Polyethylene (PE) piping for water supply is a replacement product for steel pipes and polyvinyl chloride (PVC) drinking water pipes.
PE pipes can withstand certain pressures, usually requiring high molecular weight PE resins with good mechanical properties, such as HDPE resins. LDPE resins have poor rigidity, poor dimensional stability during molding and processing, and are difficult to connect, making them unsuitable for pressure water pipes. LDPE, especially LLDPE resins, have become common materials for producing drinking water pipes. LDPE and LLDPE resins have low melt viscosity and good fluidity, making them easy to process, and thus offer a wide range of melt index choices, typically between 0.3-3g/10min.
Compared to traditional piping materials, HDPE pipe systems feature a range of characteristics:
1. Polyethylene pipe systems are connected using electric heat fusion.
2. Polyethylene has a low-temperature brittleness point that allows for use within a temperature range of -60 to 60°C. During winter construction, it is less prone to pipe cracking.
3. HDPE pipes are resistant to corrosion from a variety of chemicals. Chemicals present in the soil do not cause degradation to the pipes. Therefore, they are less prone to rot, rust, or electrochemical corrosion. Additionally, they are not conducive to the growth of algae, bacteria, or fungi.
4. Excellent Flexibility: The flexibility of HDPE pipes makes them easy to bend, allowing for routing changes to navigate around obstacles in engineering. In many cases, this flexibility can reduce the need for fittings and lower installation costs.
5. Low hydraulic resistance: HDPE pipes feature a smooth inner surface with a Manning coefficient of 0.009. The smoothness and non-adhesive characteristics ensure HDPE pipes have a higher conveying capacity than traditional materials, while also reducing pressure loss in pipelines and water conveyance energy consumption.
6. Easy to Handle: HDPE pipes are lighter than concrete pipes, galvanized pipes, and steel pipes, making them easy to transport and install. This requires less labor and equipment, which means reduced installation costs for the project.
7. Various Construction Methods: HDPE pipes offer a range of construction techniques, including conventional excavation, as well as non-excavation methods such as jacking, directional drilling, lining, and bursting. This is an excellent choice for locations where excavation is not permitted.
