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15 June 2024, Volume 43 Issue 6 Previous Issue   

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Research progress and challenges of new thermal disasters of lithium-ion batteries under liquid immersion conditions Zhou Biao, Ge Muying, Wang Kai, Ren Changxing, 2024, 43 (6):  767-773.  Abstract ( 1149 )   In the context of “peak carbon dioxide emissions and carbon neutrality”, immersion liquid cooling technology is one of the lithium-ion battery thermal management technologies with good application prospects. In the new generation of thermal management systems, the thermal runaway-induced fire of lithium-ion batteries is still a major safety hazard. This paper provides a comprehensive overview of current research advances in immersion liquid-cooling technology, and multiple modes of thermal damage in lithium-ion batteries under immersion conditions are analyzed, and the research trend of thermal damage in new lithium-ion batteries is proposed. Firstly, immersion liquid cooling technology, its advantages and disadvantages, liquid cooling methods and liquid cooling medium are introduced, focusing on phase change liquid cooling technology and the physical parameters of some commonly used liquid cooling agents. Secondly, the progress and policies of immersion liquid cooling technology in recent years are sorted out. Thirdly, from the immersion conditions of lithium-ion battery aging, thermal runaway and secondary disasters and other aspects， the new lithium-ion battery thermal disaster mode is in-depth analyzed and discussed, pointing out the existing research deficiencies. And finally put forward in the future immersion liquid-cooling conditions, the new lithium-ion battery safety and protection technology research development direction. The research of this thesis will help to improve the thermal safety of lithium-ion battery packs under immersion conditions and enhance the post-disaster emergency response capability after thermal disasters. Related Articles | Metrics

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The smoke characteristics of refractory cable under strong fire source and feasibility study on adsorption and detection Liu Hongyong, Luo Shaoxiang, Wu Xinyu, Zhang Jiaqing 2024, 43 (6):  774-779.  Abstract ( 126 )   Due to the presence of halogen elements, the smoke of flame-retardant cables is toxic and has high fire hazards. Accurate detection is the key to discover and control accidents. This article uses the JCY-2 building material smoke density meter to carry out the YJV flame retardant cable under strong fire source ignition experiment. The density of the smoke generated by the cable outer sheath when the adsorbent material adsorbs for 20, 50, and 100 seconds is tested, and electron microscopy images of the adsorbent material are taken. ImageJ software is used to process and analyze the surface grayscale and characteristics of the adsorption particle. And discuss the feasibility of adding adsorbent material to improve the detection accuracy of existing photoelectric smoke detectors. The results show that the longer the cable is under poor ventilation conditions during the combustion process, the lower the smoke density peak, and the higher the grayscale of the adsorption material surface; The adsorbent material can effectively adsorb and enrich smoke particles, and the smoke particles exhibit changes in surface adhesion, network adhesion, and cylinder adhesion with the change of adsorption time; The diameter of the adsorbent material mesh fiber less than 9 μm can achieve good adsorption effect. The research results provide new ideas for cable fire warning and detection as well as fire investigation in wind flow environments. Related Articles | Metrics

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Study on thermal runaway characteristics of low-temperature cyclic aging Li-ion batteries Zhao Luyao, Tong Jun, Xu Guo, Zhang Junming 2024, 43 (6):  780-786.  Abstract ( 1657 )   Lithium-ion batteries working at low temperatures will inevitably experience cyclic aging, resulting in performance declines such as reduced battery capacity and increased impedance, which will exacerbate the risk of thermal runaway of the battery. In this study, a thermal runaway experiment platform was built to study the thermal runaway characteristics of lithium-ion batteries after cyclic aging at low temperature, and the effects of different aging degrees, charging states and coupling conditions on the thermal runaway characteristics of lithium-ion batteries were analyzed. It is found that under -10 ℃ low temperature environment, the time of thermal runaway explosion is advanced, the injection is more intense, and the temperature rise rate of the battery is more obvious, but the temperature on the upper part of the battery surface (near the pressure relief valve) decreases with the increase of the number of cycles. Since there is no jet port in the lower part of the battery, the heat accumulation causes the lower part of the battery to be slightly warmer than the upper part. At the same time, the evolution law of voltage and mass loss of the battery under different aging degree and charged state is given. This work helps to improve the understanding of thermal runaway characteristics of aging lithium-ion batteries, and provides theoretical basis and data support for the safety of lithium-ion batteries operating in low temperature environment. Related Articles | Metrics

