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15 November 2022, Volume 41 Issue 11 Previous Issue    Next Issue

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Research on dynamic response of galley cart under implosion field Xie Jiang, Pan Hanyuan, Fu Boyu, Feng Zhenyu 2022, 41 (11):  1477-1482.  Abstract ( 925 )   The galley cart can provide a potential solution for the emergency disposal of suspected explosives in the cabin. Taking the full-size galley cart as the research object, this paper carries out implosion test and numerical simulation, reveals the dynamic response and failure characteristics of galley cart under implosion field, studies the dynamic response of galley cart under different initiation positions and different charge quantities, and compares and analyzes the influence of internal filler on the deformation mode and failure behavior of galley cart. The results show that compared with other structures of the galley cart, the side plate has the strongest energy absorption ability, but its flying speed is the largest, and the speed increases linearly with the increase of the dosage. When the explosive is placed at the middle baffle, the flying speed of the side plate of the galley cart is the smallest, so it can be used as the placement position of suspected explosives. The seat cushion under the implosion field can prevent the spread of flames, absorb the implosion energy, reduce the deformation and energy absorption of the structure of the galley cart, and play an important role in reducing the degree of explosion damage. Related Articles | Metrics

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Research on combustion and explosion characteristics of activated carbon before and after adsorption of toluene Zhang Jinfeng, Yan Zhongqing, Dong Hongyu, Ren Hongwei 2022, 41 (11):  1483-1486.  Abstract ( 1025 )   Coconut shell activated carbon was modified by quaternary ammonium salt ionic liquid, the ignition and explosion parameters of activated carbon before and after modification and before and after adsorption of toluene were compared to explore the ignition and explosion law of gas-solid heterogeneous mixture in VOCs adsorption process of activated carbon. The spontaneous combustion point of activated carbon increased from 319.3 oC to 345.7 oC, and the spontaneous combustion point of activated carbon increased from 307.7 oC to 327.1 oC after adsorption of toluene before and after modification. Using a 20 L spherical explosion test device, the lower limit of explosion of powder was increased from 1.5~2.5 g/m3 to 7~8 g/m3 before and after activated carbon modification. The lower explosive limit of the mixture adsorbed toluene by activated carbon before modification is less than 1.5 g/m3, and the lower explosive limit of the mixture adsorbed toluene by activated carbon after modification is 2~3 g/m3. Under the condition of 200 g/m3, the maximum explosion pressures are 0.57 MPa and 0.53 MPa, respectively, and the explosion pressures decrease. The results show that the activated carbon modified with quaternary ammonium salt ionic liquid has not only enhanced the adsorption capacity of VOCs, but also reduced the risk of ignition and explosion. Related Articles | Metrics

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Study on long-distance spraying characteristics and jet features of perfluorohexanone Zhou Tiannian, Chen Jie, Chen Baohui, Wu Chuanping 2022, 41 (11):  1487-1490.  Abstract ( 1045 )   This study attempts to obtain the jet features of perfluorohexanone so as to provide a guidance for the application of perfluorohexanone in fire prevention for large space such as the valve hall. A series of experiments considering different nozzle types and injection pressures were carried out. Results demonstrated that a single orifice nozzle should be employed to achieve the long-distance injection of perfluorohexanone. The spraying distance can reach 18~22 m using the spraying guns of DN 16 and DN 28 under the pressure of 0.8~1.0 MPa. However, the atomization at the end of the jet flow was observed significantly when the spray gun with a larger diameter of DN 40 was used, consequently, the spraying distance was reduced. In addition, the horizontal angle was more conducive to acquiring a long-distance spraying of perfluorohexanone. The coverage of perfluorohexanone was far beyond that of aqueous medium and it was in a range of 6~10 m. Related Articles | Metrics

