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15 July 2022, Volume 41 Issue 7 Previous Issue    Next Issue

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Experimental study on extinguishing efficiency of 2-BTP on battery fires XU Hui-sheng, CONG Xiao-min, ZHAO Lin-shuang, WANG Xi 2022, 41 (7):  873-876.  Abstract ( 1417 )   Abstract: A set of fire extinguishing experimental platform was set up, the rated capacity of 75 Ah ternary flexible lithium-ion battery was taken as the research object . A constant power of 1 000 W aluminum casting heating plate was used to induce thermal loss of the battery. The combustion characteristics of the battery under 50% SOC were analyzed, and the effect of 2-BTP on battery fire suppression and cooling was studied.?Compared with water, FM-200 and HFC-125 under equal working conditions, the fire extinguishing time, maximum temperature and re-ignition of different extinguishing agents were analyzed.?The experimental results show that under the set conditions, 2-BTP is the fastest to extinguish the flame within 13 s. 2-BTP not only has the fastest fire-extinguishing speed and the best cooling effect, but also can effectively inhibit the re-ignition of lithium ion battery. Related Articles | Metrics

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Study on fire resistance behavior of Long-Span Deck Suspension Bridge under vehicle fire LI Yan-bing, LI Wei, NI Ya., YIN Liang 2022, 41 (7):  877-882.  Abstract ( 1422 )   Abstract: To study the fire resistance behavior of long-span double-layer suspension bridge under different vehicle fire scales, the extra-large-span double-deck suspension bridge with the main span of 2 180 m is taken as the research object. Firstly, the thermal analysis model of the suspension bridge is established by using the fire dynamics software FDS, and the influence of different fire source power, fire source location, environmental wind direction and other factors on the temperature distribution law of the double-deck suspension bridge is studied. Besides, the temperature-time relationship curve of the key components of the suspension bridge is obtained. Then, the thermal mechanical coupling numerical simulation analysis of double-layer suspension bridge is carried out by using the finite element software ABAQUS, and the thermal parameters of the steel and high-strength steel wire at high temperature are selected to study the time-varying characteristics of the high-temperature mechanical properties of the suspension bridge hangers, stiffening beams, and bridge decks. The structural stress, deformation, and component damage behavior of double-deck suspension bridges under the working conditions of environmental wind speed, truss height, fire source characteristics and location were compared to determine the key fire resistance parts and fire resistance requirements of the extra-large-span double-deck suspension bridge. Finally, based on the results of numerical simulation, a preliminary proposal for the fire protection design of the double-deck suspension bridge structure is put forward.The results show that when the vehicle fire position is located on the lower deck of the bridge, the lower deck structure is less affected by the fire due to the thermal insulation effect of the bridge deck pavement. The temperature of the upper structure is significantly higher than that of the lower part which is caused by the hot air flow, and the temperature of the upper longitudinal and transverse beams, bridge decks, hangers and other components near the fire source rises rapidly. Due to the thermal expansion effect of steel, the component is rapidly heated up and expanded, and the expansion is limited by the surrounding rod members, resulting in the gradual increase of compressive stress.The stress development and failure location of the bridge section under fire are closely related to the location of fire source, power and environmental wind direction. （1） Location of fire source: when the fire source is located in the middle lane of the transverse bridge direction, the high stress area is concentrated in the upper longitudinal and transverse beams and bridge decks of the non-motorized vehicle lane. When the fire source is located in the non-motorized vehicle lane of the transverse bridge, the strength failure of the upper deck near the fire source occurs. （2） Fire source power: With the increase of fire source power, the effect of the fire field on the high temperature of the bridge increases, the temperature of key components gradually increases, and the range of high temperature influence becomes larger. The fire source power is 30 MW, and no strength damage occurs within 6 000 s; the fire source power is 100 MW, and its fire resistance time is 653 s; the power of fire source is 200 MW, and its fire resistance time is 413 s. With the increase of the fire source power, the fire resistance time of the bridge structure is significantly reduced, and the maximum reduction can reach 93.11%.（3） Environmental wind direction: when the fire source is on the emergency lane of the transverse bridge, the upper deck connected with the trusses on both sides will suffer strength damage under the action of outward wind; under the action of inward wind, the upper deck near the non-motorized lane will suffer strength destruction. The fire resistance time of the bridge section under the inward wind is 528 s, increased by 3.0% compared with that under the condition of outward wind. For the long-span double-deck suspension bridges under vehicle fire, the fire resistance grades should be classified according to the risk of the fire-affected structure, and the fire protection design should be carried out according to the grades. Related Articles | Metrics

