Precautions for laying polyethylene coil
1. The pipeline laying shall be carried out after the elevation of the trench bottom and the quality of the pipeline foundation have passed the inspection. Before laying the pipeline, the appearance of the pipes and pipe fittings shall be inspected again, and the pipes and pipe fittings found to have problems shall not be used.
2. The thickness of covering soil on the top of pipe under the roadway shall not be less than 0.7rru
4. When the pipe trench is excavated manually, the bottom of the trench shall be flat, dense and free of sharp objects. The bottom of the trench may be undulated, but the pipe must be smoothly supported. If there is over excavation, it must be backfilled and compacted. During mechanical excavation, 200mm allowance shall be reserved at the bottom of the design groove, which shall be cleaned manually.
5. When laying, the direction of polyethylene pipeline can be changed. Pre-customized elbow fittings can be used, or the natural flexibility of the pipe can be used within a certain limit. When the bending radius is greater than or equal to 30-100 times (determined according to the pipe well, wall thickness, maximum allowable stress value of materials, etc.), the natural flexibility can be used without elbow (but the pipe should not be bent mechanically or by heating).
6, the pipeline set valve, fire hydrant, telescopic and other accessories, its weight shall not be supported by the pipeline, must be set up concrete or brick support, support should have sufficient body and stability.
7. The polyethylene coil pipe is laid by ploughing into the buried pipe, but it is not suitable for the pipeline engineering in the rocky area and the slope requirement.
8, embedded wall laying, buried polyethylene water supply pipe due to the medium around the pipe has sufficient resistance to resist thermal stress, can not set up expansion facilities, but in the elbow, tee should be set up full-bag type fixed town.
9. When the pipeline is buried in marshland and river bottom, due to the small friction force of backfill soil, both ends of the pipeline directly bear stress, and both ends of the pipeline must be traced.
10. Separate concrete support shall be set at the connection between polyethylene pipe and pipe and pipe fittings of other materials.
11. The pulling force shall not be greater than 50% of the yield tensile strength of the pipe when the pipe towing method is adopted for the laying of the coil.
12. When laying the water supply pipeline under water, the pipeline shall be connected on the shore, and the ballast shall be stuck, drifting to the predetermined position and sinking into the water. The distance between pipe ballasting shall be determined by calculation.