Search

Since the 1970s, researchers have developed semi-empirical models to describe fire smoke movement inside buildings, but there are three major issues. Firstly, several plume models are available to estimate the smoke production rate and the capacity of smoke extraction fans, but their discrepancy or accuracy is unclear. Secondly, the phenomenon of stratification affects the vertical transportation of smoke, and influences the activation time of the detectors and the efficiency of the smoke extraction system. A stratification model is available in the literature to calculate the maximum height that smoke can rise, but it cannot cover all design scenarios. Thirdly, the size of the smoke reservoir has been regulated in fire regulation. The regulation does not consider the factors that strongly affect the movement of smoke in the reservoir, such as the ceiling height, reservoir shape, smoke temperature, etc. These models are difficult to directly apply to a practical design project, and some clauses of the fire regulation do not address the requirements correctly and become a hurdle of design. This paper depicts the cases encountered during the design over the past decades and provides detailed processes of solving these issues. The approach of the design process demonstrates how fire engineers further develop the fire models and fill the gap between research and engineering practice. This paper systematically examines fire smoke models for the plume, vertical transportation of the smoke, the ceiling jet, and smoke spreading underneath the flat ceiling, and provides practical solutions for each of the smoke development stages.

In recent years, vulnerable populations have become the main targets of casualties in many building fire accidents. It is of great significance to study the behavioral patterns of vulnerable populations during emergency evacuation and to design specialized strategies conducive to the evacuation of vulnerable populations to improve evacuation efficiency and reduce casualties. In this paper, simulations are carried out using AnyLogic based on a social force model to explore the impact of dedicated exits in public places on the evacuation of vulnerable populations. A model of a normal room with three exits was created in which pedestrians were divided into two categories: normal and vulnerable populations with different evacuation speeds and footprint sizes. Simulation results show that dedicating middle exits reduces evacuation time in most cases while dedicating side exits significantly increases evacuation time. Middle exits as dedicated exits can balance the evacuation speed of vulnerable and normal populations, and improve the overall evacuation efficiency of vulnerable populations. Calculating the balance analysis index OPS for building evacuation, the results show that the balance of exits is the key to the evacuation time, and the closer the OPS value is to 0 the better the evacuation balance, which leads to a shorter evacuation time. This paper illustrates the impact of dedicated exits on the evacuation of vulnerable populations. Also, it provides a basis for the need for dedicated exits in different situations by calculating OPS values.

In the context of rapid urbanization, urban security has a huge impact on social stability, such as huge property losses and casualties. Especially in extreme weather conditions, disasters will increase, thus the study of urban safety early warning systems is necessary. Firstly, this paper introduces the current situation and problems of urban security. Then, the urban safety early warning systems and emergency response mechanisms under snowstorm conditions are established and discussed according to the current situation. Finally, this paper puts forward suggestions and measures for the urban safety emergency rescue guarantee mechanism in snowstorm conditions.

China has a population of 1.4 billion, ranking first in the world. With the increase in China's economic development and population, the construction of various types of buildings in China is also increasing, and associated safety hazards are gradually increasing. Therefore, it is necessary to study the safe evacuation of people inside and outside the building in emergency situations. In recent years, some scholars have used the traditional statistical method of literature review to analyze the research frontiers in the field of safety evacuation, but few scholars have used bibliometric methods to analyze and review the current situation of research in this field. Therefore, this paper adopts the analysis method combining bibliometrics and traditional literature review to summarize the research status of crowd evacuation published by Chinese scholars in the Web of Science core database, and uses VOSviewer to analyze the authors, institutions, and keywords of the literature search results, so as to identify their research hotspots. The results show that the last three years have been the peak period of crowd evacuation studies, with many disciplines involved in this field and they are closely related, led by the number of papers related to architecture. Simulation, model, behavior, among others, have been the most used keywords in this research field, and the research on path planning and exit selection behavior has also increased significantly. According to the keyword analysis, three hot spots of safety evacuation research, namely large-scale group evacuation, evacuation path planning and evacuation exit selection are analyzed in detail.

