Polyethylene (PE) piping for water supply is a replacement product for steel piping and polyvinyl chloride (PVC) drinking water pipes.
PVC water supply pipes can withstand certain pressure, usually requiring the use of PE resins with high molecular weight and good mechanical properties, such as HDPE resins. LDPE resins have poor rigidity, poor dimensional stability during molding processing, and are difficult to connect, making them unsuitable for water supply pressure pipes. LDPE, especially LLDPE resins, have become commonly used materials for producing drinking water pipes. LDPE and LLDPE resins have low melt viscosity and good fluidity, making them easy to process, and thus have a wide range of melt index choices, typically between 0.3-3g/10min.
Compared to traditional piping materials, HDPE pipe systems possess the following range of characteristics:
1. The polyethylene pipe systems are connected using electric hot-fusing methods.
2. Polyethylene has a low cold brittleness temperature, making it usable 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 various chemicals. Chemical substances present in the soil do not cause degradation to the pipes. Therefore, they are not prone to rotting, rusting, or electrochemical corrosion. Additionally, they are also not conducive to the growth of algae, bacteria, or fungi.
4. Excellent Flexibility: The flexibility of HDPE pipes allows them to be easily bent, enabling engineers to navigate around obstacles by altering the pipeline direction. In many cases, this flexibility can reduce the need for fittings and lower installation costs.
5. Low Flow Resistance: HDPE pipes feature a smooth inner surface with a Manning coefficient of 0.009. The smoothness and non-adhesive properties ensure HDPE pipes have higher conveying capacity than traditional materials, while also reducing pressure loss in the pipeline and water transportation 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, resulting in reduced installation costs for projects.
7. Various Construction Methods: HDPE pipelines offer a range of construction techniques, including traditional excavation, as well as trenchless methods such as jacking, directional drilling, lining, and pipe bursting. These options are ideal for locations where excavation is not permitted.
