Polyethylene Pipes (PE)

Polyethylene pipes are of two types; medium density polyethylene (MDPE) and high density polyethylene (HDPE) made of a virgin thermoplastic material. 20 to 630 mm OD pipes are manufactured by extrusion process. 300 to 3000 mm inner diameter pipes are manufactured by helical winding process. An extruded strip of molten HDPE is continuously wound helically around a pre-heated mandrail (rotating drum) with overlapping edges. The size of the mandrail determines the inside diameter of the pipe. During the continuous process of the helical winding, the extruder with the strip heater moves on rails parallel to the axis of the mandrail. Length of the pipe is 6 m long. In pipe design the depth of burial is the main criterion and not the internal pressure.

Advantages of MDPE/ HDPE Pipes:

1. Inner surface of the pipe is very smooth.
2. Don’t rust and free from incrustation, thus reducing the pumping cost in the long run,
3. Light in weight, thus saving in the cost of handling and transport.
4. High resistance to impact thus nullifying breakage losses,
5. Easy to join, thus speeding installation and saving cost.
6. Highly resilient and flexible, thus permitting use below traffic loads and in areas with poor ground conditions or where there is risk of ground subsidence.

Disadvantages of MDPE/ HDPE Pipes

1.  The performance and limitations are still the subject of investigation,
2. They are not recommended for use in pumping main applications under major carriage
   ways or other critical locations where consequences of mains failure may be serious, fusion welding of pipes requires specialized tools and skilled operations