Disaster early warning information, if it reaches the communities at-risk with enough lead time, allows individuals to evacuate and subsequently save their lives and livelihoods. However, in many areas of Asia, early warning information does not reach the communities at-risk. Even if it does reach them, the warning information is unclear, distorted, or delayed. This paper aims to understand the underlying factors affecting the dissemination of early warning information, and how it hinders community evacuation in the event of a disaster. It specifically looks into the tools and procedures that are adopted in early warning systems (EWS) as well as the challenges that the communities experienced in receiving the warning information. The paper presents three case studies, including the coastal communities in Bangladesh, the Himalayan communities in Bhutan, and the herder communities in Mongolia to investigate the challenges in EWS. In these communities, the ground-based telecommunication systems, internet and cellular network, have limited coverage. Additionally, the communication infrastructures in these areas are vulnerable to disruptions during extreme disaster events. Using satellites to transmit the warning information to communities at-risk will not only augment the existing ground-based EWS but will also improve evacuation procedures. While this paper builds the case for using the Quasi-Zenith Satellite System (QZSS) to enhance the effectiveness of disseminating early warning information, such effort alone is not enough. Subsequent policy and practical actions must be also undertaken to improve the early warning systems to facilitate effective evacuation.

The study of the distribution pattern of fire risk in ancient buildings can provide a starting point for emergency measures to be taken in case of possible fires. Based on the fire characteristics, system complexity, and geographic information attributes of large palace ancient building complexes, this paper adopts a fuzzy comprehensive evaluation method combining fuzzy mathematics and analytic hierarchy process to construct a fire risk evaluation system for ancient buildings, which includes six criteria and 28 indicators such as the value index, and the fire likelihood. For the evaluation method of this system, the expert scoring and Analytic Hierarchy Process are used to determine the weights of various indicators. Then, the multiple rounds of expert analysis with a review of relative literature, the membership degree of each indicator is analyzed one-by-one, and the final risk model, and risk factor are determined. By combining MHMapGIS technology, this comprehensive evaluation method was applied as an example to the Imperial Palace (large Ming and Qing ancient architectural buildings) in Beijing (China) for grid and visual analysis, and the rationality of the results were verified. The evaluation results can intuitively and reasonably show the distribution of fire risk, indicating that the constructed evaluation system and its model method display a certain of feasibility.

This study addresses the significant fire hazards associated with using thermoplastic materials, particularly PMMA (poly methyl methacrylate), which are prone to flammability and high calorific values. By employing a methodology that combines small-scale experiments and theoretical analysis, this paper investigates the impact of material width on the behavior of discrete flames in open spaces, using specimens ranging from 5 to 10 cm in width. The findings indicate that an increase in specimen width positively affects the burning area and brightness, while the dimensionless flame height and heat release rate per unit width exhibit a negative power law decay with increasing width. This suggests that beyond a critical width, further increases in width have little influence on flame propagation. The results of this study contribute to a better understanding of fire dynamics in thermoplastics and provide valuable insights that could lead to enhanced fire safety standards and material designs. The originality of this research lies in its detailed analysis of how material dimensions influence flame behavior, a topic that has not been extensively explored before, offering significant practical value in applications where fire safety is crucial.

According to the provisions on fire separation distance between industrial and civil buildings in the latest 'General Code for Fire Protection of Buildings and Constructions' (GB 55037-2022). Radiant heat intensity is one of the main factors in calculating the fire separation distance between buildings. Therefore, the design process involves a lot of calculation of radiant heat intensity. This paper mainly studies the prediction model of radiant heat flux. Three different view factor calculation models, Mudan, Mudan-Sparrow, and Rai-Kalelkar, are used to evaluate the influence of key factors such as the diameter of the pool and the distance between the target and the center point of the liquid pool on the calculation results of radiant heat flux. The results show that when it came to estimating the radiant heat flux, the Mudan and Mudan-Sparrow models yielded comparable results. The calculation of the Rai-Kalelkar model shows that the radiant heat flux is about half of the heat flux in the first two models. When calculating the minimum fire separation distance for combustible liquid storage tanks with a fire dike, the results show that all three models can provide a larger safety margin than the point source model.

