PPR, CPVC, uPVC and HDPE: Choosing the Right Plastic Pipe

Plastic piping is selected by service, temperature and jointing method rather than by price alone. Each of the four common materials has a clear place.

PPR

Polypropylene random copolymer is fusion welded: the pipe and fitting are heated and pushed together to form a single homogeneous joint with no additional material. Widely used for hot and cold potable water distribution inside buildings. Requires a fusion machine and trained operators, but produces a very reliable joint when done correctly.

CPVC

Chlorinated PVC is solvent-cemented and handles higher temperatures than standard PVC, which is why it appears in hot water services. Installation is quick and needs no heating equipment, but cure time before pressurising must be respected — rushing this is the most common cause of leaks.

uPVC

Unplasticised PVC is solvent-cemented and used for cold water, drainage and waste. It is not suited to hot water service. Cost effective and easy to install, with a wide range of fittings.

HDPE

High-density polyethylene is butt fused or electrofused and is flexible enough for long buried runs. Common for underground water mains, irrigation and drainage where ground movement and long lengths matter.

Selection points

• Is the service hot, cold, drainage or buried?
• What jointing equipment and skills are available on site?
• What working pressure and temperature does the system see?
• Is the pipe exposed to sunlight during storage or after installation?

A note on storage

Plastic pipe left in direct sun on a Gulf site degrades. Store under cover, support it evenly to avoid permanent bowing, and keep solvent cements sealed and within their shelf life.