Research

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19 pages, 4195 KiB

Open AccessArticle

Critical Egress Parameters Governing Assisted Evacuation in Hospital Buildings

by Venkatesh Kodur, Ankush Jha and Nizar Lajnef

Fire 2024, 7(3), 85; https://doi.org/10.3390/fire7030085 - 13 Mar 2024

Viewed by 824

This paper presents the critical egress parameters that influence emergency evacuation in a typical hospital building. A parametric study of a 20-story hospital building is conducted using a computer model “Pathfinder” to simulate the evacuation efficiency and assess the influencing parameters. The main [...] Read more.

This paper presents the critical egress parameters that influence emergency evacuation in a typical hospital building. A parametric study of a 20-story hospital building is conducted using a computer model “Pathfinder” to simulate the evacuation efficiency and assess the influencing parameters. The main egress parameters that influence the evacuation efficiency, including the location of stairways, number of stairways, location of the fire, exit width, and number of low-speed occupants are varied. Two scenarios are simulated: one being the regular (practice) evacuation drill and the other is the actual fire drill. The result shows that the location of stairways significantly affects the total evacuation time with the optimal stairway arrangement consisting of one stairway outside the core of the building. Similarly, the story level at which the fire occurs is another key parameter with fires at lower levels being critical to dictating the evacuation time in a hospital building. The total evacuation time when the fire occurs between the third and sixth floor is found to be 170 min which is 36% and 15% higher than fires at the top story levels (15–18th floor) and the intermediate story levels (9–12th floor), respectively. Full article

(This article belongs to the Special Issue Building Fire Dynamics and Fire Evacuation)

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13 pages, 4377 KiB

Open AccessArticle

Exploring the Impacts of Exit Structures on Evacuation Efficiency

by Xiaoge Wei, Zhen Lou, Huaitao Song, Hengjie Qin and Haowei Yao

Fire 2023, 6(12), 462; https://doi.org/10.3390/fire6120462 - 05 Dec 2023

Viewed by 1699

Abstract

In the context of a fire emergency, safe and efficient exits are of paramount importance for pedestrian evacuation. The recent rapid development in the construction industry has rendered exit structures more diverse and complex. However, little attention has been paid to the influence [...] Read more.

In the context of a fire emergency, safe and efficient exits are of paramount importance for pedestrian evacuation. The recent rapid development in the construction industry has rendered exit structures more diverse and complex. However, little attention has been paid to the influence of exit structures on the efficiency of crowd evacuation processes. In this paper, a tentative experiment was designed to preliminarily reveal the effects of five exit structures (Exit 1, Exit 2, Exit 4, Exit 5, and Exit 3 as examples for comparison) on crowd evacuation. Exit 1 has door leaves opening outward. Exit 2 has door leaves opening inward. Exit 3 has no leaves. Exit 4 consists of double-layer exit doors with the doors opening outward. Exit 5 comprises double-layer exit doors with the doors opening both sides outwards Subsequently, according to the properties of this experiment, a social force-based simulation model was established using the AnyLogic software 8.8.4. By changing the exit width and the crowd density, data such as evacuation time, flow rate, crowd density, and time delay were investigated in detail. The results revealed a notable variation in the evacuation efficiency depending on the deign of the exit. The respective flow rates for Exits 1, 2, 3, 4, and 5 were 0.66 people/(m·s), 0.77 people/(m·s), 0.80 people/(m·s), 0.71 people/(m·s), and 0.66 people/(m·s). Although Exit 3 excelled in terms of evacuation efficiency, it is not directly applicable to real architectural structures. Therefore, Exit 2 emerged as a highly promising solution in terms of flow rate and population control in the exit area, underscoring the effectiveness and practicality of its structural design. It is prospective that the results of this study can offer engineering and technical professionals valuable references and guidance concerning the design of exit structures. Full article

(This article belongs to the Special Issue Building Fire Dynamics and Fire Evacuation)

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19 pages, 7664 KiB

Open AccessArticle

Cellular Automaton Model for Pedestrian Evacuation Considering Impacts of Fire Products

by Yuechan Liu, Junyan Li and Chao Sun

Fire 2023, 6(8), 320; https://doi.org/10.3390/fire6080320 - 17 Aug 2023

Cited by 3 | Viewed by 1285

Abstract

To accurately simulate realistic pedestrian evacuation from a fire, a cellular automaton model of the dynamic changes in pedestrian movement parameters is developed in conjunction with fire dynamics software. The fire dynamics software is used to simulate the spread of smoke within the [...] Read more.