Wherever coal mining occurs, so do coal seam and coal mine fires. Besides depleting non-renewable resources, coal fires create health hazards through venting of hot combustion gases and toxic fume emissions, create large surface cracks, fissures and other subsidence openings as the coal burns, trigger wildfires and have forced entire communities to be abandoned. Unfortunately, the same properties that make coal valuable as a fuel source make these fires extremely difficult to extinguish. Each coal fire is unique and the extinguishment method or combination of methods that offer the best opportunity for success will be a function of the local site conditions and length of time the fire has been burning. As a result, it is important to understand the specific instances or situations in which various mine fire abatement techniques have been successful. Equally as important, is a detailed understanding of the reasons or cause for failure under conditions and in situations for which the methods used were unsuccessful. To aid in this process, this paper provides an overview of coal mine fire extinguishment methods, their applicability to various active or inactive mining situations, and relative effectiveness based on published results where possible. This review can serve as an initial screening tool and also hopefully promote research into more reliable and cost-effective extinguishment methods.

Since the corrosion defects in gas pipelines have similar corrosion characteristics to the surrounding soil, the random growth of these defects may be correlated, so we can not simply treat the corrosion defects as completely correlated or independent. Therefore, this paper proposes a method that can accurately calculate the failure probability of the pipeline system considering the correlation of corrosion defects: using MATLAB software to fit the parameters of the GEV model to select an appropriate distribution model; using Monte Carlo simulation (MC), considering different correlation coefficients and quantities, the system failure probability of pipeline corrosion defects is calculated; the results show that the system failure probability of the pipeline and the correlation coefficient are basically linear; when the correlation coefficient is increasing, the pipeline is regarded as an independent. There is a large error between the calculated failure probability of the series system and the actual result; the system failure probability of the pipeline increases with the increase of the assumed number of corrosion defects. When the correlation coefficient is greater than or equal to 0.6, the system failure probability of the pipeline increases significantly. An increase and the system failure probability of the pipeline decreases significantly.

This paper presents a review of the research progress and practical application of emergency plan construction in China over the past two decades by using the literature analysis method and the case analysis method. The main content includes the development process and current status of the national emergency plan research, the basic structure of the emergency plan and the problems in practical application. The VOSViewer is introduced to analyze the improvement research conducted by Chinese scholars in the above aspects, and four main research directions is determined by literature keyword overlay visualization, namely technical models, emergency planning frameworks for different types of emergencies, overall emergency management, the epidemic situation of COVID-19. It can be concluded that at present, while some achievements have been made in the management and research of China's emergency plans there are still some shortcomings in the practical application, such as a lack of public awareness of emergency plans, insufficient coordination and cooperation between departments, and the lack of attention to training and implementation of emergency plans. The combination of practice and theory still has room for improvement. Therefore, this review provides direction for improving the operability of research results and China's emergency plan management system in the future.

Disasters can have detrimental impacts on lives, reputations, trust, and resources. The aim of this paper is to illustrate how root cause analysis methods can be used to learn from failures in both security and safety domains. Utilising two case studies within the security and safety domains, respectively the 22-7 terrorism and Norway and the COVID-19 pandemic within the UK, we investigate how using a hybrid model approach consisting of Fault Tree Analysis (FTA), Reliability Block Diagram (RBD) and Minimum Cut Set Analysis (MCSA), helps identify the causality between failures and the catastrophic events. Results illustrate the benefits of using a hybrid of root cause analysis techniques to extract learning lessons, in order to mitigate against future similar incidents. We applied techniques that can assist organisations to apply the concept of learning from failures in practice. More specifically, the Fault Tree Analysis - for analysing causality, Reliability Block Diagram - for analysing relationships between causal factors, and Minimum Cut Set Analysis - for analysing vulnerable scenarios, were applied to the two cases, demonstrating how these models can aid in their 'de-blackening'.

