14 Taboos of Installing a Valve (Part One)

It's not easy to install a valve, and do you know that there are 14 taboos for installing a valve? If you break the taboo, there will be some consequences. How are you going to solve the problem caused by breaking a taboo?

Taboo 1
The hydrostatic test is taken under subzero temperature during winter construction.

The consequence: The pipe will be damaged due to the frozen liquid in the pipe when the hydrostatic test is taken.

The Measure: Take the hydrostatic test before winter construction, and completely remove water in the pipe after the hydrostatic test, especially the water in the valve. Otherwise, the valve will be damaged due to the frozen liquid.

If the hydrostatic test must be taken during winter construction, the temperature should be above 0℃. Remove water in the valve after the hydrostatic test. When the hydrostatic test can not be taken, the compressed air test can be conducted.

Taboo 2
The pipeline system is not flushed properly before it is completed, and quantity and flow rate can not meet the requirement of flushing the pipeline. Drainage of the hydrostatic test is used for flushing the pipeline.

The consequence: Quality of water doesn't meet the requirement of the pipeline system, often resulting in smaller cross section of pipes and the cross section being blocked.

The measure: Flush the pipeline with the maximum flow rate within the system or at a flow rate not less than 3 m/s. When the color and transparency of water in the outlet of the pipe is basically the same as the inlet of the pipe, flushing of the pipe is qualified.

Taboo 3
The closed water test is not taken for pipes used for sewage, rain and condensate water.
The consequence: Water leakage may happen and cause loss for users.
The measure: The closed water test should be strictly in accordance with inspection and acceptance of its standards.

Taboo 4
When the hydraulic pressure test and tightness test are taken, pressure and water level is only observed and leakage is not checked properly.

The consequence: Leakage occurs after the pipeline system is operated, affecting normal operation.

The measure: When a test is taken for the pipe according to design requirements and construction rules, carefully exam the pipe to know if there is a leakage problem besides observing the pressure and water level.

Taboo 5
Use normal flanges for butterfly valves.

The consequence: Sizes of flanges used for butterfly valves are different from those of normal flanges. Some of flanges have small inner diameter. However, a butterfly valve has a big valve clack, which will cause damage to the valve, because the valve can not be opened or is opened by force.

The measure: Manufacture the flange based on the actual size of the flange used for the butterfly valve.