The standard specification of HDPE pipes can be classified by both of their nominal pressure (the maximum pressure that an HDPE pipe can withstand) – PN 2.5, PN 4 or PN 16, and by the material used – PE100, PE80, PE63 or PE32.
The two most commonly used HDPE pipes include PE80 and PE100.
- PE 80 – gas pipe for natural gas distribution network with pressure rate up to 4 bars or drinking water pipe with pressure rate up to 16 bar. It is also an ideal piping material for industrial and wastewater applications.
- PE 100 – high demands piping applications that provide long-term strength and creep resistance. It has a significant advantage over PE 80 at low temperatures since it is extremely crack resistant down to -30°C
HDPE pipe is very durable and flexible and can be bent on site to a radius twenty-five times the nominal pipe diameter – for SDR11 and SDR17 pipe, at or below 20°C ambient temperature. This provides major cost savings, when compared to different pipe systems, some of which require glued fittings, restraints or thrust blocks for even minor changes in direction. Because of the high impact resistance and flexibility of HDPE pipe, it is well suited to installation in dynamic soils including in earthquake-prone areas. HDPE pipe has very high flow capacity, because of its smooth bore and end-to-end jointing methods. HDPE pipe does not corrode in the environment, and will maintain its flow capabilities over time, unlike ferrous piping systems, which will rust and build up internal resistance to fluid flowing through it.
Because food-grade polyethylene virgin material is used to fabricate HDPE pipes, they are safe for the transfer of drinking water, provided that any initial debris has been flushed out. HDPE pipe is resistant to many chemicals, facilitating its use in process plants or around corrosive or acidic environments, without needing to use protective coatings or galvanising, as is required on steel pipes. As HDPE has a very low thermal conductivity, it can maintain more uniform temperatures compared to metal pipes when carrying fluids, which will greatly reduce any need for insulation to control condensation around the pipeline
