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PolyB in-floor heating

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This is probably one of those topics which has been discussed in detail for many years, but being new to plumbing in general I need to do some catching up! My question/problem is regarding an in-floor heating system which uses polyB piping. There seems to be a lot of spook out there about how polyB is oxygen permiable (mine does not have a barrier) and there at least two major lawsuits (DuPont and Shell) regarding degredation of the piping and fittings. My question is how and why does the pipe become unreliable? The system I have has been in place for about a decade, and it has just now shown a leak. Can I safely assume that the break was caused by the infamous polyB "breakdown" and not freezing or heaving of my slab? Do I fix the leak or tear out the slab? From your perspective is polyB safe for use in slab floor heating systems? I also read somewhere that polyB is no longer available in the states. . .sounds unreliable, does anyone know? I appreciate any insight anyone has on this topic in general! Thanks,

"Canuck" Cam

Comments

  • hr
    hr Member Posts: 6,106
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    Poly b

    there is lots of it out there in slabs. I put in plenty dateing back to the early 80's. Actually in radiant applications, low temperature, low pressure, closed loop it seems to be holding up well, although I wouldn't go back to it.

    I think chlorine in domestic water applications had a lot to do with the breakdown. It was also a fairly thin walled product and probably doesn't hold up to slab movement well. If your system has a leak and is constantly taking on chlorinated make up water, combined with the energy you are wasting....

    Depending on the make up of the components boiler pumps etc the systems may last a long time if controlled with a corrosion inhibitor or piped with non ferrous components. A lot of the original PB systems were fired with copper tube boilers leaving only the pump and possibly air purger attackable. Pull a pump from the housing and check the condition.

    I understand PB is still used in Europe, according to articles in Global Pipe newsletters. I think it is used quite a bit in the UK and O2 barrier PB tube is available also. Gary, formerly from UK, spoke about PB from time to time here.

    PB is still extruded here in the US and the Thawmaster carwash melt systems still provide it as well as some manufactured housing applications. I believe Vanguard still extrudes it. Now the acteal fittings are a different story, I luckily avoided these and used brass or copper.

    This graph is from the Global Pipe newsletter showing copper still way ahead of any other product. Interestingly composite pipe is closing in on PEX. Check out www.kwd-globalpipe.com for a good online newsletter.

    hot rod

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  • JerryJ
    JerryJ Member Posts: 19
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    P B Pipe

    I used many many feet of pb for radiant and also for plumbing and have never had a problem. Jerry
  • Canuck
    Canuck Member Posts: 57
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    Poly - B

    I'm in with hotrod. All that I've ever read about the breakdown of PB had to do with chlorine attack. There were a lot of homes in western Canada that had their domestic plumbing installed with PB. A lot of class action lawsuits as well.
  • Duncan_2
    Duncan_2 Member Posts: 174
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    What's the leak look like?

    I'm curious about what the leak looked like. A split? A pinhole? A shear or crush from a slab crack?

    From what I've heard, the polybutylene lawsuits were generated by failures of acetyl fittings that were attacked by chlorine and became brittle and failed, not the tubing itself. Maybe I'm wrong.

    I've seen graphs of oxygen permeabilty through polybutylene tubing, and at low temperatures (below 120 degrees F) it's not too bad. Not up to DIN standards, but not bad. Joe Fiedrich wrote an article about it years ago.

    I've had it in my own home in a slab for ten years now, with no dramatic effects. Just a bit of rust in the system, but no failures of iron components. On the other hand, I've also seen it run at high temps in staple up systems, and rust and component failures were significant. By that, I mean an expansion tank every few years, an iron circulator now and then. Unecessarily costly, but not crippling. But who knows what kind of rust sludge is in the bottom of the boiler? One thing about low mass copper fin tube boilers is that they sometimes have wet wall headers, so sludge doesn't settle where the fire meets the iron. I'm not advocating that kind of system, by the way.

    I'd say hot rod summed it up pretty well. Run your system at the lowest temperature possible. Personally, I'd stay away from chemicals, but hot rod's a pretty smart guy, and may know something more about that than I do. If it were me, and it started springing more leaks, I'd be making plans for another heat emitter.

