Toward understanding ignition vulnerabilities to firebrand showers using reduced-scale experiments

Abstract

Over the past few years, the large outdoor fire problem has been a growing concern throughout the world. It is recommended to clear the combustibles around homes and within communities to avoid potential loss of properties, as firebrand shower ignition is a dangerous threat. One of the common combustibles around homes is mulching materials. A reduced-scale experimental protocol was developed to study ignition of mulching materials by firebrands and resulting impact to adjunct wall assemblies. Reduced-scale experimental results were compared with full-scale experimental results. Specifically, two trends were of interest in the comparisons. First, the ranking of the ease of ignition for various mulch types from exposure to firebrand showers. Second, if a given mulch type ignited from exposure to firebrand showers, was the resulting mulch bed fire able to ignite the adjacent wall assembly. The reduced-scale experimental results captured some of these trends observed from full-scale experiments but not completely. The findings still suggest that the reduced-scale experiments may give insights into how easily different mulch beds may be ignited by firebrands, as compared to much more costly and time-consuming full-scale experiments. While it is interesting to conduct full-scale experiments, this is very expensive and not always practical, so the authors are devising far cheaper reduced-scale experiments to provide more in-depth scientific understanding of firebrand shower ignition of construction components.