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Effect of C2HF5 on the lean-burn side of thermal runaway gas flame of lithium-ion battery ZHAO Chen-yu, HUANG Ao, FU Xiao-qian, GUO Zi-dong 2022, 41 (7):  883-887.  Abstract ( 1384 )   Abstract: As an excellent halon substitute, C2HF5 has a good effect on extinguishing thermal runaway fires of lithium-ion batteries. The gas composition of the thermal runaway gas of the lithium-ion battery was obtained in previous studies.Using CHEMKIN-Pro, the promotion of C2HF5 and mixed gas on the lean burn side was studied from two aspects of radical concentration and sensitivity analysis by simulation. The results show that the concentration of radicals H, O, and OH on the fuel lean side reach the peak at Xa=0.04, with C2HF5 showing a promotion effect; on the fuelrich side, the concentration of radicals decreases with the increase of C2HF5, showing an inhibitory effect;in the sensitivity analysis, the elementary reaction R1: H+O2=O+OH is the most sensitive. On the fuel lean side, under low C2HF5 addition, the elementary reaction is dominated by promotion. As the addition of C2HF5 increases, the inhibitory effect continues to strengthen; on the fuelrich side, the addition of C2HF5 appears as an inhibitory effect. The process of interaction between C2HF5 and flame is controlled by the competitive relationship between self-combustion promotion heat effect and chemical suppression effect. Related Articles | Metrics

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Ignition mechanism of SMC insulating separator under high voltage breakdown arc SONG Si-qi, REN Mei-jie, LI Cheng-gang, XIE Qi-yuan, 2022, 41 (7):  888-894.  Abstract ( 1299 )   Abstract: Insulation partition is an important part of high voltage switchgear. An experimental setup was developed to simulate the high-voltage arc and material ignition. Ignition experiments were carried out for SMC insulation separator with thickness of 5mm and 10 mm. The change rules of mass loss rate, residual flame time, temperature curve with arc duration were studied. The results show that under the high voltage, the two electrodes first form an inverted U-shaped clamping heating arc around the SMC vertical plate. The ablation process of SMC samples under the continuous arc can be divided into four stages: arc rising, clamping ignition, side arc falling and remaining burning. The residual flame of 10 mm sample is produced later, and need longer time to form significant self sustaining combustion and the carbonization ablation degree is lower. It illustrates that thicker SMC insulation partition is better for the integrity of partition structure and fire resistance. The surface temperature curves of different areas of the sample also indicate the heating intensity of the arc root on the surface of the sample is weaker. Namely, the temperature rise of the sample surface is affected by both of the arc column distance and the self-sustaining flame. It contains multiple mutually influencing heat process. The results can be used for the scientific selection and optimal layout of insulation diaphragms of high-voltage switchgear, and provide scientific support for improving the fire safety performance of switchgear. Related Articles | Metrics

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Fire hazard analysis of fiberglass mesh and XPS composite layer CHENG Jing, SHI Bi-ming, BAN Hong-yu 2022, 41 (7):  895-898.  Abstract ( 1290 )   Abstract: In order to explore the influence of glass fiber mesh on the fire hazard of XPS material, the pyrolysis characteristic parameters of the material XPS were measured by the thermogravimetric instrument, and the combustion characteristic parameters of XPS and the common 3 pore size glass fiber mesh composite layers were obtained by cone calorimeter, and the fire hazard degree of the insulation layer composite with different pore size glass fiber mesh was calculated by analytic hierarchy process. Experimental results show that the XPS material starts pyrolysis from 280 °C and reaches the maximum pyrolysis rate at 425 °C; adding the glass fiber mesh will promote the combustion reaction of XPS, the smaller the pore size of the XPS composite glass fiber mesh, the higher the amount of heat and flue gas released by combustion, and the greater the fire hazard. It is explained that the glass fiber mesh will exacerbate the fire hazard of XPS insulation materials, and the use of small pore fiber mesh should be reduced or avoided in the design of building exterior wall insulation. Related Articles | Metrics

