Both polyvinyl chloride (PVC) and high-density polyethylene (HDPE) conduit systems are cost-effective; however, there are considerations other than material cost that you should take into account when making your selection.
One is the capability of your installation crew. PVC is easy to work with and can be carried in the back of a pickup, but it can take longer to install. HDPE, on the other hand, can be rolled out quickly but it comes on large reels that may require the use of a special-purpose trailer.
Another consideration is the number and size of the bends required in your design. PVC runs need to be as straight as possible, with gentle sweeps where required using manufactured bends. Even for PVC rated for direct bury, it is recommended that bends with a curvature radius of less than 80 feet be encased in concrete. This is to avoid the possibility of the joints separating during cable pulling operations.
Alternatively, continuous runs of HDPE can handle bends without encasement, but HDPE tends to suffer from another problem. Because it is delivered on reels, HDPE will not roll out flat. Ideally, the HDPE should be rolled out next to the open trench and allowed to sit in the sun until the serpentine curves relax before being installed. This will help to minimize friction during cable pulling operations.
This was first published in June 2010