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Research on the fire extinguishing efficiency of low-pressure water mist in urban underground utility tunnel cable fires Li Bin, Ning Zhaoyu, Zhang Zhiwei, Jia Boyan 2024, 43 (6):  787-791.  Abstract ( 89 )   In order to study the effectiveness of low-pressure water mist fire extinguishing in urban underground integrated pipe corridor cable fire and to identify the key factors influencing its efficiency, a scaled-down test platform for low-pressure water mist fire extinguishing in utility tunnels was constructed, and a serial of fire extinguishing tests were conducted. The test results demonstrate that low-pressure water mist can rapidly and effectively extinguish cable fires in utility tunnels, with the quickest fire extinguishing time of 7 s. Within 50 s of activating the system, the internal temperature of the tunnel can be reduced from 650 ℃ to 40 ℃. The changes in pressure and nozzle flow coefficient have a significant impact on the fire extinguishing efficiency of low-pressure fine water mist. The fire extinguishing time is shortened by up to 75% and 66.7% respectively, and the average cooling rate is highest at 8.2 ℃/s and 7.43 ℃/s; The change in nozzle spacing has a relatively small impact on fire extinguishing efficiency, with a maximum reduction of 47.3% in fire extinguishing time and an average cooling rate of 6.1 ℃/s. Related Articles | Metrics

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Experimental study on the dismantling of high-speed train carriage panels Cui Kunpeng, Guan Yanpeng, Liang Xiaoliang, Lin Jinliang, He Zhehong 2024, 43 (6):  792-796.  Abstract ( 93 )   In order to study the dismantling effect of high-speed train carriages, the carriage panels of a certain CRH380 model were taken as the research object. Seven dismantling methods were used to carry out dismantling and cutting experiments, and the efficiency and advantages and disadvantages of each method were compared and analyzed with cutting speed as the main indicator. The results show that the cutting efficiency of toothless saw (diamond saw blade), oxy-acetylene flame cutting, and hydraulic shear cutting high-speed railway carriage panels is extremely low, and the dismantling is ineffective; Plasma cutting and laser cutting can be used to break down carriage panels, but the instruments are bulky and not suitable for use on rescue sites; The grinding wheel toothless saw and the double wheel opposite direction saw can achieve effective cutting and dismantling, with an average cutting speed of about 3.38 mm/s and 5.68 mm/s, respectively. The average time for cutting an isosceles triangle with a side length of 60 cm is 532,317 s, respectively. During cutting, a large amount of heat is generated, and the saw blade is severely worn. For general high-speed train carriage dismantling and rescue scenarios, it is recommended to prioritize using grinding wheel toothless saws and double wheel opposite direction saws to cut the carriage. Related Articles | Metrics

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Fire risk assessment based on comprehensive evaluation entropy algorithm Ding Shiyi, Yang Han 2024, 43 (6):  797-799.  Abstract ( 91 )   Explore how to use big data to enhance decision-making and real-time command capabilities in the field of fire protection, integrate and analyze fire data through technology, and achieve more refined fire prevention and control, more intelligent firefighting and rescue, and more efficient logistics management in various fire scenarios. Using the comprehensive evaluation entropy algorithm to optimize fire protection strategies, deeply analyzing the characteristics of fire protection business, and exploring the key elements of data governance in the field of fire protection. Discuss in detail the methodology for constructing these strategies, data acquisition and processing techniques, and how to effectively integrate these strategies into existing firefighting practices to achieve the above goals. The core purpose of the research is to create value and improve the efficiency and effectiveness of fire response in the field of fire protection through scientific data management and technological integration. Related Articles | Metrics

