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Current assessment models and experimental tests on gas toxicities in a fire hazard are mainly based on the hypothesis that uniform smoke and gas layers exist in the compartment. This study, through experiments conducted in a reduced-scale compartment—corridor model, examines the assumption and explores the characteristics of spatial distribution of toxic gases in smoke transport from a fire hazard. The results suggest that the toxic gases in the upper layer in the corridor are characterized by uniform expansion, while those in the lower layer are not. It has also been found that evolutions of the gases in different layers are not synchronous, while they are identical at the same height where the densities are close. Further analyses indicate that the formation of CO from the deoxidization of O2, CO2, and the unburned hydrocarbon in the smoke movement delays the time of the maximum concentration.

Fire differs remarkably from other natural disasters because of its close relationship with human behaviors, which are affected by socioeconomic factors. In this article, research on the relationship between socioeconomic factors and fire in China is presented. Correlation analysis shows that in China, socioeconomic factors have a notable influence on fire. But the degree of correlation between them is different from that in other countries. In China, tendency of fire incidence and serious fire situations occur with the development of economy, which is a distinctive characteristic of the relationship between fire and socioeconomic factors. The fire data from China sounds paradoxical between two periods under study and the research indicates that fire rate has a poor relationship with college education, while in developed countries they are revealed as negative correlation. Finally, we discuss how socioeconomic factors influence fire and some predictions made on the fire situation in China.

The ignition of combustible materials is an important process in a fire incident. In this work, an experimental study on the ignition process of wood exposed to a variable heat flux has been carried out. Increasing heat flux is adopted and adjusted to simulate a practical fire environment. The time to ignition, temperature distribution, and mass loss are measured for two species of wood. Both, the increasing rate of incident heat flux and the properties of wood, especially density, obviously affect the results. A conduction model is developed to calculate the surface temperature. A compound ignition criterion is brought out for a variable heat flux.

The smoke concentration at a distant location down a hallway as a function of different openings of the room of fire origin is considered. A series of tests is reported and the smoke sustaining (residence) time, the concentration peak and the concentration buildup rate are investigated as functions of the size of the opening. The smoke sustaining (residence) time, the most important factor concerning smoke toxicity, is described by a novel concept, wavelength, in this study. Furthermore, it is worth emphasizing that the smoke concentration at the sampling point exhibits a phenomenon of vibration in the case of the smallest opening during the test.

This paper presents a microdiscrete evacuation model which emphasizes the human behavior and is focused on studying the generic properties of occupant evacuation from crowded large, open spaces after a fixed premovement stage. By using Cellular Automata (CA) in developing the rules, the model achieves the advantages of effectively capturing the behavior of occupants at the individual-level while attaining realistic collective level activity. The lively demonstration of the evacuation process offers an easy examination of occupant movement on computer. The studies on some important characteristics in evacuation such as the existence of different velocities of people and the different structure of building offer some key factors affecting evacuation efficiency. By studying on evacuation from a corridor, with and without widen part, we found disordered moving states will badly decrease the evacuation efficiency. It enables us to understand the special phenomena in evacuation and is helpful in performance-based building design.

Experimental measurements have been done for mass loss rate of some woods usingcone calorimeter and radiation platform for studying fire performance of materials at early stage, respectively. The experiments have indicated that both sample scale and apparatus scale affect the mass loss rate obviously. Generally, average mass loss rate of larger sample is higher than that of smaller sample. Scale has little effect on the first peak of mass loss rate, but it shows a distinct effect on the second peak. The second peak of mass loss rate of larger sample is much higher than that of smaller sample. There may be a critical sample size for the second peak existence. The sample in cone calorimeter can be ignited easily with stable and long time continuous flame compared with radiation platform under the same heat flux.

Hazards caused by detonation of hydrocarbon‐air mixtures are a continuing problem. Of the factors affecting detonation hazards of hydrocarbon‐air mixtures, additives play an important role. In this paper, a series of experiments are described addressing the influence of chemical additives on the detonation of some hydrocarbon‐air mixtures under confined (rectangle shock tube tests) conditions. The experimental results show that NT (nitric ether or RONO2), PO (1,2‐epoxypropane), and BPO (benzoyl peroxide) have a clear sensitizing effect on the detonation hazards of these mixtures. The mechanistic influence of additives is simply described, according to the chain reaction theory of detonation.

Generally speaking, some characteristics describing the early stage of fire include: heat release, smoke release, flame spread, toxic effluents, melting and dripping. To study these characteristics, an experimental setup must first be established. This paper presents results of experiments and mainly discusses the increase in flame image area of a fire during its early stage. The analysis shows that the flame image area of a fire at an early stage increases continuously, and the increase rule can be described using a geometrical function.

Hazards caused by detonation of hydrocarbon‐air mixtures have been a matter of concern for a long time. In this paper, critical initiation energy of detonation of some hydrocarbon air mixtures have been measured in confined (rectangle shock tube tests) and unconfined (plastic bag tests) condition. Based on the concept of explosion length, a formula for estimating the critical initiation energy of detonation under unconfined condition is presented. Detonation safety analysis of the studied hydrocarbons is carried out using the experimental results.