Chapter Ⅱ Installation（5. Installation and Heat Insulation for Pipelines of Water System）
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Maximum Distance for Support/Hanger Frame of Cold Water Pipe (mm)
Nominal outer
diameter dn
Maximum Distance for Support/Hanger Frame of Hot Water Pipe (mm)
Nominal outer
diameter dn
5.1.3 Inspection of gas proofness
1）Test pressure of cold water pipe should be 1.5 times of the design pressure of cold water
pipe system, and should not be less than 0.9MPa;
2）Test pressure of hot water pipe should be 2.0 times of the design pressure of hot water
pipe system, and should not be less than 1.2MPa;
3）Water pressure test of pipe should satisfy the following requirements:
a. Pressure test should be conducted only after the pipe has been installed and the outward
appearance is checked to be passed;
b. For the pipes are connected by welding, water pressure test should be conducted 24 hours
after the connection is done;
c. Pressure test medium is clear water under normal temperature. If the pipe system is large,
the test can be conducted by layer or by area;
4）For the pipes embedded in the top layer of floor or wall, pressure test should be conducted
before sealing or filling up the groove. The constructor can continue to work only after it has
reached the pressure test requirements. For the large construction project, pipe pressure test
work can be conducted by phase according to construction schedule;
5）When conducting water pressure test in winter in cold area, there should adopt effective
anti-frost measures, and should drain the pipe in time after the pressure test.
5.2 Installation of Water Flow Switch
The water flow switch is used for measuring water flow of the circulating water side. When the
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