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Effect of subway train door opening strategies on passenger evacuation efficiency Nie Hui, Shen Yixin, Li Zhihua, Ma Jian 2024, 43 (6):  800-805.  Abstract ( 69 )   In the event of a subway train fire, the number and combination of train door openings have a significant impact on evacuation efficiency when using interval personnel evacuation strategies. This article proposes 8 door opening strategies, constructs a personnel evacuation model and verifies it, and conducts comparative analysis based on simulation. The results show that during one-way evacuation, the evacuation efficiency is highest when all doors are opened, which is 57% higher than the end door evacuation and 33% higher than the passenger compartment door evacuation; When all car doors are opened for evacuation, the mobility inside the carriage increases. The number of people evacuated through carriage one increases by 88% compared to the evacuation through the passenger compartment door, and the connection between carriages is prone to congestion; When evacuating in both directions, the flow rate of the doors in the upstream and downstream directions is the highest. As the number of evacuees increases, the flow rate of each door shows a significant imbalance. Related Articles | Metrics

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Study on influencing factors of personnel evacuation in escape rooms Li Hua, Sun Linxia, Zhang Yurong, Yi Peng 2024, 43 (6):  806-812.  Abstract ( 89 )   Accurately identifying the factors that affect the evacuation of personnel in escape rooms during emergencies such as fires, and objectively and systematically analyzing the hierarchical relationship and importance of the factors, is crucial for emergency evacuation in escape rooms. Based on the industry norms and current situation of escape rooms, 26 influencing factors were extracted from four dimensions: personnel, building structure, environment, and fire management. A three-level hierarchical structure model of the influencing factors for personnel evacuation in escape rooms was constructed using AISM (Adversarial Explanatory Structure Model) and MICMAC (Cross Influence Matrix Multiplication) methods. The relationship between the factors was comprehensively analyzed, and the corresponding responsibility relationships between the factors and the management, operation, and player levels were analyzed. Then, the weights and rankings of each influencing factor were determined using the ANP (Network Analytic Hierarchy Process) method. The results show that the fundamental factors affecting the evacuation of personnel in escape rooms are mainly the completeness of system and regulations, the type of plot in the room, the form of spatial combination, and the number of nested layers in the space. These factors can be optimized by driving the middle level characteristics such as the operating position of the room, the linkage of door locks, the dimness inside the space, the type and quantity of props, and the evacuation guidance ability of NPC (Non Player Character). Key common factors such as the completeness of fire protection facilities, the preparation of emergency plans, safety education and training can be standardized, ultimately improving the emergency evacuation ability of players. Related Articles | Metrics

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Numerical simulation on the influence of ambient pressure on smoke exhaust in tunnel shafts Zhao Jiangping, Bao Wangwang 2024, 43 (6):  813-819.  Abstract ( 76 )   Through FDS numerical simulation, the influence of ambient pressure on the smoke spread law, smoke stratification characteristics, and vertical shaft smoke exhaust effect of tunnel fires was studied. Research has shown that the smoke on the tunnel ceiling in low?pressure environments has a higher temperature, and the longitudinal attenuation curves of the ceiling temperature of the fire source?vertical shaft and downstream area of the vertical shaft follow an exponential distribution. The temperature attenuation coefficient decreases with the increase of ambient pressure; The smoke movement in the fire source vertical shaft area is dominated by thermal buoyancy, and the trend of layering curve change is not obvious. The layering curve in the downstream area of the vertical shaft is greatly affected by ambient pressure. As the ambient pressure decreases, the layering curve shows a clockwise rotation trend, the layering intensity decreases, and the stability of the smoke layer decreases; The smoke exhaust effect of a vertical shaft in a low?pressure environment is better than that of a vertical shaft under normal pressure, and the critical height for the occurrence of suction penetration at the bottom of the vertical shaft has also increased. Therefore, compared with general altitude areas, when a tunnel fire occurs in higher altitude areas, the smoke exhaust effect of the higher vertical shaft is better, the critical height of suction is higher, and the impact on the stability of the downstream smoke layer is smaller, which is more conducive to evacuation and smoke exhaust. Related Articles | Metrics

