PEXa, PEXb, PEXc. Crosslink bonds, who wins?

[fastline12]

We will be selecting a PEX system for use in a radiant tube system in concrete as well as several geothermal loops. I am finding it exhausting trying to find anyone but a salesman to talk with on the subject of properties of PEX. It seems the high end or most expensive is the PEXa but some have indicated PEXb has a higher burst pressure.

Obviously, since a radiant system rarely used higher pressures, the real concern becomes elasticity over time to handle any geological or structure shifts. As I mention to all these salesmen is, who really cares what it does 30 days after mfg and is nice and flexible. What I really care about is what is it going to be like 30 yrs down the road. My experiences with other plastics indicates a large reduction in elasticity.

I am also looking for something that will at least handle a higher temp to provide a large margin for any boiler issues.

 

[tygerdawg]

Watching the thread, seeing no response. So I'll offer the suggestion: quit wasting your time with PEX stuff salesmen. Talk to the manufacturer's design or application engineers for the answers. Digging deeper, I would chase down the application engineers of the plastics producer who makes the pellets for the plastic tubing. If those guys act like most big companies, they won't say yes/no either way and would take the position that you must prove their material is suitable for your own purposes. But it may give you some insight into a lifetime testing analysis for the plastic material itself.

Then the interface of the tubing material and the hardware couplings...well, good luck finding lifetime info on that.

TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering

http://www.bluetechnik.com

 

[fastline12]

LOL. Wouldn't you know it, I have now talked with a few apps engineers for mfgrs and all of them specifically recommend their own products as being far superior... As well, they are recommending the O2 barrier stuff exclusively yet geo systems are being designed every day with good old HDPE black pipe and equipment is lasting reasonably long.

Any ideas where A guy might go to get unbiased information on materials and performance over time? Seems the multi-line distributors don't know enough to be dangerous and the mfgrs only provide info on why their product is superior.