High density polyethylene (HDPE) piping systems have been used for municipal and industrial water applications for over 50 years. Within PPI's Building & Construction Division, HDPE pipes are used for ground source geothermal applications, also known as earth energy or geoexchange systems.
For other applications of HDPE piping systems, please refer to the webpages of PPI's other divisions.
HDPE is currently produced from compounds with pipe material designation codes of PE 3608 or PE 4710, and a color and ultraviolet stabilizer code of C or E, per ASTM D3350.
HDPE is available in both IPS (iron pipe size) and CTS (copper tube size) sizes. IPS sizes are more common in geothermal ground loop applications. HDPE tubing and pipe are produced in coils and straight lengths. Consult the specific HDPE manufacturer's literature and listings for appropriate pressure ratings.
High density polyethylene (HDPE) is a plastic resin made by the copolymerization of ethylene and a small amount of another hydrocarbon. The resulting base resin density, before additives or pigments, is greater than 0.941 g/cm.
The piping material is critical to the overall success of the ground source geothermal system. It must provide corrosion resistance, chemical resistance, flexibility, impact resistance, resistance to slow crack growth, long-term hydrostatic strength (pressure capability), and temperature resistance. In addition, the ground loop heat exchanger material must provide suitable heat transfer capabilities.
HDPE is a tough, durable piping material with unique performance properties that allow for its use in a broad range of applications, utilizing a variety of different construction techniques. In the ground source geothermal industry, HDPE was one of the earliest piping materials utilized, thanks to its combination of characteristics which meet the specific demands of these applications, as listed above.
HDPE piping systems are approved for geothermal ground loops in all model codes across the United States and Canada.