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Research on GA-WOA-BP fire probability prediction model based on multi-feature parameters Liu Quanyi, Wu Mengyang, Ai Hongzhou, Zhu Pei, 2024, 43 (6):  820-825.  Abstract ( 65 )   In order to further improve the accuracy of fire probability prediction, a GA-WOA-BP fire probability prediction model based on multi-feature parameters is proposed to solve the problems of low detection accuracy and poor generalization ability in the fitting process of BP neural network. Firstly, the fire characteristic parameters of beech and cotton rope smoldering and open burning were collected by experiment, and the corresponding probability of fire type was obtained after calculation. Secondly, by using genetic algorithm to optimize the hidden layer structure of BP neural network and whale optimization algorithm to optimize the initial weight of BP neural network, GA-WOA-BP model was constructed to improve the fitting ability of fusion algorithm. Finally, multi-characteristic fire parameters are used as model input and different types of fire occurrence probabilities are used as output to predict the fire probability. The results show that compared with the simple BP neural network, the model has better prediction performance, and its evaluation indexes RMSE, MAE and R2 are 0.020 22, 0.014 33 and 0.992 31, respectively, which can provide data reference for fire probability prediction. Related Articles | Metrics

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Construction of emergency knowledge graph for gas leakage and fire accidents at gas storage facility sites Song Xu, Wen Ming, Hu Jinqiu, Gong Jianhua 2024, 43 (6):  826-830.  Abstract ( 77 )   Aiming at the difficulty of rapid decision support and plan formulation in the firefighting and emergency response process, this article proposes an emergency model for gas leakage and fire accidents at gas storage facility sites. This model uses a knowledge graph as a means of risk characterization, employing Bidirectional Encoder Representations from Transformers (BERT) and Bidirectional Long Short-Term Memory Model Conditional Random Field algorithm (Bi-LSTM-CRF) for entity recognition and relationship extraction from textual intelligence. The emergency knowledge graph for gas leakage and fire accidents at gas storage facility sites is constructed using the Neo4j graph database. The results show that compared to traditional emergency handling and firefighting strategy research methods, the emergency model proposed in this paper for gas leakage and fire accidents at gas storage facility sites not only enables early emergency handling but also identifies the risk propagation paths of accidents, providing support for firefighting emergency command and emergency decision-making. Related Articles | Metrics

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Research on the new digital warning linear temperature detector and its adaptability in cable tunnel fires Jia Boyan, Zhang Peng, Huang Xingwang, Xie Youliang 2024, 43 (6):  831-835.  Abstract ( 85 )   In order to solve the problem of traditional linear temperature sensing cables being unable to effectively locate and accurately warn fires in cable tunnels, a new type of digital linear temperature sensing detector is developed. On the basis of traditional temperature sensing cable technology, distributed insertion of fire protection chips is combined with existing thermosensitive materials for fire source localization and data processing; Applying multi-source data fusion and adaptive algorithms, considering environmental impacts, and integrating multiple types of data, accurate warning is achieved; Upgrade the output warning method, allowing multiple devices to observe real-time temperature and temperature cloud maps along the cable. After passing the technical index verification of the product, referring to national standards and cable tunnel environment, small fire source performance testing, differential temperature alarm performance testing, and boiling water testing were carried out. The results showed that the detector meets national standards, operates stably in humid and hot environments, and has strong reliability. Related Articles | Metrics

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The design research on forest fire breathing protection and self-rescue equipment Wang Jian, Wang Pei, Li Pengyun, Mu Shaoyu, Liu Wei, Hu Jiabin 2024, 43 (6):  836-841.  Abstract ( 88 )   This article focuses on the practical respiratory protection need of individual firefighters in forest and grassland fire suppression, designs a forest fire respiratory protection and self-rescue device, aiming to ensure the safety of the firefighters' facial skin and respiratory system during forest and grassland fire suppression tasks. The device mainly consists of a head mask assembly, smoke filtration assembly, and air supply system assembly. It is featured by lightweight, portability, ease of operation, and functional adaptability. Through flexibly switching between three air supply modes: dust filtration, smoke filtration, and oxygen-enriched supply, it can effectively meet the respiratory protection and self-rescue for forest firefighters in various situations such as advancing into the fire line, fighting the fire, and emergency evacuation. The samples have been tested and validated by the Shanghai Fire Science and Technology Research Institute and field testing by firefighting teams. It fully proves the progressiveness of this device and can provide valuable reference for the development of respiratory protection equipment for forest firefighting. Related Articles | Metrics

