Example analysis of drainage system in high-rise building?

What is the specific content of the example analysis of drainage system in high-rise buildings? Zhong Da Consulting will answer your questions below.

With the continuous development of market economy, the proportion of high-rise buildings in urban buildings is increasing, and almost every new building is a high-rise building. High-rise building construction is an extremely complex and precise process, and often some small factors may determine the quality of the whole building. The design and construction of high-rise building drainage system is one of the most critical links [1]. The drainage facilities in high-rise buildings serve a large number of people, are frequently used, have a large load and a large flow, which requires that the drainage facilities must be safe and reliable and save space as much as possible. There are many drainage devices in the drainage pipeline of high-rise buildings, and the probability of these devices draining at the same time is high, so the water flow in the riser is large, which is easy to form water plug flow, which makes the lower part of the riser form negative pressure, thus destroying the water seal of sanitary ware and other equipment. The ventilation problem is generally solved by setting drainage and ventilation system, that is, double riser drainage system, which is connected by ventilation pipe and drainage pipe into a system. There is no water flow in the ventilation tube, which can strengthen the air circulation in the drainage tube and control the pressure change. The system has good drainage performance and reliable operation, but the system is complex, with large investment, large land occupation and difficult construction. Since the Swiss teacher Ma Su put forward a new type of single riser drainage system for high-rise buildings in 1959, after decades of development, a complete theoretical system has been formed.

1 new single riser drainage system for high-rise buildings

The new single riser drainage system of high-rise building uses special fittings to reduce the pressure change in the riser, keep the air flow in the pipeline smooth, improve the drainage capacity of the pipeline system and reduce the project cost. The new single riser drainage system includes the following four design forms.

1. 1 Suweto drainage system

In 1959, Suma of Switzerland put forward a new type of single vertical pipe drainage system, which uses gas-water mixing or separation fittings to replace ordinary components. It combines the functions of drainage pipeline and ventilation pipeline into one, including two basic fittings, gas-water mixer and gas-water separator, and has the function of self-ventilation, thus saving a lot of pipelines, reducing costs, improving design quality, accelerating construction progress and realizing industrial construction. 1. 1. 1 gas-water mixer The gas-water mixer is a special pipe fitting (see figure 1), which is installed at the joint of the riser and each horizontal pipe. The gas-water mixer has three special structures: baffle, I-bend and a gap about 1cm above the baffle. Its working principle is: when the sewage descending from the branch pipe passes through the B-bend, the water flow collides and disperses and mixes with the surrounding air to form a foam-like gas-water mixture. Because the specific gravity of sewage becomes lighter, the falling speed slows down and the suction decreases. The water discharged by the horizontal branch pipe is blocked by the partition plate, and no water tongue is formed, so that the air flow in the vertical pipe can be kept smooth and the air pressure is stable. 1. 1.2 Gas-water separator The gas-water separator is usually installed at the bottom of the riser, which is a special pipe fitting consisting of a concave-convex structure and an air escape pipe (see Figure 2). Its working principle is: the gas-water mixture flowing from the riser splashes when it meets the bump, so that 70% of the gas is separated from the sewage, thus reducing the volume of the sewage, reducing the flow rate, balancing the discharge capacity of the riser and the horizontal main pipe, and preventing the airflow from being blocked at the corner. In addition, the released gas is guided to the downstream of the main pipe through the running pipeline to prevent the bottom of the riser from generating excessive back pressure.

1.2 cyclone drainage system

1967, France put forward a new type of single riser drainage system (see figure 3), which was widely used in high-rise buildings with 10 floor, with the characteristics of small pressure fluctuation and good performance. The system mainly has two kinds of special fittings: one is a cyclone joint installed at the joint of horizontal pipe and vertical pipe, which consists of a main chamber and a side chamber, and there is a side wall between the main chamber and the side chamber to eliminate the negative pressure attraction to the horizontal branch pipe when the vertical pipe falls. The lower end of the riser is equipped with full-flow blades, which can arrange the water to flow downward along the longitudinal axis of the riser, which is beneficial to maintain the air core in the riser, keep the air pressure in the riser stable and effectively control the drainage noise. The second is the large curvature guide elbow at the joint between the bottom of the riser and the discharge pipe. The convex dike of the elbow is provided with guide vanes, which force the water flow to the concave dike, thus slowing down the impact of the water flow on the elbow, eliminating part of the water flow energy, avoiding the excessive change of the air pressure at the bottom of the riser and straightening the water flow.

