Discussion on water supply and drainage engineering design of high-rise building
This paper introduces the design of water supply system, drainage system, indoor fire fighting and hot water system of high-rise building in detail, summarizes the problems existing in water supply and drainage of high-rise building at present, and probes into the water-saving measures of water supply and drainage, so as to ensure the rational utilization of water resources.
Keywords: building water supply and drainage; High-rise building; Design; Water saving measures
1, design method of water supply and drainage engineering for high-rise buildings
Compared with common multi-storey buildings and low-rise buildings, the water supply and drainage engineering of high-rise buildings has the same basic theory and calculation method, but high-rise buildings have many floors, large height and complex structure. In recent years, the design method of building water supply engineering has been improved.
Example: design water supply and drainage for a high-rise building 15 floor;
The residential building is a *** 15-story frame structure with a height of 2.9m The outdoor water supply pipe network is located on the north side of the building, away from the external wall 10m, with the buried depth of the connection point 1.6m and the pipe diameter of 400 mm. The pipe is ductile iron water supply pipe, which provides a water head of 0.3MPa all the year round. Indoor fecal sewage can only be discharged into the municipal pipe network after being treated by septic tanks. Outdoor drainage pipe network is located on the south side of the building, with a buried depth of 2m and a pipe diameter of 600 mm. The pipes are polyethylene double-wall corrugated drainage plastic pipes.
1. 1 design parameters
Domestic water quota: qd= 150L/ (person. d)； Maximum hourly domestic water consumption: Qh=4.92m? /h； Maximum daily water consumption: Qd=47.25m? /d； Hourly variation coefficient: kh = 2.5 population per household: m=3.5 people; ***90 households; Indoor fire water consumption:10l/s; 10 minute The water volume of the fire water tank is 6m before the fire? ; Fire fighting water quantity of storage tank: calculated according to the water quantity that the fire lasts for 2 hours; Rainwater return period: 2 years.
1.2 design content
1.2. 1 water supply system design
The pipeline is connected with steel-plastic composite pipe (lined with plastic and galvanized outside) by thread, and the main pipe, riser and branch pipe are installed. After the pipeline installation is completed, the water pressure test shall be carried out, and the pressure shall be set to 1.0MPa. The installed pipeline shall be well protected against corrosion and heat preservation, and the pipeline shall be flushed for water pressure test.
According to the Design Manual of Water Supply and Drainage for Buildings, the maximum hydrostatic pressure of sanitary ware should not exceed 0.35MPa, so the water supply system of high-rise buildings must be partitioned. The design task book gives that the water pressure provided by the municipal water supply network is 0.3MPa all the year round. According to the estimation method of the minimum required water supply pressure, 1 layer is 0. 10MPa, the second layer is 0. 12MPa, and it needs to be increased by 0.04MPa for more than two layers. The pressure of 0.30MPa can be directly supplied to the sixth floor, which is 0.02MPa more. So 1 ~ 6 layer is an area, and the upper 7 ~ 15 layer is an area, so there are two areas in total. 1 ~ 6 floors are directly supplied with water by the municipal pipe network, and the bottom floor and 2 ~ 6 floors are separately provided with pipes.
Considering that the design object is a high-rise building with 15 floors. The pressure provided by municipal pipe network cannot directly supply water, so domestic water must be upgraded or pressurized. High-rise building design generally uses high-level water tank for water supply, and the water supply pressure is relatively stable. This design also uses a high-level water tank. Therefore, this design is oriented to high-rise civil residential buildings. According to the layout of the building, the bearing capacity of the floors and the fact that the water tank itself occupies a large building area, that is, there is no building area in the middle of the floor to allow the water tank to be placed, so it is impossible to supply water in series. Therefore, the high water supply should be lifted to the water tank on the ground by water pump.
Compared with scheme (2), scheme (1) has relatively less pipeline consumption and engineering investment, but relatively higher quality requirements for pressure reducing valves. Once the pressure reducing valve is damaged or its performance is reduced, the hydrostatic pressure in the low area will rise rapidly, which will affect the use of sanitary ware. Scheme (2) adopts direct water supply from municipal pipe network in low area, which eliminates the phenomenon of reducing hydrostatic pressure by pressure reducing valve to reduce water supply in low area. Based on the engineering quality and the reliability of water supply quality and water pressure, the scheme (2) is finally selected.
