Sprinkler System Supported Only by Pipe Stands?

3/15/2024

I have an existing penthouse that has limited (no) access to the structure at the roof and requires sprinkler coverage. We have a variance from the AHJ to omit sprinklers from non accessible areas.

Has anyone designed a sprinkler system supported from the floor entirely by pipe stands or pipe racks?

I'm aware of the requirements of NFPA 13-16 CH 9.1.1.2.

The structural engineer on my project is not eager to get involved so alternative options especially pre-engineered options would be great. I'll push back if there aren't better options but looking for any advice.

I'm also aware of NFPA 13-22 CH 17.5 however 8-0'' tall pipe stands don't seem especially stable. Preferably I'd like a Unistrut solution a contractor can assemble in field and place as required say every 10-0'' ( see pictures)

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8 Comments

Craig Hanson link

3/15/2024 08:43:45 am

If they use unistrut they have to use half straps or U-bolts. Unistrut pipe clamps (those two piece straps you see on plumbing and electrical) are not UL listed for sprinkler piping. They are ok for drain and test piping, but cannot be used on system piping.

As for the rest of it, it has to be engineered as per chapter 9 and braced, not just thrown together.

3/15/2024 08:52:05 am

We've had to do it something like that before but not at that height.

AHJ requested protection under cannabis grow tables that were fixed in place and over 4'-0 wide.

We used a PF651 reversible channel bracket and a PF1100 rigid pipe clamp to attach the pipe to the bracket. The bracket was used as a "stanchion"

The bracket was attached to the concrete floor using drop-in anchors, hex bolts and washers.

This is NOT a listed method to do this so definitely get approvals.

Todd E Wyatt

3/15/2024 09:24:39 am

“We have a variance from the AHJ to omit sprinklers from non accessible areas.”

I recommend getting this “variance” in writing from the AHJ as subsequent plan reviewers and/or inspectors may cite this as non-compliant based on the applicable scoping Code (e.g. IBC-2021) and the referenced standard (e.g. NFPA 13-2022).

NFPA 13-2022 Section 9.2 contains a consolidated list of (18) specific locations where sprinklers can be OMITTED and “non-accessible areas” is not one of these (unless it is referring to “Concealed Spaces.”)

The AHJ (IBC : Building Official) is “authorized and directed to enforce the provisions” of the Code, “render interpretations” of the Code, and “adopt policies and procedures in order to clarify the application of its provisions.” These policies and procedures shall “not have the effect of waiving requirements specifically provided for” in this Code, however. The AHJ, per IBC-2021 104.10 Modifications, is permitted to “grant modifications for individual cases” where there are “practical difficulties involved in carrying out the provisions” of the Code.

Todd E Wyatt

3/15/2024 09:25:05 am

REFERENCES
NFPA 13 - 2022
CHAPTER 9 Sprinkler Location Requirements
9.2 Allowable Sprinkler Omission Locations.

ENHANCED CONTENT
Section 9.2 contains a consolidated list of specific locations where sprinklers can be omitted. It was developed to consolidate all the specific allowances that were scattered throughout Chapter 8 of the 2016 edition.

Section 9.2 can be expected to be a very active part of NFPA 13 during future revision cycles. It is the one section where the basic principle of NFPA 13—that sprinklers must be installed throughout the premises—is allowed to be altered. During each code development cycle, the Technical Committee on Sprinkler System Installation Criteria acts on inputs and comments seeking to “excuse” a specific portion of a building from the requirements of sprinkler protection due to a special situation. The case is typically made that, under certain conditions, the presence of sprinklers does not provide any greater protection, and the omission of sprinklers in those specific areas and spaces within a building should be permitted. (Section 9.3 identifies those spaces and conditions.)

It is important to note the following two points regarding Section 9.2:

It is imperative that when the elimination of sprinklers from a space based on Section 9.2 is being considered, the space must comply exactly with the description and requirements found within the applicable paragraph(s). In other words, any deviation from the description in an applicable paragraph negates its application, and, as a result, the space must be sprinklered.
If a space is not specifically detailed in Section 9.2, it is intended to be protected by sprinklers under 9.1.1(1).

9.2.1* Concealed Spaces Not Requiring Sprinkler Protection.
9.2.2 Spaces Under Ground Floors, Exterior Docks, and Exterior Platforms.
9.2.3* Exterior Projections.
9.2.4 Dwelling Units.
9.2.5 Closets and Pantries.
9.2.6* Electrical Equipment Rooms.
9.2.7 Cloud Ceilings.
9.2.8 Revolving Doors Enclosures.
9.2.10 Small Temporarily Occupied Enclosures.
9.2.12 Noncombustible Vertical Shafts.
9.2.13 Noncombustible Stairways.
9.2.14 Elevator Hoistways and Machine Rooms.
9.2.15 Duct Protection.
9.2.16 Open-Grid Ceilings.
9.2.17 Drop-Out Ceilings.
9.2.18 Skylights.

IBC-2021
Chapter 1 Scope and Administration
Section 104 Duties and Powers of Building Official
104.1 General
The building official is hereby authorized and directed to enforce the provisions of this code. The building official shall have the authority to render interpretations of this code and to adopt policies and procedures in order to clarify the application of its provisions. Such interpretations, policies and procedures shall be in compliance with the intent and purpose of this code. Such policies and procedures shall not have the effect of waiving requirements specifically provided for in this code.
104.10 Modifications
Where there are practical difficulties involved in carrying out the provisions of this code, the building official shall have the authority to grant modifications for individual cases, upon application of the owner or the owner's authorized agent, provided that the building official shall first find that special individual reason makes the strict letter of this code impractical, the modification is in compliance with the intent and purpose of this code and that such modification does not lessen health, accessibility, life and fire safety or structural requirements. The details of action granting modifications shall be recorded and entered in the files of the department of building safety.

David Williams

3/15/2024 09:36:54 am

Unistrut has an engineered design group that could handle structural design if needed. They are often called on for OR equipment supports and the like.

Jack G

3/15/2024 09:41:36 am

I ve used pipe stands on exposure systems around transformers as outlined in exposure protection phamplet. I m sure if provuded simularley they would be acceptable.
At six flags, the log jam ride, the platform rotates 360 degrees all day. At the jackson nj locatikn, over 38 years ago we installed sprinklers inside the 5 foot clear space. ( and its still standing )
So I dont think pipestands if appropriately installed are a problem for an entire systrm.
Opinion.

Jesse

3/15/2024 09:47:52 am

Lots of good comments about Unistrut and their engineered design group. We done things similar to this (though not at this scale) for protecting freezers / coolers outside of a restaurant. They might be able to help.

I really want to reinforce what Todd said about getting the variance in writing. We had a project where a fire marshal and the fire chief agreed to something so far outside the norm of NFPA 13 and NFPA 20 it boggled my mind. And then both left to go to another AHJ. Get it in writing

RYAN HINSON

3/15/2024 09:55:55 am

Consider getting AHJ buyoff on using NFPA 15 (2022) Standard and Annex Sections 6.3.2 for pipe supports and system stability bracing requirements. We use this often for similar applications.

Sprinkler System Supported Only by Pipe Stands?

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