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15 October 2020, Volume 39 Issue 10 Previous Issue    Next Issue

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Fire safety evaluation of mall based on fuzzy preference planning and cloud model CHEN Jia 2020, 39 (10):  1134-1338.  Abstract ( 2667 )   In order to solve the problem that the uncertainty, randomness and ambiguity of shopping mall fire safety evaluation indicators make it difficult for decision-makers to choose a suitable method to evaluate shopping mall fire safety, a shopping mall fire safety evaluation model based on fuzzy preference planning and cloud computing is proposed.The evaluation index system is constructed from six aspects: fire hazard source, building fire protection capability, surrounding firefighting capability, personnel evacuation capability, daily management capability, and safe evacuation capability. The combined fuzzy theory and analytic hierarchy process, introduced fuzzy preference programming model to calculate the index weight. The cloud model is used to switch between the two characteristics of qualitative and quantitative indicators. The method was used to evaluate the fire safety of a shopping mall in Zhengzhou, and it was concluded that: the fire safety level is high; It is necessary to pay attention to the distribution of combustibles, building characteristics, distance from the fire brigade, personnel distribution, fire safety investment, and evacuation passageway width.The study can provide feasible suggestions for daily fire management. Related Articles | Metrics

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Research on jet trajectory recognition under smoke cover PAN Lu, LI Wei, ZHANG Shuai-shuai, ZHU Jin-song, LIN Da, GAO Hong-zhuang 2020, 39 (10):  1331-1334.  Abstract ( 2665 )   In view of the poor recognition effect of jet trajectory image caused by dense smoke occlusion, this paper proposes a jet trajectory recognition method under smoke occlusion. Firstly, the moving targets such as jet and smoke are extracted and preprocessed by the mixture Gaussian background modeling;secondly, the front jet trajectory recognition method is used to identify the front jet trajectory. The front jet trajectory recognition method includes two processes: the first is to determine whether the number of points with gray value of 255 in the adjacent column has increased dramatically to determine whether it occurs,and reserve the uncovered part; the second is to calculate the midpoint coordinates of each column of pixel value of 255 in the reserved part, and judge whether the midpoint coordinates have an upward trend. Finally, the jet trajectory equation is established, and the front jet trajectory is modified. The trajectory equation is used to replace the part of jet trajectory covered by smoke. Experiments show that the method proposed in this paper has good recognition effect. Related Articles | Metrics

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Effect of the coupling of roof and side wall of a building on vented natural-gas explosion YANG Kai, HU Qian-ran, REN Jia-qi, LI Si-gang, PANG Lei, 2020, 39 (10):  1339-1344.  Abstract ( 1834 )   The numerical model of typical industrial plant was established based on the computational fluid dynamics theory.The coupling vented explosion of roof and walls on both sides under natural gas explosion are studied, and the distribution characteristics of indoor explosion overpressure load due to coupling venting are mainly studied. The results show that: Under the coupling of roof and walls on both sides, there are two significant overpressure peaks and multiple oscillatory peaks in the explosion overpressure load in the plant. The first peak overpressure mainly depends on the minimum value of the activation pressure of the entire vent, which is less affected by the coupling vented explosion of roof and walls. The second peak overpressure is more significantly affected by coupling vented explosion of roof and walls on both sides. When the roof is only set with vent, the second peak overpressures are smaller. When the walls on both sides are only set with vents, the second peak overpressures are larger. When both the roof and the walls on both sides are set with vents, the second peak overpressure reach their maximum overpressure away from the ignition source at one end. The roof vent can be more effective to reduce the second peak overpressure within the plant, and the effect of the roof vent area on the peak overpressures and the arrival time is insignificant. The conclusion of the study provides scientific basis for the safety design of the venting explosion facilities of industrial plants, and the investigation and analysis of natural gas explosion. Related Articles | Metrics

