1949 since the establishment of People's Republic of China (PRC), building water supply and drainage has experienced three stages of development: one is the stage of building sanitation technology and equipment, that is, the initial stage, from 1949 to 1964, which was tried out in the Code for Design of Indoor Water Supply and Drainage and Hot Water Supply. Second, the indoor water supply and drainage stage is a reflection stage, from 1964 to 1986 when the Code for Design of Building Water Supply and Drainage was approved. Third, the stage of building water supply and drainage is a development stage, from 1986 to the present.
Since the establishment of 1949 People's Republic of China (PRC), the water supply and drainage of buildings in China has gone through three development stages:
First, the stage of building sanitation technology and equipment is the initial stage, from 1949 to 1964 when the Code for Design of Indoor Water Supply, Drainage and Hot Water Supply was tried out. Its main sign is that water supply and drainage specialty has been set up in China, and housing sanitation technology and equipment has been identified as an independent professional course. The first generation of building water supply and drainage professionals trained by professionals took up their jobs and began to form their own professional teams.
Second, the indoor water supply and drainage stage is a reflection stage, from 1964 to 1986 when the Code for Design of Building Water Supply and Drainage was approved. Its main sign is that through the engineering practice, the mistakes brought by foreign machinery are seriously summarized and reflected, and then the technical system of building water supply and drainage with China characteristics is formed and established.
Third, the stage of building water supply and drainage is a development stage, from 1986 to the present. Since 1986, with the development of construction industry, the specialty of building water supply and drainage has developed rapidly and become an indispensable and unique part of the specialty of water supply and drainage. In the development stage, the professional team already has the design, construction and installation management personnel who have accumulated certain experience and received professional training; In terms of technology, we have accumulated previous practical experience and learned from foreign new technologies, and our professional technology has made obvious breakthroughs and developments, especially the development of fire water supply system in building water supply and drainage. Organizationally, the National Building Water Supply and Drainage Engineering Standards and Technology Committee and the Building Water Supply and Drainage Professional Committee of China Water Supply and Drainage Society were established. In recent years, academic activities have been active and international technical exchanges have been strengthened.
The development status of building water supply and drainage in building water supply, building drainage, hot water supply and building fire protection technology is as follows:
1 About building water supply
1. 1 pressurization facilities
In China's urban water supply, the water supply capacity of some cities is insufficient, and the development speed of urban water plants lags behind residential buildings and public buildings. In addition, the aging of pipelines and the decline of pressure-bearing capacity make many cities not only boost water supply for high-rise buildings, but also meet the requirements of upper water pressure for general multi-storey buildings, which makes secondary pressurization equipment widely used in China, and pressurization facilities have become the largest and fastest-growing equipment in building water supply. The commonly used pressurization facilities in China include water pump, pneumatic water supply equipment and variable frequency speed regulation water supply equipment, and the application of the latter two technologies has become increasingly mature.
1.2 water storage device
The adjustable water storage tank located on the roof is a common water storage device, but due to its shortcomings such as serious secondary pollution, the water tank has been greatly improved in materials and processing, and is developing towards diversification. The new water tank is made of galvanized, enamel, composite steel plate, plastic coating, glass fiber reinforced plastic and stainless steel. The inner surface in contact with water is not easy to rust, and it has no pollution to water quality, thus reducing the structural weight and solving the problem of inconvenient construction. When the material changes, the forming mode and shape of the water tank will also change. Combined water tank and assembled water tank can improve the quality of water tank, which is beneficial to industrial production, shorten the time of on-site construction and installation, and reduce the dead water area of the inner bottom of water tank. Spherical water tank and trough water tank have changed in appearance. Using breathing valve instead of floating ball valve solves the problem of water leakage caused by loose closure of floating ball valve, and at the same time makes the water tank change from gravity water supply to pressure-gravity water supply. Reinforced concrete water storage tank is also a common water storage device, and the bottom and inner wall should be paved with white tiles.
1.3 high-quality water supply
In the process of building a modern living environment and a high-quality living community, people put forward higher requirements for the quality of drinking water. In order to improve the quality of drinking water, small household water purifiers were used to treat drinking water in China at first, and the main way was adsorption and filtration with activated carbon, but it was difficult to control the replacement of filter materials during use. In recent years, the concept of "quality drinking water" has emerged. Refers to the water that can meet the quality standard of direct drinking water, including ultra-pure water, pure water, distilled water, mineral water and advanced treatment water. The source of high-quality drinking water comes from urban tap water or underground mineral water, and its treatment processes include ion exchange, ultrafiltration, membrane filtration, distillation, disinfection and sterilization. Water supply methods include barrel water supply and pipeline branch water supply. Barrel water supply is to set up centralized high-quality water supply stations to send to residents' homes or take them for themselves, which currently accounts for the majority; Shanghai residential district has built a pipeline water supply system with different quality. Ozone oxidation, activated carbon adsorption, fine filtration of pre-coated membrane, micro-electrolysis and ultraviolet sterilization can remove organic substances harmful to human body, especially carcinogenic, teratogenic and mutagenic substances, while retaining minerals and trace elements beneficial to human body in water. High-quality drinking water is sent to every kitchen after purification, and the frequency conversion and constant pressure water supply system is adopted, and the end of the pipeline circulates to ensure the water quality requirements.
