Quantifying Firebrand Production and Transport Using the Acoustic Analysis of In-Fire Cameras

Journal Article · 01 February 2022 · Fire Technology

DOI: https://doi.org/10.1007/s10694-021-01194-y · OSTI ID:1876802

Thompson, Dan K.  ^[1]; Yip, Daniel A. ^[2]; Koo, Eunmo  ^[3]; Linn, Rodney Ray  ^[3]; Marshall, Ginny ^[4]; Refai, Razim ^[5]; Schroeder, Dave ^[6]

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1. Natural Resources Canada, Sault Ste. Marie, ON (Canada)
2. Wildlife Conservation Society Canada, Whitehorse, Yukon (Canada)
3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
4. Natural Resources Canada, Edmonton, AB (Canada)
5. FPInnovations Wildfire Operations Research, Edmonton, AB (Canada)
6. Alberta Agriculture and Forestry, Edmonton, AB (Canada)

Firebrand travel and ignition of spot fires is a major concern in the Wildland-Urban Interface and in wildfire operations overall. Firebrands allow for the efficient breaching across fuel-free barriers such as roads, rivers and constructed fuel breaks. Existing observation-based knowledge on medium-distance firebrand travel is often based on single tree experiments that do not replicate the intensity and convective updraft of a continuous crown fire. Recent advances in acoustic analysis, specifically pattern detection, has enabled the quantification of the rate at which firebrands are observed in the audio recordings of in-fire cameras housed within fire-proof steel boxes that have been deployed on experimental fires. The audio pattern being detected is the sound created by a flying firebrand hitting the steel box of the camera. This technique allows for the number of firebrands per second to be quantified and can be related to the fire's location at that same time interval (using a detailed rate of spread reconstruction) in order to determine the firebrand travel distance. A proof of concept is given for an experimental crown fire that shows the viability of this technique. When related to the fire's location, key areas of medium-distance spotting are observed that correspond to regions of peak fire intensity. Trends on the number of firebrands landing per square metre as the fire approaches are readily quantified using low-cost instrumentation.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: US Department of Agriculture
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 1876802
• Report Number(s): LA-UR-21-22060
• Journal Information: Fire Technology, Journal Name: Fire Technology Journal Issue: 3 Vol. 58; ISSN 0015-2684
• Publisher: SpringerCopyright Statement
• Country of Publication: United States
• Language: English