1.2.2 drainage system design
The indoor drainage system is a sewage and wastewater confluence system. The aboveground part is directly discharged to the outside, and the underground part is provided with a sump to collect sewage and wastewater from the basement. The submersible pump is automatically controlled by the sump, and it is lifted to the outside. In order to protect the water seal performance of the trap, keep the air pressure in the drainage system in balance with the atmospheric pressure, make the drainage in the drainage pipeline smooth, introduce fresh air into the drainage pipeline, keep the ventilation in the pipeline, and prevent the harmful gas accumulated in the outdoor pipeline system from hurting maintenance personnel and causing fire and pipeline corrosion. And also reduce the noise of the drainage system, and set up ventilation pipes in the drainage system.
1.2.3 indoor fire fighting project
Indoor hydrant water supply system has two ways: zoning and non-zoning. When the hydrostatic pressure of fire hydrant exceeds 0.80MPa, it is necessary to supply water in different zones. However, this design is a small high-rise building with 15 floors, with a height of less than 50m and a hydrostatic pressure of less than 0.80MPa, without zoning. At the same time, this design building is a small high-rise residential building with 15 floors, with few fire hazards, quick evacuation and little difficulty in fighting, and there is no need to set up high-pressure fire water supply all year round. A special fire pump is set up to extract fire water from the storage tank. In the early stage of fire, the domestic water supply tank can be used to supply water in advance 10min, and a check valve is set up, which not only eliminates the floor load of the fire water tank, but also reduces the project investment. This design is a small high-rise building with 15 floors, 2.9m high, and the total height of the building is no more than 45m. According to the design manual of building water supply and drainage! It is stipulated that the maximum hydrostatic pressure of fire hydrant should not exceed 0.8MPa. This design does not need fire water supply in different regions, and fire pump can be used to directly supply water to meet the requirements.
1.2.4 Indoor hot water engineering
Technical and economic comparison should be made according to building use, heat source supply, hot water consumption and sanitary ware layout to determine which hot water supply mode. There are the following types of hot water supply. According to the scope of supply, there are: central heating, local heating and regional heating.
2. Problems existing in current building water supply and drainage.
2. 1 Control the waste of water generated by overpressure outflow.
After the domestic water supply system is vertically partitioned according to the regulations, there is still the problem of high water pressure at some water distribution points of sanitary ware, which is often ignored. The rated flow of sanitary ware is less than the water output per unit time, which affects the normal water distribution of water supply system. If the pressure reduction and throttling measures are not taken, it will lead to the waste of water resources, high water pressure, increased water leakage and other disadvantages, and it is easy to produce water hammer, noise and vibration, resulting in the damage and rupture of pipe fittings. The waste of this water cannot be ignored.
2.2 damage to pipes and valves
We can see that there are water leaks in the roadside water supply pipeline at the joint of the pipeline and the joint between the flange and the valve, but we don't know how many water leaks are underground. The pipeline is damaged and corroded, and the valve is not strict, which leads to a lot of water loss.
2.3 The hot water system wastes a lot of water.
Building hot water supply has become an important part of building water supply. Due to improper design, its waste has been very serious, causing certain losses. Therefore, the pressure of cold and hot water should be balanced in the water supply system, and the circulation system should be adopted to ensure that every household has hot water when turning on the faucet and reduce the waste of water.
3. Water-saving measures for building water supply and drainage in China
3. 1 Improve water use efficiency
1) Strictly implement the domestic water quota standard, and supply drinking water, domestic water, landscape water and greening water respectively according to the water quality requirements.
2) Adopt water-saving system, such as water-saving sanitary ware, water head for limiting the outlet of sanitary ware, infrared sensing faucet, toilet, etc.
3) Choose renewable energy sources, such as wind energy, solar energy, hydro energy, ocean energy, geothermal energy, bioenergy and other non-fossil energy sources for hot water supply of buildings. Different heat sources are used in different occasions.
3.2 Utilization of rainwater
The rainwater collection system is used to recover qualified water quality for greening irrigation, and the treated rainwater can also be used to flush toilets, which not only reduces water consumption, but also reduces pollution. Improve the water retention capacity of foundation, rationally plan the rainwater flow path, and introduce rainwater sedimentation tank for reuse.
3.3 Sewage Discharge and Secondary Utilization
Building water system is a typical device for sustainable utilization of resources. It collects and treats sewage and wastewater generated by buildings, and reuses domestic sewage and wastewater on the basis of saving resources and protecting the environment.