1.4 water-saving technology
The lack of water resources in China, coupled with water pollution, has become one of the main factors restricting the economic development of China. In building water supply and drainage, the focus of water saving is to popularize water-saving accessories and waterways in buildings. Water-saving fittings include hydraulic flushing water tank fittings, second-gear flushing toilet fittings, roof water tank counterweight check valve, hydraulic multifunctional valve and water supply sanitary ware fittings, which can have the functions of current limiting, automatic temperature regulation and high temperature limitation. The improved fittings also pay attention to saving water and preventing water leakage. The application of waterway in buildings has become the development trend of building water supply and drainage. Bath drainage and toilet drainage can be used as water sources for flushing toilets, and reclaimed water can also be used for fire fighting, car washing, cleaning and greening, which can save water and alleviate water shortage. The reclaimed water source can be taken from domestic wastewater and cooling water, which can be generally selected in the following order: cooling water → bath drainage → washing drainage → laundry drainage → kitchen drainage → bathroom drainage. Hospital sewage is not easy to be used as renewable water source. In the design of reclaimed water in buildings, sewage and wastewater are reused after biochemical treatment. At present, Beijing has built dozens of reclaimed water projects, including Capital Airport, International Trade Center and Tsinghua Bath. Dalian, Tianjin, Qingdao, Taiyuan, Shenzhen and other cities have also built a series of reclaimed water projects. Some of these cities have explicitly requested sewage reuse to save energy and protect the environment.
2 About building drainage
2. 1 sanitary ware
The improvement of living standard puts forward new requirements for sanitary ware, paying more attention to comfort, reliability, quietness and energy saving. In recent years, the more representative sanitary wares are: hydraulic massage bathtub, which can produce a large number of whirlpool bubbles, and impact the water flow with nozzles, which can achieve healthy and leisure effects; The integrated vortex toilet with low flushing water tank has low noise and good flushing effect, which can save flushing water; High-standard automatic toilet can realize the automation of all processes such as normal use, flushing, cleaning human body and drying; Leisure sanitary appliances, including sauna equipment, steam bath equipment, thermal shock massage equipment and physical function conditioning exercise equipment. Many well-known foreign manufacturers have also entered China to produce various new products.
2.2 Drainage and ventilation technology
The main purpose is to provide the escape of gas in drainage and achieve the function of ventilation; Prevent negative siphon and positive splash of water seal in drainage system to ensure air circulation; Quickly keep the drainage smooth and quiet. In China, five standards have been established that can adapt to different building standards and different requirements, namely, extended ceiling ventilation pipes, non-extended ceiling ventilation pipes, professional ventilation risers, circular ventilation pipes and appliance ventilation pipes. On the basis of ventilation system, a single riser drainage system with ventilation valve and special fittings was developed. Ventilation valve is a valve with ventilation function, which can reduce ceiling ventilation and replace special ventilation pipes. It is made of high quality plastic and rubber. The single air inlet valve can be installed at the top of indoor vertical pipe or horizontal branch pipe, which can not only replenish air but also prevent the gas in the pipe from entering the room; Two-way ventilation valve can be installed at the top of outdoor riser instead of ventilation cap, and one-way air inlet valve is the main one when used. Code for Design of Single Riser Drainage System for Special Accessories has been issued, and the water flow capacity of risers has been increased by 1/3, and the number of risers has been reduced. But this product is now limited to cast iron products.
3. About hot water supply
Hot water supply technology is the weak link of building water supply and drainage technology, but in recent years, due to the improvement of building standards and the popularization of hot water supply projects, hot water supply technology has also developed significantly.
3. 1 hot water heating mode and equipment heat consumption
Water heating methods include direct heating and indirect heat exchange. Among the heating equipment using hot water boilers, there are mainly gas-fired hot water boilers and oil-fired hot water boilers. Generally speaking, the efficiency of primary heat exchange is higher than that of secondary heat exchange. At present, the fully automatic and efficient hot water boiler studied in China has basically solved the safety problem of the hot water boiler located upstairs, so as to adapt to the area without heating pipe network in the south. In direct heating, the utilization of solar energy has also made great progress. In recent years, domestic hot water supply, heating methods, equipment and other issues have been discussed many times. In the indirect heating mode, steam and hot water are the main heat media used. The theory of heat exchange equipment has developed to a certain extent. The concept of "turbulent heating" is put forward in the design of volumetric hot water, that is, the flow rate of heat medium and hot water is increased to improve the heat release coefficient of heat medium to the pipe wall and the heat release coefficient of pipe wall to the hot water, thus improving the heat transfer effect. In the secondary heating equipment, there are split-flow volumetric heat exchangers, semi-volumetric heat exchangers and semi-instantaneous heat exchangers. In the design, we have realized that we should comprehensively consider the safety and advanced nature of the equipment, as well as the one-time investment and occupied area of the equipment.