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Study on calculation of critical wind speed of tunnel fire under blocking effect Zhao Xiangling, Mei Hua, Wang Fengcang 2022, 41 (11):  1491-1496.  Abstract ( 878 )   In order to obtain a more accurate critical wind speed algorithm for tunnel fire, the fire source blocking ratio φ1 is considered in this study, blockage ratio upstream of fire source φ2 are set of 0, 0.23, 0.41 and 0.64, and the heat release rates of 1.6, 3.2 and 9.3 kW fire sources are selected. The critical wind speed values under 48 blocking conditions are calculated through orthogonal numerical experiments. The dimensionless correction algorithm of critical wind speed under simple fire source blocking, simple fire source upstream blocking and simultaneous blocking of fire source and upstream is deduced. The results show that whether the blockage ratio at the fire source is increased or the blockage ratio upstream of the fire source is increased, the critical wind speed will gradually decrease, and the blockage at the fire source has a greater impact on the critical wind speed. As the heat release rate of fire source increases, the critical wind speed will also increase. When only the fire source is blocked, the critical wind speed is proportionate?to (1-φ1)2/3. When only the upstream of the fire source is blocked, the critical wind speed is proportionate?to (1-φ2)1/3. When the fire source and upstream are blocked at the same time, the critical wind speed is proportionate?to (1-φ1)2/3(1-φ2) 1/3. Related Articles | Metrics

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Optimization research of micro continuous powder feeding of lithium battery dust inerting apparatus Chu Shiyun, Xie Xiaopeng, Lu Xiaohui 2022, 41 (11):  1497-1502.  Abstract ( 848 )   The optimization research for the inerting device is to solve the problem that the dust inerting device of lithium battery always forms material arch, which can not guarantee the safety of lithium battery production. Based on the analysis of the main structure and working principle of the inerting device system and the established mathematical model of silo pressure of the conveying system, the influence of silo pressure on inert powder conveying and discharging rate was studied. Combined with the influence and search optimization algorithm, the size range of the discharge port was determined. The optimization method of the pneumatic arch-breaking device is derived from the arch-breaking mechanism revealed by the numerically simulated and analyzed of the pneumatic arch-breaking auxiliary powder feeding device. The results showed that according to the calculation and experimental analysis results, the higher the silo pressure is, the more difficult it is to transport inert powder. The maximum amount of inert powder added in a single time is 3.6 kg in the original structure, and the device with the improved outlet size of 89 mm is up to about 20 kg. Compared with the single nozzle, the arch-breaking effect of the new double inclined nozzle is improved by 30.9%. The optimized inerting device has no interruption of powder feeding, and the amount of inert powder can be up to 25 kg per time, and the amount of powder feeding per hour fluctuates between 0.16 kg and 0.37 kg. Related Articles | Metrics

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Study on the influence of temperature and pressure field after gas leakage and explosion in underground utility tunnels Cui Kunpeng, Zeng Tao, Cui Yingjie, Li Xue 2022, 41 (11):  1503-1506.  Abstract ( 853 )   The equal-equation equation of homogeneous turbulent combustion time, k?ε turbulence model and Ebu-Arrhenius combustion model in ANSYS Fluent software were used to simulate the explosion process of methane air premix gas in the gas bunker of integrated pipe gallery with built-in obstacles, and the influence of different fire source positions on the ignition process in the gas bunker of integrated pipe gallery with built-in obstacles was discussed. The results show that when the height of ignition source is lower than the level of obstacle in the vertical direction, the flame is disturbed the most and the flame propagates the slowest. In the horizontal direction, the smaller the distance between ignition source and obstacle, the slower the pressure rise rate. Related Articles | Metrics

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Study on smoke characteristics of the scheme of smoke exhaust replacing part of air shaft in metro long tunnel Zhong Xiaoqing, Wang Jingwei, Yu Zeyang, Jiang Xuepeng 2022, 41 (11):  1507-1511.  Abstract ( 841 )   In the design of smoke control and exhaust system of long interval tunnel, the middle air shaft is usually set, but the setting of the middle air shaft is easily restricted by many factors, so the smoke exhaust can be used instead of part of the middle air shaft. In order to verify and expand the feasibility of the alternative scheme of smoke exhaust, the smoke control methods corresponding to three smoke exhaust setting schemes were analyzed theoretically. Based on a certain subway in Guangzhou, numerical simulation was conducted to verify the smoke control effects of three kinds of smoke control methods under different conditions. The results show that, when the single-side air supply is 1.6 m/s and the smoke exhaust volume is 140 m3/s, the fire can basically effectively control the smoke discharge in the middle ventilation section. When the fire is located near the air shaft or below the smoke outlet, the air speed of 1.4~1.6 m/s and the smoke exhaust volume of 140~150 m3/s can effectively control the smoke, which proves that the smoke exhaust can replace part of the middle air shaft reliability, and expands the applicability of the scheme. Related Articles | Metrics

