With the continuous progress of the living environment of residential communities, the design of water supply and drainage in small areas should also face the future, be based on the residents, reflect the technological level of the times, reflect humanistic care, reflect the harmonious coexistence of man and nature and society, reflect the design concept of environmental protection, water conservation and energy saving, and achieve the goal of sustainable development. If we can take effective measures and adopt different countermeasures and technologies for different functions of the building, we can save a lot of energy and water consumption, which is a great thing for the benefit of the country and the people.

　　Overview of green residential building water supply and drainage design

　　Green residential building water supply and drainage design mainly includes three aspects: first is to improve the water efficiency of the living space, mainly including the water supply operation according to the different water quality needed for living and working, such as the living space is mainly divided into domestic water supply, drinking water supply, greening and landscape water supply and so on.

There is also the need to do a good job of water recycling system, especially in some public spaces inside the hand-washing sink using induction water system and slow-closing valve and some new water-saving equipment or water-saving system; etc.

In the construction of the required water technology or some water-saving equipment, we should pay attention to the reuse of water resources, as far as possible to achieve multiple uses of water, the key is to strengthen the management of construction water in the construction process, to be able to measure the amount of construction water in construction, but in many construction sites, the abuse of water resources or no reasonable arrangement of water still exists.

Second is to do a good job in the construction process of rainwater and construction sewage and the correct treatment and discharge work, in order to maximize the use of rainwater and the residual value of waste water, we must do a good job of rainwater, sewage and waste water discharge separately, so as to facilitate the recycling of rainwater, but also to better treatment of sewage.

　　Analysis of drainage pipe laying and material selection

　　(A) strengthen the bathroom drainage pipe set

　　Bathroom floor slab sinking, sewage cross-pipe set in the sinking room. This way is more convenient for the construction of drainage pipes, but it is very difficult to repair the pipes. In the actual engineering process, it often happens that leakage occurs in the floor and side walls of the lower floor tenants against the bathroom.

Because of the inability to find out the cause of the leak, the upper floor occupants can only cut open the entire bathroom floor refurbishment, chiseled open only to find the sunken room full of water, water seepage through the side wall into the lower level. The bathroom uses a back outlet toilet, side drainage floor drain, bath or shower padding, each sanitary appliance drainage horizontal branch pipe along the bathroom floor at the foot of the wall to the external wall. Ware storage bend, drainage cross pipe and standpipe are set at the exterior wall of the building. Using this method, can avoid the situation of sinking water, but should pay attention to several points.

First, as far as possible, the sanitary ware, especially the toilet is set up against the external wall.

Secondly, because the drainage pipes and risers are set in the external wall, inevitably affect the appearance of the building, so in the design phase of the building program, drainage professionals should intervene to arrange the bathroom in the building recess to minimize the negative impact on the building façade.

　　(B) Material selection of drainage pipes

　　According to the regulations of the Ministry of Construction, UPVC plastic drainage pipes are currently used in new multi-story residential buildings, and the types of indoor UPVC drainage pipes are ordinary UPVC solid-wall pipes, UPVC core foam pipes (PSP pipes) and UPVC spiral silencer pipes.

Ordinary UPVC solid wall pipe is noisy, while the same wall thickness of UPVC core layer foam drainage pipe is about 20%-30% lighter than UPVC solid wall pipe, while it has the effect of heat insulation and sound insulation, especially suitable for building drainage, can significantly reduce the noise of running water, the trend of replacing the UPVC solid wall drainage pipe. Compared with other drainage pipes of the same diameter, the drainage capacity is greatly improved.

　　Energy-saving measures for the design of water supply and drainage engineering of green residential buildings

　　(A) choose the most reasonable way of hot water circulation

　　There are many reasons for the loss of hot water dry pipe circulation, such as improper construction methods or poor management or even the design of the building water supply and drainage engineering itself has problems.

And in the engineering design stage, the choice of what kind of hot water circulation mode, will directly affect the size of the loss caused by ineffective cold water. At present, China’s hot water circulation mainly includes three ways: standpipe + dry pipe circulation, branch + standpipe + dry pipe circulation and dry pipe circulation three, through observation and analysis can be concluded that the branch, standpipe, dry pipe circulation way of hot water circulation waste the least amount of water, but the cost is relatively high, dry pipe circulation caused by the most serious loss of water resources, standpipe, dry pipe circulation way is in Between the two.

In the actual operation, for the overall economic efficiency and cost constraints, it is impossible to make all the hot water supply systems adopt the design of branch, standpipe and dry pipe circulation. For hot water supply, the choice of standpipe, dry pipe circulation also has a very obvious effect on the conservation of water resources, and relatively easy to do.

　　(B) strict control of overpressure water flow

　　In order to effectively use water resources, the maximum control and reduce the loss caused by invisible water resources, the most direct and effective way is to reasonably control the pressure of the system distribution point.

First of all, scientific zoning, different areas, the most appropriate hydrostatic pressure by the nature of materials, equipment performance, management and maintenance and building layers and external water supply pressure and other different conditions and different, should be a combination of these different factors for high-rise building water supply system zoning, which is also the country’s relevant existing norms clearly specified.

For example, the hydrostatic pressure at the lowest water distribution point in the vertical partition of residential buildings and hotels should be kept at 300–350kpa, while office buildings should be kept at 350–450kpa.

Secondly, the tank water supply as the main water supply method, the advantage of the tank water supply is not only can provide water supply when there is no water supply capacity in the municipal network, and the water pressure is relatively balanced, which is conducive to the conservation of water resources.

Finally, the installation of pressure-reducing devices before the household pipe position and water meter, in general, the water pressure standard of the water outlet parts of the bath tub is 6-10M, while the water pressure of the parts in other locations can not be higher than 6M, so when the household water pressure reaches 10M and the minimum water pressure at 6M will be able to reach the residents’ use standards.

　　conclusion

　　With the development of society, countries around the world are paying more and more attention to building energy and water conservation. Green building has become an inevitable trend in the development of architecture, and the concept of green building design will become the mainstream of future architectural design. The design of water supply and drainage engineering has great potential for water conservation and energy saving in buildings.

While meeting the water demand of users, the full consideration of water resources and energy saving is a subject that must be fully understood and given sufficient attention in the design of water supply and drainage engineering.