Uponor Solutions:
Commercial Plumbing

Uponor PEX Tubing and Plumbing FAQs for Engineers

What is PEX?
What is the difference between PEX-a, PEX-b and PEX-c?
What are the temperature and pressure ratings for Uponor PEX?
What are the Uponor PEX manufacturing standards?
What are the Uponor PEX listings?
What are the Uponor PEX codes?
Why is PEX better than copper?
Has Uponor PEX piping undergone extensive testing?
How long has Uponor PEX been used in plumbing systems?
Where can I find specifications and submittals?
Does Uponor offer a warranty on its PEX plumbing system?

PEX is an acronym for crosslinked polyethylene. It is a flexible, durable, corrosion-resistant product that possesses distinctive properties that make it ideal for plumbing systems. There are three different types of PEX tubing: PEX-a, PEX-b and PEX-c. Uponor manufactures PEX-a tubing, which is considered the superior type of PEX in the industry.

All three PEX manufacturing processes generate tubing that is crosslinked to varying degrees and are acceptable for potable-water and hydronic radiant floor heating applications.

  • PEX-a is manufactured using the  Engel or peroxide method
  • PEX-b is manufactured using the Silane method
  • PEX-c is manufactured using the E-beam (electron beam) or radiation method

Uponor manufactures PEX-a tubing. The PEX tubing industry considers PEX-a superior because the crosslinking is done during the manufacturing process when polyethylene is in it amorphic state (above the crystalline melting point). Because of this, the degree of crosslinking reaches around 85% (higher than PEX-b or PEX-c), resulting in a more uniform, more flexible product with no weak links in the molecular chain.

Uponor PEX carries the following hydrostatic temperature and pressure ratings.

  • 200°F (93.3°C) at 80 psi
  • 180°F (82.2°C) at 100 psi
  • 120°F (48.9°C) at 130 psi (½" piping only)
  • 73.4°F (23°C) at 160 psi

In accordance with ASTM F876 Standard Specification for Cross-linked Polyethylene (PEX) Piping, the excessive temperature and pressure capability for Uponor AquaPEX® is 210°F (99°C) at 150 psi.

Uponor PEX tubing is manufactured to the following standards.

  • ANSI/NSF Standard 14 — Plastics Piping System Components and Related Materials
  • ANSI/NSF Standard 61 — Drinking Water System Components — Health Effects
  • ASTM F876 — Standard Specification for Cross-linked Polyethylene (PEX) Piping
  • ASTM F877 — Standard Specification for Cross-linked Polyethylene (PEX) Plastic Hot and Cold Water Distribution Systems
  • ASTM F1960 — Standard Specifications for Cold Expansion Fittings with PEX Reinforcing Rings for use with Cross-linked Polyethylene (PEX) Piping
  • ASTM F2023 — Standard Test Method for Evaluating the Oxidative Resistance of Crosslinked Polyethylene (PEX) Piping and Systems to Hot Chlorinated Water
  • ASTM F2657 — Standard Test Method for Outdoor Weathering Exposure of Cross-linked Polyethylene (PEX) Piping
  • ASTM E84 — Standard Test Method for Surface Burning Characteristics of Building Materials
  • CAN/ULC-S102.2 — Standard Method of Test for Surface Burning Characteristics of Flooring, Floor Covering and Miscellaneous Materials and Assemblies
  • ASTM E119 — Standard Test Methods for Fire Tests of Building Construction and Materials
  • UL 263 — Standard for Safety for Fire Tests of Building Construction and Materials
  • CAN/ULC-S101 — Standard Methods of Fire Endurance Tests of Building Construction and Materials
  • ASTM E814 — Standard Test Method for Fire Tests of Through-Penetration Fire Stops
  • CAN/ULC-S115 — Standard Method of Fire Tests of Firestop Systems
  • AWWA C904 — Cross-linked Polyethylene (PEX) Pressure Pipe, ½ in. (12 mm) Through 3 in. (76 mm) for Water Service
  • CAN/CSA B137.5 — Cross Linked Polyethylene (PEX) Piping Systems for Pressure Applications
  • CAN/CSA B214 — Installation Code for Hydronic Heating Systems
  • UL 1821 — Standard for Safety for Thermoplastic Sprinkler Pipe and Fittings for Fire Protection Service
  • CAN/ULC/ORD-C199P — Combustible Piping for Sprinkler Systems

Uponor PEX tubing conforms to the following listings. Be sure to visit the listing agency’s website for complete details.

  • cNSFus-rfh
  • cNSFus-pw
  • cNSFus-fs
  • cQAIus
  • UL
  • CSA
  • WH
  • ETL
  • PPI TR-4
  • ICC-ES
  • BMEC
  • CCMC

Uponor PEX tubing meets the following codes:


  • ICC
  • IPC
  • IMC
  • IRC
  • UPC
  • UMC
  • NSPC
  • HUD
  • UFGS
  • NPC of Canada
  • NBC of Canada

Uponor PEX tubing has several benefits over copper pipe. Because of its flexibility, Uponor PEX can bend with each change in direction. This means fewer connections are required, which, in turn, means fewer potential leak points. This flexibility also enables it to expand up to three times the piping’s diameter, which means it is more resistant to damage from frozen water in the system.

Yes. Uponor PEX tubing has undergone decades of rigorous testing. In 1973, Uponor (then Wirsbo), submitted PEX tubing samples to an independent laboratory. For three decades, these samples underwent continuous hydrostatic tests at extreme temperatures and pressures — up to 203°F and 239 psi. When the 30-year life cycle tests were concluded, not a single piece of Uponor PEX had experienced any breakdown or failure.

Uponor, formerly Wirsbo, was the first to bring PEX radiant floor heating to North America more than 40 years ago. And Uponor was the first to bring PEX tubing for plumbing to the market in 1993 — more than 20 years ago — longer than any other flexible plumbing system on the market.

You can find specifications, submittals and other technical documentation in the Technical Support section on www.uponorpro.com.

Yes. Uponor proudly backs the PEX tubing and ProPEX® fittings in its plumbing systems with a 25-year limited warranty when installed by an Uponor-trained professional.