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Study on the influence of ternary lithium-ionbattery diameter and state of charge on thermal runaway propagation XU Liang, 2022, 41 (7):  899-904.  Abstract ( 1285 )   Abstract: With the continuous development of new energy vehicles in my country, lithium-ion batteries are the most important energy storage devices for new energy electric vehicles. Due to their high energy density, there is rapid combustion, explosion, and thermal runaway transfer of adjacent batteries. The safety hazard restricts the application and promotion on a larger scale and seriously threatens the safety of people's lives and property. The thermal runaway of a battery is mainly related to its shape, state of charge, and connection method. The research on the thermal runaway of batteries under the coupling conditions of different states of charge and different diameters is the focus of research to improve the safety performance of lithium batteries.In order to investigate the main influencing mechanism of the thermal runaway propagation process of lithium-ion batteries, this paper uses ternary lithium-ion batteries with different diameters (10440, 14500, 18650, 21700, 26650, 32650) and different charge states (50%, 70%, 100%) as the research object. The characteristics of thermal runaway propagation time and thermal runaway spatial propagation rate under the one-dimensional linear arrangement are investigated, and then the influence mechanisms of cell diameter and state of charge on thermal runaway propagation time and thermal runaway spatial propagation rate are analyzed in depth. A computational model for blocking the thermal runaway propagation chain of batteries was developed using a combination of experimental data, heat transfer theory, and dimensionless analysis, and then predicted the thermal runaway propagation time between batteries. The characteristic relationship between thermal runaway propagation time and cell diameter (10,14,18,21,26,32 mm) for different charge states (50%,70%,100%) was obtained by combining dimensionless analysis, and a prediction model for thermal runaway propagation time of lithium-ion batteries in the one-dimensional arrangement was proposed. The experimental results show that when the battery state of charge is certain, the larger the battery diameter, the higher the total thermal resistance, which in turn leads to an increase in thermal runaway propagation time and a decrease in the spatial thermal runaway propagation rate. Under the condition of the same total electric power, the higher the charge of the Li-ion battery, the higher the heat production. The influence of cell diameter on the thermal runaway propagation process of the battery mainly depends on the change of thermal resistance in the heat transfer process of the battery, and the thermal resistance formula of the whole lithium-ion battery module is established by using the aggregate model theory, Fourier theory and the interface continuity condition, and the relationship between the charge state of the lithium-ion battery and the heat production of the battery is deduced by the formula. The research results show that when the cell diameter is certain, the total heat production of the thermal runaway process of the cells in the module increases with the increase of the battery state of charge; the thermal runaway propagation rate between the cells will also increase significantly under the high-temperature environment.In this paper, we design a computational model to block the propagation chain during the thermal runaway propagation time of lithium-ion batteries, and then predict the thermal runaway propagation time between batteries. The relationship between the average dimensionless thermal runaway propagation time between single cells and the cell aspect ratio and cell state of charge at 50%, 70%, 100% is fitted with the dimensionless analysis coefficients, and the prediction model of thermal runaway propagation time between adjacent single cells in the module is proposed. Related Articles | Metrics

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Research on smoke resistant performance based on a kind of structural steel fire resistant door LI Xi-quan, FENG Wei, GUO Zhan-sheng, RUAN Tao 2022, 41 (7):  905-908.  Abstract ( 1245 )   Abstract: This study developed a full-size smoke resistant performance test device for fire resistant doors, and established a set of testing procedures to study the smoke leakage rate of fire resistant doors under different pressure differences and temperatures. Single and double steel fire resistant doors with typical structure on the market are selected to test their smoke resistant performance. It is found that typical steel fire resistant doors have large leakage rate under different temperature and pressure difference, and their smoke resistant performance is poor, which can't effectively prevent fire smoke. Select the fire resistant door with the same size, add triangle hollow smoke resistant sealing strip and conduct smoke resistant performance test, the results show that the smoke resistant sealing strip can effectively reduce the gap between the door and the door frame, so as to reduce the smoke leakage rate of the fire resistant door, improve its smoke resistant performance; The number of door leaf has a certain influence on the sealing effect of smoke resistant sealing strip at different test temperatures, the smoke resistant performance can improved more after added triangle hollow smoke resistant sealing strip, and the smoke resistant performance of the single fire resistant door added sealing strip can be improved at medium temperature, but the smoke resistant performance of the double fire resistant door added sealing strip can be improved at ambient temperature. Related Articles | Metrics

