CSLB C-46 Solar ContractorPhotovoltaic System InstallationMedium
A solar designer is planning a large commercial PV installation on a flat membrane roof. To optimize energy production and minimize roof penetrations, they opt for a ballasted racking system. What is the primary method used to prevent the array from being dislodged by wind uplift in this type of system?
- AAnchoring the racking directly into the structural roof members.
- BEmploying active hydraulic dampeners to counter wind forces.
- CDistributing static weight (ballast) across the racking structure.
- DUsing adhesive bonding agents to secure modules to the roof surface.
Show answer & explanationAnswer & explanation
Correct answer: C. Distributing static weight (ballast) across the racking structure.
Ballasted racking systems rely on the distributed weight of ballast (e.g., concrete blocks) to counteract wind uplift forces and hold the array in place, minimizing roof penetrations.
Why the other options are wrong
- A. This describes a penetrative racking system, not a ballasted one.
- B. Active hydraulic dampeners are not a standard or practical solution for preventing wind uplift in typical PV racking.
- D. Adhesive bonding is not typically used for large-scale PV racking systems due to durability and shear strength concerns.
Ballasted Racking Wind Resistance
Method where the weight of ballast material (e.g., concrete blocks) is distributed across a PV racking system to counteract wind uplift forces without penetrating the roof.
- Primarily used on flat roofs.
- Minimizes roof penetrations, reducing leak risks.
- Ballast weight calculations are critical for structural integrity.
Memory trick: Wind Resistance: Weight, Weld, or Wedge