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Effect of Salicylaldehyde Schiff base flame retardant on thermal performance and flame retardant performance of EP He Liangchao, Yang Yicheng, Liu Hong, Kong Qinghong, 2024, 43 (6):  842-849.  Abstract ( 77 )   In order to explore the effect of different P/N contents on the flame retardant properties of EP composites and the effect of different Schiff Bases functional groups on the thermal properties of EP composites, three new phosphorus-containing Schiff Bases flame retardants of SAPO, SPPO and SMPO were prepared using salicylaldehyde (SAL), 3-amino-1,2,4-triazole (ATZ), p-phenylenediamine (PPD), melamine (MEL) and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) as raw materials, SAPO is triazole-Schiff Base flame retardant, SPPO is benzene ring-Schiff Base flame retardant, SMPO is triazine-Schiff Base flame retardant. 1H-NMR and FT-IR were used to characterize the structures of the three flame retardants, and the successful synthesis of the three flame retardants was demonstrated. The three flame retardants are not only different in structural composition, but also in the number of Schiff base functional groups: 1 mol SAPO, SPPO, SMPO contain 1 mol, 2 mol, 3 mol Schiff base functional groups, respectively. Vertical combustion testing, limiting oxygen index testing, thermo-gravimetric analysis and Cone calorimetry testing were used to explore the thermal properties and flame retardant properties of EP composites. The results showed that the vertical combustion testing of EP/6%SAPO, EP/6%SPPO and EP/6%SMPO all reached V0 level, the LOI values reached 32.9%, 32.3%, 33.5%, respectively, the carbon residue increased to 23.6%, 24.7%, 25.1%, respectively, the PHRR values decreased by 20.2%, 25.8%, 27.9%, respectively, the THR values decreased by 15.2%, 17.8%, 20.3%, respectively. The flame retardant properties of EP composites increased with the increase of P/N content. The thermal properties are enhanced with the increase in the number of Schiff Bases functional groups. The flame retardant mechanism is mainly attributed to the capture of free radicals by P element in the gas phase, the chain reaction of cutting off the chain, and the promotion of carbonization and dehydration in the condensed phase to form a carbon layer, which isolates gas exchange and heat conduction. N element releases non-combustible gas when burned, reducing the concentration of combustible gas and taking away heat. Related Articles | Metrics

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Study on the synergistic fire extinguishing efficiency of C6F12O/N2 mixed N2 Ma Jianqin, Xian Xuelei, Zhao Qingsong, Wang Haoxuan, 2024, 43 (6):  850-854.  Abstract ( 93 )   In order to study the fire extinguishing efficiency of mixed gas-liquid flow of C6F12O/N2, developed a fire extinguishing concentration test device of mixed gas and a two-phase flow fire extinguishing concentration test device based on a scaled fire extinguishing model. Then measured the fire extinguishing concentration of C6F12O/N2 and the two-phase flow fire extinguishing concentration of C6F12O after nitrogen atomization，and verified by full-scale fire extinguishing experiment. The results show that the fire extinguishing concentration of C6F12O gas and liquid after atomization is linearly positively correlated with the oxygen concentration. The scale fire extinguishing model can accurately measure the extinguishing concentration of liquid fire extinguishing agent after atomization, and the deviation is less than 1.36%. Based on the two-phase flow spray scheme mixed with C6F12O/N2, the fire extinguishing concentration of C6F12O was reduced by reducing the oxygen concentration in the protective space during the fire extinguishing process. At the same time, under the large?aperture nozzle, realized the low pressure, large flow atomization and rapid spray of C6F12O. Finally, through the physical fire experiment, the concentration and amount of C6F12O can be reduced by 27% under the fire extinguishing condition of 100 m3 total flooding. Related Articles | Metrics