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Analysis of burning behavior of organic thermal insulation materials in SBI test Zhang Yidong, Liu Qing, Meng Tianchang, Xu Sheng 2022, 41 (11):  1512-1515.  Abstract ( 914 )   Based on the SBI test of organic thermal insulation materials commonly used in engineering, the burning behaviors of different materials were discussed according to the heat release rate curves. The results show that the fire risk of thermoplastic insulation materials (EPS and XPS) is higher than that of thermoset insulation materials (polyurethane board). There was a great difference between organic insulation materials with different thickness in the burning process, especially XPS. Color steel plate has a certain protective effect on the insulation core material, but will also be weakened by the extension of time and temperature rise. For the boards with a certain thickness, the installation method has an impact on the test results, so it is recommended to confirm installation method according to the sample used in the actual project. Related Articles | Metrics

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Research on remote unmanned identification equipment for liquid hazardous chemicals Li Ziting 2022, 41 (11):  1516-1519.  Abstract ( 894 )   To meet the demand of rapid preliminary unmanned detection in fire and explosion accidents caused by liquid hazardous chemical leakage, the experimental collection of Raman spectra of 37 kinds of key supervised liquid hazardous chemicals in China was made by using the OEM core of handheld laser Raman spectrometer, and after data processing, a Raman spectral database containing key supervised liquid hazardous chemicals in China was established, and on this basis, a rolling liquid hazardous chemical detection ball mounted by a fire fighting robot was independently developed. It can realize the unmanned automatic sampling, identification and data transmission of leaking liquid hazardous chemicals, which can provide technical and equipment support for the perception and diagnosis of liquid hazardous chemicals leakage and fire or explosion accident situation, and ensure the personal safety of firefighters. Related Articles | Metrics

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Design of airborne composite fire detection system based on KNN algorithm Deng Li, Wu Dandan, Zhu Bo, Liu Quanyi 2022, 41 (11):  1520-1523.  Abstract ( 860 )   Aiming at the problems of single detection parameter of smoke detectors in aircraft cargo compartment, high false alarm rate and no visual interaction, a composite fire detection system based on machine learning using Raspberry Pi is designed and implemented. Raspberry Pi is used as control center and to connect CO sensor, TVOC sensor, PM10 sensor for data collection. The KNN algorithm is used for multi-sensor data fusion, the output result is fire and no fire, the accuracy rate reaches 98%, and the processed data is stored in the SQLite database. The Raspberry Pi builds a Web server and connects to the onboard server local area network, the device realizes the interaction of the visual interface by accessing the HTML web page. Through the experimental test, the system can generate an alarm indication within 46 s in a cargo hold with a height of 2 m. The functional indicators meet the design requirements of cargo hold fire detection, and the underreport rate is 0 and the false alarm rate is less than 1%, and provides a reliable solution for the design of the airborne fire detection system. Related Articles | Metrics

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Study on the improvement of fire cyclone generator based on geometric conductivity and its formation law Zhou Yunhan, Che Hui, Yang Jiahui, Liu Yitong 2022, 41 (11):  1524-1528.  Abstract ( 832 )   In order to design a more reasonable fire whirlwind generator, the formation conditions and related laws of the fire whirlwind are explored based on the method of geometric conductivity, and then the relationship between the height of the fire whirlwind and the gap size, and the burning speed of the oil pan is proposed. The results show that the formation of fire whirlwind requires a certain amount of vortex, generated vortex, fluid sink and friction; The change of gap size will make the mass burning rate of oil pan show a parabola trend. When the bottom edge size of the fire cyclone generator is 400 mm × 400 mm, the oil pan diameter is 150 mm and the gap is 10 mm, the fire whirlwind height is the highest; When a 200 mm oil pan is used, the height of the fire whirlwind is the highest when the gap is controlled at 30 mm, and the fire whirlwind will be affected by both the burning rate and the shear flow field. Related Articles | Metrics

