通风环境下保温材料XPS的火灾特性

Fire Characteristics of Thermal Insulation Material XPS Under Ventilation Environment

在0,0.6和1.2 m/s机械通风条件下,实验研究不同火源距离和火源位置时挤塑聚苯乙烯泡沫塑料(XPS)的火灾行为、引燃特性及烟气特性.结果表明,随着风速的增大,XPS表面火焰蔓延速度逐渐增大且较早出现结焦现象.通风风速和火源位置相同时,XPS引燃时间与火源距离近线性相关;火源位于垂直墙面位置时,风速从0.6 m/s增加到1.2 m/s,XPS最大引燃距离从0.2 m缩短至0.15 m.与其他工况相比,风速为0.6 m/s时,烟气温度达最大值,且氧气、二氧化碳及一氧化碳浓度变化量最小,XPS燃烧速率随着风速的增加先增大后减小;当风速较小时,氧气浓度增加对XPS燃烧起主导促进作用;随着风速的进一步增加,其热效应对燃烧的抑制作用显著增强.

The fire behavior,ignition characteristics and smoke characteristics of XPS(extruded polystyrene)were studied experimentally with various distances and locations of the fire source under the mechanical ventilation velocities of 0,0.6 and 1.2 m/s.The experimental results showed that the flame spreading speed on the surface of XPS gradually increased and coking appeared earlier with the increase of wind speed.The XPS ignition time were nearly linearly related to the fire source distances under the same ventilation velocity and fire source location.The maximum ignition distance of XPS decreased from 0.2 m to 0.15 m with the increase of ventilation velocity from 0.6 m/s to 1.2 m/s when the fire source was perpendicular to the wall.In addition,the maximum temperature of smoke and the minimum variation of the concentrations of oxygen,carbon dioxide,and carbon monoxide were obtained when the ventilation velocity reached to 0.6 m/s.Therefore,the XPS burning rate increased first and then decreased with the growth of ventilation velocity.When the ventilation velocity was low,the increase of oxygen concentration promoted the XPS combustion.The thermal inhibitory influence of new air on the XPS combustion was enhanced significantly with the further increase of the ventilation velocity,thus the XPS combustion rate reduced.