To accurately simulate realistic pedestrian evacuation from a fire, a cellular automaton model of the dynamic changes in pedestrian movement parameters is developed in conjunction with fire dynamics software. The fire dynamics software is used to simulate the spread of smoke within the scene to obtain visibility and CO concentration data within the scene. We imported the smoke data into the cellular automata and adjusted the pedestrian movement speed over time, resulting in simulation data that closely align with reality. The results show that for the single-room scenario, as pedestrian density increased from 0.1 to 0.5 persons per square meter (

p / m^{2}

), the influence of the percentage of pedestrians familiar with their location on evacuation efficiency decreased from 44.93% to 24.52%. Conversely, in the multi-room scenario, it increased from 23.68% to 38.79%. The proportion of pedestrians less affected by smoke decreases and stabilizes as the CO yield increases. In the single-room scenario, when the CO yield is below 10%, the crowd with a low percentage of pedestrians familiar with the site is more affected by smoke than those with a high percentage. In the multi-room scenario, the victimization rate of the crowd follows an increasing-then-decreasing curve, ultimately stabilizing with changes in CO yield. Full article

(This article belongs to the Special Issue Building Fire Dynamics and Fire Evacuation)

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25 pages, 17614 KiB

Open AccessArticle

Fire Egress System Optimization of High-Rise Teaching Building Based on Simulation and Machine Learning

by Muchen Zhou, Bailing Zhou, Zhuo Zhang, Zuoyao Zhou, Jing Liu, Boyu Li, Dong Wang and Tao Wu

Fire 2023, 6(5), 190; https://doi.org/10.3390/fire6050190 - 06 May 2023

Cited by 6 | Viewed by 1842

Abstract

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 [...] Read more.

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

(This article belongs to the Special Issue Building Fire Dynamics and Fire Evacuation)

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25 pages, 8151 KiB

Open AccessArticle

Algorithm and Examples of an Agent-Based Evacuation Model

by Xiaoting Cui, Jingwei Ji and Xuehe Bai

Fire 2023, 6(1), 11; https://doi.org/10.3390/fire6010011 - 30 Dec 2022

Viewed by 1681

Abstract

This research establishes a “detect-decide-action” agent-based evacuation model based on the social force model, introducing an active steering force into the basis of the dynamic equation with the combination of the behavioral decision model and the probability model. In the AEM, the detection [...] Read more.

This research establishes a “detect-decide-action” agent-based evacuation model based on the social force model, introducing an active steering force into the basis of the dynamic equation with the combination of the behavioral decision model and the probability model. In the AEM, the detection algorithm is used to identify pedestrians or obstacles within the detection radius to provide the next walking direction and apply the active steering force. The obstacle avoidance algorithm is the core of the “action” link. This research focuses on the establishment of the following and bypassing algorithm when moving in the same direction, and the algorithm of a detour when moving in the opposite direction, applying C++ programming language to achieve the basic evacuation behavior simulation of avoiding pedestrians and obstacles in the actual scene. The results show that compared with the grid model and the general social force model, the agent model (AEM) solves the problem of the distortion of evacuation behavior to some extent, and the pedestrian is more flexible in the choice of evacuation path. Full article

(This article belongs to the Special Issue Building Fire Dynamics and Fire Evacuation)

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13 pages, 7594 KiB

Open AccessArticle

Evacuation Simulation in a Cultural Asset Fire: Impact of Fire Emergency Evacuation Facilities for People with Disabilities on Evacuation Time

by Jyh-Jye Hu, Hao-Yu Wu and Chung-Chyi Chou

Fire 2023, 6(1), 10; https://doi.org/10.3390/fire6010010 - 30 Dec 2022

Cited by 3 | Viewed by 1847

Abstract

More cautious fire safety evacuation assessment and escape route assistance are required when people with disabilities encounter a fire hazard in a historical museum. This study uses the old Chiayi City Hall, which is mainly used for an exhibition space, as the example. [...] Read more.