Computer vision technology has broad application prospects in the field of intelligent fire detection, which has the benefits of accuracy, timeliness, visibility, adjustability, and multi-scene adaptability. Traditional computer vision algorithm flaws include erroneous detection, detection gaps, poor precision, and slow detection speed. In this paper, the efficient and lightweight YOLOv5s model is used to detect fire flames and smoke. The attention mechanism is embedded into the C3 module to enhance the backbone network and maximize the algorithm's suppression of invalid feature data. Alpha CIOU is adopted to improve the positioning function and detection target. At the same time, the concept of transfer learning is used to realize semi-automatic data annotation, which reduces training expenses in terms of manpower and time. The comparative experiments of six distinct fire detection algorithms (YOLOv5 and five optimization algorithms) are carried out. The results indicate that the self-attention mechanism based on the Transformer structure has a substantial impact on enhancing target detection precision. The improved location function based on Alpha CIOU aids in enhancing the detection recall rate. The average recall rate of fire detection of the YOlOv5+TR+αCIOU algorithm is the highest, which is 68.5%, clearly outperforming other algorithms. Based on the surveillance video, this optimization algorithm is utilized to detect a fire in a factory, and the fire is detected in the 9th second when it starts to appear. The results demonstrate the algorithm's viability for real-time fire detection.

On the basis of systematically sorting out the potential risk sources of underground structure construction, this paper describes the surrounding medium of underground structure as soil mass and rock mass. The main risk source of the underground structure based on soil medium comes from the construction mechanics analysis in the construction stage, and the leading factor of the underground structure loading in the construction stage is the stress-strain relationship of soil based on the unloading path. The deep underground engineering structure is faced with a series of disasters such as high-strength water escape, high-strength rock burst, large deformation of soft rock, boulder collapse and rock burst under the action of unloading. In view of the unloading paths faced by the above two different media, the corresponding physical models are developed to describe the above phenomena according to their respective disaster evolution mechanism and disaster breeding mechanism, and the corresponding indexes required for the safety of engineering structures are obtained by solving the physical equations. According to the above indicators, the engineering structure and surrounding media in the construction process are monitored accordingly, and the feedback of the monitoring data is used to obtain the risk assessment and modify the current construction sequence, so as to provide a reference for better serving the construction safety of underground engineering structures.

How does seismic risk influence individual disaster preparedness? Previous research demonstrates that differences in individual preparedness in at-risk communities can be attributed to a variety of individual-level characteristics such as disaster experience, risk perception and risk preferences, cognitive heuristics and biases, perception of hazards, and their ability to interpret information and understand probabilistic forecasts. However, less is known about how localized seismic risk affects individuals' preparedness for earthquakes. In this paper, we combine localized data about seismic risk with novel survey data from a sample of 680 Californian residents to test how individuals' seismic risks influence their individual preparedness for earthquakes. Our results demonstrate that seismic risk is positively associated with individual preparedness, while controlling for alternative explanations. On the other hand, household income is not a good predictor of individual earthquake preparedness. Our results demonstrate that individuals are generally responsive to the risks in their environment, while also providing several avenues for information campaigns to implement lessons from this study to further encourage preparedness.

In this paper, the physiological emergency ability of college students and its influencing factors are analyzed using the experimental method. College students are grouped according to gender, age, emergency knowledge mastery, psychological condition, professional background, origin of students, interest in emergency knowledge, whether they have conducted emergency drills, whether they are the only child, etc. The difference between each influencing factor and individual physiological index is significant. It provides a theoretical basis for improving the emergency ability of college students, and makes up for the theoretical gap that few experimental methods are used to study the emergency ability of college students.