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Research and development of fire hose drying equipment based on open and close integrated heat pump Li Yongzhen, Liu Long, Yu Hao, Huang Chen 2022, 41 (11):  1529-1533.  Abstract ( 837 )   In order to solve the problems of slow natural drying rate of fire hose and time-consuming and laborious manual winding, a fire hose drying equipment based on open and close integrated air source heat pump was designed and developed. The equipment could not only realize the function of automatic winding, but also could stably and continuously provide hot air of 40~60 ℃, which greatly shorten the drying cycle of the fire hose. The main components of fire hose drying device were heat pump and drying chamber. First of all, the main components of heat pump were selected to achieve hot air output under different environmental conditions. Secondly, the structure of drying chamber was designed to make full use of heat energy. The left and right rotating shafts of the drying chamber were driven by the motor with clutch to realize the forward and reverse rotation of the fire hose, the hose was arranged in the "M" shape in the drying chamber, which extended the drying distance of the fire hose and further improved the drying efficiency. Related Articles | Metrics

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Research on fire truck channel management and control system based on Internet of Things Lin Hui, Yan Xiaomin 2022, 41 (11):  1534-1536.  Abstract ( 883 )   According to the current situation that the blockage of fire lanes in residential areas leads to the expansion of casualties and losses caused by residential fires, and combined with the actual work of fire supervision, this paper proposes a fire truck access control system based on Internet of Things technology. The camera is used to patrol the fire truck access, identify the license plate, send prompt, warning, punishment SMS or voice phone to the owner. The system will analyze and judge the statistical data and carry out law enforcement activities for the communities with difficult traffic control problems. The system is aim to thoroughly solve the problems of obtaining evidence, supervising and renovating the fire truck access and to create a new situation of fire truck access regulation. Related Articles | Metrics

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Study on flame retardant effect of functionalized lanthanum phenyl phosphonate in epoxy resin Kong Qinghong, Song Xiaoyu, Li Weixi, Wang Yuan 2022, 41 (11):  1537-1541.  Abstract ( 799 )   In this study, layered material lanthanum phenylphosphonate (LaPP) was synthesized by reflux method and the surface of LaPP was grafted modified by hexachlorocyclotriphosphonitrile (HCCP) in order to improve the thermal stability and flame retardancy of epoxy resin (EP). As a result, HCCP-LaPP was created and used to the preparation of HCCP-LaPP/EP composites. In addition, the synergistic effect of LaPP and HCCP on the flame-retardancy and thermal stability of EP was studied. The results show that the addition of HCCP-LaPP can significantly improve the thermal stability and residues weight of EP composites at higher temperatures. Conical calorimeter test results show that compared with those of pure EP, the THR and TSP of 6% mass HCCP-LaPP/EP reduced by 39.9% and 24.6%, respectively. Meanwhile, the LOI value was increased from 25.7% to 30.3%, the UL-94 rating was enhanced from NR to V-1 and the residues weight of 6% HCCP-LaPP/EP composites was 25.7% while the pure EP had only 18.5% at 700 ℃. It is proved that HCCP-LaPP has a good synergistic effect in flame retardant EP. Excellent carbonization, lamellar barrier and phosphorus and nitrogen coeffect of LaPP and HCCP make the flame retardancy, smoke suppression and thermal stability of EP composites significantly improved. Related Articles | Metrics

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Experimental study on fire suppression and burn resistance of compressed air foam Wang Yueyong, Yang Zhen, Gao Xuhui, Xiao Liang 2022, 41 (11):  1542-1546.  Abstract ( 857 )   In order to further quantify the performance characteristics of compressed air foam, the fixed compressed air foam extinguishing system was adopted, and the performance of compressed air foam and conventional suction foam on fire control, fire extinguishing, reignition and fire resistance was investigated through standard oil-pan fire comparison test, and multiple performance indexes of the two characteristic foams were tested. The results show that: Based on the same fire experimental model and test method, the two type of foam can put out 92# gasoline fire and oil fire has not been reignited, but under the condition of low intensity of extinguishing, the fire control, cooling, extinguishing, burn resistance of the compressed air foam is obviously better than the suction air foam under the condition of high fire intensity. The basic performance characterization shows that the compressed air foam has more solid thin membranous tissue, and the low temperature environment has a maintenance effect on the compressed air foam structure group, there will be no freezing phenomenon. Using CAF sprinkler can generate high-quality foam fire extinguishing agent and it can uniformly cover the protected area without blind spots, which broadens the application mode of compressed air foam, and has certain guiding role in the follow-up focus on the indoor fire safety demonstration of tall and high-risk buildings with compressed air foam. Related Articles | Metrics