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The effect of fluorocarbon chain length on the physicochemical properties of surfactants at different temperatures Zhu Xinhua, Huang He, Zhang Yuqiang, 2024, 43 (6):  855-859.  Abstract ( 65 )   In this work, the effects of temperature (0~40 ℃) on physicochemical properties (surface activity, foaming property and spreading property) of three surfactants with different fluorocarbon chain lengths were studied. The results show that with the increase of temperature, the critical micelle concentration (CMC) of the fluorocarbon surfactant increased, the surface tension (γCMC) decreased. And the longer the fluorocarbon chain of the surfactant, the stronger the micelle formation ability, in which the CMC of the FC8 surfactant solution was the smallest (0.23 mmol/L), and the γCMC value was the lowest (15.07 mN /m). At low temperature, the foaming ratio of fluorocarbon surfactant is the lowest (especially FC4 is only 3.70 times at 0 ℃), and the foaming ratio reaches the best (6.00~8.73 times) when the temperature rises to 20 ℃. The surfactants achieve the best foaming ratio at a temperature of 20 ℃, and further heating has little effect on the foaming ratio. At the same temperature, the longer the fluorocarbon chain, the larger the foaming ratio, and the foaming ratio of FC8 reached 8.73 times at 20 ℃. Moreover, the spreading coefficient (S) of fluorocarbon surfactant increases with the increase of temperature, and the change of S tends to be gentle when the temperature reaches 20 ℃, and the longer the fluorocarbon chain is conducive to reducing the consumption of surfactant per unit area and saving cost. It can be seen that low temperature has a great impact on the performance of short fluorocarbon chain surfactants, especially when the foaming ratio is too low to meet the use requirements. If it is used in aqueous film forming foam extinguishing agent, it needs to be compounded to improve its use performance. Related Articles | Metrics

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Study on the correlation between meteorological elements and potential forest fire risk Guo Hanwen, Yang Xiaolong, Zhang Yuchun, Gao Yunji 2024, 43 (6):  860-866.  Abstract ( 65 )   In order to explore the correlation between complex climate and forest fires in southwest Sichuan, this paper analyses the potential connectivity between various meteorological elements and forest fire occurrence through local-scale meteorological anomaly changes in Muli County, Liangshan Prefecture, Sichuan Province, as an example. Then, through FWI and FFDI, the historical fire risk changes in Muli County were analysed to verify the association with forest fires in Muli County. The results showed that there were different cycles of continuous increase (or decay) in barometric pressure, air temperature, humidity, wind speed, and evapotranspiration before and after the occurrence of forest fires. Meanwhile, the forest fire risk indices FWI and FFDI of Muri County showed an interannual oscillation and gradually increasing trend, and the annual average correlation coefficient (46.9%) and monthly average correlation coefficient (80.7%) of forest fire frequency with FWI in Muri County were larger than those with FFDI (annual correlation coefficient of 38.7% and monthly correlation coefficient of 53.1%). In addition, extreme anomalies in forest fire risk values are also closely related to climatic events occurring in the same period (or year). Therefore, the persistent high temperature, low humidity and windy meteorological conditions caused by climatic anomalies are one of the essential reasons for the rapid increase of forest fire risk level or major forest fire accidents. Related Articles | Metrics

