors or unprotected penetrations directly into the dwelling unit.

R. Scott

11/2/2023 02:30:03 pm

they are "interior" open-ended corridors per the IBC definition, but I see the argument that they are "exterior" of the dwelling unit. We plan to provide coverage in them regardless of if the exception was acceptable.

11/2/2023 11:24:55 am

Again I reiterate: the answers above include reference to a 30 minute rating ( reduced from 1 hour per IBC chapter 6)
If the rating of the construction was reduced, then 13R is not the right choice for the suppression system—- NFPA- 13 should be the applicable design. Consult Meyer Fire 13, 13R, or 13D .

11/2/2023 02:30:59 pm

the ratings are not reduced, they are 1-hr

How to Treat Storage Room in 13R Apartment?

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