Solar Builder - Problematic Fastener Selection

Mature industries are characterized by well-developed engineering practices, standards, quality management processes and highly reliable systems. The solar PV industry has generally not achieved this level of maturity in its structures and fastener technology. During the 2022 RE+ event in Anaheim California, this past September, a research team walked the Exhibit Hall and found many stark examples of industry immaturity. The team performed an informal survey and spotted common misspecification and, in two cases, particularly extreme examples of misapplications. In one example, the team spotted car headliner fasteners, and with the second, a chain link fence component — both nonstructural but called upon to maintain structural integrity. The importance of fasteners within PV racking and tracker systems is often overlooked by system designers. Although composed of relatively simple and inexpensive components, fasteners play a critical role in the structural reliability of PV systems. Joint engineering practices and standards in structural steel and transportation industries have matured over the past century and become widely adopted. As a result, failures of fastened joints (or bolted joints) in buildings and transportation are now rare. In comparison, the solar PV industry is relatively young and lacks the depth of engineering practices and standards of other industries. Loose, missing or broken bolts in solar are surprisingly common. When it happens, modules can become damaged, detached, or even worse, systems can collapse. All of these can increase maintenance costs, reduce system performance, or worst of all, create life-safety risks.

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