Study On Layout Of Urban Fire Station And The Improvement Of Rescue Capability Under The Constraint Of Fire Risk

With continuous increase in the area and density of urban buildings in China,the fire risk is greatly expanded year by year.Urban fire has become an important factor causing casualties,economic losses and environmental damage.Fire station serves as the basic unit in guaranteeing the public fire safety.The high efficiency rescue ability of fire station can ensure the safe and rapid development of the city.In order to improve the rescue capability of urban fire station,spatial distribution,classification and influence factors of urban fire in China are firstly analyzed in this dissertation.Based on the fire demand point,spatial distribution of urban fire risk level is achieved and its visualization is realized.Note the fire demand point is derived from the concept of“Point of Interest”(POI)in Geographic Information System.Under the constraint of fire risk,spatial layout of urban fire stations is optimized,which improves the compatibility between fire rescue capability and fire risk in respect of spatial dimension.Subsequently,the capability of single fire station is evaluated.According to the evaluation result,the measures to strengthen the rescue capability are put forward.The dissertation aims to provide support for improving the rescue capability of urban fire stations from the aspects of overall layout and individual construction.The main conclusions are listed as follows.(1)The fire accident frequency and associated damage are always high in China.Occurrence frequencies,casualties and direct economic losses of the fire accidents are higher than 100000 times,1500 persons and 1.5 billion yuan,respectively,per year.Spatial distribution of the fire accidents presents obviously regional characteristics.It is mainly concentrated in three provinces of Guangdong,Zhejiang and Jiangsu,which are economically developed and densely built.Urban area is the most severely damaged area of fire accidents.Residential buildings are the main places of fire accidents,accounting for 32.2%of the total number of fire accidents.Electrical and domestic fires are the main causes,which occupies about 50%of the total number of the collected fire accidents.(2)The fire rescue task in China is still arduous.In the past 10 years,the number of rescue times triggered by fire accident shows an upward trend,and the average number of deaths of fire fighters can reach 12 people per year.Taking the historical statistical data as the basis,this study puts forward a prediction model for rescue task by using genetic algorithm and BP neural network.The average error of the prediction results using the obtained model to the sample data is reduced to 1.1%,which means the developed model is capable to accurately predict the fire rescue times.According to the model,the number of fire rescue task in 2020 and 2021 of China reaches 1097000 and 1606000 times,respectively.The prediction results show that China will still face high fire rescue pressure in the future.(3)Fire risk places are divided into eight categories according to the classifications of POI data.Based on the newly proposed method,named as"historical data-expert experience"based method,the weight of fire risk in different places is obtained.Then,the research area is divided into grids and the kernel density of POI data is analyzed.The fire risk of the target area is obtained by weighted superposition of fire risk weight and kernel density analysis results of all involved places.Moreover,the fire risk is divided into five levels,which are very high,high,medium,low and very low.Finally,the determined fire risk level is assigned to the corresponding grid to realize visual analysis of spatial distribution of urban fire risk.(4)Based on the spatial distribution of POI data and fire risk,an optimization method of urban fire station spatial layout is proposed.Firstly,the number and initial location of fire stations are determined based on the principle of minimizing the number of facilities and maximizing the coverage model.In this case,the aim to use the least fire stations to maximize the coverage of fire demand points is satisfied.Secondly,according to the POI data assigned to the fire stations,the service area of the fire stations is identified by using the topological partition method of convex hull.By introducing topological convex hull division method into the identification of fire station service area,requirements of maximizing the coverage area of service area and minimizing the overlapping coverage area is realized.Thirdly,the fire risk distribution map and the spatial layout map of fire stations service area are superimposed.According to the superposition results,the location of fire stations is adjusted to ensure the full coverage of high-level fire risk area.This step achieves the best match between fire risk and fire rescue capability in spatial dimension.Finally,in order to grasp the areas that cannot be reached within the critical time,the sensitivity of fire station approaching area to responding time of the station is analyzed.(5)The above methods are used to optimize the spatial layout of fire stations in Zhongyuan District of Zhengzhou city.The seven existing fire stations cannot meet the coverage requirements of the fire rescue demand within the area.Less than 72%of the fire demand points are effectively covered.The coverage ratio of the service area identified with topological convex hull method only reaches 31.34%of the total area.On the basis of the existing fire stations,three new fire stations are needed to be constructed,which can achieve the coverage rate of more than 95%of the demand points.Besides,the full coverage of the high fire risk area is realized.After that,the accessibility of the 10fire stations after short-term planning is analyzed.The results show that the area reached in 4.3 minutes increases to 108.8 km~2,which is 50%of the whole area.About 94%of the research area can be reached in 10 minutes,and all areas can be reached in 15 minutes.The overall accessibility is well.(6)A comprehensive evaluation model is established to evaluate the emergency rescue capability of urban fire station.The model takes the emergency rescue capability of fire station as the target layer.The index of criterion level is divided into five aspects,named personnel,equipment,environment,management and economic input.The subcriteria layer is divided into 25 fire rescue related indexes.The seven fire stations in Zhongyuan District of Zhengzhou City are taken as an example to analyze their rescue capability.The evaluation results show that the fire emergency rescue capability of the Teqin3 fire station,Tongbai fire station and Gaoxin fire station is"very high",and that of Longhai West Road fire station,Fumin Road fire station,Youai Road fire station and Zhutun fire station is"high".According to the inequality between the rescue capability evaluation results and the rescue demand of the service area,some measures are put forward to improve the rescue capability of the fire station.(7)A fire rescue case in Zhongyuan District of Zhengzhou is presented to analyze the rescue capability and efficiency.The actual driving time of the fire vehicles is 6minutes.After optimizing the spatial layout of the fire station and the rescue capability of the single fire station,the travel time needs 2.5 minutes,which is 3.5 minutes less than the actual time.The above results are verified by an in-situ experiment.The slope of fire frequency-fire area curve is positively proportional to the arrival time of fire rescue force.It shows that reducing the arrival time of fire vehicles can effectively improve the rescue efficiency and hence,reducing the fire area and disaster losses.