Search Results (14)

At 2:54 A.M. on 14 October 2021, a devastating fire erupted in a high-rise building in Kaohsiung City, Taiwan, involving 12 floors above ground and a basement level, resulting in 46 fatalities and 41 injuries. The official investigation pinpointed regulatory deficiencies and negligence among relevant department officials. The persistence of major fires globally underscores that merely relying on post-incident investigation reports is insufficient to fully uncover the underlying problems, highlighting the complexity of fire-related systemic challenges. This study adopts a systems thinking approach and synthesizes findings from various sources, including the investigation reports of this fire and the Grenfell Tower fire, research on fatal fires, and literature on high-rise building fires. It examined the systemic issues related to fires from three angles: resident characteristics, building factors, and situational factors. The analysis exposes the deep complexity of fire-related systemic problems and the interconnections among various contributing elements. Comprehensive initiatives that span educational, legislative, policy, and economic domains must be launched to reduce the frequency of fires and enhance survival rates. The insights from this study offer a profound understanding of the fundamental problems associated with fires and aim to inform strategies to prevent similar tragedies in the future. Full article

This study explores the impact of key evacuation features on occupant safety in complex buildings with underground connections in Seoul, the city with the highest concentration of such buildings in the country. By analyzing factors like exit spacing, exit width, stairwell distances, and stairway configurations, the study assesses evacuation safety using fire and evacuation simulations, comparing available safe egress time (ASET) with required safe egress time (RSET). Reducing interior exit facility spacing from the legal standard of 100 m to 50 m improved evacuation time by 77.5% (from 36 min to 8 min and 7 s), with a further reduction to 40 m improving performance by an additional 23.3% (to 6 min and 13 s). In downward evacuations, reducing the walking distance to exterior exits from over 50 m to 30 m cut evacuation time by at least 59.9% (from 23 min and 55 s to 9 min and 35 s), ensuring successful evacuations. These findings demonstrate that optimizing evacuation routes, addressing bottlenecks, and improving evacuation feature standards can significantly enhance safety and minimize casualties. By adjusting building design and fire safety regulations, these optimizations promote resilient urban infrastructure, reduce disaster-related socio-economic impacts, and inform evidence-based policies, offering valuable insights for policymakers and guiding future improvements in fire safety and evacuation protocols. Full article

(1) Background: In Iran, burn injuries are the second leading cause of death among children, surpassed only by traffic accidents. This study aims to simulate fire emergency evacuations in an elementary school using Pathfinder software, focusing on identifying architectural factors that influence evacuation efficiency. Children are particularly vulnerable in emergencies due to their limited understanding of danger and tendency to panic, making the development of effective evacuation strategies essential for their safety. (2) Methods: We analyzed the emergency evacuation of 522 occupants at a selected elementary school in Qazvin City, Iran. Using Pathfinder 2021 software, we examined various evacuation scenarios, including evacuation density, traffic patterns on different routes, and flow at exits. We calculated the Required Safe Egress Time (RSET) and Available Safe Egress Time (ASET) from the simulation data. Data collection involved a comprehensive assessment of the school’s geometric characteristics, as well as the demographic and anthropometric profiles of the occupants. (3) Results: The simulations revealed a total evacuation time of 386 s, with an ASET of 180 s. The average passenger flow rate was only 1.35 persons per second, indicating a slow evacuation process. Our findings highlighted that specific architectural features, such as classroom size and door dimensions, significantly affect evacuation times. Additionally, when simulating an evacuation with 170 fewer students, the total evacuation time decreased by 128 s, suggesting that adhering to recommended class size standards can enhance evacuation efficiency. Notably, the RSET consistently exceeded the ASET (180 s) across all simulations. (4) Conclusions: This research deepens our understanding of school evacuation dynamics and underscores the need for improved architectural designs and safety protocols to protect vulnerable populations, especially children. Future studies should focus on implementing targeted interventions based on these findings to mitigate risks associated with school fires. Additionally, the results indicate that installing automatic fire alarms and extinguishing systems, along with conducting regular emergency evacuation drills for students, could significantly reduce RSET. Full article

