PEX Tubing & Piping

Applications & Properties of PEX Piping

Installing both building water supply piping and heating supply piping (and radiant heating) can be significantly faster using PEX tubing because of its ability to bend around turns, avoiding some elbows, 45's and other fittings.

PEX piping is used in both hot and cold water applications (see the blue and red colors below). By convention the builder uses blue PEX for cold water and red PEX for hot water supply piping lines.

Generally you will find PEX piping or tubing marked with the nominal pipe size, wall thickness, and pressure rating and other information (see the illustration just below).

Temperature and pressure ratings for PEX, according to Zurn Manufacturing's engineering specifications is 160 PSI at 73°F, 100 PSI at 180°F, and 80 PSI at 200°F.

Illustration of PEX tubing markings - courtesy Zurn Manufacturing (permission requested 12/2010). [Click any image or table to see an enlarged, detailed version.]

When installing PEX piping, care must be taken that the pipe does not contact heating ducts.

If the pipe freezes, it is less likely to burst than and copper piping. Also, most types of plastic water pipe tend to sag and should be well supported by hangers

Watch out: PEX plastic water piping should not be installed outdoors or exposed to sunlight for long periods. The red and blue PEX piping shown below (right) were delivering hot and cold water in a newly-constructed home. The larger black ABS plastic pipe is probably a drain line.

Watch out: do not use plastic piping nor any other type of piping in applications for which it was not intended, or the result could be dangerous. For example, do not use PEX tubing for LP or natural gas piping.

PEX Tubing Connectors: Types, Tools, Requirements

Watch out: a variety of patented PEX tubing push-fit and clamp connecting fittings (at least six types) and connector crimping tools are on the market.

You may not obtain a proper and secure PEX connection if you mix tubing connector fittings and crimping tools improperly.

We recommend choosing a specific connector type and crimping tool and using it consistently at a given plumbing installation.

See PEX BRASS CONNECTOR LEAKS for an update on field reports of de-zincification corrosion and leaks at brass PEX pipe connectors, elbows & tees.

Examples & Photographs of the various types of PEX fittings and the special tools used include:

• Clamp type PEX fittings (photo at left) using a brass connector and stainless steel clamp-rings (e.g. Hydro-Pex clamping tool). These connectors were in use in our PEX installation photograph above. Popular, easy to use.
  
  Note in our PEX photo at left that on the cold water (blue) Tee fitting one of the clamp fittings remains to be completed. (Photo courtesy Galow Homes).

• Crimp type PEX fittings (photo above - Crimp type PEX fittings on white PEX tubing (from Zurn) in a Haddonfield New Jersey home) (e.g. Watts Radiant PEX cramping tool) using Hydro-Pex fittings.
  
  The copper crimp rings are used with most PEX connectors.
  

• Compression type PEX fittings (photo at left) (radiant heating and other applications) uses three parts (connector, compression ring or ferrule, threaded nut) to connect PEX tubing to a radiant heating manifold.
  
  Threaded nut and ferrule are used with an insert to prepare the tubing for connection to the manifold.
  
  No special tools are needed and compression type PEX fittings work with standard and Pex tubing.

• Expander type PEX fittings (photo at left, Expander type PEX fittings in a Tivoli NY home), e.g. ProPEX brass connecting fittings and the ProPEX expander tool from Uponor (formerly Wirsbo PEX fittings).
  
  The expander tool actually expands or "stretches" the PEX tubing to accept the connecting fitting. A ProPEX ring of larger diameter covers and completes the expanded fitting connection. Popular with professional plumbers.
  
  Our PEX tubing photo (left) illustrates three PEX installation details: use of expander-type PEX fittings, and at the photo bottom (blue cold water piping) a protective sleeve or bushing at the floor joist penetration, and a steel nail plate to protect the tubing from puncture by ceiling drywall (to be installed).
  
  Watch out: use only with PEX A-quality fittings. lower quality tubing will not make secure PEX connections with this method.
  
  Watch Out: : in best construction practices all holes drilled through structural floor joists (shown at left) would be made in the center of the joist, not near the bottom as in our photo.