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Test on uniaxial compressive behavior of molybdenum tailings concrete exposed to high temperature XI Yu-fei, LI Wei, PAN Yan-chong, GAO Shan 2022, 41 (7):  909-915.  Abstract ( 1225 )   Abstract: In order to study the mechanical properties of molybdenum tailing concrete under uniaxial compression at high temperature, the axial compressive strength, peak strain, elastic modulus, Poisson's ratio, failure mode and mass changes of molybdenum tailing concrete specimens at different target temperatures (20, 200, 300, 400, 600, 800 ℃) were tested. The results showed that the mass loss rate of molybdenum tailing concrete specimens increased with the increase of temperature, and the average mass loss rate was 6.52% at 800 ℃. The axial compressive strength gradually decreases with the increase of temperature, with an average decrease of 70.04% at 800 ℃ compared with room temperature, and decreases with the increase of molybdenum tailings admixture. While the peak strain decreases first and then increases with the increase of temperature. Both the modulus of elasticity and Poisson's ratio decreased with the increase of temperature, and the modulus of elasticity and Poisson's ratio decreased by 88.22% and 35.66% on average at 800 ℃ compared with room temperature. For the modulus of elasticity, it generally decreased with the increase of molybdenum tailing admixture, while for Poisson's ratio, the concrete with 100% molybdenum tailing admixture was slightly larger than the concrete with 50% admixture. According to the test results, the uniaxial compression stress-strain constitutive equation of molybdenum tailing concrete after high temperature is established. Related Articles | Metrics

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Design and research on fire ventilation network system of three-pipe parallel highway tunnel at high altitude based on disaster prevention zone LIU Xia-lin, LI Xue-feng, ZHANG Xuan, SHU Heng 2022, 41 (7):  916-921.  Abstract ( 1234 )   Abstract: In order to explore the control of ventilation system under the fire mode of super-long highway tunnel, a method of dividing disaster prevention intervals based on the dual control of smoke and evacuation was proposed for TianshanShengli Tunnel. By using the analysis method of ventilation network, considering the high altitude environment and the slope of tunnel polyline, the ventilation system control calculation of multi-intersection airflow in different positions of each disaster prevention interval was carried out, and finally the number and position of disaster prevention fans in the service tunnel, cross passage and main tunnel on the left and right lines were obtained.The results show that the TianshanShengli Tunnel has divided the left and right lines into 31 and 30 disaster prevention zones considering smoke control, evacuation, and electrical and mechanical control factors, and determined the specific sections and number of wind turbines. The left and right main tunnels have 112 and 114 SDS112T-4P-37 wind turbines respectively, and 168 SDS63T-2P-15 wind turbines were installed in the service tunnel. Related Articles | Metrics

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Fire resistance and parameters influence of concrete filled double steel tubular columns CHEN Yan-fang, ZHANG Jin-chuan, HOU Li-qun, CHEN Shi-cai 2022, 41 (7):  922-926.  Abstract ( 1192 )   Abstract: Double concrete-filled steel tubular composite column is provided with internal steel tube on the basis of ordinary concrete-filled steel tubular column. Because the inner tube is protected by outer concrete, its fire resistance will be improved. In this paper, the fire resistance of this kind of double steel concrete composite column is studied by refined numerical simulation method, the effects of internal diameter thickness ratio, external diameter thickness ratio and internal and external tubular diameter ratio are comprehensively analyzed, and the different section combination types (inner circle and outer circle, inner square and outer circle and inner circle and outer circle) under the same steel content are compared and fire resistance of concrete filled double steel tubular short columns are analyzed. The results show that increasing the thickness of the inner steel tubular when the diameter is constant and increasing the diameter of the inner steel tubular when the thickness is constant are conducive to the improvement of the fire resistance；Under the condition of keeping the overall steel content unchanged, the fire resistance limit of concrete-filled double steel tubular columns with different section combinations is almost the same, but on the whole, the fire resistance of concrete-filled double circular steel tubular short columns is better; In addition, the fire resistance of double concrete-filled steel tubular composite columns is much higher than that of ordinary concrete-filled steel tubular columns. Related Articles | Metrics

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Study on critical velocity for railway tunnel fire smoke control considering the train blockage effect LIN Shuai, ZHANG Rong-shuai 2022, 41 (7):  927-932.  Abstract ( 1214 )   Abstract: Aiming at the existing critical velocity research, less consideration is given to the obstacles in the tunnel or only the small obstructions in the tunnel are discussed. Taking a railway tunnel as the research object, the numerical calculation model of the train fire of the railway tunnel is constructed, the influence of train blockage on the critical velocity is analyzed. The results show that the numerical simulation results are in good agreement with the Li model under block-free conditions. The increase in the tunnel blockage ratio tends to bring about a decrease in the critical velocities. Based on the simulation data analysis, the correspondence between the critical velocity reduction rate ε and the tunnel blocking ratio φ is corrected, a theoretical model of the critical velocities of railway tunnel train fire is obtained, and the reliability is verified by the existing tunnel fire experimental data and CFD accident simulation results. Related Articles | Metrics

