By Dan Felix, IronRidge training manager
In the realm of solar mounting, codes are “alive” in that they are constantly being updated to keep pace with an ever-changing industry. These codes protect installers from making dangerous mistakes and from scenarios that have led to failure in previous installations. Therefore, it is critical to keep up with changes that local authorities having jurisdiction (AHJs) have put into place.
Working in the solar industry necessitates understanding more than one type of code, unlike, for example, an electrician who may just need to know the National Electrical Code (NEC). Building codes (IBC), fire codes (IFC) and structural engineering codes (ASCE) also come into play when adding solar to an existing structure. Here are a few codes all solar installers should be familiar with when working on rooftop projects.
International Building Code
Flashings and attachments
The IBC states in article 1503.2 that “flashing shall be installed in such a manner so as to prevent moisture entering […] penetrations through the roof plane.” The IBC also states in article 1507.2.9 that “flashing shall be applied in accordance with this section and the asphalt shingle manufacturer’s printed instructions.”
To prevent moisture from damaging the roof or entering the structure, a sealant is typically placed in holes and underneath the flashing. To this end, the IBC code requires an attachment flashing and a sealant that meets the requirements of the roofing manufacturer.
Fire considerations
In article IBC 1509.7.2, it says that “rooftop-mounted PV systems must not diminish the fire classification of the roof system.”
In order to meet the IBC code here, one must ensure the system and equipment used have a UL fire-tested class rating that either matches or exceeds that of the existing roofing material.
Structural loading considerations
IBC section 3403 says “alterations to the existing building or structure shall be made to ensure that the existing building or structure together with the addition are no less conforming with the provisions of this code than the existing building or structure was prior to the addition.”
This means that when adding solar to an existing structure, an installer cannot exceed what the building or structure was originally engineered to support.
Each jurisdiction seems to enforce this code differently to make sure the roof is not overloaded. For example, here are a couple stances IronRidge has seen AHJs take:
- Some authorities are rigid: “The maximum spacing of PV supports is stipulated to be twice the rafter spacing and alternating such that all rafters carry the proposed system.”
- Some authorities are flexible: “45 lbs has been used by some jurisdictions as a reasonable level, below which point loading of roof joists and trusses can be ignored.”
One should contact the local AHJ to understand the requirements for point-loading a system. And if in doubt, one can always contact a structural engineer to review the structure and the planned added weight of the proposed system.
One way to evenly distribute weight across a solar system is to stagger attachments to the structure. This is a best practice, since staggering attachments means there will be less weight on each rafter.
International Fire Code
The IFC states in article 605.11.3.2.1 that “modules should be located in a manner that provides access pathway for firefighters.” It also says in article 605.11.3.2.4 that “panels/modules installed shall be located no higher than 3 ft below the ridge to allow for fire department ventilation operations.”
Combined, these codes require a 3-ft clearance down from the ridge of a pitched roof to allow for fire departments to ventilate the building. Additionally, a clear 3-ft pathway needs to be available for firefighter access to the roof.
3-ft clearance shown (Photos from Cal Fire)
National Electrical Code
NEC 690 defines electrical safety requirements for PV systems.
Equipment grounding required: Exposed non-current-carrying metal parts of PV module frames, electrical equipment and conductor enclosures must be grounded.
Structure as equipment grounding conductor: Devices listed and identified for grounding the metal frames of solar modules or other equipment can bond exposed metal surfaces or other equipment to mounting structures. Metal mounting structures (other than building steel) used for grounding purposes should be identified as equipment-grounding conductors or have identified bonding jumpers or devices connected between the separate metal sections bonded to the grounding system.
PV mounting systems and devices: Devices and systems used for mounting PV modules that are also used to provide grounding of the module frames should be identified for the purpose of grounding solar panels.
Adjacent modules: Devices identified and listed for bonding the metal frames of PV modules can bond one panel to an adjacent one.
To ensure NEC requirements are met, one should follow the racking manufacturer’s torque specifications to tighten down all connection points. These connections provide the bonding and grounding for the system when assembled properly.
The UL listing of the racking system should be checked to make sure it has been tested and listed under UL 703 for the provision of bonding and grounding required within the codes.
It’s important to remember that all codes are written for protection from system failures that could risk life and property. National codes are not always adopted and enforced by all states or local jurisdictions, so solar installers should always research what exactly is required by each AHJ.
For more information on designing and installing a solar system, check out IronRidge’s free webinars—each valid for 1 NABCEP CE credit.
I have a question I’m putting solar panels on the rear side of my A-Frame house this full access to the front roof is there any reason I cannot cover the entire back side of my roof with shoulder panels my town code says there’s an exemption if they can access the front but the Solar Company is telling me that they cannot accommodate what I’m asking I’ve done the calculations it would afford me four more panels approximately 1,600 Watts and I have high usage
Are the installers required to follow the manufacturers instructions for the roof mounts during an installation? What requires them to do so?
Thank you
Great article!
Do walkway distances apply to attached patio awnings? I have a patio attached to the south facing rear side of my house. It is a sloped awning with asphalt shingle roof. Electrical runs in the interior to provide power for two ceiling fans. Would placement of panels require a 3ft walk way, or could I cover the entire surface with solar panels?
