高温烟气层对室内非连续介质着火的影响

摘要

室内发生火灾时,经常遇到一处首先着火,然后和火源间隔一定距离的可燃物也开始着火的现象.以木材为例,通过小规模火灾实验,测量不同环境条件下和火源间隔一定距离的木材发生着火燃烧时的烟气层温度,研究了室内火灾中高温烟气层对非连续介质着火的影响.研究表明,高温烟气层温度达到非连续介质的自燃点是其着火的必要条件,高温烟气层在非连续介质着火过程中起到了＂点火源＂的作用.因此,可以通过阻止烟气层温度达到非连续介质的自燃点或避免非连续介质可燃挥发份和高温烟气层相接触等措施防止室内火灾时非连续介质着火,从而防止火灾的蔓延扩大.%When indoor fire happened,it is often occurred that a local fire first appears in a place,then the combustibles spaced certain distance with the occurred fire will be ignited and begin to burn.As an example,the smoke temperature was measured when the wood keeping a certain distance away from the ignition source caught fire in different environments,and the influence of the hot smoke layer on the discrete objects ignition was studied through small scale fire experiments.The results show that the smoke temperature reaching the self-ignition point of the discrete objects is a qua non of their ignition,and the hot smoke layer plays an important role as an ignition source when the discrete objects catch fire.So,the measures such as stopping the smoke layer temperature reaching the self-ignition point of the discrete objects or avoiding the combustible volatiles of the discrete objects contacting with the hot smoke layer can be adopted to prevent the discrete objects ignition in enclosure fires,and therefore to prevent the spreads of the fires.