How to Protect Storage with a 10'-20' Clearance?

2/13/2023

I am trying to figure out how to protect an existing building that has never had a sprinkler system.

The building peaks at 46'-5" and in that area you can only have a max height of 25'-0 in storage, due to operable cranes in the bay.

Additionally, the building is constructed using 12" purlins, so ESFR pendants are out unless we want to put them on return bends.

I am trying to give the owner as much storage space as possible, and commodities as they plan to rent the building out to tenants in the future. I have searched through CMSA, CMDA, ESFR and storage to find a situation that best describes it.

The issue I always come up on, is the distance from top of storage to ceiling. Every scenario I have looked at, we seem to exceed the 10' or 20' maximum distance.

Does anyone have some criteria they used that is close to the situation above?

Thanks in advance.

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6 Comments

Peter Howard

2/13/2023 07:54:58 am

A couple of ideas, please take all with a grain of salt:

with ESFR pendents on return bends, is there one that gets you 18" below deck? That'll get you under 45'-0" for deflector height and make it so you could have a 20 foot difference.

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You're calculating to a maximum storage height. Just because they're actual storage is peaking out at 25'-0", is there any reason you can't calculate a system that would allow them to have 30'-0" or 35'-0" storage in the future? Especially with ESFR heads.

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The difference between 46'-5" and 45'-0" just isn't that much. Can you talk to and convince the AHJ to "grandfather" in a coverage that while it hasn't been tested to a full listed/per code acceptance.... is so close that the difference is negligible and the system should still protect any conceivable fire situation long enough for fire department support, especially if there is standpipe present and high temperature heads. Especially if the architecture of the building forces you to go outside of accepted codes and standards anyway.

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Ultimately, I know nothing about the project and can't research this fully, so again, take with a grain of salt, but maybe it's some things to think about.

Glenn Berger

2/13/2023 08:15:22 am

Storage Occupancies are difficult to provide one size fits all solution. You are pretty much on the right track in your procedures. I did not see any statement on the propose commodity to be stored.

Todd E Wyatt

2/13/2023 09:05:40 am

The scoping Code (e.g. 2021 IBC) determines “Where Required” an automatic sprinkler system (ASPS) is required per the Occupancy Classifications (OC) of the building.

The referenced standard (e.g. 2019 NFPA 13) determines HOW “sprinklers shall be installed throughout in accordance with NFPA 13.”

This building would (probably) be classified as a Group S-1 Moderate-Hazard Storage ... an ASPS is require if the building includes (1) of the (4) conditions:
1. A Group S-1 fire area exceeds 12,000 square feet.
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.
4. A Group S-1 fire area used for the storage of commercial motor vehicles where the fire area exceeds 5,000 square feet.

Assuming this building meets one of these requirements, an ASPS is required.

For buildings including “high-piled combustible storage” (HPCS), the 2021 IBC references the 2021 IFC :

Section 413 Combustible Storage
413.1 General
High-piled stock or rack storage in any occupancy group shall comply with the International Fire Code.

The 2021 IFC includes an entire chapter on HPCS : Chapter 32 High-Piled Combustible Storage. I recommend you request additional information (e.g. Commodity Classification) from the Client to determine the prescriptive requirements for the “General Fire Protection and Life Safety Features” (Section 3206) for this HPCS.

REFERENCES
2021 IBC
Chapter 9 Fire Protection and Life Safety Systems
Section 903 Automatic Sprinkler Systems
903.1 General
Automatic sprinkler systems shall comply with this section.
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.
903.2.9 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).

2021 IBC
Chapter 32 High-Piled Combustible Storage
Section 3201 General
Section 3202 Definitions
Section 3203 Commodity Classification
Section 3204 Designation of High-Piled Storage Areas
Section 3205 Housekeeping and Maintenance
Section 3206 General Fire Protection and Life Safety Features
Section 3207 Solid-Piled and Shelf Storage
Section 3208 Rack Storage
Section 3209 Automated Storage

Jesse

2/13/2023 09:49:58 am

I'm curious to know commodity to be stored and roof pitch.

Jay

2/13/2023 10:26:48 am

If the roof pitch is greater than 2/12 then you can't use the high piled storage chapters of NFPA 13.

Franck

2/13/2023 02:39:51 pm

One solution, if you can find a sprinkler design solution for 35 ft stge in 45 ft bldg, is to consider a 35 ft high storage to design your sprinkler density at 45 ft.
This would be acceptable per NFPA.
It is the same, if you have 10 ft stge in 30 ft building, design as for 20 ft stge in 30 ft building.

Another solution, out of the scope of NFPA is to provide in-rack with one last level at the top tier.
It is out of the scope of any standard and need to be accepted by the AHJ, but is a solution to provide confidence on fire control.

But if your slope at ceiling is more than 17% (2:12), then no solution… out of the scope of NFPA 13 for storage and definitely not suitable for ESFR.
You can still try to convince the AHJ with a top tier level of IRAS as for high clearance, but I won’t personally accept it as it is a non-approved and not-tested solution…
Could be acceptable with saw-tooth roof, but not for peak roof.

How to Protect Storage with a 10'-20' Clearance?

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