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Fire early warning algorithm based on QPSO-BP neural network GAO Jian-feng, WANG Yan, JIN Juan-hua 2020, 39 (10):  1345-1349.  Abstract ( 2745 )   In order to further improve the safety of the fire protection system of the oil depot, the fire information system has been improved, and a fire intelligent early warning algorithm based on the quantum particle swarm optimization optimized BP neural network is developed, with temperature, smoke concentration and CO concentration data as the input of the neural network, the probability of no fire, open fire and smoldering fire is used as the output of the neural network. The quantum particle swarm optimization algorithm is used to optimize the weights and thresholds randomly generated during the operationof the BP neural network, accelerate the convergence rate of the neural network to the expected error, and enhance the global search capability. The model of the intelligent fire early warning algorithm was simulated by MATLAB software. In the result, the fire probability output by the model was basically consistent with the actual value, and a multi-sensor data acquisition device was designed to obtain fire scene data to further verify the effectiveness of the algorithm. Entering the experimental data into the network model can effectively identify open flames, smoldering fires, and no- fire conditions, proving that the algorithm has achieved the purpose of improving the accuracy of the fire warning system. Related Articles | Metrics

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Fire whirls experiment research induced by environment wind in middle scale square oil pool GUAN Bao-ning, ZHANG Guang-hui, LIANG Yong, JIANG Wei 2020, 39 (10):  1349-1353.  Abstract ( 1784 )   To obtain the dynamic process and characteristic parameters' law of fire whirls formation, and do a comparative analysis with ordinary fire's risk, a new experiment platform was designed, using wind tunnel to generate environment wind,and the square oil pool length was 6 m and width is 6 m, using hot wire anemometers, DV and heat release rate instrument to collect data. Experiment results verified that the fire whirls formation process includes four stages as ordinary oil fire, intermittent fire whirls, steady fire whirls and boilover. At stable stage,the fire whirls' maximum quality loss rate is 2.44 times that of ordinary fire, the average flame height is 1.49 times; The average radiation in vertical direction is 1.89 times, and the flame temperature will increase with the space rate occupied by fire whirls. Related Articles | Metrics

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Research on the thermal response behavior of double-layer oil storage tank in fire WANG Ya-zhen, LIU Di, ZHANG Jie-dong 2020, 39 (10):  1354-1357.  Abstract ( 1824 )   Fluent is used to simulate the behavior of the double-layer-tank exposed to the pool fire of its adjacent tank. It is found that the temperature rise of double-layer-tank is 20% less than that of the single- layer- tank in 300 seconds of radiation.And the pressure rise of double-layer-tank is 15% less than that of the single- layer- tank. The evaporation rate of liquid hexane in double- layer- tank is much lower than that of single- layer tank. Double- layer- tank can effectively prevent wall damage caused by radiation, slow down the evaporation rate of light oil and reduces the VOCs emission under the pool fire accidents.This will significantly reduce the probability of secondary fire and explosion accident. Related Articles | Metrics

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Study on the heating and ignition characteristics of PVC conductor under overload GUO Zi-dong 2020, 39 (10):  1358-1362.  Abstract ( 1910 )   Using the experimental platform, the thermal characteristics and ignition capability of wires with different materials and cross-sectional areas under overload were studied under the conditions with or without of combustibles such as scrap paper and cotton. The results show that the temperature rise curve of the wire conforms to the trend of single exponential function in all cases. All final temperature values of the wire are generally divided into 4 or 5 stages corresponding to overload multiples.Copper wires with a cross- sectional area of 1.5 mm2 have the highest temperature. The relation between parameters of the fitting function of the wire temperature rise curve and the overload current multiple is linear when there is no combustible,and is quadratic or cubic polynomial when there is combustible.Under the same conditions, the final temperature of the wire is higher when there is combustible material. Except that the copper wire with a cross- sectional area of 1.5 mm2 had the highest temperature due to paper burning, the temperature of the other wire wrapped by cotton was relatively high under 4 Ie. Until the end of the experiment, cotton was only smoldering. The conclusions of this study can provide reference for the prevention and recovery of overload electrical fire and fire investigation. Related Articles | Metrics

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Experimental study on effect of high temperature on mechanical properties of blast furnace slag concrete CHEN Shi-lin 2020, 39 (10):  1363-1365.  Abstract ( 1823 )   In order to study the effect of high temperature on the properties of concrete containing ground blast furnace slag, the mass loss, carbonation depth, residual compressive strength and elastic modulus of concrete were measured at 150 ℃ to 700 ℃ when the proportion of ground blast furnace slag was 0，10%,30% and 50% respectively. The results show that the mass loss and carbonation depth of concrete samples increase with the increase of temperature, and the mass loss and degree of carbonation increase with the increase of slag content. In addition, the compressive strength and elastic modulus of concrete samples decrease with the increase of temperature. The relative compressive strength of concrete samples with 10% slag content is the highest, and the relative elastic modulus of concrete samples with high slag content is lower than that of concrete samples with low slag content. Related Articles | Metrics

