(1)The valves used on the water supply pipeline are generally selected according to the following principles:

1. When the pipe diameter is not greater than 50mm, a stop valve should be used. When the pipe diameter is greater than 50mm, a gate valve or butterfly valve should be used.

2. When it is necessary to adjust the flow and water pressure, a regulating valve and a stop valve should be used.

3. Gate valves should be used for parts requiring small water flow resistance (such as on the water pump suction pipe).

4. Gate valves and butterfly valves should be used for pipe sections where water needs to flow in both directions, and stop valves are not allowed.
5. Butterfly valves and ball valves should be used for parts with small installation space.

6. Stop valves should be used for pipe sections that are often opened and closed.

7. The outlet pipe of the larger-diameter water pump should adopt a multi-function valve

(2) The following parts of the water supply pipeline should be equipped with valves:
1. The water supply pipes in residential quarters are introduced from the municipal water supply pipes.

2. The nodes of the outdoor ring pipe network in the residential area should be set according to the separation requirements. When the annular pipe section is too long, segmental valves should be installed.

3. The starting end of the branch pipe connected from the main water supply pipe of the residential area or the starting end of the household pipe.

4. Household pipes, water meters and branch risers (the bottom of the standpipe, the upper and lower ends of the vertical ring pipe network standpipe).

5. The sub-trunk pipes of the ring pipe network and the connecting pipes that run through the branch pipe network.

6. The starting point of the water distribution pipe connecting the indoor water supply pipe to the households, public toilets, etc., and the water distribution point on the distribution 6 branch pipe is set when there are 3 or more water distribution points.

7. The outlet pipe of the water pump and the suction pump of the self-priming water pump.

8. The inlet and outlet pipes and drain pipes of the water tank.

9. Water supply pipes for equipment (such as heaters, cooling towers, etc.).

10. Water distribution pipes for sanitary appliances (such as toilets, urinals, washbasins, showers, etc.).

11. Some accessories, such as the front of the automatic exhaust valve, pressure relief valve, water hammer eliminator, pressure gauge, sprinkler cock, etc., the front and rear of the pressure reducing valve and the backflow preventer, etc.

12. A drain valve should be installed at the lowest point of the water supply pipe network.

(3) The check valve should generally be selected according to factors such as its installation location, water pressure in front of the valve, sealing performance requirements after closing, and the size of the water hammer caused by closing:
1. When the water pressure in front of the valve is small, swing check valve, ball check valve and shuttle check valve should be selected.

2. When tight sealing performance is required after closing, it is advisable to choose a check valve with a closing spring.

3. When it is necessary to weaken and close the water hammer, it is advisable to choose a quick-closing noise-eliminating check valve or a slow-closing check valve with a damping device.

4. The disc or core of the check valve should be able to automatically close under the action of gravity or spring force.

(4) Check valves should be installed in the following sections of the water supply pipeline:

On the inlet pipe; on the water inlet pipe of the closed water heater or water equipment; on the water outlet pipe section of the water tank, water tower, and high ground pool where the water pump outlet pipe inlet and outlet pipes share one pipeline.

Note: It is not necessary to install a check valve in the pipe section equipped with a pipe backflow preventer.

(5) Exhaust devices should be installed at the following parts of the water supply pipeline:

1. For the water supply pipe network used intermittently, automatic drains should be installed at the end and highest point of the pipe network.
gas valve.

2. For areas with obvious fluctuations and gas accumulation in the water supply pipe network, an automatic exhaust valve or manual valve has been installed at the peak point of the area for exhaust.

3. For the air pressure water supply device, when the automatic air supply type air pressure water tank is used, the highest point of the water distribution pipe network should be equipped with an automatic exhaust valve.