窗墙面积比对高层住宅外墙外保温火灾蔓延的影响分析

外墙外保温火灾发生后,窗口不仅成为火焰进入室内的通道,而且提供大量的新鲜空气,可能导致室内发生轰燃。为了研究住宅窗墙面积比（以下简称窗墙比）对火势的蔓延速率和火场温度的影响,采用了美国标准与技术研究所开发的场模拟软件FDS（火灾动力学模拟器）,模拟了不同窗墙比情况下的住宅外墙外保温火灾。分析结果表明：随着窗墙比的增大,火灾蔓延速率变快,蔓延范围增大,但峰值温度降低;起火面窗墙比为0.25时,测点峰值温度远大于对照组,起火面窗墙比为0.30时,起火房间有明显的轰燃现象,起火面窗墙比为0.35时,充分对流通风,环境冷空气进入室内,峰值温度较低;非起火面窗墙比变化基本符合上述规律,但当窗墙比过小（0.20）时,火焰难以进入室内,火势较小。

Analysis of Influence of Window-wall Ratio on Exterior Insulation Fire Spread of Highrise Residence

When exterior insulation fire occurs, windows not only become passageway, which brings flame inside, they also provide considerable amount of fresh air that may cause indoor flashover. In order to study influence of window-wall ratio on fire spreading rate and tempera- ture,this article uses field simulation software FDS（Fire Dynamics Simulator） to simulate resi- dential exterior insulation fire scenarios with different window-wall ratio. It concludes that as the window-wall ratio increases, both the fire developing speed and spreading scope increase, peak temperature however decreases. When window-wall ratio of burning side is 0.25, the peak tem- perature of measuring point is much higher than other control groups. When the ratio is 0.30, flashover takes place in the burning room. When the ratio is 0.35, sufficient fresh air flows in, then the peak temperature drops. For none-burning side, its characteristic fits above regularity basically. When the ratio is too small（ 0.20）, it is hard for flame to get to room and therefore the situation is not severe.