Consequences: Nuanwei construction, ticking building structure, or even cut off the reinforced steel, affecting the safety performance of buildings.
Measures: Familiar with HVAC construction drawings, according to the pipeline and hanger installation needs, take the initiative to seriously cooperate with the construction of the structure to reserve holes and embedded parts, with specific reference to the design requirements and construction specifications.
Taboo 7: Pipe welding, the wrong pipe after the mouth of the mouth is not a centerline, counterparts do not leave gaps, thick-walled tube does not shovel groove, weld width, height does not meet construction requirements.
Consequence: the wrong pipe is not a centerline directly affect the quality of welding and perception of the quality. Counterparts do not leave gaps, thick-walled tube does not shovel groove, the weld width, height does not meet the requirements of the welding does not meet the strength requirements.
Measures: welded pipe counterparts, the pipe can not be wrong, to a centerline, the counterpart should stay gap, thick-walled pipe to shovel bevel, the other weld width, height should be in accordance with the requirements of the standard welding.
Taboo 8: The pipeline is directly buried in frozen soil and untreated soil, the spacing and location of pipe pier is improper, and even the use of dry code brick form.
Consequence: As the pipe is not stable due to the support, the backfill soil during the compaction process suffered damage, resulting in rework repair.
Measures: The pipeline shall not be buried in the frozen soil and untreated loose soil, pier spacing to comply with the requirements of the construction specifications, support pad to be solid, especially at the pipe interface, should not be subject to shear. Brick piers to use cement mortar masonry, to ensure complete and solid.
Taboo 9: Fixed pipe stent expansion bolt material is poor, the expansion bolt installed pore size is too large or expansion bolts installed in the brick wall and even light wall.
Consequences: Loose pipe bracket, pipe deformation, or even fall off.
Measures: Expansion bolts must choose qualified products, if necessary, the sample should be tested for inspection, installation of expansion bolts should not exceed the aperture diameter of expansion bolts 2mm, expansion bolts used in concrete structures.
Taboo 10: Pipe flange and gasket connection strength is not enough, the connection bolts short or small diameter. Rubber mats for thermal pipes, asbestos mats for cold water pipes, and double or upturned mats for flanged gaskets.
Consequences: flange connection is not tight, or even damaged, there leakage phenomenon. Flange gasket into the tube, will increase the water flow resistance.
Measures: Pipe flanges and gaskets must meet the design pressure of the pipeline. Heating and hot water supply pipe flange liner, should adopt rubber asbestos pad; to the drainage pipe flange liner, should adopt rubber pad. Flange gasket shall not protrude into the tube, the outer flange to the flange bolt hole is appropriate. The middle of the flange should not be placed slant pad or a few pads, the diameter of the flange bolts should be less than 2mm, the protruding length of the bolt rod should be 1/2 of the nut thickness.
Taboo 11: Pipeline hydraulic pressure test and tightness test, only to observe changes in pressure and water level, the leak check is not enough.
Consequence: Leakage occurs after the pipeline system is operated, affecting normal use.
Measures: When the piping system is tested according to the design requirements and construction rules, in addition to recording the pressure value or the water level change within the specified time, it is especially necessary to carefully check whether there is a leakage problem.
Taboo 12: Sewage, rainwater, condensate pipes do not do closed water test will be hidden.
Consequences: May cause water leakage and cause user loss.
Measures: Closed water test work should be strictly in accordance with the standards of inspection and acceptance. Buried underground, ceiling, pipe and other concealed sewage, rainwater, condensate water pipes to ensure impermeability does not leak.
Taboo 13: Flushing of pipeline system before completion is not serious, and the flow and speed can not reach the requirements of pipeline flushing. Even hydrostatic test drainage instead of flushing.
Consequences: water quality does not meet the pipeline system requirements, often resulting in pipe cross-section to reduce or block.
Measures: Flush with the maximum flow rate within the system or at a flow rate not less than 3 m / s. Should be the outlet color, transparency and water color, transparency, visual consistency as qualified.
Taboo 14: Winter Construction Hydrostatic test at negative temperature.
Consequence: As the tube quickly freeze in the hydrostatic test, the tube is frozen.
Measures: As far as possible before winter water pressure test, and after the pressure test to water purge, in particular, the water inside the valve must be cleared in the net, otherwise the valve will be cracked. The project must be carried out in the winter hydrostatic test, to maintain the indoor temperature, after the pressure test to water purge. In the hydraulic pressure test can not be carried out with compressed air test.
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