• Press-fit type PEX fittings from Wirsbo, Mr. PEX, and Viega. (do not assume you can mix fittings and tools among these three manufacturers). Use the Viega PEX press tool requires using Viega fittings, for example.
  
  The Viega press PEX fittings are sold separately from the required stainless steel press PEX rings OR you can buy Viega pex press fittings that include the crimp ring already combined with the fitting.
  
  When using the Viega method with the integrated fitting and crimp ring you'll need to look closely to assure that you have inserted the fitting fully into the tubing before crimping the sleeve using the Viega tool. Works with standard and Pex tubing.

• SharkBite PEX push-fit fittings (photo at left) - push-in fittings (also work with copper and CPVC). No tools or rings are required.
  
  We used the SharkBite fitting shown at left to temporarily cut and discontinue active hot and cold water plumbing lines during a building renovation/addition project. The fittings avoided having to drain piping and solder end caps onto pipes that were later to be further cut back, excavated, and permanently capped below the slab.
• SharkBite Plumbing Solutions, SharkBite USA 2300 Defoor Hills Rd. NW Atlanta, GA 30318 USA Tel: 1-877-700-4242
  
  SharkBite Canada 74 Alex Avenue Vaughan, Ontario, L4L 5X1 Canada, tel: 1-888-820-0120 retrieved 2020/01/19 original source: https://www.sharkbite.com/
  
  SHARKBITE INSTALLATION GUIDE [PDF] (2018) Reliance Worldwide Corporation 2300 Defoor Hills Rd NW, Atlanta, GA 30318 Phone: 1-877-700-4242 Fax: 1-877-700-4280 rwc.com Reliance Worldwide Corporation (Canada) Inc. 74 Alex Avenue Vaughan, Ontario, L4L 5X1 Phone: 1-888-820-0120 Sales Inquiries: canadasales@rwc.com Orders: canadaorders@rwc.com retrieved 2019/08/13 original source: https://www.sharkbite.com/sites/g/files/rgohfh321/files/2018-05/SharkBite_Installation_Instructions_2018_WEB.p


• PEX Tubing cutter - used to make a clean end-cut, e.g. Wirsbo (now Uponor) PEX cutter

See PEX BRASS CONNECTOR LEAKS for an update on field reports of de-zincification corrosion and leaks at brass PEX pipe connectors, elbows & tees.

Types of PEX Cross-Linked Polyethylene Tubing

Four methods of creating cross-linked polyethylene, each possibly imparting different properties to the PEX piping or tubing, include

1. PEX-A or PE-Xa = using peroxide, developed by Engel, PAM, Frankische and others, this form of cross-linked polyethylene uses peroxides (oxygen atoms with an oxidation state of -1) to provide the highest level of molecular cross-linking at the atomic level in the plastic as the plastic polymer is formed.
   
   PEX-A is the most-flexible and most kink-resistant of these forms of polyethylene tubing.
2. PEX-B or PE-Xb = using silane, developed by DOW Corning / Sioplas. Pex-B is also referred to as "steam" or "moisture" cross-linked polyethylene.
   
   Unlike PEX-A, PEX-B cross-linking occurrs after the high-density polyethylene has been extruded into tubular form; the tubing is then passed through steam supplemented by silane (a catalyst) to form cross-links in the polymer tubing.
   
   PEX-B is not expandable and has a lowered kink-resistance.
   
   Excerpting from Conbraco, APOLLO PEX-B PIPE Submittal Sheet [PDF] Conbraco Industries, Inc., Matthews NC 28105 USA, Tel: 1-888-229-2874, Web: apolloflow.com
   Excerpts:
   PEX tubing is cross-linked, high-density polyethylene. It’s available in white, red, or blue colors for easy identification of hot and cold water lines. The silane method, also called the “moisture cure” method, results in PEX-B. In this method, cross-linking is performed in a secondary post-extrusion proce
   
   ss, producing cross-links between a cross-linking agent. The process is accelerated with heat and moisture. The cross-linked bonds are formed through silanol condensation between two grafted vinyltrimethoxysilane (VTMS) units, connecting the polyethylene chains with C-C-Si-O-SiC-C bridges.1 PEX tubing is for use in hot and cold potable water distribution systems as well as hydronic radiant heating systems.
   
