Several problems in water supply and drainage design of multi-storey residential buildings.

Multi-storey residential buildings are very popular with real estate developers and residents in small and medium-sized cities because of their simple supporting facilities, low cost and convenient property management. It is the responsibility of every designer to improve the design level of well-off housing and create a comfortable living space for every household according to the requirements of "Guidelines for Planning and Design of Residential Areas in Science and Technology Industry Engineering" in 2000. As the heart of the house-kitchen and bathroom, it is a space with complex functions, high requirements for hygiene, safety and comfort, complex creation and high technical requirements. Therefore, designers must consider the installation of water supply and drainage pipes and equipment in kitchens and bathrooms with the concept and method of overall design. The following is a discussion with colleagues on the selection of water supply pipes, the laying of pipes, the setting of water meters, the setting of household water heaters and the discharge of condensed water from air conditioners in the water supply and drainage design of multi-storey houses.

(a) Selection of water supply pipes

The traditional water supply pipe generally adopts galvanized steel pipe. Because galvanized steel pipe is easy to corrode, its service life is short, and it can't meet the sanitary standard of domestic water, the Ministry of Construction is vigorously promoting the application of plastic water supply pipes. Many cities expressly prohibit the design and use of galvanized steel pipes and promote the use of plastic water supply pipes. Compared with metal pipes, plastic water supply pipes have the advantages of light weight, good compressive strength, low resistance to liquid transportation, strong chemical corrosion resistance, convenient installation, steel and energy saving, and long service life. Plastic pipes for water supply mainly include: rigid polyvinyl chloride (PVC-U), high density polyethylene (HDPE), crosslinked polyethylene (PEX), modified polypropylene (PP-R, PP-C), polybutylene (PB), aluminum-plastic composite pipes (PE-AL-PE, PEX-AL-PEX) and steel-plastic composite pipes. The following table is the performance comparison of several building water supply pipes.

Advantages and disadvantages of pipe performance Long-term use temperature Short-term use temperature Hard polyvinyl chloride pipe (UPVC-U) has strong corrosion resistance, hard texture, easy construction, high requirements for pipe joint bonding technology, long curing time ≤400℃ Modified polypropylene (EN-US)PP-R, PP-C) has good temperature resistance and creep resistance, simple construction, and is only connected by metal pipe fittings; The local head loss of water flow is large, so it cannot be recycled. 900C950C aluminum-plastic composite pipe (PEX-PEX) has good temperature resistance and thermal insulation (EN-US). Under the same pressure and medium temperature, the pipe wall is the thickest and is connected by hot melt. Need a special connecting tool ≤600C≤900C Aluminum-plastic Composite Pipe (PE-AL-PE) is easy to bend and shape to completely extinguish oxygen.

1) Long-term service temperature means that the service life of the pipeline reaches 30 ~ 50 years within this temperature range.

2) Short-term service temperature means that the service life of the pipeline reaches 10 ~ 20 years within this temperature range.

The selection of pipe is an economic and technical comparison process, which should be determined from the aspects of pressure, temperature, use environment and installation mode, combined with the requirements of the owner and the grade of the house, after comprehensive consideration of economy and technology. The plastic water supply pipe can be used as a residential water supply pipe. Affordable housing and poverty-stricken housing are mainly for low-and middle-income residents, and sanitary PVC-U can be used as water supply pipe to reduce costs. Middle and high-grade commercial houses can use aluminum-plastic composite pipes (PE-AL-PE, PEX-AL-PEX) or other plastic water supply pipes as water supply pipes. The temperature of hot water at residential water distribution points does not exceed 600C, so most of the above pipes can be used as hot water pipes for residential buildings except rigid PVC-U and PE-AL-PE.

(2) Pipeline laying problem

1. Water supply and drainage riser laying generally has the following ways.

1) installed in the corner of the kitchen and bathroom. In the past, this paving method was widely used in residential design to facilitate construction, but the exposed pipes hindered the beauty of the room, and most residents would use light materials to hide it in the secondary decoration.

2) Installed at the internal corner of the external wall of the building. This method is only suitable for warmer weather areas in the south, and the lowest temperature in winter should not be lower than zero degrees Celsius, so as to avoid the water in the water pipe freezing into ice and bursting, which will affect the use of households. Laying pipelines on the external wall will not only affect the beauty of the building, but also be inconvenient for future management and maintenance.

