Experimental investigation of firebrands: Generation and ignition of fuel beds

A series of real scale fire experiments were performed to determine the size and mass distribution of firebrands generated from Douglas Fir (Pseudotsuga menziesii) trees. The results of the real scale fire experiments were used to determine firebrand sizes to perform reduced scale ignition studies of fuel beds in contact with burning firebrands. The firebrand ignition apparatus allowed for the ignition and deposition of both single and multiple firebrands onto the target fuel bed. The moisture content of the fuel beds used was varied and the fuels considered were pine needle beds, shredded paper beds, and shredded hardwood mulch. Firebrands were constructed by machining wood (Douglas Fir) into small cylinders of uniform geometry and the size of the cylinders was varied. The firebrand ignition apparatus was installed into the Fire Emulator/Detector Evaluator (FE/DE) to investigate the influence of an air flow on the ignition propensity of fuel beds. Results of this study are presented and compared to relevant studies in the literature.