PP-R pipe

Entry in PEX and plastic supply pipe · Updated October 29, 2026 · Written by the Know Your Pipes editors from the sources listed under References

PP-R pipe, also written PPR, is pressure pipe made from random-copolymer polypropylene, a high-temperature plastic used for plumbing and for hydronic heating and cooling.^[1] Its lengths and fittings are joined by heat fusion, which melts the mating surfaces into one piece instead of using glue or mechanical rings.^[2]

The Plastics Pipe Institute says PP-R pressure piping was launched in Europe in the 1980s and introduced to North America in the 2000s.^[1] Aquatherm, a German maker founded in 1973, says its products were first sold in North America in 2005.^[3] Like PEX pipe and CPVC pipe, it is a plastic option for hot and cold water lines.

1 Material and standards

The main North American product standards are ASTM F2389 for pressure-rated polypropylene piping, first published in 2004, and CSA B137.11 for PP-R and PP-RCT pipe and fittings, first published in 1993.^[1] CSA B137.11 also covers PP-RCT, a related polypropylene grade.^[1]

One large maker, Aquatherm, says its resin is 97% polypropylene random copolymer, with the remaining 3% a masterbatch of pigments and stabilizers.^[2] Its pipe colors mark the intended use: the green line is approved for potable water, while the blue line is engineered for non-potable heating, cooling and industrial systems.^[2][3] Pressure ratings depend on the pipe's SDR and the water temperature, and are published in each maker's tables.^[3]

2 Heat fusion

PP-R is joined with a heated tool that melts the joining surfaces of pipe and fitting, which then cool as a single, homogeneous piece.^[2][3] Fusion is covered in more detail under heat fusion joints.

Methods and temperatures are from Aquatherm's published answers.^[2] Aquatherm also says work by installers who have not taken its training cannot qualify for its warranty.^[2] Transitions to other materials are made with threaded metal adapters, flanges and similar transition fittings.^[3]

3 Copper and hot-water recirculation

A 2025 Plastics Pipe Institute technical note warns that dissolved copper can sharply speed up oxidation of PP-R by chlorine or dissolved oxygen, leading to early failure.^[1] The cases reported involved mixed commercial systems in which copper tube served the mechanical room and hot-water recirculation returns.^[1] The note lists conditions that must all be present: constantly replenished chlorine and oxygen, circulating water hotter than 140°F, excessive flow through the copper, and water chemistry aggressive to copper.^[1] It calls this kind of attack rare.^[1]

The note says the concern does not apply to brass or bronze, to cold-water plumbing or to closed hydronic and geothermal systems, and that proper sizing and balancing of the system avoids it.^[1]

4 Sunlight and freezing

Aquatherm says regular UV exposure will discolor its pipe, that pipe can be stored outdoors unprotected for up to six months, and that exposure beyond six months ends warranty coverage.^[2][3] It describes the pipe as freeze-tolerant but not intended for places with repeated freezing and thawing.^[2]