Pex

In the international plumbing code it mentions two types of PEX
one says "PEX tubing" and the other says "PEX-AL pipe".....
What are the differences and what are the applications of each?

Thanks Dave

Pex-al-pex is designed for radiant heating applications. There is an aluminized layer in the middle that prevents oxygen migration, which can hurt heating systems (boilers and pumps). This isn't an issue on potable water use, since there's always some disolved O2 in the water. You just don't want a constant new supply in your closed heating system...constantly adding O2 will just corrode any ferrous metals a lot quicker. Pex without the oxygen barrier should only be used for potable...for heating systems, use one with an oxygen barrier. Now, could you use it for potable...probably...I don't know, it shouldn't matter, but there may be another issue that would.

Thanks

Thanks very much for the response it was a great help.