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Numerical analysis of anti-explosion property of prestressed concrete beams under explosion load XIAO Xia, CUI Lei, LIU Jin-zhao 2020, 39 (10):  1366-1370.  Abstract ( 1805 )   The mechanical properties of prestressed concrete beam under explosion load is simulated by LS-DYNA. The antiexplosion property of four groups of prestressed concrete beams under explosion load are numerically simulated, the impact of prestress and strength of concrete on the anti-explosion property of beams are investigated. The maximum mid-span displacement, residual mid- span displacement, crack pattern, stress of rebar and the shear stress of concrete near support are analyzed and compared to the unprestressed concrete beams under the same explosion, and the influence rule of prestress on reinforced concrete beams is obtained. Related Articles | Metrics

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Dynamic assessment of building fire risk based on Internet of Things technology HUANG Jun-bin, ZHANG Guo-wei, YAN Su, , LIU Jian-xiang 2020, 39 (10):  1371-1375.  Abstract ( 1823 )   In order to dynamically reflect the fire safety status of the commercial complex in real time, the Internet of Things technology is used to establish a dynamic fire risk assessment model for the commercial complex. On the basis of the analytic hierarchy process, combined with the definition of fire risk, the assessment indicators are selected, the selected assessment indicators are classified dynamically and statically, and the classification indicators are quantitatively converted to make them a unified standard data, eliminating the previous data types due to different indicators. One- to- one correspondence between the monitored data and standard data through the Internet of Things technology is introduced into the fire dynamic evaluation model. The evaluation results dynamically change with the changes of the Internet of Things monitoring data, making up for the lack of node-style static response fire risk in the past. The result of an example shows that the method can accurately and quantitatively assess the fire risk of a commercial complex in real time and improve the dynamic management of fire risk in a commercial complex. Related Articles | Metrics

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Fire tests of different shaft structures in natural ventilation tunnel HUANG Tian-rong, ZHANG Yin-ping, SONG Fei 2020, 39 (10):  1376-1379.  Abstract ( 1785 )   In order to reveal the influence of shaft structure on natural ventilation of urban traffic tunnel, two types of shaft structures, the central vertical type and the lateral inclined type, are designed by using the tunnel model with the scale of 1:10, and the comparative tests are carried out. The longitudinal and vertical temperature and flue gas diffusion under two types of shaft structure were investigated. The results demonstrated that the longitudinal temperature and vertical temperature of the central vertical shaft tunnel are lower than the lateral inclined shaft, and the smoke control effect is better than that of the lateral inclined shaft tunnel. This originated from that the central vertical shaft has larger effective exhaust area and the energy of the flue gas decays faster in it. This conclusion could provide technical reference for the design and construction of similar projects. Related Articles | Metrics

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Research on estimation of fire probability in Shopping Mall based on Bayesian network YANG Shi-quan, HUANG Xiao-jia, XIE Shui-bo, WU Dong-li, ZHAO Yao, ZHANG Lei, YAO Wei-jie 2020, 39 (10):  1380-1383.  Abstract ( 1826 )   In view of the shopping malls- one of the crowded places, the characteristics of the fire in the mall, the analysis of the fire hazard factors, and the Bayesian network model of the mall fire were constructed. Use the National Bureau of Statistics and the "China Fire Yearbook" and "Foshan Statistical Yearbook" multi-year statistical data to calculate the initial probability of the node,and according to the Bayesian network transmission principle, calculate the probability of the occurrence of the mall fire. The results show that the Bayesian method can be effectively applied to fire analysis. Related Articles | Metrics

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Analysis of difficulties in fire design of a large international convention and exhibition center HAN Yu-ping 2020, 39 (10):  1384-1386.  Abstract ( 1881 )   Taking a large international convention and exhibition center as an example, the problems of overlarge fire compartment and overlong safety evacuation distance exists due to the operation needs. This paper analyzes the design difficulties of the fire lane, fire compartment, safe evacuation, smoke control and smoke exhaust caused by the functional requirements,and puts forward the optimization solutions for the fire protection design according to the relevant code. The results can provide references for fire design of non- traditional large space buildings with special function, large span or large space. Related Articles | Metrics

