Short Communication: Effects of Char Oxidation on Re-ignition Characteristics of Wood-based Materials

摘要

The term 're-ignition', often used in fire safety science, refers to the reappearance of a stable flame in the volatile gas stream evolving from a solid object after it had been extinguished by a suppressant such as water. The re-ignition phenomenon is of particular interest not only as a fundamental combustion problem, but also as a serious and sensitive fire safety issue. Surprisingly, only a limited number of investigations has been carried out on this topic. Such investigations, however, have been quite successful in identifying some of the key parameters which control the mechanism of re-ignition. In the case of charring solid fuels (e.g. wood-based materials), fuel porosity, the percentage of pre-burn, and the amount of water applied during the suppression phase have been identified as the key parameters. The heterogeneous secondary char oxidation rate has been also highlighted as an important controlling parameter, especially after the suppression phase when there is no flame to envelop the fuel surface. The impact of char oxidation process on the re-ignition mechanism of wood-based materials is the focus of the present investigation.