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Effects of ammonium polyphosphate and MoO3 on flame retardancy of flexible polyurethane foam Gao Shansong, Liu Quanyi, Zhao Yinlong, Zhi Maoyong, 2022, 41 (11):  1547-1551.  Abstract ( 841 )   Flame retardant flexible polyurethane foam (FPUF) were prepared by one-step foaming with ammonium polyphosphate (APP) and molybdenum trioxide (MoO3) as flame retardants. The effects of MoO3 and APP on the cellular structure,thermal stability, flame retardancy and smoke production of polyurethane foam were studied by means of scanning electron microscopy, limiting oxygen index, thermogravimetric analyzer and cone calorimeter. The results show that MoO3 and APP can improve the flame retardant performance of flexible polyurethane foam. Compared with pure flexible polyurethane foam, when the addition of APP and MoO3 is 7.5%, the total heat release and total smoke production of flame retardant flexible polyurethane foam are reduced by 44.2% and 66.3% respectively, showing better flame retardant and smoke suppression performance; The flame retardant mechanism of APP and MoO3 flame retardant flexible polyurethane foam is discussed. APP plays a flame retardant role in the gas phase and condensed phase. Free radicals in the gas phase are captured by generating phosphorus containing functional groups in the gas phase. The condensed phase plays a role in catalytic carbonization. MoO3 promotes the catalytic carbonization of pyrolysis polyurethane, improves the carbonization rate, compacts the carbon layer, and improves the thermal stability of flexible polyurethane foam. The fire safety of flexible polyurethane foam is effectively improved. Related Articles | Metrics

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Study on properties of magnesium sulfate whisker composite polystyrene plate Hui Fei, Jiang Lili, Zhang Yinan, Wang Xin 2022, 41 (11):  1552-1555.  Abstract ( 855 )   The magnesium sulfate whiskers were prepared with low-grade magnesite by hydrothermal synthesis. Magnesium sulfate whisker composite polystyrene plate was prepared by filling the whisker grout into the polystyrene plate by vacuum absorption. Then the influence of whisker content on the calorific value, tensile strength, thermal conductivity, smoke density and fire effluents hazard of the composite polystyrene plate were also studied . Related Articles | Metrics

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A study on the distribution of forest fires in Wenshan prefecture, Yunnan province based on buffer zone analysis Wang Hechenyang, Zhao Heng, Gao Zhongliang, Wei Jianheng 2022, 41 (11):  1556-1562.  Abstract ( 872 )   To study the distribution characteristics of forest fires in Wenshan prefecture, forest fire data in Wenshan prefecture from 2012-2019 were selected, and the relationship between residential, roads, river systems, GDP and forest fires was explored using buffer zone analysis and overlay analysis of ArcGIS, and fire distribution maps were drawn to establish residential buffer zones Ⅰ, Ⅱ, Ⅲ, road buffer zones Ⅰ, Ⅱ, Ⅲ, river system buffer Ⅰ, Ⅱ, Ⅲ, Ⅳ, and four GDP buffer zones to analyze the distribution characteristics of forest fires in Wenshan prefecture, Yunnan province. Results showed that, forest fires occurred most frequently in road buffer zone II, residential buffer zone II, river system buffer zone III, and GDP buffer zone I, with the highest fire risk level. During 2012-2015 and 2016-2019, the number of forest fires obeyed a normal distribution within the residential, road and river system buffers. The number of forest fires in road and residential buffer zone II accounted for 60.28%, 62.30%, 53.73% and 59.01%, respectively, and the number of forest fires in buffer zones I and III were below 28%; the number of forest fires in river system buffer zone III accounted for 37.85% and 39.34%, respectively. Other regions are stepped down, it shows that the order of the number of forest fires in Wenshan prefecture river system buffer zone in the first time period is zone Ⅱ > zone Ⅳ > zone Ⅰ, and zone Ⅳ > zone Ⅱ > zone Ⅰ in the second time period. The average fire decline rate from 2012 to 2019 was ranked as GDP buffer > river system buffer >residential buffer > road buffer. the highest forest fire decline rates were 89.74%, 83.67%, and 80% in GDP buffer zone II, residential buffer zone III, and river system buffer zone I, respectively. The priority of forest fire prevention and control is road buffer >residential buffer > river system buffer > GDP buffer; the priority of forest fire prevention and control should be in road buffer zone II, residential buffer zone II, river system buffer zone III, and GDP buffer zone I. The study can provide technical support for forest fire prevention in Wenshan prefecture and Yunnan province. Related Articles | Metrics

