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GENERAL
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Polyethylene (PEX) is a thermoset material made from medium or high density polyethylene that is modified to have improved properties. Pipes made from these materials are produced to meet the requirements of ASTM F876, ASTM F877, AWWA C904 and/or CSA B137.5.
PEX piping has been used in hot and cold water distribution systems and for hydronic radiant heating in Europe for decades. Introduced into the United States in the 1980's, PEX is the most widely-used flexible plumbing piping
PEX tubing is manufactured by extrusion in sizes from ¼"-2" diameter to copper tube size, OD controlled (CTS-OD) dimensions. The wall thickness is based on Standard Dimension Ratio 9 (SDR 9) values. It is available in coils and straight lengths.
SUSTAINABILITY (GREEN BUILDING)
A significant benefit of plastic pipe is its small environmental impact compared to other materials. To learn more click here.
USES/APPLICATIONS
PEX tubing can be used in service lines or potable water distribution systems provided it has been tested in accordance with the governing standard, meets the requirements of ANSI/NSF Standard 61, and bears proper certification from a recognized testing agency. PEX tubing is also widely used for heat transfer applications - both low-temperature (radiant floor heating, snow melting, and ice rinks), as well as distribution piping for temperatures up to 200 F (hot water baseboard, convectors, radiators, etc.).
CODE
STATUS
PEX tubing is recognized as acceptable for water distribution piping in all major model plumbing codes.
AVAILABILITY
PEX tubing is available from plumbing wholesalers, building centers, and manufacturers throughout the U.S.A. and Canada.
MARKING
PEX tubing must be labeled as follows:
- The manufacturer's name or trademark
- The standard to which it conforms (ASTM F876, F877, AWWA C904 and/or CSA B137.5)
- Tube size and CTS
- Material designation code (PEX0006)
- Pressure/temperature rating(s)
- SDR9
- If the tubing is for potable water, a laboratory seal or mark attesting to suitability for potable water
- ASTM fittings designations approved for use by the tubing manufacturer
The marking interval is required to be no more than five feet long.
ADDITIONAL RESOURCES
The Online Piping & Usage Specification by the Mechanical Contracting Education & Research Foundation (MCERF) informs users on pipe types, materials, applications and joining methods.