HPR3614: Everything You Always Wanted to Know About PEX Part 02- The Joy of PEX - What is it and how is it us

Everything You Always Wanted to Know About PEX
Part 02- The Joy of PEX - What is it and how is it used?

What is PEX?

According to Wikipedia, Cross-linked polyethylene tubing is commonly abbreviated PEX, XPE or XLPE -https://en.wikipedia.org/wiki/Cross-linked_polyethylene
This tubing is made of crosslinked polyethelene chains
Type A, Type B, & Type C
These differ based on the process used to make them and the resulting properties of the resulting tubing
PEX is used for a variety of products
Insulation on high voltage high tension electrical cables
Domestic water pipes
Irrigation and hydroponic systems
Natural gas and oil pipes
Chemical handling and storage systems

Domestic plumbing

Advantages
Flexible – easy to install and fish through walls and crawl spaces
It will stretch a little – Less likely to rupture if water contained in PEX freezes
Does not rust or corrode
Less expensive than copper
Multiple colors for easy identification
Easy to cut
Connections are easy

Type A – Expansion PEX
Process

A roughly 1/2" - 3/4"sleeve of slightly larger PEX expansion sleeve is slipped over the end of the PEX-A tubing
A special tool is inserted into the end of the tubing which stretches it outward a predefined amount.
The tubing is slipped over the end of the desired PEX-A connector and allowed to shrink back to normal size, creating a seal
Video: https://www.youtube.com/watch?v=Xot95W8vni0

Advantages

Fast and easy to install
Can install in tight places, since tool does not need to be at the connector
More resistant to damage from kinks if bent over too tight a radius
More resistant to damage from freezing

Disadvantages

The tool is expensive (~$300 - $600 USD)
In the United states, PEX-A connectors have limited availability in typical hardware and home improvement stores

Type B – Crimp PEX (Doesn't stretch)
Process

A metal ring or band is placed around the end of the PEX-B tubing
The tubing is slipped over the end of the desired PEX-B connector
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
Video: https://www.youtube.com/watch?v=U-t-ZeHv9s0

Advantages

Fast & easy to install
Crimping tools are less expensive
Higher availability of a wider range of connectors at typical home improvement stores in the United States

Disadvantages

If PEX-B is kinked, that portion is no longer safe to use and it must be replaced.
Can be more difficult to connect in tight places
This can be remedied with the use of SharkBite press on fittings.
Less resistant to damage from freezing.

Connections are also easily removed
Disadvantages
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)

https://www.doityourself.com/stry/how-long-can-pex-piping-be-exposed-to-sunlight
https://www.flowguardgold.com/en-us/blog/the-influence-of-uv-light-on-plastic-plumbing-systems

Long term durability yet to be proven
Non-conductive (electrical ground)
Not rigid – Must be supported
May induce an odd taste to water for the first few weeks.
Some say PEX can leach toxins into water

Norwegian Institute of Public Health study says PEX is safe https://www.sciencedaily.com/releases/2011/11/111108132905.htm
Ewg.org article expresses doubts to safety https://www.ewg.org/news-insights/news/amid-pipe-wars-researchers-wary-plastic-pipes-leaching-chemicals