   PEX tubing can also be used in “continuously recirculating” plumbing systems up to 140° F while maintaining chlorine resistance. The tubing may be installed in concrete, gypsum based lightweight concrete, sand, asphalt, in or under wood flooring, or behind wallboard or plaster.
   
   Watch out: do not try to connect PEX-B by shoving its end over a fitting that would cause expansion of the tubing. Doing so will lead to a plumbing failure and leaks.
3. PEX-C or PE-Xc = using electronic irridiation. Unlike PEX-A, PEX-C cross-linked after the polymer material has been formed, but instead of using steam and silane (PEX-B process) PEX-C uses gamma radiation or an electron beam.
4. PEX-D or PE-xd = using AZO (Gustavsberg-Lobonyl) - not currently in production

- Bean (2007)

Decoding PEX & Plastic Tubing Acronyms

1. HIPS Polystyrene Tubing = High Impact Polystyrene Plastic Tubing: this is a high-impact-strength tubing, NOT-PEX tubing that is used in the food industry and other industrial applications.
2. HDPE Polyethylene Tubing / PEX = High Density Polyethylene: posessing very good impact resistance, good rigidity, good heat distortion resistance at higher temperatures, a "fair" coefficient of thermal expansion, and a "fair" resistance to weathering when exposed outdoors.
3. LDPE Polyethylene Tubing / PEX = Low Density Polyethyethylene Tubing, less costly, similar in properties to HDPE but less rigid.
4. LLDPE Polyethylene Tubing / PEX = Linear Low Density Polyethylene: a form of polyethylene with increased flexibility, tensile strength, conformabilty, crack resistance. Described as imparting no odor or taste to water passing through the tubing.
5. PETG Polyethylene Tubing / PEX = Polyethylene Terephthalate Glycol plastic tubing: this is a chemical-resistant tubing (does not tolerate outdoor exposure)
6. POLYPROPYLENE (plastic) tubing: this is a lightweight NOT-PEX tubing that is heat resistant, used in automotivbe, food and beverage, automotive, appliances and other applications.

Example Colors of PEX Polyethylene Pipe / Tubing

Below the rainbow of 3/8" OD LLDPE polytethylene tubing is provided by FreshWater Systems.

In these examaple Pex tubing color choice photos, we show that PEX tubing or pipe is produced in a range of colors that include at least

Black, Blue, Gray, Green, Orange, Red, Yellow, White and also not quite "clear" but translucent such as Uponor TrffPEX SDR9 PEX-A tubing shown just below.

Below: Black Viega PEX tubing

Below: Blue & Red PEX tubing installed in a New York home.

Below: two examples of green colored PEX and PEX-B tubing from SeaTech & Zoro.

The SeaTech PEX cross-linked polytethylene tubing shown here is manufactured in a range of sizes from 3/8" CTS (1/2" OD) to 1" CTS (9/8" OD),

also 15mm and 22mm OD, and is rated for 160 psi and 80º F @ 100 psi OR at 72º F @ 160 psi.

The Zoro polyethylene pipe example is 1/4" OD, 5/32" ID, 3/64" wall thickness, 2" tubing bend radius, and rated for -50 D°F to 140°F.

Above: Gray Pex B02 tubing

Above and below: two examples of white PEX

Keep in mind that PEX or other types of plastic pipe or tubing may be installed but "disguised" by other coverings such as pipe insulation.

Below: an example of factory-insulated PEX tubing provided by Badger Insulated Pipe.

Badger describes this product: This listing is for Insulated Pipe used for Outdoor Wood Furnaces/Boilers, Geo Thermal, Solar Heating or anywhere you need to transfer heated or chilled fluids. - retrieved 2019/11/08, original source: Badger Insulated Pipe W8359 State Rd 82 Mauston, WI 53948 1-800-571-7002 rsd@badgerpipe.com

Standards, Listings and Approvals for PEX Plumbing Systems

The following standards and building codes list at least some elements of PEX plumbing systems.

