Type selection, design and maintenance of fire hyd

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Selection, design and maintenance of outdoor fire hydrants

as the name suggests, fire hydrants are a device used by fire departments to take water and extinguish fires in the event of fire disasters. The types of fire hydrants can be roughly classified according to the following situations, which can be roughly divided according to the layout of fire hydrants: indoor fire hydrants and outdoor fire hydrants. According to the installation form of outdoor fire hydrant, it can be divided into aboveground type and underground type. According to the number of fire hydrant outlets, it can be divided into single port type, double port type and three port type. Outdoor fire hydrants are usually installed on municipal water supply pipes. According to the design code for fire hydrants on municipal water supply pipes, the spacing of fire hydrants should not exceed 120 meters, so its number is no less than that of water supply pipe valves, and it is one of the important facilities on water supply pipes

the special function of the fire hydrant determines its particularity in the municipal water supply pipe. It is different from other facilities on the municipal water supply pipe, and its use, maintenance and management are undertaken by the water supply enterprise. With the exception of fire hydrants, their use is mainly satisfied with the use of fire management departments, while the maintenance and management are borne by the water supply enterprises themselves. In some cities, the maintenance and management of fire hydrants are undertaken by the fire department. Like a soldier, the fire hydrant is a fire-fighting and water intake control equipment that "raises troops for a thousand days and uses them for a while". Once a fire occurs, it must meet the requirements of the fire department for water intake and fire extinguishing. Therefore, as the daily maintenance and Management Department of fire hydrants, the management of fire hydrants is more important than Mount Tai

when necessary, protect and dispose of the fire hydrant. As an important facility on the municipal water supply pipe, its connection form with the pipe is: connect the horizontal special branch pipe, set up the control valve to connect the fire hydrant, and its fire hydrant well room is located next to the main water pipe. There are also fire hydrants set up on branch pipelines that are not dedicated to fire hydrants, which are often installed in a well with the main control valve, commonly known as fire hydrant wells. That is, the valve connected to the fire hydrant not only closes the valve and stops the water supply when the fire hydrant needs to be repaired, but also controls the water flow in the downstream pipe section for installation, maintenance, etc. There are also installation forms such as adding tee directly to the water transmission and distribution pipeline, and the fire hydrant standing upright on the back of the pipe. With the increase of urban buildings and population density, as well as the change and improvement of the specification and performance of fire-fighting equipment (mainly refers to fire engines), the outlet diameter of underground fire hydrants is φ 100mmsx-100 type, while the former sx-65 type gradually withdrew from the urban water supply pipe

many water supply enterprises only pay attention to the management of valves in the management of water supply pipe facilities, thinking that if the valves are well managed, the water supply pipe will be well managed, and often neglect the management of fire hydrants. However, once the management of fire hydrants is wrong, the consequences and social impact will be greater. This should cause the water supply enterprises responsible for the maintenance and management of fire hydrants to be highly vigilant

to ensure the use and maintenance management of fire hydrants, it is necessary to talk about the selection of fire hydrants, the design and installation of fire hydrants, and the daily maintenance and management of fire hydrants

I. selection of outdoor fire hydrants

1. The selection of underground fire hydrants and above ground fire hydrants should be adapted to local conditions. In the municipal water supply pipe, the planning and setting of fire hydrants in some urban water supply pipes emphasize the use of underground type, while in some cities, the original underground type is completely transformed into ground type. Underground fire hydrants have the advantages of strong concealment, no impact on the beauty of the city, less damage, and antifreeze in cold areas. However, as the use and management department, it is not very convenient to find maintenance, and it is easy to be buried by construction vehicles, etc. Jinan new era Gold Testing Instrument Co., Ltd. has put forward the problem clearly and pressure when doing the technical data. A large number of underground fire hydrants need well protection, and the capital investment is large. At the same time, it occupies a lot of positions in the urban underground pipe planning, which brings difficulties to the planning. On the contrary, the above ground fire hydrant is eye-catching, easy to find, convenient to use and maintain, but easy to be damaged and easy to steal water. If a fire hydrant is really set at 120 meters according to the specification, it is bound to have a certain impact on the urban street scene. Fire hydrants are mainly used for fire fighting and water intake. Therefore, as the department using fire hydrants, how to quickly find fire hydrants and how to take water quickly, conveniently and easily is the desire and requirement of the fire department. It should not only meet the use, but also consider the city appearance and scenery, but also be conducive to maintenance and management. Therefore, the selection of fire hydrants should be based on local conditions and the combination of underground and ground type. And the specifications and models of fire hydrants should not be too many, which is convenient for use and maintenance

2. the outlet diameter of the fire hydrant shall not be less than φ 100mm。 With the increase of urban buildings and population density, it is more difficult to extinguish the fire. In order to ensure the water pressure and volume requirements of fire extinguishing, it is necessary to ensure that at least one outlet diameter of the fire hydrant is not small φ 100 mm。

3. the opening and closing directions of fire hydrants should be unified, and they should be closed clockwise and opened counterclockwise. The screw rod shall be made of stainless steel, the sealing cup shall be made of ethylene propylene diene rubber or nitrile rubber, and the corrosion prevention in the cavity shall meet the sanitary indicators of drinking water, which shall be consistent with the requirements of the valve