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Study on relying on unit fire pool to construct public fire water intake MENG Xian-he, MEI Ying-ting 2020, 39 (10):  1387-1389.  Abstract ( 1830 )   At present, in Heilongjiang Province, there are still some cities and counties can not guarantee the municipal water supply for 24 h. During water suspension period, fire water cranes, municipal fire hydrants can not be used. Relying on units fire pool to construct fire water intake has the advantages of short construction cycle，low cost，cold prevention and convenient usage, which can effectively solve the problem of the insufficiency of city public fire water supply. Related Articles | Metrics

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Scheme study on rail top heat exhaust system cooperating with platform fire smoke exhaust QIU Shao-hui 2020, 39 (10):  1390-1394.  Abstract ( 1761 )   Through numerical simulation and experimental tests, different cooperative smoke exhaust schemes are studied when a fire occurs on the platform of a subway station in Wuhan. The results show that the scheme of the rail top heat exhaust system cooperating with platform fire smoke exhaust is feasible, and the air flow of no less than 1.5 m/s downward can be formed at the escalators of each building to prevent the smoke from spreading upward; when the smoke outlet on the top side of the rail is uniformly arranged, the platform fire linkage equipment is the least, and the cooperative smoke exhaust effect is the best. There is a risk that the wind speed at the escalator entrance of the building is less than 1.5 m/s, when adopt the scheme of special smoke exhaust duct at the end of the platform cooperates with platform fire smoke exhaust, if there are a large number of escalator entrances in the station building, so it should be carefully selected. Related Articles | Metrics

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Analysis of evacuation design of multi-storey sunken square KAN Qiang, CUI Hai-hao 2020, 39 (10):  1394-1396.  Abstract ( 1840 )   With the development and utilization of underground space in urban construction of China, multi-layer sunken square becomes more and more common. But, the evacuation design of multi- layer sunken square has not been solved properly. Based on GB 50016- 2014 Code for Fire Protection Design of Buildings, the evacuation characteristics and difficulties of multi-storey sunken square was analyzed, the evacuation design scheme was put forward, and the feasibility of scheme was verified with simulation analysis of evacuation. Related Articles | Metrics

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Safety analysis of a building gray space case based on the public security triangular theory GU Jia, MA Zhe, ZHU Xing-fei, LU Shou-xiang 2020, 39 (10):  1397-1400.  Abstract ( 1885 )   It is difficult for many building gray spaces to define from current norms. In particular, the stability requirements of building components under the conditions of aging, wind disaster, fire and many other disasters can not achieve a balance between the landscape effect and security prevention. Based on the actual case of a city’s gray space landscape construction and combined with the Public Security Triangular Theory, from the point of fire safety,this paper explores the safety analysis method for standardizing such scenarios from the analysis process and contents. Related Articles | Metrics

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Development of security reset double power electric actuator NIE Jian-jun, YANG Hui, YAN Hong-zhen 2020, 39 (10):  1401-1403.  Abstract ( 1762 )   Emergency shut-off valve is an important safety facility in the petrochemical industry. In order to meet the technical requirements of emergency shut- off valves for flammable and combustible liquid storage tanks, a safety reset type dual power electric actuator is designed and developed. First of all, according to the requirements of protection level, the security design of electric actuator is carried out. Then, according to the load operation characteristics and system requirements, the parameters of the super capacitor module are calculated and determined and the auxiliary power supply based on super-capacitor is developed by using the characteristics of super capacitor such as high current fast charge and discharge characteristics and good temperature environment adaptability. Finally, the system integration of the security reset dual power electric actuator is completed, which provides technical guarantee for the realization of safety production in petrochemical industry. Related Articles | Metrics

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Method for predicting air consumption rate of air respirator based on activity intensity ZHANG Hong-yuan, LI Meng-qi 2020, 39 (10):  1404-1408.  Abstract ( 1817 )   Aiming at the differences in personalities and reasonably predicting the air consumption time of air respirator, a method to calculate the air consumption rate of air respirator based on the activity intensity level of personnel with air respirator is proposed. This paper proposes four levels of activity intensity for personnel with air respirator. By collecting data on personal dynamic and static heart rate ratio, air consumption rate of air expiratory and the influencing factors of air expiratory static air consumption rate, the correlation coefficient matrix is used to determine air expiratory air consumption of different activity. The main influencing factor of the rate is used as the independent variable and the gas consumption rate as the dependent variable, and establishes a regression model to calculate the air expiratory gas consumption rate based on the activity intensity. It has been verified that the model has a high degree of fit and has a good effect on predicting the air consumption rate of the air respirator. Related Articles | Metrics