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Research on the fire protection design ofair-supported membrane structure exhibition buildings LI Bing-ke 2022, 41 (7):  933-936.  Abstract ( 1390 )   Abstract: With the development and application of building membrane materials, there are more and more exhibition buildings with air-supported membrane structure, but the related fire-protection technical standards has not been promulgated. Starting from the concept of air-supported membrane structure and the combustion characteristics of common membrane materials,based on engineering examples, this paper analyzes the fire risk and fire protection design difficulties of air-supported membrane structure, from the aspects of structure, fire?compartment division, personnel evacuation control, interior decoration fire-prevention method, fire water supply, fire detection, smoke control, fire-fighting and rescue method. Then the strengthened fire-protection technical measures of air-supported membrane structure exhibition buildings are explored, and a feasible special fire-protection design scheme is put forward combined with the current fire-protection technical codes and fire simulation results. Related Articles | Metrics

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Accident consequence assessment of hydrogen-doped gas station based on FLACS CHEN Qiang-feng, WANG Xi-ming, TANG Min-hua, LI Xiang 2022, 41 (7):  937-941.  Abstract ( 1402 )   Abstract: Aiming at the safety of mixed hydrogen transportation in gas stations, the accident scenario of hydrogen doped gas stations was constructed based on FLACS software. The consequence assessment was carried out on three typical accidents: gas leakage, gas cloud explosion and jet fire. The results show that in the middle and late stage of leakage, the development scale of gas cloud increases, and the dispersion velocity and leakage velocity of gas cloud boundary will reach a dynamic balance. The increase of hydrogen doping ratio shortens the explosion area of natural gas to a certain extent, and leads to the decrease of overall leakage cloud. When the hydrogen doping ratio is 20%, the overpressure value and risk coefficient produced by gas cloud explosion are the highest. The volume energy of hydrogen is small, and the hydrogen doping behavior will reduce the energy content of the gas. With the increase of hydrogen ratio, the risk range of jet fire decreases. Related Articles | Metrics

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The fire risk assessment system for high-risebuildings based on unascertainedclustering method AN Jing, ZHANG Li-ning, PANG Xiao-na, CUI Cai-yun 2022, 41 (7):  942-945.  Abstract ( 1262 )   Abstract: The fire prevention and control problem of high-rise buildings has not been effectively solved. Aiming at the problems of the evaluation indicators acquisition that is unscientific and the index system varies greatly in high-rise civil building fire risk assessment, the typical fire event analysis method was used in this study, and combining with the code for fire protection design of building, 12 major uncertainty risk factors affecting the fire prevention capacity of high-rise buildings were obtained, to build a more scientific fire risk assessment index system. Then the unascertained clustering theory is introduced to build a new high-rise building fire risk assessment model. And the fire risk data of 8 typical high-rise civil buildings were taken as examples to conduct empirical analysis. Study shows that the system is effective. The research results can provide a new way for the fire prevention and control of high-rise civil buildings. Related Articles | Metrics

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Fire risk assessment model of high-rise buildings based on entropy right-attribute mathematics LI Wei, YU Zhao-yang 2022, 41 (7):  946-950.  Abstract ( 1209 )   Abstract: According to the correlation of fire influence factors and the ambiguity of indicators, the fire risk assessment model based on entropy right-attribute mathematics is constructed. The fire evaluation system is established from the three aspects of fire prevention ability, fire extinguishing ability and safe evacuation ability, focusing on the use of attribute measurement theory to divide the single index level. Take a high-rise building in Nanchang as an example, the application of the built model is carried out to evaluate the fire risk level, the evaluation results are consistent with the reality, and the comprehensive evaluation results of the gray system, which shows that the model is feasible and the evaluation results are more objective and reasonable, which also provides a new idea for the fire risk assessment of high-rise buildings. Related Articles | Metrics

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Application technology analysis of automatictracking and targeting jet suppression system QI Xin, YANG Bing-jie, YANG Qi 2022, 41 (7):  951-953.  Abstract ( 1264 )   Abstract: Combined with the provisions of the national standard GB 51427-2021, Technical standard for automatic tracking and targeting jet suppression system, and through the comparison with the standards such as GB 50084-2017, Code for design of automatic sprinkler system and CECS 263:2009, Technical specification for large space intelligent active sprinkler system, this paper analyzes the type selection and application scope of automatic tracking and targeting jet suppression system, and discusses some design points. The engineering application technical requirements of automatic tracking and targeting jet suppression system are put forward. Related Articles | Metrics

