Everything You Always Wanted to Know About PEX

Part 02- The Joy of PEX - What is it and how is it used?

1. What is PEX?
   1. According to Wikipedia, Cross-linked polyethylene tubing is commonly abbreviated PEX, XPE or XLPE -https://en.wikipedia.org/wiki/Cross-linked_polyethylene
   2. This tubing is made of crosslinked polyethelene chains
   3. Type A, Type B, & Type C
   4. These differ based on the process used to make them and the resulting properties of the resulting tubing
   5. PEX is used for a variety of products
   6. Insulation on high voltage high tension electrical cables
   7. Domestic water pipes
   8. Irrigation and hydroponic systems
   9. Natural gas and oil pipes
   10. Chemical handling and storage systems
2. Domestic plumbing
   1. Advantages
   2. Flexible – easy to install and fish through walls and crawl spaces
   3. It will stretch a little – Less likely to rupture if water contained in PEX freezes
   4. Does not rust or corrode
   5. Less expensive than copper
   6. Multiple colors for easy identification
   7. Easy to cut
   8. Connections are easy
      1. Type A – Expansion PEX
      2. Process
         1. A roughly 1/2" - 3/4"sleeve of slightly larger PEX expansion sleeve is slipped over the end of the PEX-A tubing
         2. A special tool is inserted into the end of the tubing which stretches it outward a predefined amount.
         3. The tubing is slipped over the end of the desired PEX-A connector and allowed to shrink back to normal size, creating a seal
         4. Video: https://www.youtube.com/watch?v=Xot95W8vni0
      3. Advantages
         1. Fast and easy to install
         2. Can install in tight places, since tool does not need to be at the connector
         3. More resistant to damage from kinks if bent over too tight a radius
         4. More resistant to damage from freezing
      4. Disadvantages
         1. The tool is expensive (~$300 - $600 USD)
         2. In the United states, PEX-A connectors have limited availability in typical hardware and home improvement stores
      5. Type B – Crimp PEX (Doesn't stretch)
      6. Process
         1. A metal ring or band is placed around the end of the PEX-B tubing
         2. The tubing is slipped over the end of the desired PEX-B connector
         3. A special tool us used to crimp the metal ring or a different tool may be used to tighten the metal band, creating a seal
         4. Video: https://www.youtube.com/watch?v=U-t-ZeHv9s0
      7. Advantages
         1. Fast & easy to install
         2. Crimping tools are less expensive
         3. Higher availability of a wider range of connectors at typical home improvement stores in the United States
      8. Disadvantages
         1. If PEX-B is kinked, that portion is no longer safe to use and it must be replaced.
         2. Can be more difficult to connect in tight places
         3. This can be remedied with the use of SharkBite press on fittings.
         4. Less resistant to damage from freezing.
   9. Connections are also easily removed
   10. Disadvantages
   11. Easily damaged by ultraviolet light from sunlight or even LED & fluorescent lights (Check manufacturer specifications. Most rated for only 30-60 days of sun exposure)
       1. https://www.doityourself.com/stry/how-long-can-pex-piping-be-exposed-to-sunlight
       2. https://www.flowguardgold.com/en-us/blog/the-influence-of-uv-light-on-plastic-plumbing-systems
   12. Long term durability yet to be proven
   13. Non-conductive (electrical ground)
   14. Not rigid – Must be supported
   15. May induce an odd taste to water for the first few weeks.
   16. Some say PEX can leach toxins into water
       1. Norwegian Institute of Public Health study says PEX is safe https://www.sciencedaily.com/releases/2011/11/111108132905.htm
       2. Ewg.org article expresses doubts to safety https://www.ewg.org/news-insights/news/amid-pipe-wars-researchers-wary-plastic-pipes-leaching-chemicals