Posted By BadgerBoilerMN on 06 Sep 2012 06:17 PM
Oxygen permeability is directly related to design water temperature. Consequently, PEX used for the typical slab radiant panel will likely never see water temperatures above body temperature (my last three designs were in the low 70's). The barrier is the last thing I think about in PEX. It is all better than it needs to be for most low temperature radiant applications. The proof of this it the several million feet of PB we sold in the 90's and billion sold in the world.
We recently replaces a PB snow melting system installed in 1977, which would still be operational but for the neglect of the anti-freeze. It is becoming more difficult for the manufacturers to differentiate their products, thus the emphasis of the irrelevant. If you happen to have a qualified application requiring a 100% oxygen barrier (beyond the industry standards) then a PEX-AL-PEX will be more that sufficient.
What is used in Europe is PB, and various brands of PEX including PEX-B being the most popular here and there, that made with the Saline method...the most competitive and indistinguishable once installed. We use them all preferring a soft PEX-A, for certain applications and rarely pay more for radiant slab PEX since it is the least challenging for any PEX tube. Since Rehau requires and insists on, their own fittings, tools, manifolds etc. those of us that install radiant systems nearly exclusively can't afford to handle one brand, more especially when that one brand is not rated for potable water and space heating. Viega barrier pipe is good for plumbing and heating the lack of waste paying for the inconvenience of using their very convenient and exclusive crimp system.
If PB is so great then why have there been many many law suits due to failures. This is very old news. O2 issues are not ALL about temp and if that were so there would be no issues with using un-barriered tubing in low temp situations. We know there are issues and if I am going to put in a system that I want to outlast me, I will use a better tube. Rehau does not demand that their fittings or manifolds be used with their tubing with one exception, emergency joints underground. From my experience most fittings for REHAU are now made off shore and not by or through REHAU.
PP is used in Europe for straight piping and I have yet to see a current ad for PB anywhere. PEX-A or B are fine, I see no problem with either. Veiga is good to but what I am hearing from you is mostly your preference due to the way you run your business, which if fine, of course.
No need for a pissing contest.