1. It is necessary to truly understand that direct-buried laying of heating pipelines is divided into two methods: compensated direct-buried laying and uncompensated direct-buried laying, in both design and construction. By truly mastering the two working methods, their characteristics and application scenarios, a reasonable choice can be made in design, and construction can be safe, reliable, and economical.

　　2. Inspect carefully after entering the site. Before construction, it is necessary to investigate the manufacturer. Reject unqualified insulated pipe.

　　3. Welding of PU insulated pipe is a key task that ensures project quality in pipeline construction.

　　4. The construction quality of each chamber directly affects project quality and pipeline service life. If chamber waterproofing is poor, parts will be damaged by immersion. Construction shall therefore be carried out carefully to ensure quality.

　　5. Pressure conditions must be met, and attention must be paid to pipeline pressure testing. First fill the line with water and vent the air, then complete the test in two steps: no leakage within 10 minutes after pressure is stabilized. Strength test: after the pressure in the pipe is raised to 1.5 times the working pressure, tap each weld around the weld with a 1 kg hammer. Tightness test: when the pressure is reduced to working pressure, 30 minutes with no leakage and a pressure drop not exceeding 0.2 atm is acceptable. Pressure-test records shall be prepared in accordance with the code.

　　6. Because the insulated pipe is buried underground, most of the work at project acceptance is concealed. If final acceptance is not thorough, as-built data will not be detailed, which will affect future

　　7. Joints and backfill shall be carried out after the pipeline has been tested. After measurements and cleaning are complete, sand of the specified thickness must be backfilled according to the construction characteristics of PU insulated pipe, and corners must not be cut.

　　8. This must be given sufficient attention. Field-joint insulation may be carried out only after the pressure test has passed. This item is specific to the construction of PU insulated pipe, and construction quality directly affects service life. There are two methods: field foaming and insulation-tile (preformed) insulation. Whichever method is used, there must be no annular voids, cracking, delamination, or other defects. There are various ways to apply the protective jacket (for example HDPE and FRP jackets), but all must ensure the integrity, tightness, and water resistance of the joint.

　　That concludes the special points to note in design and construction of PU insulated pipe. We hope it is helpful. For more information, please follow us. Jinan Insulated Pipe