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Hydraulic characteristics research on polyurethane hose used in forest firefighting remote water supply system Li Xuexin, Zhang Yu, Chen Afeng, Jing Qi 2024, 43 (6):  867-871.  Abstract ( 59 )   The remote water supply system for forest fire fighting is an important technical means for forest fire fighting. In order to study the water conveying effect of the system, theoretical analysis and experimental research on the hydraulic characteristics of polyurethane hose were carried out. The results show that the frictional resistance loss of polyurethane hose along the pipeline is related to Reynolds number (Re) and wall roughness (??). Its flow is generally in the turbulent region. In the smooth pipe turbulent region, the frictional coefficient λ is only related to Re. In the mixed friction region, λ is related to both Re and ?. In the rough pipe turbulent region, λ is only related to ?. Under the same flow rate, the smaller the diameter, the larger the Re, and the greater the frictional resistance loss, and the earlier the flow state enters the next interval. For the same section of pipeline, the lower the roughness, the smaller the λ，and when the roughness decreases by one order of magnitude, the hydraulic loss decreases by about 40%, which can greatly improve the water conveying efficiency. Through experiments, it is measured that the absolute equivalent roughness of the single-layer DN100 polyurethane hose selected by the system is about 0.3 mm. The pipeline characteristic curve of the 10 km remote water supply system is calculated based on this, which is basically consistent with the experimental results, verifying the scientific nature of the water supply system working under the design flow rate. Related Articles | Metrics

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Exploration and reflection on firefighting and rescue techniques in commercial complexes Chen Zhiang 2024, 43 (6):  872-876.  Abstract ( 94 )   The firefighting of commercial complex fires is not only a major challenge in current firefighting and rescue efforts, but also a hot research topic both domestically and internationally. In order to enable firefighting and rescue personnel to quickly understand the characteristics, rescue difficulties, and typical operation modes of commercial complex fires, improve their ability to extinguish commercial complex fires, and more efficiently respond to commercial complex fire rescue, this article combines the on?site investigation of typical commercial complexes in Jiangsu Province, analyzes the characteristics of fires, firefighting and rescue difficulties, main fire forms, and other aspects, explores the typical operation modes and key disposal points of key parts of commercial complexes, and provides some measured data to provide reference for the firefighting of commercial complex fires. Related Articles | Metrics

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Exploration and research on the grassroots fire safety management model of “person to person+” Liu Xin, Hao Wenlei 2024, 43 (6):  877-880.  Abstract ( 81 )   Grassroots fire safety has always been a weak point in fire prevention and control work. This article proposes a “person to person+” comprehensive management model for grassroots fire safety, which integrates into the government's grassroots governance system. Starting from clarifying the responsibilities of grassroots grid fire joint prevention and control, strengthening the construction of grassroots fire stations, and standardizing the operation mechanism of township fire safety committees,integrated the “three lines” fire safety functions, and built a “person to person+” five level comprehensive management grid. By leveraging the precise control advantages of “one person monitoring one area, one level monitoring one level”, we can achieve a more sound system,more precise control,and smoother sharing and co-governance. Implementing it in areas with high fire incidence in grassroots townships in China can effectively improve the efficiency of grassroots fire safety management. Related Articles | Metrics

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The compliance mechanism and construction path of the judicial application of the crime of dangerous operation in the field of Liu Fan, Chen Suhao, Ge Yuehong 2024, 43 (6):  881-883.  Abstract ( 73 )   The addition of the crime of dangerous operation in Criminal Law of the People's Republic of China is conducive to enhancing the strength of fire administrative law enforcement with the deterrent of punishment. Based on the high professionalism and social focus of fire fighting work, the necessity of introducing the compliance mechanism into the judicial application of dangerous operation crime is discussed by combining the current status and problems of the application of dangerous operation crime, so as to smooth the two-way connection channel of execution, transform the “penalty potential energy” into “rectification kinetic energy”, and maximize the effect of fire safety management. The path of building compliance mechanism is elaborated from three aspects: the normative system of compliance obligation, the program design of compliance assessment and the organization of compliance management. Related Articles | Metrics

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Exploration of the application of 5G diagnosis and treatment system in earthquake emergency medical rescue Liu Le, Liu Juan, Wang Zhaoxia, Zhu Wei, Wang Zhenling 2024, 43 (6):  884-887.  Abstract ( 58 )   To study the application of 5G diagnosis and treatment systems in earthquake relief, improve earthquake rescue capabilities and efficiency, based on the practical exercise experience of 5G diagnosis and treatment systems in on-site first aid, reporting monitoring center, expert remote consultation, and remote guidance of medical cabin surgery in "Emergency Mission · 2022", clarify the specific application value of 5G diagnosis and treatment systems in earthquake emergency medical rescue, and explore the organizational management system of on-site medical rescue. The application of 5G diagnosis and treatment system in earthquake emergency medical rescue can efficiently achieve the input and sharing of injury information, remote real-time consultation of experts, and the provision of treatment and treatment plans, as well as the refinement and summary of organizational management system. The application of 5G diagnosis and treatment system can fully improve the information management and treatment efficiency of earthquake rescue, reduce mortality rates, and improve the effectiveness of emergency medical rescue. Related Articles | Metrics

