P. P. Yin, N. A. Liu, H. X. Chen, J. S. Lozano and Y. L. Shan (2014) New Correlation Between Ignition Time and Moisture Content for Pine Needles Attacked by Firebrands. Journal/Fire Technology 50 79-91. [In English]
Web link: http://dx.doi.org/10.1007/s10694-012-0272-y
Keywords: Firebrand, Spotting fire, WUI fire, Ignition time, Moisture content, Heat transfer, HIGH WINDS, FUEL BEDS, FLAMMABILITY, TRAJECTORIES, FIRES

Abstract: The capacity of firebrands for ignition is closely related to fuel conditions which include fuel type, moisture content (MC), fuel distribution and fuel bulk density, among which MC is the most important. In this paper, a new correlation between ignition time (t (ig)) and MC of fuels is established by theoretical consideration of the heat transfer processes that occur when fuels are ignited by glowing firebrands that have settled on a fuel bed. The results suggest a linear relationship between t (ig) (1/2) and MC. This linear correlation is verified by data from six groups of firebrand ignition experiments in which pine needles were used as the fuel to be ignited, with MCs ranging from 12.9% to 65%. The wind speed during experimentation was maintained at 3 m/s (+/- 0.2 m/s). The studies by Jolly et al. support the theoretical correlation.