Uponor Solutions:
Commercial Plumbing

Uponor PEX Plumbing FAQs for Contractors

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 listings?
What are the Uponor PEX codes?
What’s the difference between PEX and CPVC?
Why is PEX tubing better than copper?
Has Uponor PEX tubing undergone extensive testing?
Where can I find specifications and submittals?
Where can I buy Uponor products and tools?

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 tubing 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, and more flexible product with no weak links in the molecular chain.

Uponor PEX tubing 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 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

Click here to learn more


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 tubing’s diameter, which means it is more resistant to damage from frozen water in the system.

Yes. Uponor PEX 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.

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

Uponor products and tools are sold through our distributor partners. You must be a professional contractor to install Uponor products and systems. To help get you started, visit our Find a Rep page to find the local Uponor manufacturer’s rep in your area.