The Las Vegas area had used flexable piping back when it was first on the market ,its been reported a disaster to fix and most plumbers revamp the whole system at a huge price .
http://www.youtube.com/watch?v=t2RTnQXPHKk

There have been several types. What type were they using that has failed?

The "grey stuff" is typically Polybutylene and had its issues. It did not do well when exposed to chlorinated water and sunlight. "PB" pipe is no longer used due to these past issues and has been replaced by PEX in this country. If you live on a well system, the acids in the water attack copper piping and cause pitting and spritz type leaks, whereas, PEX is much better in these applications as it does not corrode. Also, PEX is flexible and withstands freezing without burst pipes much better than copper. For me, I would much rather have PEX over Copper.

I built the house I still live in in 1988 and polybutelyne (PB) was all the rage. I did my own plumbing and used it throughout. I have never had a failure (knocking wood vigorously).

There was a multi-billion class action lawsuit in the mid 1990's involving (if memory serves) Dow Chemical and others involved in the manufacture and sale of Qwest brand plastic PB compression fittings. I don't recall many issues with the pipe itself. The plastic fittings were the weak link in the chain. I used none of these. I did all of my connections with copper elbows and tees that fit snugly inside the PB pie and they are secured with a ring (that looks like a copper wedding band) crimped over the internal copper fitting. The crimper for these rings cost well over $100 25 years ago so I borrowed one from a contractor friend.

Since this was the first house I ever built or plumbed, I learned a lot in the process. For instance, I had to pressurize the supply system and let it sit over night to pass the plumbing portion of the rough in inspection. I knew typical water pressures in my area would be 40 - 80 PSI, but I had no idea how much air to put in the system for the test. So I figured about twice the expected max would be good so I put about 150 PSI in it. I wasn't there when the inspector saw the gauge, but was told he never saw a system with so much pressure. But that PB held with no issues then or ever since.

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Behind every great man is a great woman. Behind every great woman is a great behind.

You are correct that the first installations of PB pipe were done with plastic elbows/connectors and these were the first areas to fail. However, depending on the concentration of chorine that was used in your public water system, this also caused failure of the PB pipe itself. Also, pipe failures were noted in areas where the pipe was exposed to sunlight. Like most things that are "new technology" improvements were made to the connectors and also things were added to the PB pipe to resist chorine and sunlight exposure. At the same time, PEX piping came out and people switched to PEX because of all the problems with PB pipe. PB pipe, as it exists today is probably OK and I believe is still used in Europe.

In my area, houses that were plumbed with PB pipe will not sell until the house is repiped. People are just afraid of it when Home Inspectors come in and make buyers aware.

I'd use it. Oxygen barrier stuff under a poured floor though.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

PEX is allowed in 2 and 3 family new build houses as per the 2008 ICC and NYC Code.

I did 88 houses in Bushwick Gardens development that used PEX for hot/cold water piping and all Baseboard heat piping in the walls but final 12" must be copper.

Wouldn't making the final 12" of PEX joined to copper actually increase the possibility of leakage? (!)

I have always been a fan of copper but with the prevelance of junk Chinese fittings on the market, and no good way to know what you are getting until it's too late, I opted to plumb all of the supply lines in our last apartment building rehab with pex. We have spec'ed, and used pex for radiant heat for years but I have to say I've become a fan for potable water as well.

We set up individual hot and cold water manifolds for each apartment in a central location in the basement. From the manifolds (that have integral valves on each branch) we ran "home runs" to each fixture, 3/8" to sinks and toilet, 1/2" to tub/showers. The pex can be run like wire, there are no (zero) fittings between the manifolds and fixtures, nothing to leak. When repair or replacement of fixtures becomes necessary it will be a simple matter of shutting the valve at the manifold in the basement to that individual fixture. Best part was that even though we used hundreds of feet more pex than we would have used in copper, because we used virtually no fittings, the cost was 1/4 of what copper would have been. We now have ultimate flexibility and simplicity for maintenance and repair and no joints (potential leaks) in walls or floors.

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2005 C240 4matic wagon (daily driver)
87 190D - 225K (on loan)
85 190D - 312K (on loan)
2011 Subaru Legacy AWD (Wife's)

That's not the way that house was plumbed, though -- it was basically a duplicate of a copper system with a hellabuncha in-line fittings. Anyway, I didn't win the auction this AM - chose not to bid because a much better deal (true 2 fam in a Springsteenian town a block from the town line of a very toney town) came back on the market in a better area.

PEX is hard to repair, if it broke in a slab you would be in trouble. Thats what a plumber told me, but I wondered if he was just not on board yet. It requires a proper crimp which might be hard to do?? But any plastic is better at flexing than any metal.

And in floor heating is nowhere near boiling point of water.

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MB-less

Any repair to piping encased in concrete would be difficult, matters not what the material is.

In floor radiant water temp is generally well below 120 degrees in a concrete floor.

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2005 C240 4matic wagon (daily driver)
87 190D - 225K (on loan)
85 190D - 312K (on loan)
2011 Subaru Legacy AWD (Wife's)

Crazy question, but for floor radiant, why not have an existing slab with NO pipes, cover it with some sort of plastic film, put the pipes into position and pour down a SECOND slab about 3-4" thick? Maybe even pour it in sections separated by plastic to ease removal.

Alternatively, is there such a thing as 3" thick bricks/tiles pre-drilled for radiant heat piping?

Existing concrete floors are very often "capped" with an additional layer of concrete for the sole purpose of encasing a radiant system.

Jim

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2005 C240 4matic wagon (daily driver)
87 190D - 225K (on loan)
85 190D - 312K (on loan)
2011 Subaru Legacy AWD (Wife's)

Question remains, does anyone make tiles that can be used as radiant heaters?