Polyethylene (PE) piping for water supply is a replacement product for steel pipes and polyvinyl chloride (PVC) drinking water pipes.
PE piping can withstand certain pressure, 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 piping materials. 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, thus offering a wide range of melt index choices, typically between 0.3-3g/10min.
Compared to traditional piping materials, HDPE pipe systems offer the following range of features:
1. Polyethylene pipe systems are connected using electric heat fusion.
2. Polyethylene has a low-temperature 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 susceptible to corrosion from various chemical agents; the chemicals present in the soil do not cause degradation to the pipes. Therefore, they are less prone to rotting, rusting, or electrochemical corrosion; additionally, they do not readily promote the growth of algae, bacteria, or fungi.
4. Excellent Flexibility: The flexibility of HDPE pipes allows for easy bending, enabling engineers to navigate around obstacles by altering the pipe's 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 that 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 Transport: HDPE pipes are lighter than concrete pipes, galvanized pipes, and steel pipes, making them easy to handle and install. This reduces the need for excessive labor and equipment, ultimately lowering installation costs for the project.
7. Various Construction Methods: HDPE pipes offer a range of construction techniques, including conventional excavation. Additionally, they can be installed using non-excavation methods such as jacking, directional drilling, pipe lining, and pipe bursting, making them an excellent choice for locations where excavation is not permitted.
