某机场航站楼自然排烟系统有效性的热烟试验研究

在许多高大空间建筑中安装有自然排烟系统,而随着空间高度增加,火灾烟气温度降低,浮力减小。在某机场航站楼二楼办票大厅进行了全尺寸火灾试验,对大厅顶部的电动自然排烟窗的排烟有效性进行检验。试验中火源为甲醇池火,添加发烟剂作为示踪粒子。共进行了6组不同排烟口面积和火源功率的试验,通过测量火源附近大厅上部烟气温度分布和排烟口速度验证自然排烟的有效性。结果表明,自然排烟窗能有效排出烟气,控制烟气沉降,降低火灾危险性。

Hot smoke test studies on the efficiency of natural venting system in an airport terminal

Natural venting systems are installed in many large space buildings.In current fire code,the natural venting systems can be installed in atria with height lower than 12 m.If the atrium is higher than 12 m,the mechanical exhausting system is required.However in fact,the natural venting systems are installed in many buildings with inner height exceeding 12 m.With the increasing of height,the smoke temperature and buoyance decrease.Thus,there is a need to study the efficiency of natural venting in high buildings.In this article,the full-scale fire tests were carried out in an airport terminal hall with the inner height about 20-24 m to check the efficiency of natural smoke venting.Methanol pool fire with size 1.7 m×1.3 m was designed.Two and three fire pools were used in the tests.Total 6 tests with different fire heat release and vent sizes were carried out.Two thermocouple trees were hanged from the roof vent near the fire source.One thermocouple tree with 21 thermocouples was 4.5 m away from the fire source center,and another with 24 thermocouples was 6 m away from the fire source center.The vertical temperature distribution under the roof vent in the hall was measured.The smoke velocity through the vent was also recorded.The results showed that the smoke velocity through the vent increased with the increase of fire source.The smoke velocity through the vent above the fire could achieve 4-5m/s,and the smoke could be controlled above 15 m.The smoke velocities through the vents have no obvious difference in the cases of different vents.The temperature near the roof was about 40 ℃.In the absence of natural ventilation,the highest temperature near the roof was 58 ℃.The smoke thicknesses in different cases were about 2-4 m.Briefly,the natural ventilation at the hall roof can control the smoke descending effectively to reduce the fire hazard.