Prohibit 1

Hydraulic test shall be carried out under Negative temperature during winter construction.

Consequence: Due to the rapid freezing inside the pipe during the hydraulic test, the pipe freezes out.

Measures: Try to conduct a water pressure test before winter construction, and after the test, blow the water clean, especially the water inside the valve must be removed completely, otherwise the valve will freeze and crack.

When conducting hydraulic tests in winter, the project must maintain a positive indoor temperature, and the water should be blown clean after the pressure test. When hydraulic testing is not possible, compressed air can be used for testing.

Prohibit 2
The pipeline system was not flushed carefully before completion, and the flow and speed did not meet the requirements for pipeline flushing. Even using hydraulic strength testing to release water instead of flushing.

Consequence: If the water quality does not meet the operational requirements of the pipeline system, it often leads to a reduction or blockage of the pipeline cross-section.

Measure: Flush with the maximum set juice flow rate in the system or a water flow rate that should not be less than 3m/s. It should be deemed qualified if the color and transparency of the discharge water are visually consistent with those of the inlet water.

Prohibition 3
Sewage, rainwater, and condensate pipes are concealed without conducting a closed water test.

Consequence: May cause water leakage and result in user losses.

Measures: The closed water test work should be strictly inspected and accepted in accordance with the specifications. Concealed sewage, rainwater, condensate pipes, etc. buried underground, in suspended ceilings, between pipes, etc., must ensure no seepage or leakage.

Prohibit 4
During the hydraulic strength test and leak test of the pipeline system, only observing the pressure value and water level changes is not enough for leakage inspection.

Consequence: Leakage occurs after the pipeline system operates, affecting normal use.

Measures: When conducting tests on the pipeline system according to design requirements and construction specifications, in addition to recording pressure values or water level changes within the specified time, it is particularly important to carefully check for any leakage issues.

Prohibition 5
Butterfly valve flanges are ordinary valve flanges.

Consequence: The size of the butterfly valve flange is different from that of a regular valve flange. Some flanges have a small inner diameter, while the butterfly valve disc is large, causing the valve to be unable to open or hard to open, resulting in valve damage.

Measure: The flange plate should be machined according to the actual size of the butterfly valve flange.