Sprinklers Req'd for PV Panels Over Parking Lot?

3/7/2024

Has anyone been asked to or required to provide sprinkler protection for at grade parking with PV panels overtop?

I've been looking online for what has been done in other jurisdictions but I can't find much. There is a lot of discussion about whether PV panels constitute a roof or not for parking garages, but my question is more along the lines of has there been research done to determine if the sprinklers can be expected to activate properly based on pitch/spacing?

Thanks in advance.

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10 Comments

Pete H

3/7/2024 06:54:11 am

I think research is ongoing.

https://www.firetrace.com/solar-farm-fire-protection

This site had a decent write up with current code references, but makes somewhat frightening points that once a PV system is exposed to light it cannot be completely shut off to a point that solar panels and wiring remain live even during a shutdown. And since they use DC currents that are difficult to detect and more unpredictable than AC sources in a fire (combined with the fact that water and electrical fires don't mix), there are no current code sprinkler requirements for these panels (that I can find) in the IFC or NFPA 855, other steps have to be taken.

The site recommends isolating the inverters and employing the "right" fire suppression technology to shut down the solar PV system inverter.

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All that said, unless the inverters are housed in a compartment, I don't know how fire sprinklers would be able to perform that task, they typically require heat collection, and if your atop a roof, there won't be heat collection, the heat will rise to the sky.

Anthony

3/7/2024 07:04:59 am

Spacing - per the hazard you're protecting in the environment you're protecting. Treat each solar panel as a partial roof/cloud/obstruction. I think you're looking at OH2 for parking structures now so 130 sqft. if the panels are all plastic then its combustible construction if they're all encased in metal then its non-combustible.

I don't think its the designer/engineers job to determine if the solar panels constitute a roof I think that's an architects job. If you're the only trade on the job then use common sense - if you can stand up there and won't get wet in a rainstorm, it's a roof. If it's one row along one parking bay it's a piece of equipment and not structure.

David Williams link

3/7/2024 08:43:22 am

PV systems installed on roofs are now usually required to have rapid shutdown, a method of mitigating the hazard of live wires on the roof where an electronic module will shut the power "off" at the panel.

I imagine this could easily be extended to other installation types, such as over parking.

Additionally, there are Class A type PV panels available where the flammable plastic backsheet is replaced with glass. It's a matter of cost and availability for this sort of stuff... but perhaps could be considered as part of a holistic fire protection analysis.

Jesse

3/7/2024 08:53:25 am

Seems like you're neck deep in one of the issues currently plaguing NFPA. Right up there with EVs and Li-ion batteries.

As for protecting below the PV panels you'd so so the same as you would any OH1 or OH2 (depending on the applicable version of 13). Your spacing and such along the pitch would be similar under a traditionally constructed roof

Todd E Wyatt

3/7/2024 11:15:56 am

The adopted scoping Code (e.g. IBC-2021) determines WHERE an automatic sprinkler system (ASPS) is required to be installed based on the building’s Occupancy Classification(s) (OC) and/or Specific Building Areas and Hazards (per IBC-2021 903.2.11).

An at grade parking lot does not meet the IBC-2021 definition of a “building” but once PHOTOVOLTAIC ROOF PANELS (PRP) were added, it could now be considered a “building” since the PRP provides “shelter” for the “Group S-2 Low-Hazard Storage.”

Review of IBC-2021 Chapter 9 Fire Protection and Life Safety Systems, 903.2.10 Group S-2 Parking Garages identifies (3) conditions WHERE an ASPS is required :

903.2.10 Group S-2 Parking Garages
An automatic sprinkler system shall be provided throughout buildings classified as parking garages where any of the following conditions exists:
1. Where the fire area of the enclosed parking garage in accordance with Section 406.6 exceeds 12,000 square feet (1115 m2).
2. Where the enclosed parking garage in accordance with Section 406.6 is located beneath other groups.
Exception: Enclosed parking garages located beneath Group R-3 occupancies.
3. Where the fire area of the open parking garage in accordance with Section 406.5 exceeds 48,000 square feet (4460 m2).

If the Project meets any of these (3) conditions, an AHJ may require it to be protected by an ASPS.

BUILDING-INTEGRATED PHOTOVOLTAIC ROOF PANEL (BIPV ROOF PANEL) are referenced in more detail in IBC-2021 Chapter 15 Roof Assemblies and Rooftop Structures. Requirements for an ASPS in Chapter 15 are not included.

Todd E Wyatt

3/7/2024 11:16:29 am

REFERENCES
IBC-2021

Chapter 2 Definitions
BUILDING. Any structure utilized or intended for supporting or sheltering any occupancy.
BUILDING-INTEGRATED PHOTOVOLTAIC ROOF PANEL (BIPV ROOF PANEL). A photovoltaic panel that functions as a component of the building envelope.
OPEN PARKING GARAGE. A structure or portion of a structure with the openings as described in Section 406.5.2 on two or more sides that is used for the parking or storage of private motor vehicles as described in Section 406.5.3.
PHOTOVOLTAIC MODULE. A complete, environmentally protected unit consisting of solar cells, optics and other components, exclusive of tracker, designed to generate DC power when exposed to sunlight.
PHOTOVOLTAIC PANEL. A collection of modules mechanically fastened together, wired and designed to provide a field-installable unit.
PHOTOVOLTAIC PANEL SYSTEM. A system that incorporates discrete photovoltaic panels, that converts solar radiation into electricity, including rack support systems.
STRUCTURE. That which is built or constructed.

