What is the layout of hot water supply pipe network in high-rise buildings?

Hot water supply pipe network layout in high-rise buildings

In high-rise buildings, the hot water system pipe network and the water supply equipment pipe network are often set up in parallel. There are many similarities with water supply systems in terms of system zoning, basic principles, methods, methods and requirements for pipe network layout and laying. However, due to the unique nature of the hot water supply system itself, there are differences in the layout and laying of the pipe network.

1. Pipe network layout

The layout of the pipe network of the centralized towerless water supply system of high-rise buildings is roughly as follows based on its piping, water supply methods, and pipeline circulation methods. Types:

(1) Single-tube type and double-tube type. These two methods are divided according to different piping methods. Hot water single-pipe system, also known as non-circulating hot water system, is suitable for accessory rooms of high-rise buildings with continuous water supply. Such as public bathroom, laundry room and kitchen, etc. It is not suitable for systems with high water temperature requirements. The hot water double-pipe system is also called a circulating hot water system. In this pipe network, the hot water circulation flow can be fully or partially circulated to meet the water temperature requirements. Therefore, it is widely used in the centralized hot water supply system of high-rise buildings. middle.

(2) The ascending and descending formula and the descending and ascending formula. These two methods are divided according to the different flow directions of hot water. Judging from the actual situation of high-rise buildings at home and abroad, the above two methods are mostly used in the upward and downward feeding systems, while few use the downward and upward feeding systems.

(3) Same program and different program. These two methods are distinguished by the hot water circulation pipeline and length. In the same program hot water system, due to its own hydraulic characteristics, the system node pressure is basically balanced, thus basically ensuring the calculated water volume and water temperature required by each water supply point. In the differential hot water system, due to the different processes of each water supply point, it is difficult to equal the head loss of each process. Therefore, the design water volume and water temperature required for each water point cannot be guaranteed. This is the fundamental weakness of heteroprogrammed systems. In engineering design, in order to overcome the above shortcomings, people usually install a regulating valve on the hot water return riser to adjust the water pressure and control the water volume. However, due to engineering construction and maintenance management issues. The effect is not ideal. With the increasing development of high-rise building construction in our country, it is necessary to promote the application of the same program system in the hot water supply system of high-rise buildings.

2. Pipe laying

In addition to meeting the requirements for water supply pipe network laying, the laying of hot water pipe networks in high-rise buildings should also pay attention to the volume expansion and expansion caused by high water temperatures. Pipeline expansion compensation, insulation, exhaust and other issues.

For hot water pipe networks that supply downwards and upwards or upwards and downwards, horizontal main pipes can be laid in the equipment layer, on the suspended ceiling or on the top of the basement. Sufficient telescopic devices should be installed on the straight section of the main pipe, and an automatic exhaust device should be installed at the highest point of the upstream and downstream supply pipe network. The highest water distribution point of the downstream and upward supply pipe network can be used for exhaust, so the circulating water return riser should be at the water distribution riser. Connect at ≥0.50m below the highest water distribution point. In order to facilitate exhaust and water drainage, the hot water horizontal pipes should have a slope opposite to the water flow, and its value is generally ≥0.003. A drain valve should be installed at the lowest point of the pipe network to facilitate the emptying of the pipe network and the storage of water during maintenance.

According to the usage requirements of high-rise buildings, hot water pipe networks come in two forms: exposed and concealed. Surface installation should be laid along the wall and column of the water point as much as possible, generally parallel to the cold water pipe. Concealed pipes can be arranged in pipe shafts, equipment floors, suspended ceilings or pre-trenches.

When connecting the riser pipe and the horizontal pipe, in order to avoid the pipe expansion stress from damaging the pipe network, the riser pipe and the horizontal pipe should be connected using an I-shaped bend.

Pipes passing through floor slabs, foundations and walls should be equipped with casings to allow them to expand and contract freely. The casing that penetrates the floor should be 5 to 10 cm higher than the floor to prevent water from flowing to the lower floor through the gap in the casing when the floor collects water. In order to adjust and balance the circulating flow of the hot water pipe network and reduce the scope of water outage during maintenance, the main pipes of the water distribution or return water annular pipe network, the end points of the water distribution risers and return water risers, as well as residential buildings and public buildings *A valve should be installed on the hot water branch pipe of each user or unit in the building.

Due to the high water temperature, low gas solubility and strong oxidation activity in the hot water supply system, metal pipes are easily corroded. Therefore, the requirements for pipe materials are higher.

When the hot water pipe diameter reaches 150mm, galvanized steel pipes and corresponding accessories should be used; for high-rise buildings with high standards, copper pipes and copper accessories should be used, and polybutylene pipes or aluminum-plastic composite pipes can also be used. In addition, heat exchange equipment, pipes, pipe fittings, etc. in the hot water system should be insulated to reduce heat loss. The construction of pipeline and equipment insulation structures includes smear type, prefabricated type, pouring type and bundled type.

The above is collected and compiled by Zhongda Consulting

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