3.4 Water saving indicators
There are three types of water-saving indicators:
1) Rainwater utilization rate: annual rainfall divided by usage or collection;
2) Water utilization rate: normal consumption divided by consumption;
3) Circulation quantity: one-time consumption multiplied by circulation times.
4. Conclusion
In the design of water supply and drainage, the system and scheme should be selected correctly and reasonably to achieve the purpose of saving water and energy and ensure the rational utilization of water resources.
References:
[1] Sun Zhikui. New exploration on the application of new energy-saving technologies in water supply and drainage of green buildings in China. China new technology and new products, 20 12 (1): 45.
[2] Yang Tianfeng, Zhang Wang. Study on energy saving of building water supply and drainage in low-carbon economy. Science and Technology Entrepreneurship Monthly, 20 10/0,23 (9):161-162.
[3] Zhao Peilin. On water saving design of green residential buildings. Development and Innovation of Mechanical and Electrical Products, 2009,22 (3): 40-41.
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Analysis of water supply and drainage construction technology of building engineering
Combined with practical work experience, the author analyzes the construction technology of water supply and drainage in building engineering, and puts forward his own opinions.
Keywords: construction engineering; Water supply and drainage; construction technique
With the continuous development of modern building technology in China, people put forward higher and higher requirements for building water supply and drainage engineering. In the design and construction, we should constantly accumulate experience, deeply analyze various common problems, and promote the development of water supply and drainage construction technology.
1 building water supply pipeline construction
1. 1 Type and selection of water supply pipeline materials
At present, the water supply pipes used in many new buildings mainly include polypropylene, polyethylene, polybutene, engineering plastics, and some composite pipes, such as steel-plastic pipes, aluminum-plastic pipes and copper-plastic composite pipes. Although there are many kinds of materials to choose from, in every specific construction project, we must choose according to the actual situation. Moreover, the selection of pipes is also influenced by many factors, and it is necessary to comprehensively consider national policies, construction standards, regional characteristics, engineering properties and construction standards to select the best pipes. It should also be noted that the use position and method of pipes need to be considered when selecting pipes, and pipe fittings and connections are also key issues that are easily overlooked when selecting pipes.
1.2 water supply pipeline construction
When hot-melt connecting water supply pipes, it is necessary to master the heating time and the depth of connection insertion. If the heating time is too long, the water pipe will melt, and if the heating time is too short, it will not be better connected; If it is inserted too deep, the cross section of the pipeline will be reduced; If the insertion is too shallow, it will also reduce the strength at the interface. Therefore, the temperature, heating time and joint pressure during heating are three key factors affecting the quality of hot-melt connection.
2 Analysis of the causes of common problems in building drainage pipes
The common problems of drainage pipes are water leakage and blockage. There are many reasons for these problems. First, there is something wrong with the construction. Most of the construction units did not choose qualified pipes for temporary economic benefits, shoddy them, or did not conduct water leakage experiments before installation, or used some unqualified materials in the project, resulting in water leakage. For example, it is common to set the casing through the wall (floor). Although some sleeves are added, they pass through the floor flush with the floor or embedded in the floor, and some pass through the wall, which is 20-50mm more than the facing. Some casings are not set or embedded, and covered (glued) with cement ring (floor) and plastic ring (wall) to hide people's eyes and ears. Some casings are only one size larger than pipes, and some are three to five sizes larger. The gap between casings and pipes is blocked with foam and oil hemp. The top of the sleeve installed in the floor should be 20mm higher than the decorative floor, and the top of the sleeve installed in the bathroom and kitchen should be 50mm higher than the decorative floor, and the bottom should be flush with the bottom of the floor. The end of the sleeve installed in the wall should be flush with the decorative surface. The gap between the casing and the pipeline passing through the floor shall be filled with flame-retardant dense materials and waterproof ointment. The end face is smooth. The gap between the wall bushing and the pipeline should be filled with flame retardant dense material, and the end face should be smooth. The interface of the pipeline should not be set in the casing? . Second, there is something wrong with the design, which makes the pipeline easy to block after installation; Third, there is a problem when residents use it.
3 characteristics of building water supply and drainage construction
3. 1 Characteristics of pipeline installation
In recent years, PP-R pipe and UPVC pipe are mostly used as water supply pipes. Because these two kinds of pipes have the characteristics of portability, high pressure resistance, corrosion resistance, quality safety, hygiene, low water resistance and long service life, the most obvious feature in installation is convenient installation. For the installation of PP-R pipe, the dust attached to the pipe should be removed before connection, and the installation should be carried out in strict accordance with the construction procedures. However, it should be noted that the pipe must not be rotated during hot melting to avoid overheating, and certain measures should be taken to cool the pipe after connection. For the installation of UPVC pipes, drainage glue must be used for bonding. After gluing, pay attention to the drying time of glue. The specific time should be adjusted according to the change of local climate and temperature, and be careful not to get wet. If it is installed in a place with large environmental temperature difference, it is necessary to use a pipe expansion joint.
