Design of hydrant water supply system for the hott

Design of fire hydrant water supply system in small high-rise residential complex abstract: This paper introduces the design trends of fire hydrant system in small high-rise residential complex, and puts forward that the variable-frequency or pneumatic water supply system with reliable standby power supply can be combined with domestic water supply system without roof fire water tank, and it is also suggested to revise the content of relevant fire protection design specifications

key words: fire hydrant water supply system design of small high-rise residential groups

1 preface

in recent years, the design of small high-rise residential groups has become popular all over the country, and Shunde has gradually emerged small high-rise residential buildings such as Xinhe Huayuan, Yongjing Haoyuan, Jiaxin city garden and so on. At first, small high-rise residential complexes were only tens of thousands of M2, and now small high-rise building complexes of tens of thousands of M2 are also common. The so-called small high-rise residence here refers to the residence with a total height of 11 or 12 floors. This kind of residence often adopts the mode of one ladder and four households, and the first floor is overhead for greening, pipeline conversion or scattered commercial points. The lower grade ones also have overhead garages, and the vast majority have additional underground garages

2 design features of small high-rise residential complexes

the design of fire hydrant water supply system of small high-rise residential complexes applies the current code for the design of high rise civil buildings (GB), which is often designed in the following ways: first, the fire hydrant system is set separately, with a temporary pressurized pump room, and the start pump button signal of each fire hydrant box should be connected to the fire hydrant pump room, and the fire hydrant pump will be automatically started by the fire signal. 2、 A fire water tank of not less than 6m3 (12m3 required by some local fire departments) must be set. When the hydrostatic pressure of the fire hydrant at the unfavorable point of the building is lower than 0.07MPa, a fire hydrant booster pump shall be set. 3、 In order to ensure that the fire water will not be used, a separate fire pool or liquid level limit will be set

according to the above design, the fire hydrant and domestic water supply system are independent, and the discussion focuses on the development of innovative design capabilities, international development trends, cutting-edge technology, market demand, policy guidance and other future development trends of the industry. The outdoor pipe location is tight and the design is difficult; In addition, large investment will affect the development profits of real estate developers; Fire water tank is set on the roof, especially in the fire water tank room without stabilized pressure pump room, which seriously affects the building facade. More importantly, the final use effect is counterproductive, so it is necessary to analyze it carefully

3 the fire hydrant and domestic water supply system of small high-rise residential groups should be combined

small high-rise residential groups are generally ordinary houses, less than or equal to 50m, and the water consumption of indoor fire hydrants should be 10L/s. If there is a commercial site on the first floor, it should be considered as a class II commercial and residential building, which should be 20l/s. If there is a garage, it should also be considered as a class I and class II parking garage, which should also be 20 L/s. Even if the domestic water consumption is calculated at 350l/(person · d) at 20 L/s, for a small high-rise residential complex of about 80000 m2, the water supply of fire hydrants is basically the same as that of domestic water. However large the area is, the domestic water supply is greater than that of fire water. Obviously, the shared pipe of domestic water and fire water will only be more conducive to fire control in terms of water volume for small high-rise residential complexes with a larger area

the difference between the water pressure of domestic water supply and the water pressure of fire hydrant is calculated to be about 0.12-0.18mpa, which can fully share the equipment. If frequency conversion water supply is adopted, the frequency of domestic water supply is reduced, and the original frequency of fire fighting is restored, the problem of slightly high water pressure energy consumption of fire hydrant for domestic water supply can be overcome

for small high-rise residential complexes, the amount of outdoor water supply works is considerable, and the separation of domestic water supply and hydrant water supply system has almost doubled the amount of outdoor pipeline works; It is sometimes difficult to find the location of the pipeline in the community with underground car garages and tight general layout. It should be noted that the statistics of fire control inspection in some places show that the former requires the use of coarse abrasive materials, but 1/3 of the former is unqualified. The reason for the "low passing rate of operation during fire shock inspection" is precisely due to the separation of domestic water supply and fire water supply. The increased investment in domestic water supply system can increase the selling points of houses or the satisfaction of residents with property management. Therefore, the problem of domestic water supply is generally valued. Because the domestic water supply pump is often on, developers are even willing to buy imported stainless steel pumps, and property management also has a perfect and standardized system. The fire hydrant water supply system is not the case. Many of them just deal with routine fire inspection and do not receive due attention. In the end, it is unsafe to set up a fire hydrant water supply system alone

the current fire code also stipulates that fire water cannot be used. There is a pool of stagnant water in the fire hydrant system, and it is not allowed to use a small amount of water, such as water for greening irrigation. It is guaranteed that the water of the fire protection system will be changed once every half a month or a month to prevent the deterioration of the fire water quality, but the most fundamental measure is to combine the fire hydrant water supply system with the domestic water supply system

