Solar Panel Structure Safety Concern
As State Architect, it is my responsibility to advise you of a situation that, although apparently isolated, may impact the safety of the solar structures on your campuses. On three occasions this year, solar panels at three school campuses dislodged from the structures to which they were attached, during winds that were recorded as moderate for the region. In each case, the structures were free-standing, open-framed, steel structures over parking lots. There were no injuries, and these are the only such incidents of which the Division of the State Architect (DSA) is aware.
Based on the limited information obtained, we believe there are several factors possibly contributing to these attachment failures:
- Advancements in solar glass panel design have resulted in thinner, higher performing, lightweight photovoltaic glass panels. Structural racking and twisting (rotation) loads caused by wind gusts resulted in deformation of the panel frame, allowing the glass panel to separate from the panel frame.
- Free-standing, open-framed, steel structures over parking lots are deflecting under certain wind loads, causing them to place structural loading on the solar panel frames, the friction clip, and bolted connections, which they were not designed to accommodate.
Additionally, while the exact cause(s) of the separations are inconclusive, variations in installation methods, inspection, and maintenance must be considered. Therefore, in the interest of safety, I strongly recommend you contact the entity responsible for the installation of any solar panels on your campus, mounted on free-standing, open-framed, steel structures, to inspect them for signs of potential panel dislodgement. This inspection may be covered under either your warranty or maintenance agreement. If you do not have a warranty or maintenance agreement, you should consult a solar panel maintenance provider to inspect them for signs of potential panel dislodgement. I also encourage regular maintenance inspections thereafter. Should retrofit be required, please do not hesitate to contact a structural supervisor at your DSA regional office if you have any questions.
For our part, I have directed DSA staff to work with the entities involved in the manufacture, design, and installation of the solar panels to determine the probable cause of the attachment failures for projects already constructed, and for those entities to develop methods to retrofit existing installations when necessary for DSA approval. To prevent additional incidents, we are reviewing attachment requirements for projects under construction, projects approved but not yet constructed, and projects in design. Additionally, we are sending letters to those involved in the manufacture, design, and installation of the solar panels, notifying them of this matter and asking that they inform their colleagues as well. For your reference, please refer to the recommendations for panel attachment to the structure for projects pending DSA’s approval.
We bring this to your attention out of an abundance of caution, as the three dislodgement incidents—out of thousands of panel installations—are the only ones of which we are aware, but we believe the issue presents a concern that merits your attention.