Journal Article Investigates Window Pane Failure During Exterior Fire Exposure
The peer-reviewed journal article “Window Pane Failure During Exterior Fire Exposure” has been published in Fire Technology. Key findings from this study support the Heat Transfer from Structure Fires research project, led by the Fire Safety Research Institute (FSRI), part of UL Research Institutes. The article was co-authored by FSRI research engineers Joseph Willi and Daniel Gorham, as well as FSRI research director Gavin Horn.
Studying Window Pane Failure is Critical for Understanding Structural Fire Spread
Window failure from fire exposure creates a potential vulnerability for structures. This failure introduces a pathway for firebrands, flames, and hot gases to enter the structure and potentially ignite interior combustibles like furniture and curtains. Investigating window failure is critical for understanding how the selection of building materials in both wildland urban interface (WUI) and urban communities may impact potential fire spread between structures.
In this study, FSRI researchers conducted eight experiments testing 16 window pane assemblies mounted on a target façade facing a post-flashover compartment fire. Researchers examined four types of double pane assemblies: (1) both panes plain glass, (2) both panes tempered glass, (3) plain glass fire side pane and tempered glass back side pane, and (4) tempered glass fire side pane and plain glass back side pane. The purpose of these experiments was to identify differences in failure of the four pane assembly types during exterior fire exposure. Researchers also quantified heat flux behind each window pane assembly and compared the measurements to critical heat flux values for ignition of common household materials.
“The valuable insights gained from this study can be used to improve the resiliency of structures in communities with a WUI fire hazard. Most notably, the addition of a back side tempered pane drastically reduced the failure rate of double pane window assemblies.”
—Joseph Willi, research engineer, FSRI
Informing Building Codes and Homeowner Guidance
This study revealed several key takeaways, which can be used to inform building codes and homeowner guidance related to the installation of tempered pane windows in areas prone to WUI fire incidents.
- Window pane assemblies with plain glass on the fire (exterior) side and tempered glass on the back (interior) side outperformed windows with the opposite configuration.
- Window pane assemblies with both panes tempered glass performed the best of the four types considered in this study.
- Heat transfer through windows has the potential to ignite interior combustibles even without window failure.
- Frames and other window components should also be considered when addressing window failure from exterior fire exposure.
About Fire Technology
Fire Technology is a leading research journal dedicated to resolving problems in fire safety and fire engineering. It publishes applied research on topics related to actual and potential fire hazards facing humans and the built environment.
