The Evaluation About The Municipal Network Fire Water Supply Capacity Based On The Water Distribution Network Model

Water distribution network models are widely used for various purposes in the world, such as long-range planning, design, water quality and operation management and fire assessment. Water distribution network is a mathematical characterization for the actual network. Water distribution network model consists of Junctions, Pipes, Pumps, Valves, Impounding Reservoirs and Towers, which are called 5 types basically element. At first, this article expound how to build the water distribution network model. Seconded, research how to confirm the Fire Flow, and put forward the method which can confirm the Fire Flow——Surrounding Economic method. Third, expound the evaluation system of urban fire supply system. Finally, on the three parts basis, evaluate the water supply capacity of fire supply system at Yulong town.What is called build model problem is that combine the 5 types basically element together which is mentioned above. Reflecting on the math is that solve the energy equation and continuity equation——which are the theoretical foundation of water distribution network. Gradient algorithm is used in this article to solve the equation set, and illustrate the hydraulic theory foundation. Then, contrastive analysis the frequently-used software about building model, including EPANE、Info Works WS、 SynerGEE Water、Water GEMS、Sangaohongyang Software. Using Water GEMS to construct the water distribution network model at YuLong county, and check it by genetic algorithm. Finally, the operating conditions of the water distribution networkon the highest day are simulated.Fire flow is the minimum amount of water needed to extinguish a fire in a municipal fire water supply system, the value shall be determined in accordance with the factors such as the size of the city, the nature of the building, the volume, height, size, fire resistance rating or fire risk, and the types of fire water supply system.Commonly used methods at home and abroad to determinate water consumption for fire protection are ISO, ISU, IIRTI, and the methods ruled in Technical specification of water supply and fire hydrant(GB5097-2014). Among these methods, the results calculated by ISO method are the most close to the actual water consumption, but its calculation process is complex and cumbersome, not easy to master, besides, the construction risk level and other factors are not exactly the same in our country, so it’s with poor practicability for our country. Although our country has issued Technical specification of water supply and fire hydrant(GB5097-2014), end the situation in our country of lacking basis for the design, construction and acceptance of fire water supply, but in the municipal fire water consumption determination is still in general, especially in determining the urban outdoor fire water consumption. And this is bound to result in a deviation from the actual fire water use. Based on this consideration, this paper will be combined with the actual situation of our country, reference to foreign calculation method, Then put forward the method of environmental economic factor creatively.The main content of evaluation of water supply capacity of fire water supply network includes technical evaluation and safety evaluation.Technical evaluation refers to the fire water supply pipe network system can transport sufficient water to the fire place with enough pressure when the fire occurs. Hydraulic parameters for evaluating the performance of the system include pressure and flow. Safety assessment refers to the fire water supply network can ensure uninterrupted water supply in the fire.Mainly through the fire water supply system pipe network and the reliability of water supply facilities to evaluate its safety. In this paper, the hierarchical analysis method is used to establish the index system hierarchically, using multivariate statistical method to construct the unified evaluation level, using expert scoring to determine the weight, using FCE(Fuzzy Comprehensive Evaluation) to analysis the advantages and disad-vantages of urban fire water supply system.On the basis of the above three aspects, evaluate the water supply capacity of fire fighting water supply system in YuLong County. Evaluation results shows that the water supply capacity is "excellent". In this paper, the application of the hydraulic model of pipe network is enriched, and the technical reference for the design and planning is provided.