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Study on effectiveness of aqueous film forming foam extinguishing agent on suppression of aviation kerosene pool fires JIA Jing-yun, ZOU Xiao-long, MENG Ya-wei, SUN Qiang, CHEN Xian-tao 2020, 39 (10):  1409-1412.  Abstract ( 1791 )   According to the national standard of fire extinguishing experiment, different foam injection rates were used to carry out fire extinguishing experiments on different sizes of aviation kerosene pool fire. The influence of oil pan size and foam spray rate on fire extinguishing effect was studied, and the largest oil pan size can be put out under the fixed spray rate was furtherly verified. The experimental results showed that when the area of oil pan is 0.8 m2, the extinguishing time is about 60 s shorter when the spray rate is 2.9 L/min than that when the spray rate is 1.3 L/min. When the foam injection rate was 1.3 L/ min, 90% of the aviation kerosene pool fire with the area of 1.0 m2 could be controlled, but the fire could not be extinguished completely. When the foam injection rate is 2.9 L/min, pool fire not bigger than 2.0 m2 can be put out completely. Related Articles | Metrics

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Combustion performance of inorganic hydrate doped thermosetting composite polystyrene plate HUI Fei, CONG Bo, JIANG Li-li, JIN Fu, ZHANG Yi-nan, WANG Xin, WANG Guang-wen 2020, 39 (10):  1412-1414.  Abstract ( 1774 )   The combustion performance of thermosetting composite polystyrene plate with the addition of inorganic salt hydrates was studied using oxygen bomb calorimeter, differential scanning calorimetry, thermal gravimetric analysis and single burning item method. The results indicated that the inorganic salt hydrates component could absorb the heat from the combustion of polystyrene particle, and then decreased the heat of the material, playing a role of fire-retardant and fireproof. Related Articles | Metrics

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Study on the fire resistance rating of the plugging structure of the converter valve side sleeve LIU Xiao-sheng, JI Jun, ZHANG Cai-you, DONG Jian-xin, WANG Jian-jun, YAO Hui, JIAO Chen-hua, NIE Jing-kai, HOU Dong 2020, 39 (10):  1415-1417.  Abstract ( 1828 )   There are many fire accidents in UHV converter station due to converter failure. The fire enters the valve hall through the plugging part of the casing at the converter valve side, which leads to the damage of the converter valve hall. In order to improve the fire safety margin of the converter station, this paper expounds the existing sealing structure form of the casing hole at the valve side of the converter transformer, and discusses the evaluation method of the fire resistance limit of the sealing structure. In view of the shortcomings of the existing sealing structure, and when the large sealing structure is not removed, the sealing structure is designed for fire resistance enhancement to form a new sealing structure enhancement system, and the fire resistance limit test is carried out according to the new evaluation standard. The results show that the enhanced system has good heat insulation performance and integrity, and meets the requirements of the fire resistance limit of the 3 h hydrocarbon temperature rise curve. It is a sealing structure for the casing at the valve side of the operation and exchange station to provide a solution for fire protection reconstruction. Related Articles | Metrics

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Experimental study on the ignition condition of EPS external insulation material by gasoline torch CHENG Zhi-ran 2020, 39 (10):  1418-1420.  Abstract ( 1774 )   The gasoline torch was used to ignite the ordinary and flame- retardant EPS external insulation material under different distances. The results showed that the two types of EPS could be ignited when they directly contacted to the gasoline torch flame.The surface of EPS only got different degrees of shrinkage and melting when there was a distance between the EPS and the gasoline torch flame, and the material was not ignited. The further the distance was, the smaller the shrinkage range was and the less the melting degree was. Related Articles | Metrics

