Taboo 1

Water pressure tests must be performed in frigid conditions during winter construction.
Consequences: The pipe was frozen and damaged as a result of the hydrostatic test’s quick pipe freezing.
Measures: Try to test the water pressure before using it for the winter and turn off the water after the test, especially the water in the valve, which has to be cleaned else it may rust or, worse, crack. When conducting the hydraulic test during the winter, the project must maintain a comfortable indoor temperature and blow out the water after the pressure test.

Taboo 2

The pipeline system has to be flushed, but this is not a major matter because the flow and speed do not satisfy the standards. Even flushing is replaced by a discharge for a hydraulic strength test. Consequences: Because the water quality does not meet the pipeline system’s operational standards, pipeline sections frequently become reduced in size or become blocked. Use the maximum amount of juice that can flow through the system or at least 3 m/s of water flow for flushing. In order for the discharge outlet to be considered, the water color and clarity must match those of the inlet water.

Taboo 3

Without doing a closed water test, sewage, rainwater, and condensate pipes are concealed. Consequences: It might result in water leaks and user losses. Measures: The closed water test needs to be examined and approved strictly in accordance with the guidelines. It is essential to guarantee that all underground, inside the ceiling, between pipes, and other concealed installations—including those carrying sewage, rainwater, and condensate—are leak-proof.

Taboo 4

Only the pressure value and water level fluctuations are noticed during the hydraulic strength test and tightness test of the pipe system; a leakage inspection is insufficient. Leakage that happens after the pipeline system is in use interferes with normal use. Measures: When the pipeline system is tested in accordance with the design specifications and construction guidelines, it is especially important to thoroughly verify whether there are any leaks in addition to recording the pressure value or water level change within the allotted period.
Taboo 5

Ordinary valve flanges are used with butterfly valves. The size of the butterfly valve flange differs from that of the standard valve flange as a result. Some flanges have a tiny inner diameter while the butterfly valve’s disc has a large one, which causes the valve to malfunction or open hard and cause damage. Measures: Handle the flange in accordance with the butterfly valve’s actual flange size.

Taboo 6

When the building structure was being built, no embedded portions were reserved, or the embedded sections were not designated and the reserved holes were either too small. Consequences: Chiseling the building structure or even chopping off the stressed steel bars will have an impact on the building’s safety performance during the installation of heating and sanitation projects. Measures: Learn the building plans for the heating and sanitation project carefully, and actively participate in the construction of the building structure by reserving holes and embedded components as necessary for the installation of pipes, supports, and hangers. Please specifically refer to the construction specifications and design specifications.

Taboo 7

When the pipe is welded, the alignment is off-center, there is no gap left at the alignment, the groove is not shoveled for the thick-walled pipe, and the width and height of the weld do not comply with the construction specification. Consequences: Because the pipe is not centered, the welding process will be less effective and will look less professional. When the breadth and height of the weld do not satisfy the specifications, there is no gap between the counterparts, the thick-walled pipe does not shovel the groove, and the welding cannot fulfill the strength requirements.
Measures: Groove thick-walled pipes, leave gaps at the joints, and arrange the pipes so that they are on a center line once the joints have been welded. Additionally, the weld seam’s width and height must be welded in accordance with the guidelines.

Taboo 8

The pipeline is buried directly over permafrost and untreated loose soil, and even dry bricks are employed. The support piers for the pipeline are also improperly spaced and positioned. Consequences: Because of the shaky support, the pipeline was harmed during the backfill’s soil compression, necessitating rework and repair. Measures: Untreated loose soil and frozen soil are not appropriate places for burying pipelines. The spacing between buttresses must adhere to the construction guidelines. For completeness and stability, cement mortar should be used to construct brick buttresses.

Taboo 9

The pipe support is fixed using expansion bolts, but the bolts’ substance is subpar, their holes are too big, or they are mounted on brick walls or even light walls. Consequences: The pipe is distorted or even falls off, and the pipe support is flimsy. Expansion bolts must choose reliable items, and samples may need to be examined for inspection. The diameter of the hole used to insert expansion bolts shouldn’t be 2 mm bigger than the expansion bolts’ outer diameter. On concrete buildings, expansion bolts must be employed.

Taboo 10

The connecting bolts are too short or have a small diameter, and the flanges and gaskets used to join the pipes are insufficiently sturdy. For heating pipes, rubber pads are used, for cold water pipes, double-layer pads or inclined pads, and flange pads stick out from the pipe. Consequences: Leakage happens as a result of the flange connection being loose or even damaged. The flange gasket sticks out into the pipe, which makes the water flow more difficult. Measures: The pipeline’s flanges and gaskets must adhere to the specifications of the pipeline’s design working pressure. For flange gaskets on heating and hot water supply pipes, rubber asbestos gaskets should be used; for flange gaskets on water supply and drainage pipelines, rubber gaskets should be used. No portion of the flange’s gasket may extend into the pipe, and its outer circle must touch the flange’s bolt hole. The centre of the flange should not have any bevel pads or multiple pads. The bolt connecting the flange should have a diameter that is less than 2 mm larger than the flange’s hole, and the length of the protruding nut on the bolt rod should be equal to half of the nut’s thickness.