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Research on fire safety strategy of an urban rail transit vehicle base Ye Yifan, Huang Haiyan, Liu Jianchun, Ren Tong 2024, 43 (6):  888-891.  Abstract ( 83 )   Taking an urban rail transit vehicle base project as an example, the fire safety problems of the vehicle base were analyzed according to its characteristics, and the corresponding fire safety strategies were proposed in combination with current norms and standards, including the design methods of fire compartment/fire partition、personnel evacuation and fire hazard. Moreover, FDS and Pathfinder software were further used to carry out numerical simulation research on smoke flow and personnel evacuation. The safety of personnel evacuation was determined according to the simulation results, and the rationality of fire protection design was verified. The results could provide a basis for fire protection countermeasures of other urban rail transit vehicle bases. Related Articles | Metrics

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Research progress on thermal damage examination of fibrous evidence Wang Peibin, Zang Zhengzhe, Di Junyi, Jin Jing 2024, 43 (6):  892-895.  Abstract ( 54 )   In incident investigations such as fires and explosions, the analysis of thermal damage traces on fibers plays a pivotal role in identifying suspects, establishing facts, reconstructing scenes, and determining causation. This paper reviews domestic and international research on thermal damage to human hair and textile fibers, highlighting their significance in forensic investigations. Additionally, the paper offers a prospective outlook on future research directions, aiming to provide valuable references for relevant studies and to guide fire and explosion investigations Related Articles | Metrics

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Research on the risk of thermal runaway and characteristics of combustion traces of 18650 ternary lithium batteries Wu Juntao, Li Fang, Yang Shengkui 2024, 43 (6):  896-901.  Abstract ( 103 )   In order to study the thermal runaway risk of ternary lithium batteries, 18650 nickel cobalt manganese ternary lithium batteries were selected as the research object, and a testing platform for measuring the characteristic parameters of battery thermal runaway process was built to explore the thermal runaway process and combustion trace characteristics of lithium-ion batteries under different states of charge, electrical abuse, and thermal abuse. The results show that the positive current collector plate of lithium batteries has a certain protective effect on thermal runaway caused by overcharging and short circuit of the battery. When the SOC is above 25%, the degree of thermal runaway damage to the battery is directly proportional to the charge. By combining the characteristics of voltage and temperature changes before and after thermal runaway in lithium-ion batteries, as well as the characteristics of battery explosion and combustion, the characteristic peaks of the temperature curve can be used to determine the state of the battery that has experienced thermal runaway, and X-ray and voltage changes can be combined to determine the fault state of the battery and trace the location of the fire in the lithium-ion battery. The research results can provide reference basis for lithium battery design, lithium battery fire extinguishing, and fire investigation. Related Articles | Metrics

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Comparative analysis of investigation mechanisms for hazardous chemical accidents between China and Europe and America Li Guangyao, Sun Zhenwen, Liu Yao, Zhou Zheng 2024, 43 (6):  902-906.  Abstract ( 89 )   Chemical accidents occur from time to time. The main manifestations of accidents are explosions and fires, which often cause many casualties, economic losses, and environmental hazards, which seriously endanger public safety. This article conducts statistical analysis and research on major hazardous chemical accidents in mainland China in the past decade, covering core information such as casualties, economic losses, hazardous substances, etc., which visually presents the status quo of hazardous chemical accidents in China. From the perspective of hazardous chemical accident investigation mechanism, a horizontal comparison between China and the major developed countries in Europe and America was carried out, and the characteristics of the investigation mechanism in major developed countries in Europe and America were deeply analyzed. Related Articles | Metrics