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Study on the chitosan/sodium alginate coatings and flame retardant polyester fabric GUAN Chong-sheng, LI Zhen-hua 2020, 39 (10):  1421-1424.  Abstract ( 1918 )   With assistance of bio-based chitosan and anionic alginate,a natural- polysaccharides- derived flame retardant coating was constructed onto the surface of poly (ethylene terephthalate)(PET) fabrics, by electrostatic-guided layer-by- layer assembly. The successful self- assembly deposition of chitosan and sodium alginate was confirmed by scanning electron microscopy.The effect of the dosage of chitosan and sodium alginate on the thermal stability, flame retardancy and smoke suppression of PET fabrics were investigated by thermogravimetric analysis and cone calorimeter, meanwhile the morphology of char residue and pyrolysis products were investigated to determine the flame retardant mechanism. As been confirmed, the deposition of bio- based polysaccharide onto the surface of PET fabric can effectively improve the thermal stability, flame retardancy and smoke suppression performance of PET fabric. The analysis of pyrolysis products and char residue demonstrated that the deposition of natural bio-based polysaccharide promoted the formation of dense carbon layer, thus protected bottom polymer and inhibited the pyrolysis process, improving the flame retardant properties. Related Articles | Metrics

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Study on spatial and temporal aggregation of forest fire in Yunnan province WEI Jian-heng, Li Zhi, MA Ze-nan, WANG He-chen-yang, WANG Qiu-hua, SHU Li-fu, YANG Yu-yu, GAO Zhong-liang 2020, 39 (10):  1425-1429.  Abstract ( 1860 )   Based on the forest fire and meteorological data of Yunnan province from 1990 to 2017, the spatial aggregation analysis of forest fire was completed using SaTScan 9.4, the ARMA model was used to predict the frequency of forest fires from 2020 to 2025 in the region. The results showed that: At the time scale, the frequency of forest fires in Yunnan province decreased with the increase of year and was concentrated from January to May; On the spatial scale, forest fires mainly gather in central, northwest, and southwest regions in Yunnan province;Based on the ARMA model, there were more fires in Yunnan province from 2020 to 2025 than in 2017, but the number showed a decline trend.The study can help mastering the characteristics of the forest fire clustering, and provide theoretical support for the prevention and control work of the forest management department. Related Articles | Metrics

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Research on evacuation response process reasoning and assessment model in building fire YAN Jun, SHU Xue-ming, HU Jun, DENG Bo-yu 2020, 39 (10):  1430-1434.  Abstract ( 1813 )   In order to prevent building fires and reduce casualties in fires, reasoning and dynamic evaluation methods of building fire development process and evacuation response process are studied by using fire big data analysis technology and Bayesian network analysis method. Through the analysis of the response state of building fire fighting facilities and the psychological and behavioral characteristics of occupants in fire, the method of fire stage division and the classification of evacuation behavior are discussed and the trajectory intersection theory of casualties in fire is put forward, and framework on fire dynamic risk and evacuation safety assessment based on Bayesian network is constructed. The reasoning process of building fire development and evacuation response are discussed respectively, and the evacuation condition assessment process is discussed Research shows that the model can fuse large fire data such as building characteristics, fire facility status information and occupant response information, evacuation response process reasoning and dynamic risk assessment model in building fire are realized, so as to improve the level of building fire safety management. Related Articles | Metrics

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Design of fire warning system and fire extinguishing system of battery energy storage system HU Zhen-kai, LI Yong-qi, PENG Peng 2020, 39 (10):  1434-1437.  Abstract ( 1882 )   Based on the actual project requirements of a echelon battery energy storage system, combined with the thermal runaway mechanism of lithium iron phosphate battery, a multi-level warning system and hierarchical early warning strategy based on VOC, combustible gas, temperature, smoke, etc. were proposed to monitor the battery in a full cycle and continuous manner to ensure the rapid and effective detection of battery thermal runaway state and realize the early intervention of fire extinguishing system. Considering the characteristics of low cost, poor safety and reignition of battery fire, a water spray fire extinguishing system was added to the traditional heptafluoropropane fire extinguishing system to ensure the complete extinguishing of the fire. Finally, the effectiveness of the fire warning system was verified by taking the thermal runaway of retired lithium iron phosphate battery as an example. Related Articles | Metrics