• ANSI/NSF Standard 14 (NSF International)
• ANSI/NSF Standard 61
• ASTM F876 (American Society for Testing & Materials)
• ASTM F877
• ASTM F1807
• CAN/CSA B137.5 (Canadian Standards Association)
• California Plumbing Code - 2010
• IPC (International Plumbing Code)
• IRC (International Residential Code)
• UPC (Uniform Plumbing and Mechanical Code)
• U.S. State & Local Regulations or Canadian Provincial or Local Regulations

Pex Tubing / Plumbing use History & Dates

Watch out: is this "red" plastic water piping PEX? No it is red-painted Polytbutylene pipe, discussed in detail

at PB POLYBUTYLENE (PB) PIPES

In the United States the use of PEX tubing in residential buildings for water supply & heating piping has been approved for use in all fifty states and in Canada in all of the provinces.

• 1933: (accidental) discovery of polyethylene following an explosion at Imperial Chemial Industries in England
• 1939: pilot plant production of polyethylene in the U.S.
• 1940's: BASF in Germany experiments with polyethylene tubing
• 1950: beginning research on cross-linked polyethylene plastics.
• 1954: Hoechst experiments with Hoestlan high density polyethylene & predicts very long life of the tubing (more than50 years). Early tubing needed further development to withstand high temperatures.
• 1965: Engel patents an economical process for successfully cross-linking polyethylene
• 1967: First licensed use of the Engel patent to produce Vernetzes polyethylene i.e. PEX
• 1970's: PEX formulation improved by Lenman, Agren et als.
• 1975: Golan produces PEX-a & PEX-c later sold to American & Canadian interests
• 1975-85: standards for PEX piping developed by Stufen, Liedelt, Stagge & Seydel et. als.
• 1980: PEX piping introduced for use in the United States & Canada. DIN 4726 created limiting Oxygen gas transmission rate, a factor in tubing success. (Oxygen permeation / outgassing created problems in hot water heating applicatyions.)
• 1984: ASTM F876/877 Lenman published for PEX Tubing
• 1984: oxygen-related boiler corrosion problems reported associated with "non-barriered" pipe used in heating systems leads to continued research on the oxygen diffusion problem
• Latter 1980's: PEX tubing radiant heat applications developing in North America and elsewhere
• 1987: DIN 4726 standard finalized.
• 1989: CSA 137.5 for PEX published by Lenman
• 1990-2007: production of PEX a,b,c (various methods of producing cross-linked polyethylene tubing), PEX-AI-PEX, and PE-RT tubing.
• 1995: begin use of IPEX-manufactured Kitec fittings later found to fail & leak
• 15 May 1999: beginning of period of defective Plumb-Pex defective component installations in North America - for class action settlement purposes
  
  See details at PlumbPex® PEX LEAKS & LAWSUIT
• 1 January 2005: begin production of NIBCO PEX products later found to be defective.
• 2005: IPEX recalls Kitec®, or Kyetec brand of brass plumbing fittings
• 2009: California approved PEX for use in all homes.
• 2007: California, one of the last adopters, did not approve the use of PEX (cross-linked polyethylene tubing) for household plumbing until 2007 (on a case by case basis)
• 31 March 2012 - end date for filing claims re: Court ordered homeowner notification program for defective Plumb-PEX components
• 31 December 2012 - end date for production of defective NIBCO PEX Tubing, fittings, and clamps, produced since 1 January 2005.
• 22 September 2013: ending date for filing claims for the Court ordered homeowner notification program for defective Plumb-PEX components
• 26 October 2018 NIBCO PEX Class Action Lawsuit [PDF] opened, petaining to owners or occupants of NIBCO PEX plumbed buildings betweeen 1 January 2005 and the date of the class action suit; (A closure date is not yet evident - Ed.)
  
  More information: NIBCO PEX SETTLEMENT CLAIMS WEBSITE at https://www.pexsystemsettlement.com/ providing claims forms, contact information and other information for consumers.
  
