Flaming Ignition of PMMA, Pine Wood and Pine Needle by External Radiation: Autoignition and Radiant Distance Effect

Flame radiation is one of the important causes wildland–urban interface (WUI) fires. PMMA, pine needle and wood are most common fuels in WUI fires, but radiant distance effect on flaming ignitions as well subsequent burning behavior still poorly understood. This work represents an experiment to investigate autoignition pine-needle pine-wood fuel beds with different distances (25 mm–100 mm) under a uniform incident heat flux, 25 kW/m2 The results show that for PMMA wood, they all transition from gas-phase ignition near cone heater solid-phase ignition. For needle, it has smoldering smoldering-to-flaming relationship between delay time approximately inverted u-shape curve, there exists critical (D = 60 minimum time. when D < mm, linear distance, D, tig−1/2.