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Study on forest fire characteristics and governmance conutermeasures in Jiangxi Province PENG Xu-jian, WU Jian-guo 2020, 39 (10):  1439-1442.  Abstract ( 1802 )   This paper is based on ArcGIS, Excel and other means of spatial analysis and mathematical statistics,to analyze the dynamic characteristics of forest fires in mountainous and hilly areas. The occurrence, causes and spatial and temporal distribution of forest fires in Jiangxi Province from 2011 to 2018 were studied. The results show that there were 202 fires in Jiangxi Province in this year. Burning paper in graves, burning carbon in wasteland and smoking in the field are the main causes of forest fires, accounting for 29%, 17% and 14% of the total, respectively. The forest fuel is mainly Middle- maturing forest and young forest, while Chinese fir and Pinusmassoniana are the main forest fuel species. Forest fires are mostly concentrated in the first half of the year, especially in January to April, and less in the second half of the year. Fire occurs frequently from 12:00 a.m. to 18:00 p.m. every day, and fewer fires occur from 22:00 p.m. to 6:00 a.m. the next day. The most frequent fires occurred in Shangrao City and Ji'an City. The hot spots were mainly located at 117°48′E，28°19′N in Shangrao and 113° 46′ E，27° 42′ N in Pingxiang. This study provides data support for forest fire management in Jiangxi Province. Related Articles | Metrics

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Research on the fire safety of Wildland-Urban Interface ZHENG Ze-xun, LI Qiang, LI Jin-mei, CHEN Xun, LI Jie 2020, 39 (10):  1442-1446.  Abstract ( 1977 )   In order to enhance fire control and prevention capability in Wildland- Urban Interface in China, this article compared the fundamental prospect and focus of International WildlandUrban Interface Codes and Code for Fire Protection and Prevention in Rural Areas as well as other China's regulations. Jindong District of Jinhua, Zhejiang was sampled to analyze current fire protection situation in WUI areas of China. The result showed that the fire protection and prevention codes of WUI areas in China lag relatively behind the ICC standards,which was a great restraint to fire protection ability development in WUI areas of China. Conducting relevant research and formulating corresponding codes and regulations are the basis for strengthening fire safety of WUI areas. Related Articles | Metrics

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Nested hierarchical coverage location model for fire station with limited capacity CHEN Zhen-nan, ZHANG Peng, WU Li-zhi, XIA Deng-you 2020, 39 (10):  1447-1451.  Abstract ( 1789 )   In order to scientifically allocate limited fire resource and elevate coverage efficiency of fire station, a nested hierarchical coverage location model for fire station with limited capacity was presented. Firstly, with the rule of hierarchy and nest, fire stations should be classified when siting, and the coverage area of high-level fire stations was allowed to establish affiliated low- level fire stations, so as to multiply covering urban area and improve coverage efficiency in suburb area. Secondly, considering limited capacity of fire station, fire risk that the same level and same type of fire station was responsible for should be averaged within a certain gap scope. Finally, genetic algorithm was designed to solve model and an example was taken to verify the model. The research proved that: compared to generalized maximal coverage model, fire station location selected by nested hierarchical coverage location model with limited capacity could cover more fire risk, multiply covering high fire risk area and average fire risk between the same level and same type of fire station. Related Articles | Metrics

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Experimental study on the behavior of walking upstairs in smoky environment LI Jun-mei, WANG Ze-hang, DONG Qi-wei, QIAO Ya-xin, ZHANG Peng, LI Yan-feng, 2020, 39 (10):  1452-1455.  Abstract ( 1774 )   In order to study the evacuation behavior in a fire, a study on the moving behavior of the people walking upstairs in the smoke environment in residential buildings was conducted.Three different visibility conditions e.g. no smoke, light density of the smoke and dense smoke were set. The research results show that when the people walking in the smoky environment,besides the walking distance, the psychological effect is also an important factor for the movement speed. The light smoke environment has little effect on the moving speed of people. In the thick smoky environment with lower visibility, the people would be panic, and would walk faster with the help of the handrail.The upward moving speed is greater than those in the smokeless and light smoky environments. Related Articles | Metrics

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Investigation method of new energy electric vehicle fire ZHANG Yu-bin, ZHANG Yi-xin, CHENG Jing-yuan 2020, 39 (10):  1456-1458.  Abstract ( 1952 )   Against the four kinds of main fire cause of new energy electric vehicle, the method and key points of fire investigation inquire was put forward, the site investigation steps and survey points of each parts of new energy electric vehicle were analyzed, and the investigation method of new energy electric vehicle fire were summarized. By analyzing the battery failure fire spreading trace, identifying the fire location, deciding the battery cell on fire, the identifying method of battery cell combustion trace was summed up. The study can provide reference for electric vehicle fire. Related Articles | Metrics