More cautious fire safety evacuation assessment and escape route assistance are required when people with disabilities encounter a fire hazard in a historical museum. This study uses the old Chiayi City Hall, which is mainly used for an exhibition space, as the example. The core of this study is the problem of fire evacuation that emerged after the historic building opened and was reused as a museum; it uses Pathfinder evacuation simulation software, discussing the difference between traditional and segregated evacuation and assuming the original evacuation, elevator emergency evacuation, and external ramp evaluation. There are three evacuation scenarios, and the number of accommodated people is set to 730, pursuant to the applicable law. Comparing the conditions of people with disabilities and ordinary members of the public during evacuation through the foregoing three scenarios, the overall evacuation time and survival rate of the original evacuation scenario are 440 s and 49.8%, respectively; and the overall evacuation time and survival rate of the barrier-free elevator emergency evacuation scenario are 332 s and 65.4%, respectively; the overall evacuation time and survival rate of the external ramp evaluation scenario are 320 s and 65.6%, respectively. The computer data analysis shows that the use of the external ramp evaluation gives people with disabilities the best evacuation time and survival rate because the architectural form of cultural heritage buildings is more fragile, specific, and fast-burning than that of ordinary buildings. As the global awareness of cultural asset preservation and revitalization is increasing, the evacuation of people with disabilities in the building in the case of fire is very important. The results of this study can be used as an emergency evacuation design recommendation for people with disabilities in the cultural assets through evacuation simulation analysis. Full article

(This article belongs to the Special Issue Building Fire Dynamics and Fire Evacuation)

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25 pages, 3403 KiB

Open AccessArticle

Research on the Influence of Narrow and Long Obstacles with Regular Configuration on Crowd Evacuation Efficiency Based on Tri-14 Model with an Example of Supermarket

by Ligang Lu, Jingwei Ji, Cheng Zhai, Shengcheng Wang, Zhen Zhang and Tiantian Yang

Fire 2022, 5(5), 164; https://doi.org/10.3390/fire5050164 - 11 Oct 2022

Cited by 2 | Viewed by 1399

Abstract

Regular shelves configuration forms unique characteristics of internal obstacles in a supermarket. It is crucial to study the crowd evacuation affected by obstacles during accidents or disasters in supermarkets as assembly occupancies. Based on the Tri-14 model, this paper studied the influence of [...] Read more.

Regular shelves configuration forms unique characteristics of internal obstacles in a supermarket. It is crucial to study the crowd evacuation affected by obstacles during accidents or disasters in supermarkets as assembly occupancies. Based on the Tri-14 model, this paper studied the influence of safety exit designs and shelves’ configuration on the crowd evacuation efficiency with different densities in a supermarket through parameters and images. The results mainly indicate that: (1) The evacuation distance of farthest grid (D_fg) is the key factor to determine the total evacuation time of a low-density crowd. (2) For a high-density crowd, the closer the proportion ratio of the number of evacuees choosing each exit is to that of designed strand numbers of crowd flow at each exit, the higher the evacuation efficiency and average utilization efficiency of exits get; the scattered arrangement of exits will not necessarily lead to improving evacuation efficiency. Shelves’ configuration could lead to the extension of D_fg, but the change may reduce evacuation time instead, especially when forming effective advanced-gathering zones. (3) Under appropriate conditions, the impact of shelves’ configuration on evacuation efficiency can be negligible. This study has certain guiding significance for obstacle configuration and architectural design in large public gathering places. Full article

(This article belongs to the Special Issue Building Fire Dynamics and Fire Evacuation)

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15 pages, 3766 KiB

Open AccessArticle

Evaluation on Egress Safety of Nursing Hospital Considering the Smoke Exhaust System

by Seung-Ho Choi, Khaliunaa Darkhanbat, Inwook Heo and Kang Su Kim

Fire 2022, 5(4), 120; https://doi.org/10.3390/fire5040120 - 18 Aug 2022

Cited by 2 | Viewed by 1729

Abstract

This study aimed to evaluate the egress safety in nursing hospitals based on the capacity of the smoke exhaust system. To this end, the available safe egress time was calculated by analyzing changes in visibility, carbon monoxide, carbon dioxide, oxygen contents, and temperature [...] Read more.