Flood risk increase due to climate change is one of the world's most pressing issues. Different countries and regions may take or have taken different approaches to deal with it. Therefore, information sharing and learning from each other are essential for achieving flood risk reduction on a global scale, especially in times of climate change. This paper provides a diagnosis of challenges in flood risk management in Japan in response to climate change. It highlights change in hazard and exposure and increase in vulnerability. Further, it placed its attention on new strategies taken by the Japanese government to counteract climate change impacts with a particular focus on the latest legal development to better support flood risk management. Although there are large amounts of research concerning climate action in the existing literature, the majority of them focus on technical and social aspects. The present study enriches literature on flood risk management and sheds new light on how to advance integrated river basin management.

Modern industrial development is accompanied by the increasingly frequent occurrence of accidental release atmospheric dispersion events, causing extremely serious human and property losses and environmental pollution, in which rapid and accurate prediction of atmospheric dispersion is an important task to mitigate the unexpected consequences. In this paper, we take the case of previous years as the starting point, firstly, the occurred hazardous chemical atmospheric dispersion accidents in the past five years are shown, and the related concepts of hazardous chemical atmospheric dispersion are given. Then, the current state of atmospheric dispersion research is reviewed, well-known experiments on atmospheric dispersion of hazardous chemicals are summarized, and correspondingly the existing atmospheric dispersion prediction models are classified into simplified-experience models, mechanism- and rule-driven models and data-driven models. In particular, for the purpose of rapid atmospheric dispersion prediction, some research on atmospheric detection and identification are analyzed in detail. Moreover, the relevant professional software for atmospheric dispersion prediction are introduced, and also their calculation adaptabilities regarding time-consumption and output accuracy are discussed. Thereinafter, according to the shortcomings of existing atmospheric dispersion prediction models in research and application fields, the development trend of atmospheric dispersion prediction research and technology is foreseen, and some feasible future research directions are proposed as follows: (1) the fusion of image processing techniques, the establishment of a database of historical accident scene information and meteorological information, (2) new correction algorithms, and (3) an emergency response system for full-scene atmospheric dispersion prediction.

The uncertainty and destructiveness of major emergencies have resulted in China attaching unprecedented importance to emergency management. Ineffective response to emergencies also exposes the shortage of emergency management personnel and professionals, highlighting the necessity and urgency of emergency science education. Based on the actual needs of the state and society for emergency disciplines, this paper analyzes the logical possibilities of the emergency science and engineering discipline system design and gives a design framework. The study also puts forth measures to support implementation, such as conducting interdisciplinary pilot research and exploring the school's tradition of emergency science education. Including emergency science and engineering disciplines in interdisciplinary disciplines is conducive to enhancing resource investment, condensing academic consensus, accurately cultivating emergency personnel, achieving emergency technology breakthroughs, and providing a reference for the development of emergency science education in China.

The characteristics of methane-air explosion in interconnected containers with different dimensions are studied in this paper, and the prediction models are established. The explosion apparatus consists of two cylindrical containers and a connecting pipe, and three structure parameters are selected as influencing factors for the experiments. The explosion pressure, the maximum rate of pressure rise and pressure growth index under different conditions are compared by changing the volume ratio (V1/V2), the length of the pipe, and the inner diameter of the pipe. During the experiment, the combustion and explosion of gas developed from the main container to the auxiliary container. Under different size effect conditions, the maximum explosion pressure in the secondary container was always higher than the maximum explosion pressure in the primary container. The maximum explosion pressure and the maximum rate of pressure rise in the primary and secondary containers both increase with increasing pipe length. With an increase in the pipe diameter, the maximum explosion pressure and the maximum rate of pressure rise both decrease gradually. When the volume ratio changes, the parameters such as the maximum explosion pressure are also affected by the volume changes of the containers at both ends. Therefore, the explosion parameters in both connected containers do not show a single development trend with the increase of the volume ratio. For practical application, in order to reduce the explosion intensity and protect the device, large-diameter pipes should be used and the volume ratio should be reduced.

