Smoke Detection Required Under Raised Floor?

5/13/2022

If NFPA 75 isn't an explicitly adopted code by the AHJ or not referenced by any of the other applicable codes is smoke detection required in a raised floor area?

NFPA 72 provides location guidance but other than that I can't find in NFPA 101/IBC where smoke detection would be required in the raise floor space. Not every jurisdiction/client adopts NFPA 75, I'm unsure what other code or standard would require below floor smoke detection.

Thanks in advance.

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9 Comments

Sanjeev Gupta

5/13/2022 08:09:52 am

It is logical to provide smoke detector under raised floor due to fire risk related to electrical cables.

Franck

5/13/2022 08:12:46 am

I don’t know if it is required by code in the US, but this is definitely a good practice as a quite important combustible load might be present (cables).
For critical activities, it might even be better to provide automatic gas protection system provided.
You may find some guidance in nfpa standards for communication rooms and IT / servers utility (not at my office, so I can’t give you the references)

Glenn Berger

5/13/2022 08:13:32 am

Need to know what items are located below the raised (access?) floor.

If it is used just as a plenum, then no sprinklers would be required.

Is the project in question an Information Technology Equipment Space? ( Background information is not stated in the question.)

Jesse

5/13/2022 08:17:01 am

NFPA 75 is indeed the standard. And I don't envy the position you're in.

More than a few years ago, I was the AHJ. As the fire chief, we couldn't possibly adopt every single element of code.

Moving on as an insurance loss control engineer, we were also a de facto AHJ.

What I learned in that time; is that even though code may not be adopted as law or an ordinance, it is still a national consensus standard and considered "best practice". And, at least in Texas anyway, a consensus standard is still admissible in a civil proceeding.

I took that to mean this; if I know something is best practice and part of a national standard, it is my duty now as an engineering manager to adhere to it whether or not it is codified as law or ordinance.

I have also qualified as an expert witness in fire cause and arson cases. The last thing I would want is defending a decision I made that would have been best practice and part of national consensus standard, but choose not to because it isn't adopted code locally - as an expert witness testifies that if I hadn't made that decision a loss would have been adverted or mitigated.

Youi also have the insurer to think about. Whether it is adopted by AHJ or not, the insurer may require it.

Danial Bartle

5/13/2022 08:24:03 am

If the jurisdiction has adopted NFPA 1, NFPA 75 is also incorporated by reference.

Todd E Wyatt

5/13/2022 09:00:51 am

Jurisdictions (federal, state, county, municipality, etc.) will adopt Building Codes (e.g. ICC ... IBC, IFC, IMC, IPC, IEBC ...) and/or Fire Codes (e.g. NFPA ... NFPA 1, NFPA 101 ...) which include other standards (e.g. NFPA 75) by reference :

2021 NFPA 101 :
Chapter 2 Referenced Publications
2.1 General.
The documents referenced in this chapter, or portions of such documents, are referenced within this Code, shall be considered part of the requirements of this Code, and the following shall also apply:

(1)* Documents referenced in this chapter, or portion of such documents, shall only be applicable to the extent called for within other chapters of this Code.
(A.2.1(1) For example, NFPA 10 is referenced in Chapter 2. This does not mean that all buildings must have portable fire extinguishers. Portable fire extinguishers are mandatory only to the extent called for elsewhere in the Code.)

(2) Where the requirements of a referenced code or standard differ from the requirements of this Code, the requirements of this Code shall govern.

(3)* Existing buildings or installations that do not comply with the provisions of the codes or standards referenced in this chapter shall be permitted to be continued in service, provided that the lack of conformity with these documents does not present a serious hazard to the occupants as determined by the authority having jurisdiction.
(A.2.1(3) The Committee on Safety to Life recognizes that it is impractical to continually upgrade existing buildings or installations to comply with all the requirements of the referenced publications included in Chapter 2.)

NFPA 101 is the scoping Code which identifies the extent (e.g. where) referenced publications like NFPA 75 are to be utilized. The refernced standard will identify the "hows" for the design, installation, inspection, and maintenance of their component.

NFPA 75 Standard for the Fire Protection of Information Technology Equipment is NOT a "referenced publication" of 2021 NFPA 101 nor is it a "referenced standard" by the 2021 IBC or the 2021 IFC.

"NFPA 75" is referenced (4) times by 2020 NFPA 70 National Electrical Code (which is typically adopted by jurisdictions as their electrical Code) and "raised floor" is referenced (10) times but no mention of smoke detection.

Alex

5/13/2022 09:03:43 am

Hi,

NFPA 75 would be the standard to follow. Even if your local jurisdiction doesn't adopt 75, there is no harm in following it. You may get push back when it comes down to the cost but I always say that hazards don't disappear when a jurisdiction doesn't adopt the standard.

Alex

Ronnie

5/13/2022 10:22:07 am

It's my understanding that the building of fire code identifies which occupancies require a fire alarm system and NFPA 72 tells you the how to install and the location to install.

NFPA 72 - 2019 Edition
17.7.3.5 Raised Floors and Suspended Ceilings. Spaces
beneath raised floors and above suspended ceilings shall be
treated as separate rooms for smoke detector spacing purposes.
Detectors installed beneath raised floors or above suspended
ceilings, or both, including raised floors and suspended ceilings used for environmental air, shall not be used in lieu of
providing detection within the room.
17.7.3.5.1 For raised floors, the following shall apply:
(1) Detectors installed beneath raised floors shall be spaced
in accordance with 17.7.3.1, 17.7.3.1.3, and 17.7.3.2.2.
(2) Where the area beneath the raised floor is also used for
environmental air, detector spacing shall also conform to
17.7.4.1 and 17.7.4.2.

Loren Rocha

5/16/2023 09:39:44 am

Does NFPA70 Article 645.4&5 allow you to ignore the low smoke requirement of NEC Article 300.22

Smoke Detection Required Under Raised Floor?

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