In recent years, the number of studio residential buildings has increased significantly in Korea, as well as in many other countries, due to changes in living patterns. In Korea especially, there have been many fire accidents in studio residential buildings, which have caused a huge number of casualties and property damages, because the buildings were not adequately equipped for firefighting. In this study, the egress safety of a typical studio residential building in Korea is analyzed. Fire simulations were performed with variables of the fire location and the capacity of the smoke exhaust system to estimate the available safe egress time (ASET); egress simulations were also performed with the variable of egress delay time, and the required safe egress time (RSET) was determined. Then, the egress safety was evaluated, and the criteria for egress safety evaluation were proposed based on the simulation results. A studio residential building with a floor plan different from the prototype was used to validate the proposed egress safety criteria. Finally, a simple evaluation model is presented to estimate the required safe egress time (RSET) without simulation and to examine the impact of bottlenecks. Full article

In South Korea, the need to link fire and evacuation simulations to compare the available safety egress time (ASET) and required safety egress time (RSET) in real time when implementing performance-based design in buildings is increasing. Accordingly, the Consolidated Model of Fire Growth and Smoke Transport (CFAST) has been discussed as an alternative to the fire dynamics simulator, which requires high computational costs, sufficient experience in fire dynamics numerical calculations, and various input parameters and faces limitations in integration with evacuation simulations. A method for establishing a reasonable computational domain to predict the activation times of smoke and heat detectors has been proposed. This study examined the validity of using CFAST to predict factors relevant to the ASET evaluation. The results showed that CFAST, which solved empirical correlations based on heat release rates, predicted high gas temperatures similarly. Moreover, the applicability of the visibility distance calculation method using smoke concentration outputs from CFAST was examined. The results suggest that despite the limitations of the zone model, CFAST can produce reasonable ASET results. These results are expected to enhance the usability of CFAST in terms of understanding general fire engineering technology and simple fire dynamics trends. Full article

Worldwide, the number of users of medical facilities is increasing due to the pandemic phenomenon and extended life expectancy. In addition, the majority of medical facility occupants are patients, leading to issues of inconvenience in movement and increased vulnerability during evacuations in the event of a fire. Therefore, the availability of nursing personnel, who serve as assistants in tasks such as transporting beds and wheelchairs essential for patient evacuation, is crucial for ensuring evacuation safety. However, a global shortage of nursing personnel has led to ongoing research on optimizing workforce allocation. In this study, the Available Safe Egress Time (ASET) and Required Safe Egress Time (RSET) were quantitatively compared for medical facilities with a combination of intensive care units and general wards, utilizing a Fire Dynamics Simulator (FDS) and Flexsim Healthcare simulations to assess fire risk. The research goal here is to provide sustainable research directions for determining the minimum ratio of nurses to patients required for evacuation in a disaster, ensuring the continuous availability of nursing personnel in medical facilities. To achieve this, the variable was set to five stages based on the total number of patients per nurse. As a result of this study, it was confirmed that when the nurse-to-patient ratio exceeded 1:6, more than 70% of bedridden patients died. Additionally, it was verified that maintaining a patient-to-nurse ratio of less than 1:1 is effective for ensuring evacuation safety. Full article

Buildings in modern society tend to gradually expand in size due to technological development and overcrowding, which increases the risk of fire. Therefore, continuous efforts are being made to ensure the evacuation safety of occupants by installing firefighting facilities and using flame retardant building finishing materials. This study aims to present a fire performance evaluation plan for building finishing materials using simulations and identify risks that arise from not using flame retardant building finishing materials in medical facilities with vulnerable occupants. A control group for fire performance evaluation was selected using polyurethane foam, while two types of cellulose-based building finishing materials with different flame retardants were chosen for analysis. The cellulose-based finishing materials included expanded graphite, magnesium hydroxide, montmorillonite, and ammonium polyphosphate. Fire performance was evaluated using FDS and path detector simulations based on NES 713 and ISO 5660-1. The results of the study showed that there was a difference of three people in the prediction of the number of deaths depending on the scope of analysis, and it was confirmed that the toxic gas detected was different depending on the added flame retardant. Additionally, construction finishing materials with flame retardant performance increased ASET by at least 130 s compared to polyurethane foam, and the evacuation safety exceeded 1, confirming the effectiveness of securing evacuation stability for occupants. Full article