This paper explores the concept of evacuation mobilization as a protective decision-making process and builds a theoretical framework that captures the factors from the perspective of risk communication. As a critical step in the decision process of disaster evacuation, in practice, mobilization has been overlooked. This study aims to embrace the varied yet inconsistent factors to a theoretical framework built upon the Protective Action Decision Model (PADM). A comprehensive review of literature of seminal and recent studies exploring the factors of mobilization and the major risk communication studies were used to build the theoretical framework explaining the variance of evacuation mobilization. Upon reviewing the aspects and factors of evacuation mobilization, this study asserts that the PADM is the most appropriate framework among those examined to theorize this process in evacuee decision-making. Specifically, the stages of receiving environmental cues and information, pre-decision processes, and perceptions, sequentially determine the on-going decision process of mobilization. This study fully discusses the issues surrounding evacuation mobilization and invites further empirical studies on early-warning disaster evacuations and more accurate simulations for late or no-warning evacuations. It also offers suggestions on how to mitigate the potential harm caused by extended mobilization.

Hydrogen has been recently utilized in many fields due to its recyclability and non-pollution characteristics. Hydrogen fuel cell vehicles and hydrogen refueling stations have become the main carrier of hydrogen energy application. However, due to the inflammable and explosive characteristics, the safety problems of hydrogen became indispensable. This paper introduces the safety problems and countermeasures of hydrogen fuel cell vehicles and hydrogen refueling stations. The research progress and achievements of hydrogen energy standards are then comprehensively discussed. Finally, the development status, existing problems and future development direction of five kinds of optical fiber sensors are pointed out.

Hazard mitigation plans address hazards such as earthquakes, hurricanes, landslides, tornados, flooding more explicitly than pandemics or other public health crises. This paper analyzes and identifies pandemic-related mitigation strategies in state-level hazard mitigation plans across the United States. This study identifies common and uncommon strategies that could be included in plan updates such as: use of personal protective equipment (PPE), self-isolation/quarantine, hygiene, restricted gatherings, vaccination, vulnerability assessment, economic consequences analysis, acknowledging the need to address pandemics, and referring Centers for Disease Control and Prevention (CDC) guidelines. The 54 state-level plans are compared based on their inclusion of the nine strategies. Findings show that vaccination, self-isolation/ quarantine, and vulnerability assessment are the strategies most listed in plans. Additional concerns made evident by the 2020 coronavirus pandemic, such as contact tracing, environmental impact, and public services, were limited across the plans. It was concluded that long-term mitigation strategies for reducing the risk and speed of spread such as identifying strategic locations for testing, vaccination, and quarantine should be devised and implemented. Pandemics should be included as a distinct class of hazards while formulating state hazard mitigation plans. Strategies for addressing the impact of long working hours on the mental health of healthcare workers should be explored. Economic and psychological impact of unavailability of essential public services, such as transport and groceries, should be investigated and strategies should be formulated in the mitigation plans accordingly.

Reaction thermal runaway has been extensively characterized as a major hazard for fine chemical industry. It is necessary to develop safety technologies for the control of reaction thermal runaway in emergencies and mitigating the subsequent hazards. To date, literature review on the loss prevention methods of chemical reaction thermal runaway is insufficient. In this paper, a comprehensive review is delivered to outline the progress of emergency response technologies for reaction thermal runaway in recent years, major principles and potential applications of those loss prevention methods. It is expected that this review article has certain reference value for the further understanding of thermal runaway, the design of mitigation systems, and the formulation of emergency response strategy for runaway reactions.