II. Installation design of outdoor fire hydrants

1. The installation design of ground fire hydrants should be designed to be installed in the intersection area of the street, in a position that ensures eye-catching and does not affect pedestrians and traffic, while considering the convenience of maintenance and daily drainage. For example, on the edge of the sidewalk, beside the rainwater drain, and on the tree side of the sidewalk. Some ground-based fire hydrants cannot discharge water because the water outlet of the fire hydrant is buried and blocked by soil after the original installation and subsequent changes in the road elevation, resulting in changes in the water quality in the fire hydrant cavity, corrosion of screw rods, etc., affecting the water quality of the pipe and the service life of the fire hydrant

2. Installation design of underground fire hydrant. The underground fire hydrant is designed and installed in the underground well, so the height and plane position of the fire hydrant outlet are the key to the convenience of water intake. Considering the relatively slow growth of this field before 2018, the height of the outlet from the ground should be controlled at about 30cm. Considering the convenience of maintenance and use, the plane position of the outlet should be close to the wellhead. If the fire hydrant well is very deep and the connecting riser of the fire hydrant is too long, the riser should be fixed in the well to ensure safety in use

3. For the design of outdoor fire hydrants around super high-rise buildings, the distance between the fire hydrants and the water pump adapters of super high-rise buildings should be considered, so that once the super high-rise buildings catch fire, the fire department can take water and add pump connections within the shortest distance

4. Due to the influence of planning and other factors, the functions of control valve well and fire well are often combined into one. It is used to be called casing well, which seems to save the planning location and achieve the dual functions of one well, but it also brings management disadvantages. First, once the fire hydrant needs to be repaired, the valve needs to be closed, which will affect the normal downstream water supply. Similarly, closing the valve when repairing the downstream pipeline will affect the normal use of the fire hydrant, and the normal use rate of the fire hydrant will inevitably be reduced. This is extremely disadvantageous to the use and management of fire hydrants. Second, because the well has dual functions, and whether the well cover is mainly a fire well cover or a valve well cover, it brings confusion in management and use. Therefore, this kind of well casing should be avoided as far as possible in the design

III. management of fire hydrants

1. As one of the auxiliary facilities, the management of fire hydrants should be equivalent to the management of other facilities. A special management team should be established to implement special management. Once the fire hydrant is found to be invalid, it should be treated in a timely manner as pipe explosion. In addition, the periodic overhaul and maintenance plan for fire hydrants should be formulated and regular maintenance measures should be implemented. The ground fire hydrant should also be painted regularly to prevent corrosion to ensure eye-catching. Regularly inspect the drainage operation of the fire hydrant, on the one hand, to determine whether the fire hydrant is effectively opened and closed, and whether the water pressure and volume meet the normal scope. On the other hand, on the distribution pipe, the water quality is also improved and ensured through the drainage of fire hydrants. In the implementation of fire hydrant drainage, in order to ensure the drainage quality and effect and prevent secondary pollution of the pipe, a hose should be used to drain the water into the rainwater well during drainage. The drainage quality is tested by on-site water samples, mainly to measure water quality indicators such as turbidity and residual chlorine. In addition, the water pressure of the pipe is measured and recorded before drainage, so as to accumulate the service pressure parameters of the pipe, so as to facilitate the operation and scheduling of the pipe as parameters

it is necessary to improve the water quality of the pipe through the fire hydrant drainage and ensure the safe operation of the fire hydrant, but at the same time, the problem brought to the water supply enterprises is that the poor sales of self supplied aquatic products of the water supply enterprises also increases correspondingly. How to carry out the drainage management economically, reasonably and scientifically is a problem worthy of in-depth discussion for the water supply enterprises

in the management of fire hydrants, according to the setting of fire hydrants, the discharge conditions of on-site enterprises after receiving orders through e-commerce platforms or other channels, as well as the material conditions of the pipelines where the fire hydrants are located and the water consumption in the area, the Chengdu water department implements hierarchical drainage management, implements periodic, time phased and key discharge according to the specific situation, and calculates the discharge amount according to the time of thanks and the water pressure at that time, In order to facilitate the accuracy of drainage, some water supply enterprises have installed water meters for each fire hydrant, and similar practices have been adopted abroad. However, the installation of water meters also increases the difficulty of management, which should be carefully considered

2. Like other facility wells, fire hydrant wells are often likely to be piled, blocked, buried and pressed. In addition to strengthening inspection, publicity and guidance of fire regulations should also be done. In particular, we should closely cooperate with the local fire department and rely on the law enforcement efforts of the fire department to maintain and manage fire-fighting facilities. The fire department implements area management in fire fighting, so the maintenance and management of fire hydrants in water supply enterprises should also be organically combined with the area management of the fire department to form a common management, which is conducive to getting twice the result with half the effort. The Chengdu Water Department sprayed yellow paint on the cover of the fire well to give warning, which not only facilitates the search and maintenance, but also plays an eye-catching role, so as to facilitate the use of the fire department. This method is worth popularizing. Of course, if possible, the fire well cover should also be painted into fluorescent and reflective marks for searching at night

3. As one of the water supply pipe facilities, the establishment and improvement of the archives of fire hydrants is the key to the management of fire hydrants. The archives should include single card drawings, maintenance records, daily inspection records, etc. If possible, a fire hydrant management information computer system should also be established to improve the means of fire hydrant management. (end)

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