UK research calls for robust approach to rooftop solar fire safety
Written by admin on December 30, 2025
Research commissioned by the UK government finds rooftop solar panels can significantly influence fire behavior, particularly when the height gap between modules and the roof surface falls below critical limits.
A research paper commissioned by the UK government has concluded that a more comprehensive approach to fire safety in rooftop solar installations is needed.
The research, carried out by Manchester-based fire and risk consultancy OFR Consultants, comprises a literature review that investigated the extent to which rooftop solar systems alter fire dynamics or pose additional risks to roof constructions and firefighting operations.
It found that the interaction between solar panels and roofing materials can significantly influence fire behaviour by increasing the incident heat flux to the roof surface and the rate of fire spread. Experiments reviewed in the research demonstrate heat fluxes reaching almost 50 kW/msq when solar panels are present on roofs. Solar panel elevation, inclination, mounting systems, wind and spacing are among the factors listed as playing a crucial role in defining fire dynamics.
The consultants said a key insight from their research was the identification of a critical gap height between solar modules and roof surfaces beyond which flame spread damage can be minimized. A review of experimental research found that flame spread can accelerate by a factor of 38 when gap height falls below critical limits, due to enhanced heat retention and re-radiation, compared to a rooftop fire scenario without a solar system. The research adds that these findings are consistent across multiple independent studies conducted at medium- and large-scale incidents.
The consultants said the findings present a potential mitigation strategy for existing and new PV installations, but warned it must be balanced by structural and environmental considerations, such as wind loads and mechanical stability.
“While the critical gap height can inform fire-safe designs, it is important to recognise that reported values are case-specific and should not be directly integrated into installation standards without further validation,” the report said.
The research also found that existing classification tests and building guidance in England do not fully capture the fire dynamics introduced by solar arrays, as they do not account for modified fire scenarios created by PV system geometry, installation techniques, or system-wide behavior.
In the absence of a test capable of addressing the unique fire characteristics created by solar arrays on roofs, the consultants say focus should be placed on mitigating fire spread and roof penetration. Recommendations include using non-combustible roof coverings below solar installations and the introduction of guidance on the configuration and layout of solar arrays, including minimum gap heights between the roof covering and PV underside and appropriate spacing between panels.
“The extent to which all or some of the above recommendations are necessary would require additional research to investigate their efficacy,” the research paper said. “The alternative to the above recommendations is to consider the development of a roof test that better represents the fire dynamics induced by the installation of PV arrays.”
The research is part of the UK government’s real fires investigation project, which is taking evidence from real fire incidents to understand how buildings perform in practice in order to help improve building safety.
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