4 the variable frequency or pneumatic water supply system should be regarded as the constant high pressure water supply system, and the roof water tank can not be set.

what is the constant high pressure water supply system, and the high standard has no clear definition. I personally understand that for water fire-fighting system, whether it is in quasi working state or during fire fighting, it can meet the requirements of fire water volume and fire water pressure, which can be considered as an ordinary high-pressure water supply system

the reason for worrying about the failure of frequency conversion or pneumatic water supply to maintain a constant high voltage is nothing more than worrying about the role of flame retardant in extruded polystyrene board in the continuous fire source for 10 minutes, limited switching time and equipment mechanical failure. In fact, the variable-frequency or pneumatic water supply system for living and fire protection has made great efforts in the design of power supply in order to strengthen its fire-fighting function. In order to ensure the function of living water supply and improve the grade of buildings, developers are also willing to spend a lot of money on high-grade generators. According to article 6.1.5.1 of code for electrical design of civil buildings (JGJ), the unit shall always be ready for startup. When the normal power supply is interrupted, the unit shall be started immediately and can be put into normal loaded operation within 15s

for small high-rise buildings, even if the fire hydrant water supply of 15s, that is, 300L, is conservatively set at 30s, that is, the water volume of the pressure stabilizing tank reaches 600L, which is enough to ensure the safety of the fire hydrant system

as for equipment failure, the domestic water supply pump and fire hydrant water supply pump are standby with each other, which greatly increases the safety of the equipment. Consumption patterns are constantly changing, not to mention the possibility that the water pool and pipeline transportation on the mountain are not absolutely free of failures. With the development of science and technology, the reliability of equipment will be further improved

the installation of roof fire water tanks is not a big problem for large high-rise buildings, but there are objections to small high-rise residential complexes. It is obviously not safe to set one fire zone at a time. There is no regulation on the number of fires in the "high standard" and the "construction standard" stipulates that no more than 25000 people will catch fire once and no more than 50000 people will catch fire twice. According to the current average per capita area of 25000 people, the residential area is at least 500000 m2; According to the high plot ratio, the residential area also needs 280000 m2, with a radius of more than 200 m. Even if the roof fire water tank is in the center, the pipeline resistance is considerable. If every small high-rise building is equipped with fire water tanks, this method is too primitive and expensive. On the contrary, reliable domestic and fire hydrant water supply combined with variable-frequency water supply system does not have this disadvantage

since the real estate industry entered the market mechanism, it has put forward higher requirements for the beauty and practicality of houses, and many new buildings have emerged. It has put forward one or another opinions on the traditional fire-fighting schemes. It is important to formulate appropriate fire-fighting specifications. Whether we can adopt more economical schemes on the premise of ensuring safety is expected to continue to improve the relevant fire-fighting design specifications

5 key points of fire hydrant water supply system design for small high-rise residential groups at this stage

before the new specification for fire hydrant water supply system of small high-rise residential groups was produced, in order to ensure the interests of owners and the more reliable fire hydrant water supply system, some alternative methods can be adopted at this stage. The key points of design are as follows:

a the fire hydrant water supply in the single small high-rise building is separated from the domestic water supply system. A solenoid valve is set on the main pipe of domestic water supply. When there is a fire alarm signal, the solenoid valve is closed to prevent the water source from being occupied by the domestic water supply system in case of fire. The reserve of common pool is the sum of domestic water and fire water, and the water volume of variable-frequency water supply device is the sum of the two

b the outdoor domestic water supply of the small high-rise residential complex is combined with the water supply of the fire hydrant, and the variable-frequency water supply pump is selected to share the maximum water volume and the maximum water pressure. The pressure of variable-frequency water pump is adjustable, and two levels of domestic water supply pressure and fire hydrant water supply pressure are set respectively. The fire hydrant water supply pressure is interlocked with the fire hydrant, and the fire signal automatically changes the setting of variable-frequency water supply pressure in case of fire

c two water inlet pipes are set between the fire hydrant water supply system in the small high-rise unit and the outdoor water supply main pipe. In addition to the gate valve, each water inlet pipe is equipped with a check valve or pipe backflow preventer. The check valve is close to the indoor end of the fire pump adapter to prevent the water supply system from being polluted

6 conclusion

a relevant fire protection specifications should study targeted provisions for the design of fire hydrant system in small high-rise residential complexes

b the definition of water fire protection normal high pressure system in the fire protection code should allow the use of modern scientific measures to maintain the normal high pressure of water supply according to the development of science and technology and engineering practice

c new breakthroughs should be made in the design of fire hydrant water supply system of small high-rise residential buildings. (end)