Omit Sprinklers in Partial-Insulated Attic Space?

1/21/2026

We are the Engineer of Record (EOR) with an RFI for building in the substantial completion phase of construction.

The contract documents called for delegated fire protection design. The working drawings called for upright sprinklers in the combustible concealed space above a vaulted ceiling.

Instead of installing the uprights, it was agreed by the fire protection sub and general contractor that the space would be filled with insulation. The FP contractor's engineer, who prepared the working drawings, observed that the concealed space was not completely filled per NFPA 13 requirements. The architect has deemed that fire sprinklers are not required for this building due to the square footage. The rest of the entire building is fully covered.

Can the combustible concealed space between the vaulted ceiling and the roof be considered a portion of the building that is not intended to be covered by sprinklers?

Meaning per New York State (NYS) Fire Code (FC) 901.4.2, the building is partially furnished for protection?

Or, is the combustible concealed space considered part of the open room assembly, meaning it must meet NFPA 13 requirements since the vaulted ceiling for the room space is protected by pendent sprinklers?

Our initial reaction is that if sprinklers are provided and not required by the NYS Building Code, then the system would be considered required per NYS FC 901.4.1 and would need to meet the requirements of NFPA-13.

What are your thoughts?

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Observation of insufficient insulation in concealed space.

8 Comments

Chad

1/21/2026 07:43:12 am

Read Section 9.2 Allowable Sprinkler Omission Locations. from 2019 NFPA 13

This is one example of your situation but you have too much air space? There are other section on insulation

9.2.1.18*
Concealed spaces formed by noncombustible or limited-combustible ceilings suspended from the bottom of wood joists and composite wood joists with a maximum nominal chord width of 2 in. (50 mm), where joist spaces are full of noncombustible batt insulation with a maximum 2 in. (50 mm) air space between the decking material and the top of the batt insulation shall not require sprinklers..

Glenn Berger

1/21/2026 08:18:51 am

I am not familiar with the NYS Building Code.

But in general - If sprinklers are provided then it must meet the applicable requirements of NFPA 13.

Incomplete sprinkler installations are considered not sprinklered and needs to be remedy. (False sense of protection!)

It appears that there are many options available to fix the situation.

Jesse

1/21/2026 08:23:04 am

I'm with Glenn in that I'm not familiar with the NYS code very well. But using 13 as my benchmark, I'd submit that this needs to be protected. I don't bdelieve that the insulation installation meets the intent of allowable ommission.

Anthony

1/21/2026 08:25:16 am

I do a significant amount of work in NYS. If utilizing the exceptions in NFAP-13 for a fully insulated combustible concealed space the space must be fully filled with insulation. There are no allowances for partial systems without AHJ approval and a variance.

NFPA13-16:

8.15.1.2.7 Concealed spaces filled with noncombustible insulation shall not require sprinkler protection.

8.15.1.2.7.1 A maximum 2 in. (50 mm) air gap at the top of the space shall be permitted.

Pete H

1/21/2026 08:32:31 am

You might be able to get a deal with the AHJ through the defense that chances are the architect has a point about square footage/occupancy and any protection of this building is optional. So you'd be providing a sprinkler system that is not equivalent to NFPA 13 because you're under no obligation from IBC to provide an NFPA 13 system.

But I see no specific code omission that gets you out of this without reclassifying the building as 13R or 13D. You got more than 2" uninsulated.

Joe M

1/21/2026 08:33:32 am

In these cases, sometimes we need to ask ourselves what our mentor say, and/or what our peers would say in court if something went wrong.

Dwight H Havens

1/21/2026 09:44:07 am

First, I see wood trusses, not joists. Second, if allowed by the AHJ for the truss system, there is no reason that a thicker insulation batt couldn't have been used. Note: Big difference in the ability of fire to spread through the open space created above the batts in a trussed space, compared to the closed space between joists.

Ryan J

1/25/2026 10:35:58 am

Im going to assume the air gap they left was for roof venting purposes.

Basically, they would have to add more insulation to the bottom edge of the truss top chord. (Yes, that would still be approx. 4 inches but at that point it's nitpicking)

Omit Sprinklers in Partial-Insulated Attic Space?

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