3.2 Water supply and drainage pipeline pressure test
After all pipelines are installed, all components shall be comprehensively tested, mainly including whether the installed pipelines, valves and other equipment meet the design and technical requirements. If there are any problems, they shall be removed immediately for replacement or maintenance. The specific method of detection is to replace the installed pipeline with a temporary short pipe, close all the openings, start pouring water from the lowest part of the pipeline, and deflate at the highest part. If there is any abnormality, stop the test in time and drain the water immediately. After the pressure test is completed, all pipelines shall be purged.
4 concrete measures to improve the construction technology of building water supply and drainage
With the development of building technology and the continuous improvement of production technology, the requirements for the design, construction, maintenance and operation management of water supply and drainage projects are getting higher and higher. In order to make the pipe network run with high quality, high efficiency and low energy consumption, besides the reasonable design scheme, the installation quality of water supply and drainage system also has a great influence on its future use.
4. 1 pipeline construction measures
For pipeline construction, it is mainly to pay attention to heating time, heating temperature and joint pressure. Steel-plastic composite pipe is widely used in construction, and its construction should adopt the method of threaded connection, and the length of inserted pipe should be strictly controlled according to the standard rotation depth. After processing the pipe ends and pipe threads, sealing is required. At this time, PTFE raw materials are needed to bring winding wires. In the construction, it is necessary to choose the pipe joint sealed by anaerobic sealant, and the pressure test must be carried out after curing for 24 hours. Special construction machines and tools should be used in the construction, and they should not be replaced casually.
Construction method of 4.2 W type cast iron pipe
Regarding the concrete construction measures of W-shaped cast iron pipe, the first step is blanking, and special tools should be selected when cutting the pipe, mainly to ensure the straightness of the nozzle. The second step is to connect. When connecting, first loosen the clamp, then take out the rubber ring in the lining, put the ferrule and rubber ring on one side of the inlet nozzle, align the nozzle, then put the rubber ring on the interface, and finally lock the ferrule and tighten the screws to complete the pipeline connection. The third step is the setting of low bracket. For general pipeline installation, it is actually possible to set a bracket every 3m, but not for W-type cast iron drainage pipe joint without socket mechanism, because it is a flexible joint. When the bracket is placed in the middle of the pipeline, the pipeline can be balanced theoretically, but in practical work, it is difficult to find the center of gravity, and it is often impossible to ensure the smooth joint of the pipeline. If every 1 is used,
4.3 Construction supervision of building water supply and drainage
The design and construction of water supply and drainage pipelines is a very complicated measure, in which the laying and installation of pipelines are prone to problems, so the supervision of pipeline construction is also a very important aspect. Because pipeline construction takes a long time to design many stages of construction projects, supervision can also be divided into multiple stages.
First of all, in the early supervision of engineering construction, we should carefully read the construction drawings before construction, fully understand the designer's design intention and purpose, and ensure that the requirements of the design drawings are not deviated during construction, and the design scheme cannot be changed at will during construction.
Secondly, it is the supervision of the construction stage of the main structure of the foundation. During the construction of the main foundation structure, when the drain pipe and inlet pipe of the drainage system pass through the external wall or underground structure of the building, attention should be paid to whether enough holes and sleeves are reserved according to the design requirements.
Thirdly, it is the supervision of the decoration stage. In the decoration construction stage, it is mainly the installation stage of water supply and drainage pipeline system. Mainly pay attention to the decoration project can not destroy the original pipeline routing settings or destroy the reserved pipelines, and must be combined with the decoration plan after all pipelines are clearly arranged.
5 concluding remarks
With the continuous development of building technology in China, the requirements for the design, construction and operation management of water supply and drainage projects are getting higher and higher. High-quality installation and construction quality and scientific management are the necessary conditions to ensure the efficient and safe operation of the pipe network system. In order to meet the technical requirements of water supply and drainage construction and improve the construction quality, construction workers must constantly learn and improve their own technical quality. Only in this way can the quality of the installation project be guaranteed and the foundation construction of the building installation project be based on.
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