CSLB C-46 Solar ContractorPlanning and EstimatingMedium
A C-46 contractor is designing a commercial rooftop PV system for a building with a flat, unused roof. The client wants to maximize energy production while ensuring the long-term integrity of the roof membrane. The preliminary site analysis indicates the roof has sufficient structural capacity but a limited load capacity for additional ballast. Which racking system would be most appropriate for this scenario?
- AFixed-tilt, penetrating racking system.
- BLightweight, non-penetrating, low-ballast racking system.
- CGround-mounted racking system.
- DHeavy ballasted racking system.
Show answer & explanationAnswer & explanation
Correct answer: B. Lightweight, non-penetrating, low-ballast racking system.
A lightweight, non-penetrating, low-ballast racking system is ideal for flat commercial roofs with limited load capacity. It protects the roof membrane from penetrations and minimizes the added weight, while still providing optimal tilt for energy production.
Why the other options are wrong
- A. Penetrating systems create holes in the roof membrane, increasing the risk of leaks, which the client wants to avoid.
- C. A ground-mounted system is not a rooftop solution and would not utilize the unused roof space as intended.
- D. A heavy ballasted system exceeds the roof's limited load capacity, making it unsuitable and potentially unsafe.
Low-Ballast Flat Roof Racking
A non-penetrating PV racking system designed for flat commercial roofs with limited structural load capacity, using minimal ballast to secure the array.
- Avoids roof penetrations to preserve membrane integrity.
- Minimizes added weight on the roof.
- Often uses aerodynamic design to reduce wind uplift forces.
Memory trick: Light, non-penetrating, low-ballast: the feather-touch for fragile roofs.