Fire safety is a top concern for many building owners and facility managers. Flat-roof solar installations introduce unique risks that can aggravate fire incidents. Recent studies and real-world cases highlight the importance of how solar systems interact with the underlying roofing materials, and how different solar and roofing designs can reduce fire risks.
The Fire Risk in Conventional Flat-Roof Solar Systems
Roof fires related to solar installations often originate in electrical connections between the panels and the building's electrical system. A notable case in 2024 at a Lidl warehouse involved an electrical fault in the solar panels that caused a fire, which rapidly spread across the roof due to the extensive coverage of panels. Traditional flat-roof solar solutions, in which panels are mounted at low angles, create cavities between the solar panels and the roofing membrane. This space acts as a channel for the fire to spread underneath the panels, intensifying the flames and causing significant damage to the roof structure.
Research has shown that fires can spread extensively in such configurations, as highlighted in studies by Kristensen and Jomaas. These studies, along with real-world cases, demonstrate that conventional solar panel setups on flat roofs allow fires to propagate beneath the array. This problem is compounded when the roof membrane consists of combustible materials like bitumen or PVC.
The Fire Safety of Over Easy Solar’s Vertical PV System
In response to the fire hazards posed by conventional flat-roof systems, the innovative design of vertical photovoltaic (VPV) panels offers a safer alternative. In particular, the Over Easy Solar VPV units have been rigorously tested to assess fire behavior, and the results reveal a significant improvement in fire safety compared to traditional solar arrays.
Recent tests conducted by the Department for Fire-Safe Sustainable Built Environment, led by fire safety expert Grunde Jomaas, specifically evaluated the fire spread on a roof segment equipped with Over Easy Solar VPV units. The report, titled “Fire Tests with Vertical PV Modules on a Roof Segment,” demonstrated that vertical installations considerably limit fire spread compared to conventional flat-roof systems. Get in touch with us if you want to have access to the full report.
Higher Fire Safety with Vertical Solar Panels
The fire tests conducted on Over Easy Solar VPV units were designed to simulate worst-case scenarios. Ignition sources were strategically placed near the junction boxes and mounting frames, the areas most prone to fire in solar installations. The test roof was constructed using common roofing materials, such as bitumen and PVC membranes, to replicate real-world conditions.
The results showed that fire spread was significantly reduced with the Over Easy Solar vertical panels. Unlike flat-panel systems, where flames can travel underneath the solar array, the vertical design of the VPV system prevented flames from spreading beneath the panels.
"It is deemed that installation of Over Easy Solar panels does not change the expected fire consequences on a flat roof that is installed according to current standards and requirements. This contrasts with results for other PV installations, which have been shown to increase the fire consequences substantially." Grunde Jomaas, ERA Chair holder and Head of Department for Fire-safe Sustainable Built Environment, ZAG
The fire with origin in a small wood-crib spread below the low angle solar panels, but stayed localized with vertical solar panels installed. Photo: Slovenian National Building And Civil Engineering Institute (ZAG)
The fire tests revealed that the roofing membrane's natural fire retardant properties functioned as expected when using the VPV system. In the absence of solar panel coverage directly above the membrane, as is typical in vertical installations, the roofing materials performed better in containing and extinguishing the fire. The Over Easy Solar VPV units allowed the membrane to retain its fire-resistant characteristics, ensuring that any ignition was quickly localized and extinguished.
Is There Reason to Panic About Conventional Flat Roof Solar?
No. Conventional solar installations built by professional PV installers, do not increase the fire risk substantially, so there is no reason to panic. However, for certain types of buildings, fire safety considerations must take center stage. Our tests demonstrate that vertical PV panels, like those from Over Easy Solar, offer a safer alternative to conventional flat-roof solar setups.
For building owners looking for safer solar solutions, Over Easy Solar’s VPV units are a forward-thinking choice that combines innovation with peace of mind. Contact us if this is of interest.