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Experimental study on carbon dioxide gas fire extinguishing technology in large buried cable tunnel LI Kun-sheng, XIONG Gang, HUANG Zhao-yun, FU Qiang-lin 2022, 41 (7):  954-958.  Abstract ( 1249 )   Abstract: In order to study the feasibility and effect of carbon dioxide fire extinguishing in large-buried cable tunnel, this paper conducts experimental study on a 220 kV large-buried cable tunnel. Three working conditions and five fire sources were set up in the experiment. The fire extinguishing time at different working conditions and fire source points, the change of carbon dioxide and oxygen concentration during extinguishing, the change of ambient temperature and humidity, the pressure attenuation of pipeline network system, and the freezing of pipelines were compared. Research shows that carbon dioxide gas can quickly extinguish cable tunnel fire, and fixed pipeline network system is especially suitable for large buried cable tunnels. Related Articles | Metrics

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Design and implementation of editable fire scene electronic sand table system based on Unreal Engine LIU Chang, HE Chang-Yuan, JIN Xue-Sheng, LU Cheng 2022, 41 (7):  959-963.  Abstract ( 1291 )   Abstract: In view of the problems faced in the current fire rescue team command teaching and case discussion, such as non editable content, lack of interaction of scene, non intuitive display form and high production cost, this paper designs an editable fire sand table software based on Unreal Engine, which realizes the technologies of rapid scene editing, AI simulation of rescue behavior and presentation of fire sand table effect. It enables users to quickly reproduce disaster scenes and deploy combat forces, and deduce and display them according to the fire fighting stage. Through the whole process of fire sand table deduction, users can clearly show the command intention, and also facilitate the audience to intuitively and completely observe the whole fire fighting process, so as to improve the effect of battle case evaluation or case deduction. Related Articles | Metrics

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Control system of fire engine ring pump type B foam mixing device DING Yu-feng, ZHOU Zun-bo, LI Cun-rong 2022, 41 (7):  964-969.  Abstract ( 1418 )   Abstract: The ring pump type B foam mixing device is a system used to mix the foam solution and the aqueous solution according to a certain standard. Aiming at the shortcomings of the traditional device, such as low mixing accuracy, poor stability and needing manual control, the foam tank fire truck was taken as the research object, in accordance with the requirements of GB 7956.3-2014, Fire fighting vehicles-Part 3:Foam fire fighting vehicle, a mathematical model of foam and water mixing ratio control was established. PID and Smith-PID predictive control algorithms were applied to follow-up control the foam and water flow ratio in the model, and the foam ratio mixing control system hardware and software were developed. A set of ring pump type B foam mixing device and experimental program was designed and developed, and the experimental results were analyzed to achieve a stable and accurate output of 3% or 6% foam solution to meet the requirements of firefighting. Related Articles | Metrics

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Situation prediction based on petrochemical fire scenario deduction software HU Ren-yuan, WANG Hui-hui, XIA Deng-you 2022, 41 (7):  970-973.  Abstract ( 1239 )   Abstract: In order to objectively predict the evolution trend of petrochemical fire scenarios under the coexistence of multiple objects, the developed petrochemical fire scenario deduction software is used to realize the objective probability deduction of scenario elements. Based on the petrochemical fire disposal organization and scenario evolution path, the trend is divided into three levels of control, stalemate and out-of-control. The probability distribution combination method is adopted to realize the prediction of the overall situation of petrochemical fires. Finally, taking a liquefied petroleum gas storage tank fire as an example, the relationship between the number and state of disaster-bearing bodies and the overall situation of petrochemical fires is obtained. Related Articles | Metrics

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Nonlinear heat transfer model for expansion size of intumescent coatings KANG Han, LI Ming-hai, ZHANG Zhao-qiang, YAO Yong 2022, 41 (7):  974-977.  Abstract ( 1212 )   Abstract: The heat transfer and radiative heat transfer in the pore will reduce the fire resistance of the coating. Considering the existence of gas produced by the decomposition of the coating between the pores, this paper describes the expansion behavior of the coating under different heating conditions through the ideal gas state equation. A finite element heat transfer model was established, which took expansion size as output term and the enhancement effect of pores on effective thermal conductivity, to explore the fire performance of coatings with different thickness under different heating environments. The results show that the expansion size model can accurately predict the expansion behavior of the coating at different temperature fields, and the maximum expansion rate of the coating decreases with the increase of the dry film thickness.The finite element heat transfer model based on the expansion size and the effective thermal conductivity of the pores is in good agreement with the experimental results. In the high heating rate environment, the intumescent coating can significantly delay the heating of steel tube and reduce its maximum fire temperature. Under different heating conditions, the fire resistance and thickness of the coating change nonlinearly. Related Articles | Metrics