1.3 core drainage system

In the early 1970s, Japan put forward a new type of single riser drainage system, which further strengthened the drainage capacity of risers and horizontal pipes on the basis of previous studies. The system mainly has the following two kinds of special fittings: 1.3. 1 Gaucci Ma connector, which is arranged at the junction of horizontal drainage pipes and risers on each floor and is inverted cone (see Figure 4). An inner pipe is arranged at the intersection of the upstream inlet and the inflow inlet of the horizontal branch pipe, and the sewage discharged by the horizontal branch pipe flows downward into the riser along the outer side of the inner pipe, thus avoiding the water tongue blockage caused by the drainage of the horizontal branch pipe. The sewage flowing out of the riser diffuses and falls after passing through the inner pipe, forming a gas-water mixture, which slows down the falling speed and ensures the smooth air in the riser. There are two ways to connect the lateral branch pipe of Gauchma joint fittings: vertical connection to the lateral branch pipe and tangential connection. 1.3.2 flare elbow flare elbow is installed at the bottom of drainage riser (see figure 5). Due to the large cross-section of the upper inlet end, the flow rate of water flowing down the drainage riser is slowed down due to the sudden increase of the cross-section of water, and the gas entrained by the discharged water is released. On the one hand, the water flow is introduced into the outlet pipe along the gently curved sliding surface of the elbow, which eliminates the phenomenon of water jump and water plug; On the other hand, due to the large internal space of the horn flute elbow, the air in the riser can be fully communicated with the space above the horizontal pipe, which ensures the smooth airflow and reduces the pressure fluctuation. 1.4 UPVC spiral drainage system The UPVC single riser drainage system with spiral guide line developed by Korea in 1990s is a simple and new type of single riser drainage system (see Figure 6). The system consists of UPVC pipe and eccentric tee. UPVC pipe is a pipe made of hard PVC material, and the inner wall of the pipe has six protruding triangular spirals, which are processed and formed together with the pipe wall to guide the water flow. The triangular spiral is about 6mm high, and the water in the pipe spirals down along the inner wall of the pipe, forming a stable and dense water film cyclone. The center of the pipe fitting is an unobstructed gas column, and the flow velocity also decreases in the process of water flow decline, which obviously reduces the pressure fluctuation in the riser and greatly improves the drainage capacity. Eccentric tee is installed at the joint of vertical pipe and horizontal pipe. The water flowing in from the horizontal branch pipe enters the vertical pipe from the tangential direction of the circumference through the eccentric tee, and the vortex descends, which can weaken the water inlet tongue of the branch pipe and avoid the formation of water plug. At the same time, it reduces the collision of water flow and has a good noise reduction effect [3].

2 engineering example analysis

A high-rise residential project is located atNo. Xiao Xin Street 10, Xinghualing District, Taiyuan City, Shanxi Province. There are 28 floors above ground and 2 floors underground, with frame-shear wall structure, the height above ground is 96.5 m, and the total construction area is 255 13m2. The basement and bicycle garage are on the first floor, and the equipment room is on the second floor. The total duration of the contract is 535 days. The drainage system of this project adopts sewage and wastewater confluence system. Due to the large number of high-rise residential buildings, large water consumption and high drainage frequency, ventilation pipes and UPVC single riser drainage system are adopted in the drainage design of this project. Ventilation pipes are provided to prevent water plugs from forming in the drainage pipes. The water plug flow will cause great pressure on the upper part of the riser, especially on the two layers below the drainage pipe, which will destroy the water seal of the nearby equipment. In order to avoid odor overflow and pollute the surrounding environment, it is necessary to set up ventilation pipes to make the gas in the drainage pipes communicate with the atmosphere, so as to replenish air and exhaust air in time. In the design of ventilation duct system, it is considered that the distance between drainage duct and special ventilation duct should not be too large, otherwise the ventilation function of ventilation duct can not be fully exerted, and each floor of ventilation duct is connected with drainage duct. Adopting UPVC single riser drainage system mainly considers low system cost and simple construction. The most important point is that the noise of UPVC pipes is well controlled, which overcomes the shortcoming of high noise of ordinary plastic pipes and improves the quality of life. However, it should be noted that the heat resistance of UPVC pipe is poor, and the instantaneous discharge temperature cannot exceed 80℃, so it is designed away from heat sources to ensure the normal use of the pipe.

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