When wildfire threatens neighbourhoods with closely-spaced homes, what determines whether flames leap from one structure to the next? The FSRI research team - Rebekah Schrader, Joseph Willi, Daniel Gorham and Gavin Horn - joins us to unveil their experimental series that methodically dissects the pathways through which fire spreads between buildings.

The team walks us through their massive outdoor experimental setup, where they created controlled compartment fires and measured their impact on adjacent walls and windows at various separation distances. They discovered that even non-combustible exterior cladding like fiber cement board won't necessarily protect a home when the underlying sheathing is combustible—especially at close distances where heat fluxes reach a staggering 75-125 kW/m².

Windows emerge as perhaps the most vulnerable component, with their research revealing dramatic differences in performance between glass types. Double-pane tempered glass significantly outperforms plain glass configurations, but the surprising finding was how much window frame materials matter. In one experiment, vinyl frames completely failed while the glass was still intact, causing entire window assemblies to drop from the wall.

Another aspect of their research are the measurements of the heat transfer through intact windows. Using specialized measurements, they found that significant radiant heat penetrates even unbroken windows, potentially igniting curtains or furniture inside before the window itself fails. Low-emissivity coatings proved remarkably effective at reducing this heat transfer.

This research offers crucial insights for homeowners, fire safety engineers, and policymakers working to create more resilient communities. The findings extend beyond wildland fire applications, providing valuable data for urban fire safety engineering across multiple contexts.

Find the research papers at:

• https://onlinelibrary.wiley.com/doi/10.1002/fam.3278
• https://link.springer.com/article/10.1007/s10694-024-01685-8
• https://link.springer.com/article/10.1007/s10694-024-01656-z

And additional resources at:

• https://fsri.org/research-update/journal-article-reports-heat-transfer-through-different-window-constructions
• https://fsri.org/research-update/journal-article-investigates-role-residential-siding-materials-spread-exterior

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