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Effect of siloxane viscosity and mica powder content on silicone foam SHANG Ke, JIANG Hui-jing, LIN Gui-de, WANG Jun-sheng 2022, 41 (7):  978-981.  Abstract ( 1206 )   Abstract: The silicone foams were prepared using different viscosity α,ω-dihydroxy polysiloxane and vinyl-terminated polydimethylsiloxane as base materials and mica powder as inorganic filler. The effects of siloxane viscosity and inorganic filler content on the microstructure, flame retardancy and thermal stability of silicone foam were investigated by means of scanning electron microscopy, limiting oxygen index, cone calorimetry and thermogravimetric analysis. The results show that the changes in the viscosity of α,ω-dihydroxy polysiloxane and vinyl-terminated polydimethylsiloxane will greatly affect the microstructure and thermal stability of silicone foam. The increase of α,ω-dihydroxy polysiloxane viscosity has a negative effect on the flame retardancy of silicone foam, while the change of vinyl-terminated polydimethylsiloxane viscosity has little effect on its flame retardancy. In addition, the introduction of inorganic fillers can significantly reduce the pore size of silicone foam and greatly enhance its flame retardancy and thermal stability. Related Articles | Metrics

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Practical exploration and thinking of the fire rescue team in flood fighting, emergency rescue and waterlogging drainage CHEN Li-xin 2022, 41 (7):  982-985.  Abstract ( 1347 )   Abstract: After the reform and affiliation transfer, the fire rescue team assumed the mission of "all disaster rescue and major emergency assistance". This article introduces how the fire rescue team built a unique operation system, during the rescue of extreme flood disasters, for flood fighting, drainage rescue, and disaster assistance, utilizing the existing fire extinguishing water supply vehicles, mobile pumps, and drainage trucks. Also, it is discussed how the system played an important role in handling extreme flood disasters and provided useful thinking about the construction of flood rescue systems and the allocation of flood fight equipment. Related Articles | Metrics

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Studies on the fire risk and fire protection measures of LED display screen ZHOU Guang-lian 2022, 41 (7):  986-988.  Abstract ( 1607 )   Abstract: With the rapid development of electronic technology, LED electronic display screen has been widely used in various fields. LED display screen is a non-linear electrical equipment, which will generate harmonic current and cause harmonic pollution to power supply and distribution grid when used, and will cause fire in serious cases. Through the test and verification of LED display screen system in large-scale event site, this paper reveals the mechanism of fire, and puts forward targeted prevention and control measures and emergency disposal methods. Related Articles | Metrics

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Analysis on influence factors of fire safety skills for staff in nursing homes YANG Yi, PAN Meng-yi, BAI Lei, DING Lin 2022, 41 (7):  989-993.  Abstract ( 1229 )   Abstract: To solve the practical problems for the lack of fire safety skills in the nursing home, this study designed a questionnaire for evaluating fire safety skills with its influence factors. The structural equation model of fire safety skills was established to explore the main reasons for affecting fire safety skills of staffs. The results indicated that the fire safety training and fire safety participation play an important role for improving the staff's fire safety knowledge and fire safety skills. A good fire safety attitude can promote the learning of fire safety knowledge and the flexible use of fire safety skills. Currently, the fire safety training for nursing home does not develop its actual effect, thereby exhibiting a poor results, which caused that the fire safety knowledge could not satisfy the requirements of fire safety skills for staffs. Therefore, the developments of fire safety rules, the creations of fire safety atmosphere, the promotion of the fire safety training effect, and the increase of fire safety training frequency can be used to increase fire safety skills, thereby enhancing the fire safety for nursing home. Related Articles | Metrics

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Research on law enforcement under the newsituation of fire law enforcement reform LV Feng 2022, 41 (7):  994-996.  Abstract ( 1269 )   Abstract: Starting with the analysis of the problems existing in the current fire law enforcement practice, combined with the new situation and new requirements, in view of the main reform tasks proposed in the opinions on deepening the reform of fire law enforcement, such as standardizing fire law enforcement activities, strengthening the construction of fire law enforcement forces, and seriously investigating the responsibilities of fire law enforcement, the author actively explores the reform measures of fire law enforcement, such as standardizing law enforcement behavior, tightening law enforcement procedures, expanding law enforcement forces, strengthening law enforcement supervision and improving law enforcement abilities. Through the countermeasures, the fire control and law enforcement has been strengthened, and the effectiveness of fire law enforcement has been preliminarily improved. Related Articles | Metrics

