On The Analysis Method Of Smoke And Temperature Hazard Based On The Spatial Distribution Of Smoke

Generally speaking, in building fire, people is hurt or killed by extra-high temperature, asphyxia caused by extra-low oxygen concentration, and toxic gases. To reduce and avoid the loss of property and life in fire disaster, it is very important to study the hazardous factors of fire, and carry out some hazard analysis.In this thesis, a series of experiments were carried out on the bench scale of"fire room-long passage"apparatus to study the spatial distribution rule of temperature and smoke in fire scenario. It is found that the vertical distribution rule of temperature at the center of the fire room is opposite to the corner. And the spatial distribution rule of temperature and smoke is inconsistent.The interactivity between the spread smoke and its refluence with lower temperature and lower smoke concentration is used to explain the unusual phenomenon of the spatial distribution rule of smoke in the long passage.It is found that it is not suitable to analyze the hazard of fire merely through the concrete temperature or smoke concentration,because of these reasons: 1) It does not include the time factor, and it may lead to wrong evaluation of smoke hazard; 2) it is a parameter with dimension and is not quantitative, so it is difficult to reveal some hazardous rule of smoke; 3) it cannot be used to analyze some unusual phenomenon, and is also difficult to integrate different hazardous factors. So based on the study of some other researchers and data from the study of spatial distribution rule, a concept named I h(Index of hazard) is proposed and used to analyze the temperature and smoke hazard in the typical building. Generally, the conclusion based on I h is consistent with the experiments, and some new rules are revealed. For example, it is found that some positions far away from the fire room may have a high hazardous grade which is close to the hazardous grade of positions near the fire room. This phenomenon reminds us to be careful with the hazardous grade at the location far away from the fire room. Meanwhile, based on the analysis of the impact of latex paint on the smoke hazard, it is found that the impact may be overrated.I his a dimensionless parameter, which involves both the time factor and concentration/temperature factor, it brings in the concept of hazardous concentration, and it is the ratio of hazard with the critical hazard. I h is much more convenient to be used and will be helpful for the analysis of smoke hazard.