A fire egress system is one of the most critical aspects of fire emergency evacuation, which is the cornerstone technology of building fire safety. The high-rise teaching buildings on campus, where vast crowds of people gather, need to be qualified for rapid evacuation in the event of a fire especially. Conventional teaching building egress system design places more emphasis on individual elements (e.g., stairwells, evacuation doors, and evacuation walkways) rather than on their co-regulation as a whole. Furthermore, there are not enough holistic and effective optimal design strategies, which is because most of the existing studies rely on experiments or simulations and often suffer from a lack of sufficient data to fully reveal the interactions of individual variables. In this study, the co-effectiveness of stairwells, walkways, and room doors in reducing total evacuation time was investigated by simulation and machine learning. We selected a typical high-rise teaching building as an example and integrated two simulation software, Pyrosim and Pathfinder, to compare the available safe evacuation time (ASET) and required safe evacuation time (RSET). Then, a framework consisting of five factors—stair flight width (SFW), stairwell door width (SDW), corridor width (CW), room door width (RDW), and location of the downward stair flight (LDSF)—was established for the optimization through statistical analysis of big data obtained by the preferred machine learning algorithm. Results indicate that (1) By modifying just one factor (SFW), the total evacuation time (TET) can be reduced by at most 12.1%, with the mortality rate dropping from 26.5% to 9.5%; (2) although ASET could not be achieved either, among 4000 cases of multi-factor combinations, a maximum TET improvement degree, 29.5%, can be achieved for the evacuation optimization compared to baseline model, with a consequent reduction in mortality to 0.15%; (3) it shows that the emphasis of the egress system optimization is on the geometric features of the evacuation stairwell; furthermore, the multi-factor combination approaches have better compromised evacuation performances than the single-factor controlled schemes. The research results can be applied as rational design strategies to mitigate fire evacuation issues in high-rise teaching buildings and, in addition, the methodology suggested in this paper would be suitable to other building types. Full article

The smoke from tunnel fires spreads over long distances and is difficult to vent. Smoke accumulation leads to high temperatures, low visibility, and high concentrations of toxic gases, which greatly hinders the evacuation of people inside the tunnel. In this paper, a representative extra-long highway tunnel—Chengkai Tunnel—is selected as the engineering background, and a tunnel model is built using FDS and Pathfinder software to simulate the fire scenario and evacuation scenario under different longitudinal wind speeds. The concept of safe evacuation reliability is proposed to describe the relationship between the ASET (available safe egress time) and the RSET (required safe egress time). The simulation results show that with the increase in longitudinal wind speed, the ASET upstream of fire source increases first and then remains unchanged, while ASET downstream of fire source increases first and then decreases. The ASET upstream of the fire source is affected by visibility, while the ASET downstream of the fire source is affected by visibility when the wind speed is low, and is affected by temperature as the wind speed increases. The bottleneck effect is an important reason for the long evacuation time of people. The blockage time is a power function of the evacuation movement time, and increasing the width of the cross passage can improve the evacuation efficiency of the tunnel. The increase in the number of evacuees will reduce the reliability of the safe evacuation of personnel. Among all simulated scenarios, a longitudinal wind speed of 2.5 m/s has the highest safe evacuation reliability, with 0.79, 0.92, and 0.99 for scenarios R1, R2, and R3, respectively. Excessive wind speed reduces the safe evacuation reliability downstream of the fire source. Full article

Some of the most critical transportation infrastructures are road tunnels. Underground passageways for motorists are provided through this cost-effective engineering solution, which allows for high traffic volumes. A crucial aspect of the operation of road tunnels is fire safety. Risk assessments have been established to ensure the level of safety in tunnels. As the existing quantitative risk analysis (QRA) models are inapplicable to assess the fire risk in UK road tunnels, this paper presents a novel QRA model, named LBAQRAMo, for UK road tunnels. This model consists of two main sections: quantitative frequency analysis, to estimate the frequency of fire incidents via an event tree; and quantitative consequences analysis, to model the consequences of fire incidents. LBAQRAMo covers the risk to tunnel users. The result of the risk analysis is the expected value of the societal risk of the investigated tunnel, presented via F/N curve. Another major result of this model is the estimation of the number of fatalities for each scenario based on the comparison between required safe egress time (RSET) and available safe egress time (ASET). Risk evaluation was carried out by comparison of the tunnel under study with the UK ALARP limit. The operation of the model is demonstrated by its application to the Gibraltar Airport Tunnel as a case study. Simulation of 34 different possible scenarios show that the tunnel is safe for use. The sensitivity of the model to HGV fire incident frequency and basic pre-movement times was studied as well. Full article

