@article {bnh-7686, title = {Determination of Firebrand Characteristics Using Thermal Videos}, journal = {Fire}, volume = {3}, year = {2020}, month = {11/2020}, abstract = {

Burning firebrands generated by wildland or prescribed fires may lead to the initiation of spot fires and fire escapes. At the present time, there are no methods that provide information on the thermal characteristics and number of such firebrands with high spatial and temporal resolution. A number of algorithms have been developed to detect and track firebrands in field conditions in our previous study; however, each holds particular disadvantages. This work is devoted to the development of new algorithms and their testing and, as such, several laboratory experiments were conducted. Wood pellets, bark, and twigs of pine were used to generate firebrands. An infrared camera (JADE J530SB) was used to obtain the necessary thermal video files. The thermograms were then processed to create an annotated IR video database that was used to test both the detector and the tracker. Following these studies, the analysis showed that the Difference of Gaussians detection algorithm and the Hungarian tracking algorithm upheld the highest level of accuracy and were the easiest to implement. The study also indicated that further development of detection and tracking algorithms using the current approach will not significantly improve their accuracy. As such, convolutional neural networks hold high potential to be used as an alternative approach

}, keywords = {wildfires; firebrands; software; detection; tracking; fire management}, doi = {https://doi.org/10.3390/fire3040068}, url = {https://www.mdpi.com/2571-6255/3/4/68}, author = {Sergey Prohanov and Alex Filkov and D. P. Kasymov and Mikhail Agafontsev and Vladimir Reyno} } @article {bnh-5141, title = {Determination of smoldering time and thermal characteristics of firebrands under laboratory conditions}, journal = {Fire Safety Journal}, volume = {91}, year = {2017}, month = {07/2017}, pages = {791-799}, chapter = {791}, abstract = {

The laboratory experiment was conducted to simulate the transfer of smouldering particles produced in forest wildfires by a heated gas flow. The pine bark pieces with the linear dimensions\ L=(15; 20; 30) mm and a thickness of\ h=(4-5)mm were selected as model particles. The rate and temperature of the incident flow varied in the range of 1{\textendash}3m/s and 80{\textendash}85{\textdegree}C, respectively. The temperature of the samples was recorded using a thermal imager. To determine the minimum smouldering temperature of pine bark, the thermal analysis was conducted. The minimum smouldering temperature of pine bark was found to be 190{\textdegree}C. This temperature will cause thermal decomposition of bark only at the first stage (oxidation of resinous components). In the study the smouldering time, the temperature and the weight of samples were obtained and analyzed under various experimental conditions. The data analysis shows that the increase in the particle size leads to the decrease in their mass loss, and the rate change of the incident flow does not practically influence the mass change. For particles with the linear dimensions of 10mm and 20mm, the mass varies from 6\% to 25\%. The maximum mass loss is observed for the flows with a rate of 1 and 2m/s. The results have shown that the increase in the particle size leads to the increase in the smouldering time. The position of the particle plays an important role, the effect of which increases with increasing the particle size. The calculations showed that the smouldering time of bark samples is long enough for the particles to serve as new sources of spot fires. The particles were found to be transported to a distance of 218m from the fire line which can certainly influence the propagation of the fire front.

}, doi = {https://doi.org/10.1016/j.firesaf.2017.03.080}, url = {https://www.sciencedirect.com/science/article/pii/S037971121730125X}, author = {Vladimir Fateev and Mikhail Agafontsev and Sergey Volkov and Alex Filkov} }