Uponor Solutions:
Residential Plumbing

Uponor PEX Tubing FAQs for Residential Plumbing Contractors

What is PEX tubing?
What is the difference between PEX-a, PEX-b and PEX-c tubing?
What are the temperature and pressure ratings for Uponor PEX?
What are the Uponor PEX listings?
What are the Uponor PEX codes?
What is the UV resistance of Uponor PEX?
Why is PEX tubing better than copper?
What’s the difference between PEX tubing and CPVC?
Where can I find specifications and submittals?
Where can I buy Uponor products and tools?
How do I get trained to install an Uponor PEX Tubing 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 radiant floor heating and 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" tubing only)
  • 73.4°F (23°C) at 160 psi

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

Uponor PEX 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 meets the following codes:


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

The test method for evaluating UV resistance as required by ASTM F876 is ASTM F2657 Test Method for Outdoor Weathering Exposure of Cross-linked Polyethylene (PEX). According to ASTM F876, PEX tubing must bear a four-digit code to signify the requirements it meets. The second digit in the code references the minimum ultraviolet (UV) resistance of the piping. For example, tubing with a 5106 marking has a “1” as the second digit, which indicates the piping meets minimum UV resistance requirements for a period of 1 month. Tubing with a “2” as the second digit indicates a resistance period of 3 months. Uponor AquaPEX White and Wirsbo hePEX piping carry a 5106 marking, indicating a UV-resistance period of 1 month. Uponor AquaPEX Red and Blue tubing (typically used for plumbing applications) carry a 5206 marking, indicating a UV-resistance period of 3 months.

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

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

Uponor PEX tubing 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.

Whether you need training online, on the jobsite or at the factory, Uponor offers a comprehensive training curriculum for HVAC and plumbing professionals. Uponor Academy offers webinars, field training and classroom training at the Uponor North America headquarters in Apple Valley, Minn. (a suburb of the Twin Cities). To learn about all our training opportunities, visit www.uponorpro.com/training.