3) Laying in the pipeline well. This way makes the living room clean and beautiful, but the pipe well occupies the area of the bathroom, so it is difficult to construct and maintain the pipe. It is an important embodiment of the living civilization of kitchen and bathroom in a well-off residence to set up a centralized pipe well in the bathroom and arrange water supply pipes and drainage pipes in it. In my opinion, the setting of toilet tube well should be considered in the architectural design of middle and high-grade commercial housing, which can not only improve the use quality of bathroom, but also solve the problem of loud water noise of rigid PVC drainage pipe and improve the environmental quality level of living room. For affordable housing and poverty-stricken housing with small bathroom area, water supply and drainage risers can be laid on the outer walls of warmer areas in the south to increase the use space of bathrooms; When the pipeline is installed indoors, it should not affect the use of various sanitary facilities in the kitchen and bathroom.

2. Water supply branch pipe laying

The diameter of residential water supply branch pipe is ≤ 32 mm, and the small-diameter plastic water supply pipe is in a bending state, so the introduction of residential water supply branch pipe adopts hidden design. Concealed ways of water supply branch pipe are as follows:

1) is hidden in a brick wall. During the construction, a trench is opened on the brick wall, with a width of 20 mm and a depth of de. The pipe is directly embedded in the pipe groove and fixed in the pipe groove with a pipe clamp.

2) For the small-caliber water supply branch pipe with de≤20mm, it can be hidden in the leveling layer of the floor (ground). During construction, pipe grooves are opened on the floor (floor) with a width of de 10mm and a depth of DE 1/2DE. The pipeline is semi-buried in the pipe groove and fixed in the pipe groove with a pipe clamp. Pipes such as aluminum-plastic composite pipe and cross-linked polypropylene pipe are connected by hardware fittings, so the size of pipe groove must be increased when concealed, and the local head loss of water flow is large. For houses with relatively concentrated kitchen and bathroom sanitary wares, water separators can be used for connection. The water separator is a plurality of pipe joints, and the water supply branch pipes of sanitary ware are respectively connected from the water separator. This can not only avoid the leakage problem of buried pipeline joints. It can also reduce local head loss and reduce the cost of pipe network.

3) Drainage branch pipe laying

Indoor horizontal drainage pipes should be located in this floor, so as to prevent pollutants such as sewage from entering neighboring households when the horizontal drainage pipes penetrate, and the normal life of neighboring households will not be affected when the pipes are maintained.

Generally, the horizontal drainage branch pipe of the kitchen washbasin is connected to the drainage riser on the floor surface of this floor; The floor drain branch pipe must be laid with the lower space. Now many colleagues think that the kitchen floor is paved with tiles, so it doesn't need to be washed when it is clean. It is not meaningful to set up a floor drain, so there is no need to set up a floor drain in the kitchen, which not only prevents the horizontal drainage pipe from entering the adjacent households, but also increases the use space of the kitchen. The concrete methods of horizontal branch pipes for toilet drainage in this floor are as follows:

1) Raise the toilet floor. Ground potential 150mm, using the back toilet. The horizontal drainage pipes of washbasin, bathtub and floor drain are buried in the cushion.

2) Adopt sunken toilet. The ground of the toilet floor sinks by 350mm, and the horizontal drainage pipe of sanitary ware is buried in the sinking space.

These two methods can realize that the horizontal drainage branch pipe of the bathroom is buried in the ground of this floor and does not enter the adjacent households. When installing buried pipelines, the construction quality must be strictly controlled, and the toilet floor construction can only be carried out after the acceptance, so as to avoid leaving hidden dangers for future use. The ground construction of the toilet can be filled with light materials such as fly ash, and it can also be constructed by laying bricks or planks overhead. The floor must be waterproof, and the practice can refer to the roof waterproof treatment, such as making two oils and one cloth rubber ointment waterproof.