The manuscript is focused on the problems of evacuation in case of fire from the buildings of museums as places with a mass presence of people. Features specific to museums and how they affect safe evacuation conditions are discussed. Most attention is paid to evacuation management, since the vast majority of museum visitors are not familiar with the layout of the building. In this case, the actions of staff in evacuation management are decisive. The paper considers the development of evacuation schemes, taking into account the spread of fire hazards in the building and the development of instructions on their basis for the staff. Using the example of the Winter Palace of the State Hermitage Museum, the solution of the marked tasks with the use of computer simulation of evacuation during a fire is given. The analysis of the simulation results showed the vulnerabilities of the museum. In this work, the evacuation schemes for the scenarios are considered. The maximum number of visitors at a single time in the Winter Palace has been set at 4000. The principles of making evacuation schemes are formulated, including taking into account the peculiarities of space-planning solutions inherent in museums, such as enfilades and the connections of rooms. Full article

The continued increase in human lifespans is accelerating the aging of the population in most countries. The increase in elderly care facilities corresponds to a relative increase in the number of people who are vulnerable in the context of evacuation. For example, an elderly care hospital is a representative facility for vulnerable populations as regards evacuation, as residents in such a hospital cannot evacuate themselves in the event of a fire. It is therefore necessary for such buildings to formulate detailed evacuation plans that consider the walking situations of their residents in the event of a disaster. In this study, the fire dynamics simulator (FDS) was used to calculate the available safety escape time (ASET)—which is the point at which evacuation is impossible from the ignition time of the fire—for inpatients in nursing hospitals. The required safety escape time (RSET), which is the time required to move to a safe place, was calculated by reflecting a patient’s evacuation speed using Pathfinder. In addition, the evacuation route was simulated with three variables—stairs, elevators, and ramps—along with the movement pattern. The simulations of evacuation performance evaluation based on time analysis showed that there were differences in the number of fatalities depending on the choice of evacuation routes and movement patterns for each disabled group. Evacuation using ramps was confirmed to reduce fatalities from at least 48 to up to 60 people compared to evacuation using stairs or elevators. The usage of ramp evacuation in elderly care hospitals has proved to be superior to other evacuation routes in ensuring the safety of vulnerable persons during fire evacuation. Full article

Ventilation velocity conditions may affect the smoke diffusion and evacuation environment in a tunnel fire, which should be fully considered in evacuation spacing designs of undersea tunnels. This study focuses on reasonable evacuation spacing under various possible velocity conditions of an undersea tunnel, providing a design method reference for calculating safe evacuation spacing. Fire Dynamic Simulator and Pathfinder software were used for numerical simulations of a 50 MW fire and evacuation process in a full-scale undersea tunnel with traffic congestion. The simulation cases contained velocity modes from zero to satisfying the critical velocity and evacuation spacings from 30 m to 80 m. The calculated distributions of the available safe escape time indicated that a low ventilation velocity, such as 1.0 m/s, is beneficial to the downstream evacuation, but turning off mechanical ventilation increased risk near the fire source. The required safe escape time is shortened with a reduction in slide spacings, but the shortened rate slowed down after spacing was less than 60 m. In addition, the slow evacuating areas from 100 m to 300 m from the fire source independent of spacing are identified. Ultimately, the reasonable evacuation spacings of 60 m, 50 m, and 30 m, corresponding to three possible ventilation velocity modes of low, medium, and high, are proposed through the comparisons of the distributions of available safe escape time and required safe escape time. Full article

Nursing hospitals have a high probability of casualties during a fire disaster because they have many patients with impaired mobility. In this study, fire and egress simulations were conducted to evaluate the egress safety of a typical nursing hospital. The available safe egress time (ASET) of the prototype nursing hospital was calculated using Fire Dynamics Simulator, and the required safe egress time (RSET) was estimated by Pathfinder, reflecting characteristics of the occupants. The egress safety of the nursing hospital was then evaluated by comparing the ASET and RSET, considering the number of egress guides and delay time. According to the simulation results, the RSET increased as the egress delay time increased and the number of egress guides decreased. In addition, it is estimated that at least 20 workers (egress guides) should be on duty in the prototype nursing hospital, even during shiftwork and night duty. Based on the simulation results, egress safety criteria have been proposed in terms of normalized numbers of egress guides and egress delay time. The proposed criteria can be very easily applied to evaluate the egress safety of a typical nursing hospital in operation. Full article