Use K25.2 Sprinklers Up to 50-ft Roof Height?

2/17/2025

I have a requirement from a client to use K25.2 sprinklers on a building up to 50-ft in height.

The design criteria that is provided under NFPA 13 is 12 K25.2 sprinklers at 50 psi, but this criteria is not available in Chapter 13 of NFPA 13.

Does anyone know where this came from, or whether it's appropriate?

It's for up to a 50-ft roof for protection of cartoned, non-expanded Group A plastics. Thank you.

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9 Comments

Mark Fessenden

2/17/2025 08:05:04 am

It’s from FMDS 8-9.

Ed Dunn

2/17/2025 09:45:45 am

Try VK 514 K-28 Specific Application

Todd E Wyatt

2/17/2025 08:56:29 am

“K25.2” is referenced in Table 20.17.2.2.3 …

NFPA 13 - 2024
Chapter General Requirements for Storage
20.17* Protection of Idle Pallets.
20.17.2.2 Protection Criteria for Plastic Pallets Stored Indoors.
20.17.2.2.3
Protection with ESFR sprinklers shall be in accordance with the requirements of Table 20.17.2.2.3.
Table 20.17.2.2.3 ESFR Pendent Sprinkler Protection for Indoor Storage of Idle Plastic Pallets on Floor or Open Frame Racks

… and Table 25.6.3.1 :

NFPA 13 - 2024
Chapter 26 Protection of Rack Storage Using In-Rack Sprinklers
25.6 In-Rack Sprinkler Protection Options Independent of Ceiling-Level Sprinklers.
25.6.3 Hydraulic Design Requirements for In-Rack Sprinkler Protection Options.
25.6.3.1 In-Rack Sprinkler System Requirements.
Table 25.6.3.1 In-Rack Sprinkler System Design for Options 1, 2a, 2b, and 3

If either of these (2) references are not applicable to the Project, inquire why “K25.2” sprinklers are required.

Mike F

2/17/2025 09:34:12 am

Can the OP provide some more details?

Like what year standard of NFPA 13 is applicable? What is the storage arrangement that the prospective tenant will be using? Is this for a spec. Building or a design build project?

Jack G

2/17/2025 10:01:16 am

Yes FM 8-9, Vikings is approved to 55 feet, (9) sprinklers at 80 psi.
Always consult the manufacturers latest cut sheet as many 25.2 s are not.

Franck

2/17/2025 10:22:07 am

No, it's not appropriate.
For NFPA 13, it is 45 ft maximum (unless you add additional levels of EC in racks as per 25.7 - In-Rack Sprinkler Protection Options Independent of Ceiling-Level Sprinklers - from NFPA 13 Edition 2025).

This is not coming from FM 8-9 as well as it limits the height of building to 40 ft (with a demand of 9 K25 ESFR @ 40 psi for cartoned unexpanded plastic in racks).

As indicated by Ed Dunn, SPECIFIC APPLICATION ESFR PENDENT SPRINKLER VK514 (K28.0) can be used for building up to 50 ft, and is apparently FM approved for that purpose (even though not in DS 8-9), pending a strict respect of all the requirements provided in the data sheet from Viking.
These are K28 sprinklers (not K25) and 10 sprinklers at 40 psi are necessary per design.

But again, this is not an NFPA 13 requirement.
And this is pending AHJ approval.

Jose R Figueroa

2/17/2025 11:57:27 am

Frank & Dunn responses are correct. Please refer to FM DS8-9.
Additionally:
Viking News Letter

ESFR K-28 For 50 ft Storage without In-Racks
June 27th, 2019
FM Based on the recent successful fire test of 50-ft rack storage in single and double row racks with cartoned unexpanded Group A Plastics (and encapsulated/ unencapsulated Class I–IV commodities), FM Global approved a new type of ESFR sprinkler for high-challenge storage applications, the ESFR K-28. It is approved as a ceiling-only, quick-response, wet-pipe, pendent storage sprinkler.

FM Global previously listed ceiling heights for cartoned unexpanded plastics only up to max. 45 ft ceiling height (K-25.2). But this large K-factor ESFR sprinkler head can be used for rack storage and ceiling heights in excess of 45 ft (currently the limit in DS 8-9 July 2018) up to 55 ft without the need for in-rack sprinklers.

The FM fire test was performed in collaboration with Viking testing the company’s new ESFR sprinkler head and design, requiring 9 heads at 80 psi each (three sprinklers installed on three adjacent branch lines). The sprinkler installation design is based on FM Global’s DS 2-0.

The ESFR type head is listed to utilize a minimum aisle width of 8-ft for 50-ft storage. The total water demand for this ESFR system is approximately 2250 gpm and in line with similar type sprinkler systems and storage heights, and most likely will require the use of a fire pump. Hose Demand is 250 gpm per FM requirements.

Daniel Contreras

2/17/2025 04:11:56 pm

Jose,

The requirements came directly from the client, we have previously built a building form them under the same design criteria yet that building was 45ft. tall, I understand that with FM we might not have an issue.
In my research I found that the K28.0(VK5141) Viking sprinkler criteria for buildings up to 48ft, a design criteria for NFPA can be 12 K28.0 sprinklers @ 35 psi.. when I found it I presented the data sheet to the AHJ, I was working to solve a similar situation with a 50ft building height, he approved it to install it at 50ft.

I'll get in contact with the AHJ of this project to present the options we have to get a better clarification and requirement.

Thank you.

Joe Meyer (moderator)

2/17/2025 11:00:51 am

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Use K25.2 Sprinklers Up to 50-ft Roof Height?

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