This study aimed to evaluate the egress safety in nursing hospitals based on the capacity of the smoke exhaust system. To this end, the available safe egress time was calculated by analyzing changes in visibility, carbon monoxide, carbon dioxide, oxygen contents, and temperature depending on the fire duration. In addition, an egress simulation was performed using the number of workers (egress guides) and egress delay time as variables, and the required safe egress time was estimated. Based on the results, the egress safety of a prototype nursing hospital was evaluated. In this study, egress safety criteria to evaluate egress safety in a typical nursing hospital were presented, which are expressed in terms of normalized egress guides, the capacity ratio of the smoke exhaust system, and egress delay time. The proposed criteria can be used to evaluate the egress safety of typical nursing hospitals and to prepare complementary measures. Full article

(This article belongs to the Special Issue Building Fire Dynamics and Fire Evacuation)

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26 pages, 9998 KiB

Open AccessArticle

Study on the Protection Effect of Sprinklers on Glass by Fire Scale in Building Fires

by Jia Gui, Dong Wang, Yaqiang Jiang, Junjun Liu and Lizhong Yang

Fire 2022, 5(4), 100; https://doi.org/10.3390/fire5040100 - 13 Jul 2022

Cited by 4 | Viewed by 2361

Abstract

Window sprinklers are commonly used to protect glass, but there is a lack of research on the effect of fire scale on protection. In this study, full-scale experiments on sprinkler-protected glass in building fires were carried out. The experimental process was simulated using [...] Read more.

Window sprinklers are commonly used to protect glass, but there is a lack of research on the effect of fire scale on protection. In this study, full-scale experiments on sprinkler-protected glass in building fires were carried out. The experimental process was simulated using CFD numerical simulation software (FDS), and the effect of the heat release rate on the protection effect was revealed based on the glass surface temperature and heat insulation efficiency. It was found that in a full-size compartment fire, the window sprinkler was able to protect the glass from being damaged by high-temperature smoke. The numerical simulation could effectively simulate the spray distribution pattern of a window sprinkler as well as the gas temperature evolution, and the simulation results matched well with the full-size experiments. The window surface temperatures all decreased rapidly and increased linearly with the HRR after the window sprinkler was activated. The steady-state window center temperatures were 40 °C, 60 °C and 76 °C when the HRR was 2 MW, 4 MW and 6 MW, respectively. The window center temperature was less than the critical temperature of glass breakage, indicating that the window sprinkler could protect the glass from fire damage well, within the fire scale of 6 MW. The thermal insulation efficiency in the edge region was slightly lower than that in the center of the window. In the range of 2 to 6 MW, there was no significant correlation between the thermal insulation efficiency and the HRR, and the thermal insulation efficiency was in the range of 54% to 59%. Full article

(This article belongs to the Special Issue Building Fire Dynamics and Fire Evacuation)

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13 pages, 13294 KiB

Open AccessArticle

A Study of Fire Drone Extinguishing System in High-Rise Buildings

by Kai Wang, Yingfeng Yuan, Mengmeng Chen, Zhen Lou, Zheng Zhu and Ruikun Li

Fire 2022, 5(3), 75; https://doi.org/10.3390/fire5030075 - 01 Jun 2022

Cited by 8 | Viewed by 7384

Abstract

Firefighting in high-rise buildings remains a difficult problem in the world because fire extinguishing equipment and tactics have many deficiencies in dealing with such building fires, especially for buildings higher than 50 m. In the present study, the LY100 fire extinguishing system is [...] Read more.