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Fire risk analysis of lithium ion battery based on cone calorimeter LIU Shu-jing, ZHU Peng, WANG Dong-Dong, Hu Hao 2020, 39 (10):  1459-1461.  Abstract ( 1784 )   The frequent electric vehicle fire accidents have drawn attention to the fire hazard and combustion characteristics of ion batteries.The combustion characteristics of several common lithium ion battery electrolyte solvents were analyzed by means of cone calorimeter, and the effects of different solutes on their combustion characteristics were discussed.The fire risk of lithium ion battery electrolyte was evaluated with the help of fire risk comprehensive index (IFHI) and flask-fire characteristic index. It was found that the solvent heat risk containing LiPF6 was in the order of LiPF6+DMC, LiPF6+DEC, LiPF6+ EMC and LiPF6+EC.Through the assessment of flashover characteristics, it is found that the intermediate fire risk level can be: LiPF6 + EC;Fire risk levels of super high are: LiPF6 +DEC,LiPF6+DMC, LiPF6+EMC. Related Articles | Metrics

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Big data visual service platform for fire product certification based on "one map" YU Wei, HU Qun-ming, ZHANG Xiao-ying, ZHANG Hao-chen, DU Guo-ao 2020, 39 (10):  1462-1465.  Abstract ( 1869 )   Abstract:Independently develop "one map" fire product certification big data visualization service platform, effectively use Internet of things, geographic information technology, data analysis and other big emerging information technology means,to show and integrate the certified enterprise information through the map, control the factory location and certified information of certified enterprise, improve the risk prevention and control of fire product certification, mark the location of the fire product enterprise and the product types. According to analysis of data and information, random information query and the risk and development trend anticipation are realized. Mine the value of certification data, improve the level of management decision, and achieve digital, intelligent operation management. Related Articles | Metrics

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A neural network predicting model for condenser scaling cumulative law in fire protection design of coal power station ZHOU Guang-hong, REN Wan-ying 2020, 39 (10):  1465-1468.  Abstract ( 1730 )   In order to prevent the condenser scaling from causing fire and explosion accidents, it is necessary to predict the law of development of fouling factor in the condenser. A fouling factor predicting model combining K-mean algorithm and Chebyshev neural network was designed. Aiming at the disadvantages of Chebyshev neural network, the K-mean algorithm can be used to improve the curve of fouling factor development over time, which can be divided into three stages: starting stage, adhesion stage and aging stage. Results showed that, the modified Chebyshev neural networks can predict the law of development of condenser fouling factor effectively, and is more accuracy than progressive prediction and power-law prediction; the algorithm is simple and has fast convergence speed. Related Articles | Metrics

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Fire characteristics and improvement of typical noise reducing materials in outdoor substation (Converter station) NIE Jing-kai, ZHANG Song-yang, LV Zhong-bin, ZHAO Fa-ping, XIAO Wei-min, ZHANG Yang, WANG Lei-lei 2020, 39 (10):  1469-1473.  Abstract ( 1792 )   Abstract: In this study, the noise reduction measures of outdoor substation (converter station) are mainly noise insulation cover and barrier. The main components of the above measures are carbon steel, glass cotton and rock wool. The electric fire is mainly composed of insulating oil and polymer combustion,and the heating rate and maximum temperature are higher than the standard fire, which has more severe influence on the material.Electric fire, mineral cotton materials will occur heat shrinkage,powdering, basically no impact on fire, but steel structure and galvanized steel plate even at 1 000 ℃ still have strength, although softening deformation, but will not break, still hinder the fire work. "High-temperature melt-down granular plate" and "High- temperature melt-down structure based on thermoplastic PA6 material" improved the fire protection conditions, and its final time service performance needs to be further accumulated in the application of test data. Low noise of transformer equipment will be the final trend of the development of electrical equipment technology. Related Articles | Metrics

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Study on the compilation of the 14th five year plan for fire protection development in county areas of Midwest China LIU Jing 2020, 39 (10):  1473-1475.  Abstract ( 1858 )   Based on preparation of the 14th five year plan, this paper focuses on the problems of fire protection development in county areas of Midwest China, and proposes the ideas, contents and methods of the 14th five year plan for fire protectio development. On the principles of field research, learning advanced areas and integration of multiple plans, this paper provides reference for relevant decision makers. Related Articles | Metrics