【正文】 ter Supply and Drainage in Building Qi Junfeng1,*, Yang Yanyan2, Hu Linpeng3 1. School of Municipal and Environmental Engineering, Jilin Institute of Architecture and Civil Engineering, Changchun, 2. Department of Thermal Energy Engineering, Collage of Automobile Engineering, JiLin University, Changchun, 3. Yatai Real Estate Development Co., Ltd. Changchun, Changchun, Abstract—According to the present situation of building water supply and drainage, analyzing the watersaving techniques of building water supply and drainage to achieve effective utilization of water resource. The watersaving techniques mainly include reasonably limiting the pressure of water distribution points and avoiding overpressure flow。 and improving the current construction of fire pool as well as developing and promoting the technology of utilization of reclaimed water and rainwater. Key wordsbuilding water supply and drainage。Although the code makes certain restrictive provision for the maximum pressure of water supply fittings and service pipe, this is considered from preventing the damage caused by high pressure of water supply fittings not from the angle of preventing overpressure flow. An experimental result of a watersaving tap shows that the maximum flow rate is L/s when tap fully open, the corresponding dynamic pressure is MPa and hydrostatic pressure is MPa. According to the rated flow q = 0. 15 L/s which is regarded as the standard, the flow rate when watersaving tap fully open is 3 times of the rated flow. In another measured survey for 67 taps, there were 47 taps which exceeded the rated flow [2]. The overlimit ratio reaches 61%. Therefore, the problem of overpressure flow in water supply system is serious and following measures should be adopted. A. Reasonably determine the pressure of water supply The pressure of water supply subarea should be acted according to Code for Design of Building of Water Supply and Drainage, while the best use hydraulic pressure of sanitary wares is between MPa and MPa, most of them are in overpressure flow. In recent years, branch pipe depression was widely used in projects, which became an important measure for watersaving. In the lower part of water supply subarea, the hydrostatic pressure of water supply after depression should take low value as possible on the condition that it satisfies the demand of rated flow of sanitary wares’ water supply fittings. It is suggested that, in higher part of water supply subarea, depression measures should be taken when the lowest hydrostatic pressure of sanitary wares’ water distribution points is more than MPa. B. Adopt depression measures Properly allocating relief fitting in water supply system means that hydraulic pressure should be limited within limiting value and reduce the threat of overpressure flow. 2020 International Conference on Digital Manufacturing amp。s living standard and improved building functions, building hot water system gradually bee a indispensable part of building water supply system. According to the survey, most central hot water supply system exist serious wasteful phenomenon, which is mainly embodied in we can not obtain satisfactory hot water in time after opening hot water apparatus, but let out some cold water to normal use. The present Code for Design of Building of Water Supply and Drainage puts forward three methods of hot water circulation, which include branch pipe circulation, stand pipe circulation and main pipe circulation. Loop free hot water system can be used in miniature hot water supply systems, such as bath centre in factory which provide timelimit hot water supply. Take the case of a 12storey apartment in Beijing, when adopted branch pipe circulation, stand pipe circulation and main