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Study on effect of fuel clearing on risk of Xichang forest fire Gao Yunji, Luo Yueyang, Yang Xiaolong, Zhang Yuchun 2022, 41 (11):  1563-1567.  Abstract ( 881 )   To study the impact of two common kinds of forest fuel clearing (evergreen broad-leaved shrub and coniferous forest litter) on forest fire hazard of Xichang, Liangshan Prefecture, FlamMap was used to simulate four kinds of eliminating methods and untreated conditions. Meanwhile, the changes of burning probability (BP) and mean flame length (MFL) before and after cleaning were compared and analyzed. The simulation results indicated that the strategy of clearing litter under evergreen broad-leaved shrub and coniferous forest can effectively break the horizontal continuity of fuel, which can reduce the BP and MFL of forest fire. The higher the ambient wind speed, the more obvious the treatment effect is. Moreover, the effect of shrub clearing strategy is better than that of coniferous forest litter. In the area where the flammable combustibles cluster together with high spreading speed, BP is evidently larger than that in the surrounding environment, and the clearing effect is manifestly better. Therefore, when deploying a fuel clearing plan, attention should be paid to the reduction of weeds and shrubs, especially in areas where flammable fuel clusters, horizontal continuity is large, and some areas are prone to ignition. Related Articles | Metrics

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Study on the development countermeasures of forest fire emergency industry of public safety Chen Yong1，Wu Zhiwei2,3，Peng Xujian1 2022, 41 (11):  1568-1570.  Abstract ( 855 )   Forest fire is one of the most serious natural disasters and public crisis events. It is of great significance to promote the development of emergency industry of forest fire, which can not only provide technical and professional services for forest fire prevention, but also facilitate the structure adjustment of forest fire-related industries. This paper analyzed the existing problems of forest fire industry system from aspects of technology, policy, service, education and market.It also puts forward countermeasures and suggestions to accelerate the development of forest fire emergency industrial system from the aspects of industrial support mechanism, market supply system, core technology training mechanism, industrial service system and professional talent training mechanism. Related Articles | Metrics

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A super strategy of personnel training for safety and emergency management based on requirements Yan Ye, Wang Qiong 2022, 41 (11):  1571-1575.  Abstract ( 849 )   In order to meet the urgent needs of high-risk society for professionals with specialties in safety and emergency response, with the help of literature analysis and research data of relevant research groups, based on the idea of “the overall safety concept”, the research scope covering 6 major disciplines is determined, and the construction of “requirements-transcending” framework is built for in-depth analysis. The research results show that there is a huge gap of safety and emergency professionals in China, the hierarchical structure and regional distribution are unreasonable, the adaptation to disaster types is not matched, and the quality of new professionals is difficult to meet the needs in the short term. The conclusion is that it is urgent for the country to go beyond the existing school-running model, discipline and professional setting and teaching model, we should speed up the establishment of high-level safety and emergency colleges and universities, reasonably set up safety science or interdisciplinary discipline, and vocational qualification systems, and take multiple measures to strengthen teachers team, implement the “three modernizations and three systems” teaching method, adopt diversified training methods such as academic education and on-the-job training, gradually expand the scale of talent training, improve the quality of talent training and the structure of talent needs adapting. Related Articles | Metrics