    That's why I was curious what the leaks looked like, I wonder what caused them. I think it's unusual and out of the ordinary.

    Duncan
  • Cam Jorawsky
    Cam Jorawsky Member Posts: 3
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    Yet to find the leak

    First of all, thank you for all the responses so far! This forum is amazing.

    As it happens I will know more about the leak tomorrow when I look more closely at the pipe. I guess I should give more details; there is a tremendous amount of sludge and rust in the system; unsurprisingly since I don't think it was properly maintained. It is in a ranch house in southern Alberta so there is definitely no chlorine in the water, and as I understand it there are codes against using fittings under the concrete slab. . .(?) I know there is some movement of the slab, but it then becomes a chicken vs. egg discussion - did the pipe break under the slab or did the leak in the pipe cause the slab to shift. The problem comes up though, do you start digging and fix the leak or do you tear out the slab (ouch!) and completely redo the system because the rest of the lines cannot be trusted? I will admit that I am yet to find any reason to distrust polyB because aside from oxygen penetration and chlorine eating the fittings, no one can give me an answer as to what is happening with the pipe itself. Unfortunately I am one of those fools who must see it to believe it! I'm convinced that the leak was caused by more than just the presence of polyB, but other than freezing and shifting of the slab, what else could cause a leak which pops up a decade after installation?
    I appreciate anything anyone has to say on the topic - and thankyou to those who have responded, you have already been a great help!
  • Bill Clinton
    Bill Clinton Member Posts: 75
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    pb

    We used a lot of it for radiant heating from 1986 to about '92. Never had a problem with the tube. The acetal fittings used for a time were a catastrophe and they are the reason for most of the failures. Yup, it is oxygen permeable and is rusting away ferrous components of your system. Either remove the ferrous components (steel and iron) and replace with copper, brass, stainless; or go to corrosion inhibitors which do require chemical maintenance. If you are getting chlorine into those tubes, my guess is it will cause premature aging of the tube. I also guess that any slab problems you are having were caused by something other than the polybutylene. I would repair but somehow leave some slack so slab can move further without stressing the pb--maybe wrap with very spongy insulation. Yes, the rule is no fittings in the floor, but I confess to have done it when mother necessity dictated: So far with no regrets.

    Bill
  • hr
    hr Member Posts: 6,106
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    Don't abandon hope

    I would spend some time finding and fixing the leak. All of the experience I have with PB indicates it is a workable material for radiant. I suspect the leak is caused by other influnces.

    Of course should you decide to accept the redo mission consider over the top retro systems first, then slab demo last.

    A professional demo company could make that slab disapper in a day but it can be messy and expensive. Weigh you options and let us know what you find.

    hot rod

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  • Cam Jorawsky
    Cam Jorawsky Member Posts: 3
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    AHA!

    So now I have a lot more information. The house is slab on grade, which turns out to be one of the major problems. We used an IR camera to trace the lines and found a few places where the lines appeared to be leaking which corresponded to cracks in the tile floor, but they were not significant enough to lose the amount of water the owner was claiming. However, when we pressure tested the perimeter zone we found it was very positively ruptured - what I suspect right now was a result of freezing (will know more when the pipe comes out). It seems that the slab has shifted since the failure, which I think would indicate that the water injected under the slab from the perimeter zone has caused the ground to erode. The shifting of the slab then caused the remaining lines to crack along the slab crack lines. What we generally have is one big mess. . .one broken zone led to four broken zones and a cracked (and sinking) slab. We are leaking approximately 2-3psi. every couple of mintues out of the remaining lines. So basically, I don't think I have a problem with the polyB anymore - but the lawsuits almost had me convinced. Thanks again for all your suggestions (and any further ones you may have!). It's really great to see such a dedicated group of professionals! Thank you,

    -Cam

    p.s. as far as fixing the problem goes. . .well. . .this will take some thinking! A retro system would probably be best, but not if that slab is going to keep on sinking! A convection air system would be another choice, but the house is a typical ranch style with no plenum space for ducting; and slab on grade makes it hard to go under!
  • hr
    hr Member Posts: 6,106
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    Sounds like a structural problem

    with the slab. Is the house built on a foundation and footing below frost level? If you are in cold country building a home on a slab on grade, without footings, can lead to problems. The radiant system may be the least of there worries.