Reasonable and economical choice of heating equipment.
3.2 Energy saving
Energy saving of hot water supply system is the focus of building water supply and drainage energy saving, and its energy saving measures mainly include: increasing water supply temperature; Reduce the use temperature; On the premise of meeting the use requirements, reduce the amount of hot water and reduce the flow; Reduce heat loss and adopt high-efficiency heat preservation materials; Improve heating mode and hot water system; Improve the heat transfer efficiency of water heater; Utilize new heat sources; Adopt energy-saving products, etc.
3.3 Water quality treatment of hot water
Mainly to prevent hot water from scaling, damage equipment and pipelines, and reduce heat transfer efficiency. When the water consumption is large and the water quality is poor, the water quality of the central hot water supply system should be softened before heating. In addition to dosing treatment, electrostatic treatment technology, electronic treatment technology and magnetization treatment technology should be adopted to ensure the stability of circulating hot water quality. In addition, the problem of Legionella in hot water has also attracted attention. China has improved the volume and structure of water heaters or water storage tanks, and adopted certain conditions to inhibit the growth of bacteria and Legionella.
4. About building fire protection technology
4. 1 hydrant water supply system
Building fire protection design has become an important part of building water supply and drainage. In the fire hydrant water supply system, more attention is paid to fighting the initial fire, and the constant pressure pump is often used to maintain the normal high pressure of the system. Add a small-caliber self-rescue water gun for non-fire professionals to save themselves. Pressure reducing valve, multi-outlet pump and pressure stabilizing valve can be used in the partition to ensure the water pressure and water output of the fire hydrant. In order to ensure the fire extinguishing device can be put into operation in time, the automatic switching device between the working pump and the standby pump is strengthened.
4.2 Automatic sprinkler technology
In recent years, China has established the principle of gradual transition from hydrant water supply system to automatic sprinkler system. The development of high-rise, super-high-rise and large-scale industrial buildings has strengthened the application of automatic sprinkler technology. Automatic sprinkler heads are not only installed in fire-prone areas, evacuation passages and crowded places, but also spread in fire spreading passages, which makes the fire difficult to be found, and extinguishes the fire-prone areas and places that need water spraying and cooling protection, which makes the fire extinguishing more timely and quickly. This is also an important measure for China's fire water supply system setting standards to gradually integrate with developed countries. In high-rise buildings, for glass curtain wall, atrium cloister, escalator entrance and common fire shutter, the sprinkler encryption method is used instead of water curtain. The elevated warehouse introduced foreign large-scale water drop nozzles and ESFR nozzles, and introduced the purpose of sprinkler from "fire control" to "fire fighting". In addition, in high-rise buildings with the building height exceeding 100m, corresponding fire prevention measures have been taken, such as setting refuge floors and setting helipads on the refuge floors and roofs. , and equipped with corresponding fire water supply facilities.
4.3 Gas fire extinguishing
Halon extinguishing agent in gas fire extinguishing is the main reason for destroying the atmospheric ozone layer. China has done a lot of work on halon fire extinguishing agent substitutes and made some progress. The application of halon substitutes, such as FM200, has accumulated some experience for the final cancellation of halon fire extinguishing agent. At present, gas fire extinguishing agents and fire extinguishing systems are increasingly diversified, including FM200, CEA, INERGEN, Trioxide and so on. In addition, water spray is applied to electric fire extinguishing and foam spray is applied to garage fire extinguishing, which expands the application scope of automatic sprinkler system.
Finally, we should pay attention to the water supply and drainage design of intelligent buildings, pay attention to the building automation system, and use computer technology to measure, monitor and automatically control the water supply and drainage equipment. Water supply and drainage major mainly puts forward monitoring requirements for sanitary equipment and fire fighting equipment. The monitoring, control, measurement and recording of flow, pressure (differential pressure), temperature and liquid level are put forward in the water supply system; In the drainage system, it is suggested that the flow can be measured, recorded and blocked. In the fire extinguishing system, the monitoring mode and position are put forward, which can reflect the running state in time. Automation system started late, but now there are intelligent building design standards. In residential areas, remote water meters have been widely used, and Xuzhou City has also begun to apply them. The newly-built science and education community has adopted this new technology, and within a few years, the urban area has fully implemented the "meter reading and going out".
In the new century, building water supply and drainage will shoulder new historical responsibilities and face new challenges. Building water supply and drainage will focus on people-oriented, with emphasis on civil buildings and industrial buildings, public buildings and residential buildings, cold water supply and hot water supply, water supply, water pressure and water quality, and embark on a comprehensive, balanced, pragmatic and safe development path.
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