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Influencing factors of mental health of firefighters Zhong Xia, Zhang Jie, Fan Weiqiao, Wang Jingyi 2022, 41 (11):  1576-1579.  Abstract ( 1039 )   To explore the factors affecting the mental health of firefighters, using the method of cluster sampling, 585 fire commanders and fighters from 17 fire stations subordinate to a municipal fire and rescue division were selected for centralized measurement. The mental health level of firefighters was evaluated by the mental health scale of fire rescue personnel. Suggestions were made based on the analysis. The results show that: hometown location and workplace have a significant impact on the mental health level of firefighters, and the impact of home location shows an obvious medium distance effect. There are significant interaction effects between hometown location, workplace and marital status. The impact of rescue experience is not significant. Therefore, we should improve firemen's work and life experience and community relations, and create a healthy and positive working atmosphere; distinguish different groups of firefighters, and pay attention to groups such as organ firefighters and unmarried firefighters;?pay special attention to the mental health status of "middle distance" groups. Related Articles | Metrics

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Study on site selection optimization of metro fire emergency rescue station Yang Shun, Peng Shaoke, Feng Haolin, Chen Qinpei 2022, 41 (11):  1580-1585.  Abstract ( 914 )   In order to enhance the fire emergency capability of Guangzhou metro rail transit, a mathematical model was built to study the optimal site selection of metro fire emergency rescue stations. First, a time limit model and a required and non-selected station model were established considering the actual situation of Guangzhou metro rail. Then, Lingo 18.0 was used to solve the time limit model, and then the required and non-selected station models were used to optimize. For the repeatedly covered fire emergency rescue service demand stations, select the nearest metro fire emergency rescue station as the departure station of the fire emergency rescue force of the demand station. Finally, 40 stations from 241 metro stations were selected as metro fire emergency rescue stations to achieve the coverage of rescue services for all metro stations. Related Articles | Metrics

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Research on influencing factors of grass-roots emergency security capacity in disaster based on SEM Cheng Genyin, Chen Junchao, Si Junhong, Li Lin 2022, 41 (11):  1586-1590.  Abstract ( 902 )   In order to ensure the disaster emergency handling capacity for grass-roots people, the index system of influencing factors of emergency security capacity in disaster was constructed from the five aspects: disaster emergency response ability, disaster prevention ability, disaster emergency rescue ability, resource security ability and post disaster experience summary ability. Amos 24.0 and SPSS 24.0 software were used to construct emergency security capacity in disaster SEM model. Combined with the questionnaire, this paper analyzes the influence degree and reasons of each influencing factor on the emergency security capability of the grassroots. The results show that grassroots emergency security capacity in disaster is mainly affected by the disaster emergency rescue ability and post disaster experience summary ability，it can strengthen the management ability of coordinating the masses to deal with the accident within the grass-roots masses and the government departments, and make the masses deepen their reflection on the accident; There are people do not understand the emergency plan and emergency rules and regulations cognition is insufficient, it is necessary to ensure that all units formulate accident prevention policies and emergency plans, and implement them to every person so as to enhance the overall disaster emergency support capacity. Related Articles | Metrics

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Fire situation analysis based on factor analysis Yang Yang, Liu Yuanhao, Jia Di 2022, 41 (11):  1591-1593.  Abstract ( 863 )   Taking the fire statistics of 31 provinces, autonomous regions and municipalities in 2019 as an example, six statistical indicators were selected, including the number of fires, the number of deaths, the number of injured, direct economic losses, burned area and the number of affected households. Factor analysis was used to analyze the indicators, and two public factors that can reflect the fire situation were obtained. Based on the results of factor analysis, the probability of fire occurrence and the consequences of fire are discussed, and suggestions for fire supervision and management are put forward. Related Articles | Metrics