P.S I live in Northern California if this helps
I have the same question but my canopy is over my garage doors. Did anyone give you an answer?
Great article,
What happens if my solar installer did not meet NEC requirements to include rapid shutdown for a residential system installed in 2022?
What type of system was installed? Todays optimizers and microinverters comply with rapid shutdown requirements. So if your system is Enphase, or SolarEdge those components both comply with rapid shutdown.
What are the grounding requirements for the solar panel brackets in Texas?
We are building a 12 unit apt. in Minneapolis. we are being told we will need a 42″ para-pit wall surrounding our solar panel lay out. Which has a 4′ clearance pathway surrounding as opposed to our stamped and approved 38.5″ height para-pit wall? Does anyone have a clear interpretation of the code that dictates this height and at what para-pit clearances? Also being told solar panels are classified as mechanical not electric.
i was told that some fire departments will not attempt to fight a fire that is in a structure that has solar panels, do to the panels still being “active”!
In my experience as a consultant who does post mortem on fires, fire depts. do, in fact, substantially delay response due to lack of education of how the rapid shutdown systems function. The fire depts. need to train their personnel working around PV. There really is no excuse, the codes have gotten so good at mitigating fire risks that structure fires are such a rarity that fire departments fire for budget relevance to be equipped for the what-if scenarios. Then they get a structure fire and blame it on the PV that they couldn’t properly fight the fire.
what fire lanes are required when installing a tilt kit for solar panel on a house without a parapet?
Why fire code is not needed on the flat roof solar installation in most of the state except NYC or other jurisdictions?
Our Solar was installed but wiring from the panels were sliced together in the attic, taped with wire nuts but not placed in any junction boxes with covers. Does this meet code?
No, splices with wire nuts should be in a junction box. Also, if the wire is not in conduit in the attic, it should be ROMEX or similar cable, not just THHN wire. (The opposite is also true. Romex cannot go in conduit as the extra insulation will cause it to overheat.)
NM cable (Romex) is designed to be run in conduit when protecting against physical damage. See NEC 334.15b
We recently contracted Titan Solar to install over 100 SilFab 300 panels to our terracotta tile roof. We inadvertently discovered that they had destroyed more than 300 tiles. This damage was due to 4 different crews and 16 different technicians stepping where they shouldn’t but also trying to drill into the concrete tiles. Now they think they can “Patch” the roof when these tiles no longer are produced. Can we get some advice on how to proceed?
Jeff,
Please reach out if you have not rectified this yet. We may be able to help.
Regards,
Simon Labrosse-Gelinas
Hello, i am a structural engineer out of Minneapolis that focusses primarily on rooftop solar panel installs. This particular question is from the 2018 IFC, specifically section 1204.3.3. A local building official is stating that one of the ventilation options in between sub arrays is required even if the sub arrays are fully contained within a 150ftx150ft area.
My interpretation of the code suggests that sub arrays can be continuous for 150 feet. Any larger requires breaks for ventilation and/or interior pathways. In the event of a fire and if roof top operations are employed a fire fighter needs to be able to traverse on the roof quickly hence the needs for the breaks.
However, some racking manufactures require breaks every 60-80 feet. Sometimes arrays must be broken up for ease of installation and or to avoid conduits or obstructions. Such is the case for a particular job right now where we have several small sub arrays in a cluster separated by 18″. From the start of the first array to the start of the last array does not exceed 150 feet. If the arrays were connected the official claims no pathways would be needed, but since they are we have to have a 4ft pathway with cut outs or an 8ft pathway between them.
To me this is in excess of what the language in the code intended to require. Please require clarification or direct me to someone who can.
Thank you
I already have all the brackets in place and I’m getting ready to set the panels up there. It looks like they might be too close to the edge of my garage, but since it’s attached to the house, firefighters can have plenty of room to go up on all sides of the house roof and across the top. I want to be in code.
great page, i was looking for code on fire setbacks for no livable structures. carports and sheds. if there is any info i would greatly appreciate it.
I am also looking for fire codes for a detached garage does anybody know where I can find that?
1204.2 exception 1
Colin could you let me know exactly where you found this article and detached garage ?
https://codes.iccsafe.org/content/IFC2018/chapter-12-energy-systems
The international fire code 605.11.3.2.4 that states “panels/modules installed shall be located no higher than 3 ft below the ridge to allow for fire department ventilation operations.” significantly decreases the attractiveness of residential solar PV because it applies to both sides of a peaked roof. Our fire chief indicated his crews need access to the peak, would in our case use a ladder truck from the north side of house which is a drive with access for the truck, and needs ability to make a vent hole near the peak, but not necessarily on both sides of the peak.
Our 45 degree south facing slope is ideal panel placement in Chicago area (latitude 41 degrees N) and could take a row of panels but for this rule. a flat roof abuts at 5 feet below the ridge, ruling out placement of panels lower on the sloped roof. I suggest this rule could give local fire chief’s latitude to determine which side of the peak they need clear.
Fire classification needs to match what is required, not what is existing.
Grounding and bonding is per UL 2703, not UL 703.
Fire classification is based on moduke testing to UL 1793, and system testing per 2703.
Technically, building steel can only be used for grounding if it is “conneced to the earth” by one of the methods described in NEC 250 (A) (1) or (2).
Good article though