  KIMBERLY COLE, et al, on behalf of themselves and all others similarly situated, [PDF] Plaintiffs, vs. NIBCO, Inc., Defendant UNITED STATES DISTRICT COURT FOR THE DISTRICT OF NEW JERSEY Civil Action No. 13-cv-7871 (FLW)(TJB)]
  
  See also PEX BRASS CONNECTOR LEAKS - web article

PEX Pipes vs Copper Piping: which is preferred?

Reader Question: Pex vs. Copper Water Supply Piping - which should I use?

Question: my daughter is doing extensive renovations on her house and the question has come up whether to use PEX or copper in the plumbing.

I did a google search and the informations is conflicted; see below

. [We read & also expanded the writer's original four web link citations in the article below - Ed.] Do you have knowledge of, and opinions about, this controversy? Any thoughts would be helpful. Thanks. Elisha Fisch, New York 2/17/2013

Reply:

Elisha I've moved this discussion on Pex pipes vs copper pipes to its own article at

PLASTIC vs. COPPER PIPES in BUILDINGS

We will continue to monitor the PEX health and contamination question and will update here. Contact Us by email to send field reports or to report on new studies.

Copper Water Supply Piping

The same PLASTIC vs. COPPER article above lists propertie of copper water supply pipes when used in buildings and compares copper pipe performance with that of plastic.

A bottom line opinion is that each plumbing material has its own vulnerabilities as well as advantages & disadvantages.

We discuss types of copper piping and their intended uses and copper fittings beginning

at COPPER PIPING in BUILDINGS.

Plumb-PEX Plumbing System Class Action Settlement - PEX piping leaks

In March 2012 people who own or previously owned a building where Plumb-PEX plumbing components were installed are notified of a proposed class action settlement involving Radiant Technology, Inc. and Uponor, Inc who sold Plumb-PEX insert fittings and stainless steel PEX tubing clamps.

Details about this PEX plastic piping failure are now at PlumbPex® PEX LEAKS & LAWSUIT

Also see PEX vs. COPPER Water Supply Piping - health & other questions

Kitec Brass Fitting & Related IPEX Plastic Pipe Leaks: Class Action Settlement

The Kitec system was a collection of brass plumbing connectors intended for use with PEX type plastic piping. Kitec, also in some sources spelled Kyetec is a brand of brass plumbing fitting that was recalled in 2005 by its manufacturer, IPEX, due to its tendency to quickly corrode. - Wikipedia [30]

Kitec plastic pipe and fittings has agreed to settle class-action suits in the United States and Canada for $125 million. The piping system that is the subject of this action was used in roughly 292,000 U.S. and Canadian homes beginning in 1995.

Details about the Kitec plastic class action suit are given in a link just below.

Is PEX the same as Kitec® ?

Is PEX the same as Kitec? How does one tell distinguish between Kitec and PEX? - Anon

Reply: Not quite: Kitec was an individual brand of PEX pipe subject of a class action settlement

Anon,

PEX (cross-linked polyethylene piping) is a general term for a type of plastic piping used in water supply, heating, and other applications.

Kitec® is a specific brand of PEX tubing that was subject of a class action settlement with an end-date for filing claims of 31 March 2012.

1. Details about plastic pipe leaks by pipe type & brand are in this topic home page:
   
   PLASTIC PIPE LEAK CAUSES
2. Kitek® PLASTIC PIPE LEAKS, CLASS ACTION SETTLEMENT discussion is found within that article.
3. PEX PIPING INFORMATION (this page) gives details about PEX across the product range
4. Information about all types of plastic piping used in buildings starts
   
   at PLASTIC PIPING ABS CPVC PB PEX PPR PVC.

Pex De-zincification Update & Research: field failure photographs of Brass PEX Pipe Fitting Corrosion & Leaks

Above left: brass tee corrosion appearing both on the Tee-fitting body (red arrow) and around the end of the PEX tubing (green arrow) on water piping in a 2009 home.

