Localized heat transfer from firebrands to surfaces

Firebrands are known to cause spot fires and structure ignition far from the fire front, but there is a limited understanding of the heat transfer from firebrands to surfaces. In this work, high resolution heat flux distributions were measured for single firebrands with different geometries using IR thermography and inverse heat transfer analysis. Localized heat fluxes from a single firebrand were measured to be 30–105 kW/m2, which is 2–6 times higher than previous work with heat flux gauges and energy balance methods that spatially average the heat transfer from the firebrand. Firebrand geometry, wind speed, and wind speed orientation relative to the firebrand affect the heat flux magnitude and duration of the exposure. •High resolution heat flux measurements from firebrands.•Firebrand local heat fluxes were measured to be 30–105 kW/m2 which is 2–6 times higher than low resolution methods.•Firebrand geometry, wind speed, and wind speed orientation affect heat flux level and duration.