    The soil composition and water table under a slab will be a concern. You may need a soil analysis and a structural engineer to help out on this job :)

    good luck

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  • John@Reliable
    John@Reliable Member Posts: 379
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    Another choice

    I'm in ma. and we have alot of slab heating which were done with copper pipe back in the 60's. Needless to say most are failing due to age + copper , dirt , concrete , water just don't mix well. Most of the time we install a baseboard loop in the house using the attic for piping plus cut floor @ door ways when needed. I know some will say this is not the way to go , but most of these houses are working people with kids etc. and they don't have the money for lay over etc. so this works great for them. Hope this helps.
  • Mark Eatherton1
    Mark Eatherton1 Member Posts: 2,542
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    Joes articles...

    can be found here http://www.stadlerviega.com/html/contractor/contr_index.html

    Lots of good information here.

    BTW Duncan, I have seen PB tubing failures where it was being used to provide heat from a solar DHW system interfaced to a fan coil (McQuay)unit. ALA Solaron Solar Hearth. The tubing failed laterally. CZLose to a water treatment plant with high chlorine.

    ME


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  • Steve Ebels
    Steve Ebels Member Posts: 904
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    If you're going to retro.....

    Think about panel radiators. VERY nice heat. The ultimate in zoning if you use a trv on each one. You can pipe them with pex or pap which saves a lot of demolition expense and time. All, and I do mean ALL, of the homes I have put them in have very happy homeowners enjoying them.

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  • Meathead
    Meathead Member Posts: 2
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    Poly b

    I have had poly B in all 3 floor of my house since 1988 , One leak , which once investigated was a abrasion on the tubing

    My installer did not place one splice in the tubing in all 7 loops on a two storey house

    I thought flushing the system every year was the way to go , it just intorduced more problems , two compression tanks , two pumps and a boiler that crapped out on newyears eve . The open syetm played havoc on my wallet , I then place a filter on the back of the boiler on the boiler loop and closed the system about 15 years ago , and I have never had a problem .

    I to wonder about adding glycol to my system , its my only source of heat in the house and we do get cold temp s in northern Alberta

    I recently drew some water from the system to be tested and it look like i could drink it , it was so clean looking .

    I had a rum instead

    Question My boiler runs at about 110 degrees most winter , if I add glycol will I need to run hotter and if i do will that effect my Poly B



    ??
  • Meathead
    Meathead Member Posts: 2
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    Poly b

    I have had poly B in all 3 floor of my house since 1988 , One leak , which once investigated was a abrasion on the tubing

    My installer did not place one splice in the tubing in all 7 loops on a two storey house

    I thought flushing the system every year was the way to go , it just intorduced more problems , two compression tanks , two pumps and a boiler that crapped out on newyears eve . The open syetm played havoc on my wallet , I then place a filter on the back of the boiler on the boiler loop and closed the system about 15 years ago , and I have never had a problem .

    I to wonder about adding glycol to my system , its my only source of heat in the house and we do get cold temp s in northern Alberta

    I recently drew some water from the system to be tested and it look like i could drink it , it was so clean looking .

    I had a rum instead

    Question My boiler runs at about 110 degrees most winter , if I add glycol will I need to run hotter and if i do will that effect my Poly B



    ??
  • kcopp
    kcopp Member Posts: 4,443
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    The poly more....

    Than likely is not the problem per se. The lack of the O2 barrier is. If you separate the radiant from the boiler that is the best approach. This is done w. a heat exchanger of some type. taco makes an X- block which is plug and play...just 1 way to do it. The other option is to chemically add oxygen inhibitors to the system every year to keep the corrosion at bay. I use a product called Rhomar that has helped me in one system. Clean the System first then add the inhibitor. You can do the glycol if you really think you need it....they make that too. I am not a fan of glycol as a rule because it does require maintenance every year.
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