Does IBC or NFPA 13 Precede When in Conflict?

9/16/2024

We have a mass timber building. It's Type III-A construction with an NFPA 13 system.

The building has a large exterior roof canopy (more than 4-ft wide) primarily used as a pedestrian walkway and building entrance.

For these types of roof projections, overhangs, canopies, etc., IBC Section 705.2.3 allows the following options:

Noncombustible construction
Combustible construction with a 1-hr FRR
Heavy timber construction (meeting minimum sizes in accordance with 2304.11)
FRTW
Or, in accordance with Section 705.2.3.1 for balconies – which basically gives you the same options as those listed above, with the additional option of extending sprinkler protection to those areas.

However, in the NFPA 13 standard (Section 9.2.3), it seems to only allow the following options for omitting sprinklers from these locations:

Noncombustible construction
Limited combustibility construction
FRTW – which is not available for most mass timber products, including CLT
If combustible construction is used, it has to be covered in a finish material that meets one of the options listed above (with additional limitations on concealed spaces).

These two codes seem to be at odds with each other and it’s not clear to me which one governs. The IBC clearly allows the use of a 1-hr rating or heavy timber, both of which would allow this particular project to omit sprinklers from the exterior roof canopy. However, NFPA 13 seems to require the use of sprinklers at these locations.

Does the IBC allowance overrule NFPA 13 here? Or does NFPA 13's requirements overrule the IBC?

What's the code basis that would support priority of one or the other?

Appreciate any insight or how you've seen these situations handled on other projects.

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10 Comments

Peter Howard

9/16/2024 06:48:42 am

I'm sorry, I don't know if I see the conflict.

IBC is telling you code acceptable types of balconies/overhangs you can install.

NFPA 13 is telling you when the projection can omit sprinkler protection.

If you built it using the IBC requirements and it does not fall into the NFPA 13 allowances, you need to protect it with sprinklers.

If you built it where it works with both, you can omit sprinklers.

And if you didn't build it using the IBC requirements, you have bigger problems.

Anthony

9/16/2024 07:55:07 am

I agree with Pete here. IBC tell you how to build it. NFPA 13 tells you how to protect the building with sprinklers.

To answer the broader question of which code takes precedent, a state adopted version of ICC model standard or NFPA 13, its always the adopted code.

Joe

9/16/2024 08:08:45 am

Hierarchy
The Administrative law adopted by the jurisdiction.
The adopted codes
The referenced standards
Code always trumps the standard

Sean H

9/16/2024 08:08:57 am

The IBC in this case wins (and calls itself the winner).

IBC 2018 example

Chapter 1 Scope and Administration > Section 102 Applicability >
102.4.1 Referenced Codes and Standards >
102.4.1 Conflicts: Where conflicts occur between provisions of this code and referenced codes and standards, the provisions of THIS code shall apply.

There's more good stuff in that front section. I can't speak to the specifics of the NFPA 13 and IBC conflicts you note above, but I found this section in the IBC interesting when I became aware of it a few years ago.

Justin Rosales

9/16/2024 08:47:28 am

Actually IBC does direct the user to follow NFPA 13 for constructing a sprinkler system so referring to Ch 1 would not be applicable.

§903.3.1.1 - "Where the provisions of this code require that a building or portion thereof be equipped throughout with an automatic sprinkler system in accordance with this section, sprinklers shall be installed throughout in accordance with NFPA 13 except as provided in Sections 903.3.1.1.1 and 903.3.1.1.2."

In the except locations they list IBC clarifies that just because something is fire resistance it is not a good enough reason to omit sprinklers. Hypothetically, if there was a conflict between IBC and NFPA the code official is going to go with the more stringent requirement that provides a higher level of safety for the occupants. The only way I could see the AHJ approving the omitting of the sprinkler is if this balcony exceeds 50 ft in height and even then they might ask for a model to prove that the sprinklers wont activate.

Zackery Geddies

9/16/2024 08:10:05 am

Usually the more stringent code applies when there is a conflict.

Glenn Berger

9/16/2024 08:10:59 am

Concur with previous responses. But in general most stringent rules would be the starting point.

Todd E Wyatt

9/16/2024 08:13:10 am

The scoping Code (e.g. IBC-2018) determine WHERE an automatic sprinkler system (ASPS) is to be installed.

The scoping Code includes “Exempt Locations” where an ASPS is not required :

Section 903 Automatic Sprinkler Systems
903.3 Installation Requirements
Automatic sprinkler systems shall be designed and installed in accordance with Sections 903.3.1 through 903.3.8.
903.3.1 Standards
903.3.1.1 NFPA 13 Sprinkler Systems
Where the provisions of this code require that a building or portion thereof be equipped throughout with an automatic sprinkler system in accordance with this section, sprinklers shall be installed throughout in accordance with NFPA 13 except as provided in Sections 903.3.1.1.1 and 903.3.1.1.2.
903.3.1.1.1 Exempt Locations
Automatic sprinklers shall not be required in the following rooms or areas where such rooms or areas are protected with an approved automatic fire detection system in accordance with Section 907.2 that will respond to visible or invisible particles of combustion. Sprinklers shall not be omitted from a room merely because it is damp, of fire-resistance-rated construction or contains electrical equipment.
1. A room where the application of water, or flame and water, constitutes a serious life or fire hazard.
2. A room or space where sprinklers are considered undesirable because of the nature of the contents, where approved by the fire code official.
3. Generator and transformer rooms separated from the remainder of the building by walls and floor/ceiling or roof/ceiling assemblies having a fire-resistance rating of not less than 2 hours.
4. Rooms or areas that are of noncombustible construction with wholly noncombustible contents.
5. Fire service access elevator machine rooms and machinery spaces.
6. Machine rooms, machinery spaces, control rooms and control spaces associated with occupant evacuation elevators designed in accordance with Section 3008.
903.3.1.1.2 Bathrooms

Otherwise, the ASPS standard referenced (e.g. NFPA 13-2019) “shall be installed throughout in accordance with NFPA 13.”

Ken Thackery

9/16/2024 10:13:09 am

When the ambiguity arises 1. clarify with an RFI ASAP and put it back into the Arch/design teams court for an answer. 2. Consult an FPE. 3. Also depending on schedule if you can submit to the AHJ also ASAP and wait for their comments, or call them. Is it 5 heads or 50? If its 5 just add them, its not worth fighting over or having to add them after the fact.

Justin Phillip Milne

9/18/2024 04:52:20 am

There is something that the others do not appear to clearly address here.

The International Building Code (IBC), is a code, meaning it has more legal authority. The NFPA 13 Standard, is a standard, meaning that it is only used when directed by a code. You are legally bound to follow NFPA 13, because the International Building Code tells you to, as mandated by law.

https://www.nist.gov/buildings-construction/understanding-building-codes

Now, apart from the code issue, Mass Timber is a completely separate concern. The IBC will be more developed on Mass Timber issues than NFPA 13. With that said, if the jurisdiction is open to it, you may have the opportunity for an engineering judgement here, if the code authority will allow it.

If you have more questions on that, feel free to reach out.

Does IBC or NFPA 13 Precede When in Conflict?

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