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Statistical analysis of smart fire protection based on chi-square test and rank sum test Wang Dapeng, Yan Su, Wang Nan, Li Zheng, 2022, 41 (11):  1594-1598.  Abstract ( 854 )   Taking the demand analysis of smart fire protection construction as the main research goal, based on the relevant survey questionnaire data, and introduces IBM SPSS Statistics 25 as an analysis tool, the chi-square test is performed on the demand item, and the rank sum test is performed on the status item. Comparing the commonalities and differences between the requirements and status quo of smart fire protection construction in different industries, and the overall situation of smart fire protection construction is analyzed. The study is conducive to in-depth research on the general needs and differentiated development of smart fire protection construction, optimize resource allocation, and assist the construction and development of smart fire protection. Related Articles | Metrics

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Research on ignition characteristics andtrace characteristics of low voltageelectrical ground faults Gao Peng, Li Yang, Lv Zhong 2022, 41 (11):  1599-1603.  Abstract ( 861 )   Ground fault is one of the main causes of electrical fire, and it is also a difficult issue in fire investigations. By building a low-voltage ground fault test platform, this paper studied the ignition characteristics of two different types of ground faults, as well as the temperature rise characteristics of the wire insulation layer and fault contact point under different ground fault currents, and analyzed the action characteristics of the air switch, the ignition characteristics of combustibles and the trace characteristics of the ground fault under different types of ground faults. The research results can provide technical support for the investigation of ground fault electrical fires. Related Articles | Metrics

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Study on flame recognition of gasoline and anhydrous ethanol combustion based on image recognition technology Li Yazhi, Che Qiang, 2022, 41 (11):  1604-1608.  Abstract ( 846 )   In order to realize the classification of oxidant in the fire scene based on video images, the characteristics of the combustion flame were analyzed. In this paper, according to the unique combustion phenomena of gasoline and anhydrous ethanol, combined with the flame video image recognition algorithm, the flame recognition of gasoline and anhydrous ethanol is well realized. First, the suspected flame area can splited based on the grayscale threshold of the image, then its H, S, I color components and area change features are calculated; and the wavelet high-frequency energy features and LBP histogram features of the combustion image are extracted; finally, the feature vector is entered into the SVM classifier for classification and recognition. Experiments show that the classification accuracy of SVM for gasoline and anhydrous ethanol combustion flames is as high as 98.5%, this method can better distinguish the combustion flames of gasoline and anhydrous ethanol. Related Articles | Metrics

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Enlightenment from a ship fire accident investigation Zhao Shuxue, Peng Shengcheng 2022, 41 (11):  1609-1612.  Abstract ( 897 )   There are relatively few ship and fires, and moreover, fewer ship fires were investigated by fire and rescue agencies. Due to the influence of water, electricity, oil, gas, narrow hull space and complex structure, it is difficult to investigate ship fire. In this fire investigation, although the cause of the fire was quickly identified through surveillance video, investigation inquiry and on-site inspection, the investigation and analysis of the fire inducement experienced difficulties and twists. Ship fires are mostly related to people's unsafe behavior, but the links such as design and construction need to be improved. Through the investigation of this fire, it is also found that there are potential risks in the design, construction, acceptance and use management of the ship. Targeted optimization suggestions are put forward. Related Articles | Metrics

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Contrastive analysis of ignitable liquid residuesidentification at fire site in China and othercountries' criterions Qian Peiwen, Jin Jing, Li Qiufanzi, Yin Guo 2022, 41 (11):  1613-1617.  Abstract ( 842 )   For arson cases involved with ignitable liquids, the identifications of ignitable liquid residues are of vital importance in determining the nature of the fire cases, hence the construction of relevant physical evidence identification standards is of great significance. Based on the overall introduction of the American Materials Testing Association, the Australian Standards Committee and China's ignitable liquid identification standard system, the study herein focused on five aspects in standards of China and other countries, including the classification of ignitable liquids, environmental conditions for preserving ignitable liquid residues, identifications of characteristic compounds in ignitable liquids, interfering factors and appraisal reports and made horizontal comparisons. The results showed that the identification standards for ignitable liquids in China and other countries varied when it comes to the specific identification procedures. Foreign standards have a certain reference for the revision of China's standards in terms of the preservation of material evidence, the analysis of interfering factors and the composition of appraisal reports, which was proved to be instructive for the improvement of the ignitable liquid identification criteria in China. Related Articles | Metrics