text: HDPE is resistant to many environmental factors and has applications where cheap but durable fluid piping systems are required. According to a press release from the Plastics Pipe Institute, "PE [polyethylene] piping has been used for water and other fluids in Europe and America since the 1950s due to its durability, leak-free joints, resistance to corrosion, and long-term cost-effectiveness".
  HDPE pipe can be joined by butt welding, electrofusion welding, socket welding, or extrusion welding. These joints heat the pipe during the joining process to create a completely homogeneous joint without the need for additional seals or jointing compounds, reducing the likelihood of failure or negative environmental effects. HDPE is less likely than PVC pipe to have problems with root intrusion and provides integrity for the pipeline, even when installed in unstable soils.
  Due to the fusion welding system, HDPE pipe does not need any additional supports around joints. This also allows for safer excavation close to the pipeline in the future, which is particularly important for high-pressure gas pipelines. HDPE pipe is highly durable and flexible even at lower ambient temperatures, enabling bends in the pipe system to be created with relative ease. Due to its high impact resistance and flexibility, HDPE pipe is well-suited for installation in dynamic soils, including those in earthquake-prone areas. HDPE has been considered to be cost-effective due to its versatility in installation and reduced need for maintenance. 
  Because food-grade polyethylene virgin material is used to fabricate HDPE pipes, they are safe for the transfer of drinking water. HDPE is resistant to many chemicals, facilitating its use in process plants or in corrosive or acidic environments without use of protective coatings or galvanization. As HDPE has a lower thermal conductivity than many metals it can maintain more uniform temperatures than metal pipes when carrying fluids, which reduces the need for insulation around a pipeline.