Firefighting in high-rise buildings remains a difficult problem in the world because fire extinguishing equipment and tactics have many deficiencies in dealing with such building fires, especially for buildings higher than 50 m. In the present study, the LY100 fire extinguishing system is taken as an example to introduce the application of the fire drone in the fire control of high-rise buildings. The LY100 fire extinguishing system mainly contains the twin-rotor drone, high-pressure liquid fire extinguishing equipment, pressure fire extinguishing equipment, associated vehicle and extinguishing agent. The LY100 system can be deployed quickly and operated flexibly. Based on such advantages, the indoor fire, exterior thermal insulation layer fire and top platform fire of high-rise building can be extinguished in a timely manner with the LY100 system. In addition, four kinds of firefighting tactics are described in this paper, including one drone operation, double drone cooperative operation, three or more drone cooperative operations, and cooperating with the lifting fire truck. Finally, the experiments are presented to verify the spraying distance of the fire drone system. Full article

(This article belongs to the Special Issue Building Fire Dynamics and Fire Evacuation)

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21 pages, 4637 KiB

Open AccessArticle

An Explorative Methodology to Assess the Risk of Fire and Human Fatalities in a Subway Station Using Fire Dynamics Simulator (FDS)

by Zaman Sajid, Yaqi Yang, Peilei You, Hao Deng, Xin Cheng and Syed Nasir Danial

Fire 2022, 5(3), 69; https://doi.org/10.3390/fire5030069 - 25 May 2022

Cited by 5 | Viewed by 3147

Abstract

Subway transportation is one of the most prevalent urban transportation methods globally. Millions of people around the globe use this medium as their mode of transportation daily. However, subway stations may be highly prone to fire, smoke, or explosion accidents. The safety of [...] Read more.

Subway transportation is one of the most prevalent urban transportation methods globally. Millions of people around the globe use this medium as their mode of transportation daily. However, subway stations may be highly prone to fire, smoke, or explosion accidents. The safety of people using subway stations demands a robust and practical framework to assess fire hazards and risks. This study provides a methodology to assess fire risk at a subway station. This study integrates fault tree analysis (FTA) and fuzzy analysis to conduct a comprehensive fire risk assessment. An integrated numerical model of fire temperature and fatality rate was developed using probit correlations for various fire exposure scenarios. The fire dynamics simulator (FDS) provides the probability distribution of casualties caused by fire. To demonstrate the operationalization of the model, Line 1 of the Harbin Metro, located in China, is used as a case study. Results show a probability of 42% of having fire risk in the subway station. Results reveal the highest fatality rate is 6.2% when evacuation time exceeds 200 s. The research helps us to understand the spread of smoke and temperature distribution due to a fire in a subway station. This study is helpful for fire protection engineers, safety managers, and local fire departments to develop a contingency plan to deal with fire in a subway station. Full article

(This article belongs to the Special Issue Building Fire Dynamics and Fire Evacuation)

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Review

Jump to: Research

42 pages, 8525 KiB

Open AccessReview

A Review of Combustion and Flame Spread over Thermoplastic Materials: Research Advances and Prospects

by Yanqiu Chen, Qianhang Feng, Yifan Nie, Jiwei Zhang and Lizhong Yang

Fire 2023, 6(3), 125; https://doi.org/10.3390/fire6030125 - 17 Mar 2023

Cited by 5 | Viewed by 3671

Abstract

As thermoplastic materials are widely used in buildings, the fire hazards of thermoplastic materials are increasingly becoming a central issue in fire safety research due to their unique pyrolysis and melting mechanisms. In this paper, the features and common types of thermoplastic materials [...] Read more.

As thermoplastic materials are widely used in buildings, the fire hazards of thermoplastic materials are increasingly becoming a central issue in fire safety research due to their unique pyrolysis and melting mechanisms. In this paper, the features and common types of thermoplastic materials are introduced first. Then, the combustion behavior of thermoplastic materials is theoretically analyzed based on the empirical formulas and heat balance equations, such as the pyrolysis kinetics, ignition time, melting and dripping, flame, burning rate and mass loss rate, temperature and heat flow, gas products, and influencing factors. The influencing factors basically include the sample properties (width, incline angle, and thickness, etc.), the façade structure (sidewalls, curtain wall, etc.), the ambient conditions (altitude, pressure, and gravity, etc.), and the flame retardant treatment. Similarly, this study also illustrates the vertical and horizontal flame spread behavior of the thermoplastic materials and the influencing factors. The utilized methods include the experimental methods, the analytical methodologies, and the approaches for numerical simulation. Finally, the problems encountered at this stage and worthy of further study in the future are presented. Full article

(This article belongs to the Special Issue Building Fire Dynamics and Fire Evacuation)

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