January 12, 2026 — Southwest Research Institute (SwRI) conducted a series of large-scale tests to investigate factors that affect flame spread beneath photovoltaic (PV) panel installations on flat, commercial and industrial rooftops. The research will help fire safety organizations update standards and fire mitigation strategies.
The team fabricated test decks to replicate large roofing assemblies with mounted PV solar panels. Researchers exposed the leading edge of the deck to flame and crosswind to better understand fire hazards and evaluate mitigation strategies. The testing provided critical data for builders, insurance groups and first responders.
SwRI performed baseline tests with three different PV panel racking orientations to determine which exhibited the fastest flame spread. The team also tested two fire prevention techniques, uncovered walkways and vertical barriers, with the selected racking orientations. Finally, a comparison test was performed with a bare deck.
“SwRI’s large indoor fire testing facilities and custom pollution abatement system allowed us to safely conduct the largest-scale evaluations of PV panels to date with greater exposure control while protecting the environment,” said Alexandra Schluneker, principal engineer on the project. “Previous testing was either done on a smaller scale or performed outdoors.”
Sponsored by the National Fire Protection Association’s Fire Protection Research Foundation and its Property Insurance Research Group, the research will help the organizations update building codes and fire mitigation protocols specifically for commercial and industrial solar panel installations.
“Large-scale fire testing of PV panels to evaluate performance, flame spread and potential prevention and suppression strategies is not just a technical necessity — it is a cornerstone of advancing fire safety to ensure renewable energy solutions remain both sustainable and secure for the communities they power,” said Karen C. Carpenter, director of SwRI’s Fire Technology Department.
SwRI’s Schluneker co-presented preliminary findings from the tests at the 2025 NFPA conference in Las Vegas, Nevada, on June 18, 2025. A second round of fire testing will be performed in early 2026 to further investigate additional mitigation strategies.
For more information, visit Fire Research & Engineering or contact Camaron Brooks, +1 210 522 2357, Communications Department, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238-5166.