Transport And Distribution Characteristics Of Fire Smoke To The Remote Location In A Simulated Typical Building

Fires are a kind of hazards from burning that is out of control. Fire smoke leads to huge hazard on lives, properties and environment. There is a distinct variation of the main reason leading to death in fires along with the new categories of synthetic materials being applied in modern buildings. It is reported that smoke suffocation and toxicosis have been the most important reason of lethality in fire. The flowing and transportation of the high temperature smoke can enlarge the fire scenario easily. Hence study on the characteristics of the smoke in generation and transportation is of great importance.In the past forty years, researches on fire smoke have been widely conducted. Victims were found at the location remote to fire origin in many fire disasters occurred in these years. The available data on smoke transport to remote location is not sufficient, especially that on the spatial distribution and the transport route of the toxic gases in the buildings, and the effect of the environment on the gases. The typical building structure is modeled in the thesis, namely the "fire room-corridor-target room" structure, to conduct the study.In this thesis, a series of experiments are conducted on a reduced-scale apparatus under different building structures and ventilation conditions, in which six kinds of materials are chosen as fuel to be observed. By analyzing the mass loss rate, smoke transport velocity and CO concentration generally are studied, which are generally taken as important parameters in fire studies. We find that the smoke transport velocity is a linear function of mass loss rate and CO concentration arises as the mass loss rate increases.Considering that boards painted with white latex paint make the concentrations of some smoke species higher significantly and increase the smoke hazard, thermogravimetry (TG) analysis and infrared spectral analysis are conducted. The experimental results shows no occurrence of split reaction in the specimen under the current temperature and enhance of smoke hazard does not attribute to effect of the heat on the white latex paintBy many tests in the reduced scale of "fire room-corridor-target room" simulated model, the spatial distribution and evolution in different layers of the toxic gases are systematically explored. Further analyses indicate the fact that CO differs form O₂ and CO₂ in the time to the maximum concentration. The concept of total toxicity is developed based on the precious research to assess the toxic species in the transporting smoke. The influence of building structure and ventilation (doors, exits and windows) on the toxic gases transport is also researched.In the study of smoke transporting to remote locations, a new smoke transport route at upper-layer is found, with the utilization of the full-scale test data and numerical simulation approach. It is determined that it takes less time for the smoke transporting to remote places than to near room, while the smoke reaching remote rooms descend to the floor more quickly than that near the fire origins does, which could be the reason of many fatalities occurring remote to the fire origins. Based on another full-scale experiment data conducted in a long underground corridor, we study the characteristics of smoke movement and species variation. The smoke transport velocity and the species concentration are measured and calculated under different conditions. It indicates that FDS model is not able to simulate the vertical layered phenomenon of the smoke temperature distribution in the long-hallway commendably. Predicted results of O₂, CO₂, and CO concentrations are consistent with those of the experiments, but predicted CO concentration peak is smaller than that measured from experiments.