What is the pipe material for residential radiant floor heating?

What is the pipe material for residential radiant floor heating?
Would like to know the most common of effective material and the approximate amount of pipe/ft2 if possible. Any sources with this info would also be great.

Thanks!


Answers:

Chosen Answer
Steve G:  Probably the most common pipe in use for new installations is PEX. PEX used for heating has an oxygen barrier. It's called PEX-Al-PEX (the barrier is aluminum).

Here's a place that carries it:

http://www.houseneeds.com/shop/atop/radiantheatingindex.asp
2010-11-28 00:29:11