Section 311 Storage Group S
311.3 Low-Hazard Storage, Group S-2
Storage Group S-2 occupancies include, among others, buildings used for the storage of noncombustible materials such as products on wood pallets or in paper cartons with or without single thickness divisions; or in paper wrappings. Such products are permitted to have a negligible amount of plastic trim, such as knobs, handles or film wrapping. Group S-2 storage uses shall include, but not be limited to, storage of the following:
Public parking garages, open or enclosed
311.3.1 Public Parking Garages
Public parking garages shall comply with Section 406.4 and the additional requirements of Section 406.5 for open parking garages or Section 406.6 for enclosed parking garages.

Chapter 9 Fire Protection and Life Safety Systems
Section 903 Automatic Sprinkler Systems
903.2 Where Required
Approved automatic sprinkler systems in new buildings and structures shall be provided in the locations described in Sections 903.2.1 through 903.2.12.
903.2.10 Group S-2 Parking Garages
An automatic sprinkler system shall be provided throughout buildings classified as parking garages where any of the following conditions exists:
4. Where the fire area of the enclosed parking garage in accordance with Section 406.6 exceeds 12,000 square feet (1115 m2).
5. Where the enclosed parking garage in accordance with Section 406.6 is located beneath other groups.
Exception: Enclosed parking garages located beneath Group R-3 occupancies.
6. Where the fire area of the open parking garage in accordance with Section 406.5 exceeds 48,000 square feet (4460 m2).

Chapter 15 Roof Assemblies and Rooftop Structures
Section 1505 Fire Classification
1505.8 Building-Integrated Photovoltaic (BIPV) Products
BIPV products installed as the roof covering shall be tested, listed and labeled for fire classification in accordance with Section 1505.1.
1507.17 Building-Integrated Photovoltaic Roof Panels
The installation of building-integrated photovoltaic (BIPV) roof panels shall comply with the provisions of this section.
1507.17.1 Deck Requirements
1507.17.2 Deck Slope
1507.17.3 Underlayment
1507.17.4 Underlayment Application
1507.17.4.1 High-Wind Attachment
1507.17.4.2 Ice Barrier
1507.17.5 Material Standards
BIPV roof panels shall be listed and labeled in accordance with UL 7103 or with both UL 61730-1 and UL 61730-2.
1507.17.6 Attachment
1505.9 Rooftop Mounted Photovoltaic (PV) Panel Systems
Rooftop mounted photovoltaic (PV) panel systems shall be tested, listed and identified with a fire classification in accordance with UL 2703. Listed systems shall be installed in accordance with the manufacturer's installation instructions and their listing. The fire classification shall comply with Table 1505.1 based on the type of construction of the building.

UL
1703—2002 Flat-plate Photovoltaic Modules and Panels—with Revisions through September 2018 1507.17.5, 3111.3.1
2703—2014 Mounting Systems, Mounting Devices, Clamping/Retention Devices and Ground Lugs for Use with Flat-plate Photovoltaic Modules and Panels-with Revisions through December 2019 1505.9
7103—19 Outline of Investigation for Building-Integrated Photovoltaic Roof Coverings Table 1504.2, 1507.16.6
61730-1—2017 Photovoltaic (PV) Module Safety Qualification - Part 1: Requirements for Construction 1507.16.6, 1507.17.5, 3111.3.1
61730-2—2017 Photovoltaic (PV) Module Safety Qualification - Part 2: Requirements for Testing 1507.16.6, 1507.17.5, 3111.3.1

Franck

3/7/2024 12:13:36 pm

Normally you put sprinklers under a roof so that a fire could not spread and damage it.
With solar panels, the threat is the roof !
Both the combustible load and the ignition source are there.
I don’t see the value to protect underneath as a fire involving the panels will spread anyway above the sprinklers and will open all of them with no benefit (only flooding the cars underneath).

Solar panels are a threat, as indicated above by other peers, and there is little you can do except having a good installation with proper safety devices and good maintenance. Then, selecting better panels can also limit the probability of fire (or consequences).

Most fires start at electrical connections (poorly installed /maintained) or at defective panels (damaged during construction or by external elements such as hail or damages by birds…).
Consequences is based on what is underneath.

Max

3/7/2024 04:39:02 pm

I required PV panels to be listed. The structure supporting the panels is not considered a roof per the IBC. The structure is not there to provide protection from the elements, does not enclose the space, and usually does not span from side to side. So it does not meet the definition of a roof. Therefore, I classify these as rooftop structures which generally do not require sprinklers. Just my 0.02.

Alex Keene link

3/12/2024 05:56:00 am

Sprinklers (water based) to provide cover for incidents around an electrical system does not sound like the right approach. There is a solution that de-energises all PV systems by delivering a temporary light blocking liquid coating to the panels, stopping the energy generation at source. The coating then dries and can be peeled off the panels when safe to do so, restoring the system without damaging it. A simple, safe and effective solution to a complicated challenge.

Danny

10/29/2024 05:33:27 pm

I have encountered this on a project, where the AHJ wanted PV canopies on a parking lot greater than 5000sf to be sprinklered. We just re-designed the array to stay under the 5000sf limit, with a 10' gap between them. I think this was specific to Santa Clara county, CA, but I can't recall if it was the building department, or Fire that pulled it out of their ass.

Sprinklers Req'd for PV Panels Over Parking Lot?

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