The choice of valve and the setting part:

　　(a) valves used in water supply pipelines are generally selected in accordance with the following principles:

　　1, the diameter is not more than 50mm, it is advisable to use a cut-off valve, pipe diameter greater than 50mm when the use of gate valve, butterfly valve.

　　2, the need to adjust flow, water pressure with the use of regulating valves, cut-off valves.

　　3, requirements of small water flow resistance of the site (such as water pump suction pipe), it is advisable to use the gate valve.

　　4, the flow of two-way flow of the pipe should be used in the gate valve, butterfly valve, not to use the cut-off valve.

　　5, the location of small installation space should be used butterfly valve, ball valve.

　　6, in the frequent opening and closing of the pipe, it is advisable to use a cut-off valve.

　　7, the diameter of the larger water pump pipe should be used multi-function valve.

　　(b) The following parts of the water supply pipeline shall be provided with valves:

　　1, the residential district water supply pipeline from the municipal water supply pipeline to the introduction of pipe. 2, residential district outdoor annular pipe network node, should be set according to separate requirements.

　　When the annular pipe is too long, it is advisable to set the sectional valve.

　　3, from the residential area of water supply pipe on the stem from the beginning or end of the pipe.

　　4, household pipe, water meter and the branches of the vertical pipe (vertical pipe bottom, vertically annular pipe network riser, the lower part).

　　5, the annular pipe network of dry pipe, through the branch pipe network connections.

　　6, indoor water supply pipeline to the household, public toilets, such as the distribution of water mains from the end of the distribution of water on the branch pipe in 3 and more than 3 settings.

　　7, water pump outlet, self-irrigation pump suction pump.

　　8. Inlet, outlet pipe and drain pipe of water tank.

　　9, equipment (such as heaters, cooling towers) of the intake of water mains.

　　10, sanitary appliances (such as large, urinal, washbasin, shower, etc.) of the water supply.

　　11, some accessories, such as automatic exhaust valve, pressure relief valve, water hammer elimination, pressure gauge, sprinkler, such as before, reducing valve and backflow preventer before and after. 12. The lowest point of water supply pipe network should be set up the valve.