(3) Outdoor installation of water meters

The water meter is located indoors, which not only has a large workload of meter reading, but also greatly reduces the safety and privacy of the house. Therefore, the domestic water meter or the digital display of the domestic water meter should be located outdoors. The outdoor setting of multi-storey residential water meters has the following forms:

1. Use remote water meter.

Replace the common water meter with a remote water meter, connect the water meter with a data collector with a signal line, and then transmit it to the intelligent management (microcomputer). Its advantage is that meter reading saves a lot of manpower and accurate data, but its disadvantage is high cost.

2. Use a magnetic card water meter.

Users buy the electronic card of the water company in advance, and then insert it into the memory of the water meter. When using water, the amount on the card will be deducted automatically. In this way, users need to pay the water fee in advance, and the water meter price is higher.

3. Ordinary water meters are used outdoors.

1) The water meter is located in the niche of the stair rest platform. The domestic water supply branch pipe enters the kitchen and bathroom after being metered by the water meter. In this way, the water meter is installed outside the house, and the engineering equivalent is low, but the water supply riser and water meter are located at the stairs, which affects the appearance. Suitable for houses with kitchens and bathrooms arranged near stairwells in warmer areas in the south.

2) Water meters are centrally arranged in the water meter room (water meter box). When downward and upward water supply is adopted, a water meter room (water meter box) is set on the ground floor, and the water supply branch pipes of each layer are laid in the pipeline well, and the southern area can also be laid along the external wall at the internal corner of the building; When supplying water from top to bottom, a water meter room (water meter box) can be set on the roof. This increases the laying length of the water supply branch pipe, and the laying of the pipe along the external wall affects the beauty of the building. The mode selection of outdoor layout of water meters must be determined after economic and technical comparison of the above feasible schemes in combination with the characteristics of residential kitchen and bathroom layout and the specific requirements of developers.

Remote water meter can be used in high-grade commercial housing with perfect property management, which is the development direction of water meter application in the future; High-grade commercial housing in residential areas with imperfect property management can use magnetic card water meters (which can be designed in areas where water companies have such businesses) or centralized water meter rooms (boxes); In order to reduce the cost, the common water meter can be set on the stair rest platform in the southern unit residence.

(d) Installation of domestic water heaters

Residential design should reserve the conditions for installing hot water supply facilities or set up hot water supply facilities. Therefore, in a house without centralized hot water supply, the installation position of domestic water heaters and the layout of cold and hot water pipes should be considered. Household water heaters generally include gas, electricity and solar energy. Gas water heaters and electric water heaters are generally installed in kitchens or bathrooms. In the design of building water supply and drainage, the installation position of water heater and the interface of hot and cold water pipes should be reserved for users to install themselves during decoration. Solar water heater is simple and safe to use, does not need fuel and electricity, has low operating cost, long service life and no pollution, and is well received by users. In recent years, solar water heaters have been installed in the design and construction of many residential quarters.

Solar water heaters are generally installed on the roof, so it is necessary to set up cold and hot water pipes between the bathroom and the roof water heater. If solar water heater is not considered in residential design, residents can only lay cold and hot pipes along the external wall of the building in the future, which not only increases the difficulty of installation, but also increases the investment in pipes and affects the beauty of the building. Therefore, in the design of building water supply and drainage, we must first seek the opinions of developers, whether to design and build solar water heaters in a unified way; Or only the installation positions of solar water heaters and hot and cold water pipes are reserved. The hot and cold water pipes of the solar water heater can be laid in the tube well; For houses without tube wells, UPVC drain pipes of de 1 10 can be added in the corner of the bathroom near the shower room as the casing of hot water pipes of solar water heaters, and tee joints of de 1 10×75 can be set on the floor of each household sanitary space 1m as the entrance of hot and cold water pipes.

(E) Air conditioning condensate discharge problem

In recent years, air conditioning has gradually entered thousands of households, and the unorganized discharge of condensed water from air conditioning pollutes the external walls of buildings, which has become an important problem affecting the beauty of residential areas. The organized discharge of air conditioning condensate should be considered in the design of building water supply and drainage. Specifically, a condensate drain pipe can be set beside the outdoor unit of the reserved air conditioner, and the drainage riser adopts PVC-U drain pipe de40. The drainage tee is reserved at the height of each air conditioner to facilitate the direct connection of the air conditioner drainage hose.

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