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Analysis study on the safety of electrochemical energy storage station CHEN Bing-an 2022, 41 (7):  997-1000.  Abstract ( 1861 )   Abstract: Electrochemical energy storage is a key link in realization of the emission peak and the carbon neutrality goal, impelling the application of breeze and photovoltaic power in the electric grid and applying to the grid peak shaving. Under the dual engine of policy guidance and market demand, prefabricated cabin energy station of lithium-ion phosphate batteries is developing rapidly. However, the lithium-ion battery is easy to occur combustion and explosion once thermal runaway, and dense arrangement layout of lithium-ion battery further increase the risk of fire disaster in the prefabricated cabin. Meanwhile, the complex fire contains of solid, liquid, gas and electrical fires, which put forward a new challenge for firefighting and rescue disposal. In this paper, the safety of electrochemical energy storage energy station had been combed and analyzed deeply. Via the full-scale experiment of the lithium-ion battery prefabricated cabin, there were various parameters such as fire temperature, smoke gas concentration and so on have been obtained. The thermal runaway mechanism of lithium-ion battery was revealed and the fire risk of the electrochemical energy storage system was analyzed in this research. The research results had shown that the cell and ambient temperature of the lithium iron phosphate battery change significantly during the thermal runaway and combustion process, and the fire temperature above 700℃. Under the conditions of massive application, the thermal runaway risk and explosion hazards of the lithium iron phosphate battery was much higher great than the experimental condition. Therefore, electrochemical energy storage power stations need to strengthen safety management and normalize in terms of product standards, design specifications, and emergency handling. Related Articles | Metrics

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Reliability analysis of independent fire detection alarm networking system XIE Jing-rong, LI Ning-ning 2022, 41 (7):  1001-1004.  Abstract ( 1184 )   Abstract: The independent fire detection and alarm networking system can obtain fire information in its protected area, timely provide guarantee for the evacuation of people facing fire threat, provide effective supervision means for the use of such fire safety products by property and fire rescue organizations, and provide relevant information support for fire rescue personnel to determine the location of fire and post disaster fire cause identification at the first time. With the development of the Internet of things, such systems have been widely used in recent years, but there are also many problems in use, which affect the reliability of the system. This paper introduces the key technical requirements to ensure the stability and reliability of the independent fire detection alarm networking system and the relevant requirements of the system platform, providing guidance for the promotion and application of the independent fire detection alarm networking system. Related Articles | Metrics

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Research progress on preservation performance of packaging containers for combustion supporting agents in fire scene YAO Yan-ru, ZHANG Wen-ting, JIN Jing, ZHANG Jin-zhuan 2022, 41 (7):  1005-1009.  Abstract ( 1251 )   Abstract: During the preservation of the combustion supporting agent material evidence extracted from the fire site, it may be polluted by many factors, which will affect its evidence effectiveness and the judicial justice. This paper combs the relevant research both in China and other countries, introduces the background interference of packaging containers on combustion supporting agent physical evidence, as well as the possible cross pollution and loss of physical evidence, and summarizes the selection of packaging containers. The study can provide reference for the scientific and effective preservation of combustion supporting material evidence. Related Articles | Metrics

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Identification and analysis of a deflagration accident FENG Mao-wu, DUAN Sheng-li, LIU Hong-yong, 2022, 41 (7):  1010-1013.  Abstract ( 1301 )   Abstract: The fire cause of a spray booth deflagration accident was investigated. The deflagration location was identified. Combining with the video analysis and the calculation of fire ball model and vapor cloud explosion damage model, the reason of the deflagration was decided. The fire cause analysis was conducted. The related fire source was excluded, and the most possible fire source was identified. By analysis of disaster cause, the fire prevention countermeasures of such places were summarized. The study can provide reference for the fire investigation of spray booth accident. Related Articles | Metrics

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Investigation and analysis of the fire cause in a sponge factory ZHANG Lu 2022, 41 (7):  1014-1018.  Abstract ( 1570 )   Abstract: The thesis has taken a fire accident in a sponge factory as an example to analyze the possible cause by fire investigation and relevant material evidence identification. Mainly focusing on the suspicious objects found at the fire point, HNMR, thermal weight experiment analysis and heat release analysis has been used to verify the possibility of spontaneous combustion by polyether polyol leakage. The thesis discusses feasible path of verifying the possibility of the spontaneous combustion of residual organic liquid in the fire accident investigation of chemical companies and summarizes the deficiencies and enlightenment during the investigation process, in order to provide a reference for the accident investigation against similar fire accidents. Related Articles | Metrics