Details about corrosion, leaks, & possible dezincification problems at brass connectors used in PEX piping systems are

at PEX BRASS CONNECTOR LEAKS

PEX Piping vs Drinking Water Contamination & Pex Piping Installation Guides

• Kelley, Keven M., Alexandra C. Stenson, Rajarashi Dey, and Andrew J. Whelton. "Release of drinking water contaminants and odor impacts caused by green building cross-linked polyethylene (PEX) plumbing systems." Water research 67 (2014): 19-32.
• HUD, PPFA, DESIGN GUIDE for RESIDENTIAL PEX WATER SUPPLY PLUMBING SYSTEMS [PDF] (2006) HUD, U.S. Department of Housing & Urban Development,
  
  Plastics Pipe Institute, Inc (PPI) 105 Decker Court Suite 825 Irving, TX 75062 www.plasticpipe.org and Plastic Pipe and Fittings Association (PPFA) 800 Roosevelt Road, Bldg. C, Ste. 312 Glen Ellyn, IL 60137 www.ppfahome.org and
  
  Partnership for Advancing Technology in Housing 451 7th Street, SW Washington, DC 20410 www.pathnet.org and NAHB Research Center, Inc. 400 Prince George’s Boulevard Upper Marlboro, MD 20774 www.nahbrc.org retrieved 2019/09/20 or\iginal source: https://www.huduser.gov/portal/publications/pex_design_guide.pdf
  
  See Figure 11.2 – Snow and Ice Melt Piping for a Driveway p. 92
• HUD PEX DESIGN GUIDE [PDF] U.S. HUD - older version of the above
• MacNevin, Lance, P.Eng., DESIGN AND INSTALLATION OF HYDRONIC SNOW AND ICE MELTING (SIM) SYSTEMS TO OPTIMIZE PERFORMANCE AND EFFICIENCY [PDF] Plastics Pipe Institute, Inc (PPI) 105 Decker Court Suite 825 Irving, TX 75062 www.plasticpipe.org retrieved 2019/09/20, original source: https://www.modernhydronicssummit.com/wp-content/uploads/sites/3/2017/09/MacNevin-Summit-2017.pdf
• PEX TUBING TECHNICAL SPECIFICATIONS [PDF] PEX Universe.com (Sales of PEX tubing) Tel: 800-818-3201 original source: https://www.pexuniverse.com/pex-tubing-technical-specs
• Plastic Pipe & Fittings Assoc. PEX INSTALLATION HANDBOOK [PDF] (2016) Plastic Pipe & Fittings Assoc. , Plastic Pipe and Fittings Association 800 Roosevelt Road Building C, Suite 312 Glen Ellyn, IL 60137 www.ppfahome.org
  
  Cross-linked Polyethylene (PEX) Hot- and Cold-Water Distribution systems And Service Lines
  Excerpts:
  This manual contains information on the installation of Cross-linked Polyethylene (PEX) tubing for hot- and cold-water distribution systems in residential and light commercial installations using tubing up to 2 inch diameter.
  
  Information in this manual shall not be separated as it is often interrelated. Consult local codes for additional installation requirements.
  
  For additional information contact: Local officials having jurisdiction (for codes) Manufacturer (for specific product information) PPFA (for general installation instructions) Plastics Pipe Institute (PPI)
  
• WattsRadiant, RADIANT PEX® INSTALLATION MANUAL [PDF] (2017) Watts Radiant, USA: Tel: (800) 276-2419 • Fax: (417) 864-8161 • WattsRadiant.com
  
  Canada: Tel: (905) 332-4090 • Fax: (905) 332-7068 • Watts.ca Latin America: Tel: (52) 81-1001-8600 • Fax: (52) 81-8000-7091 • WattsRadiant.com retrieved 2019/09/20 original source: http://media.wattswater.com/IOM-WR-PAP-PEX-PEXAL-PERT.pdf
• Zurn, ZURN PEX PLUMBING INSTALLATION GUIDE [PDF] (2010), ZURN PEX®, Inc. Highway 11 EAST, Commerce, TX, U.S.A. 75428 USA, Tel: 1-800-872-7277 Web: www.zurn.com
  
  Canada: ZURN Industries Ltd., 3544 Nashua Drive, Mississauga, Ontario, Canada L4V 1L2 Tel: 905-405-8272 retrieved 2021/07/01 original source: https://api.ferguson.com/dar-step-service/Query?ASSET_ID=927224&USE_TYPE=INSTALLATION&PRODUCT_ID=3784258