PEX-A vs Copper (Texas)
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PlumbNuts
SC Licensed Plumbing Contractor
PEX is less expensive, it is easier to install and the pipe will expand.
I use the plastic fittings daily and I have not responded to any calls where the plastic fitting has frozen but I am not saying that they cannot freeze and rupture.
IMO, when the water starts to freeze it expands and that is what causes the rupture. In copper the pipe and fittings are the same rigidity not giving the forming ice anywhere to go whereas with Pex the pipe is capable of expanding giving the frozen water in the plastic fitting somewhere to expand to.
I live in SC and we rarely see temperatures that would cause ruptured fittings and pipes but it does happen occasionally. There may be others that have more experience with extreme cold that can more definetly answer your question; I am sure they will respond shortly.
I use the plastic fittings daily and I have not responded to any calls where the plastic fitting has frozen but I am not saying that they cannot freeze and rupture.
IMO, when the water starts to freeze it expands and that is what causes the rupture. In copper the pipe and fittings are the same rigidity not giving the forming ice anywhere to go whereas with Pex the pipe is capable of expanding giving the frozen water in the plastic fitting somewhere to expand to.
I live in SC and we rarely see temperatures that would cause ruptured fittings and pipes but it does happen occasionally. There may be others that have more experience with extreme cold that can more definetly answer your question; I am sure they will respond shortly.
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what part of Texas?
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Anything ridge can crack from ice.
Tuttles Revenge
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I posted a link to a study on the survivability of PEX to freezing. Basically the PEX A can withstand several thousand freeze thaw cycles before failing... until the distance between fittings gets to 7" and below. Then theres no room for ice to expand and it builds up pressure in between plugs.. boom.
Jeff H Young
In the Trades
For future, my guess is people will build to avoid freezing. That's important generally I think copper lives longer but freezing pipes is always bad so Choosing pipes that take cold better isn't answer its preventing them freezing that's crucial
I have no experience with frozen PEX, but it seems to me that the problem wouldn't be the PEX-A pipe but the fittings which aren't flexible. Does the pipe expand near the fittings allowing the fittings to survive?
John
Fitter30
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No PEX fittings that I am aware of are truly freeze resistant. They must be made out of very rigid material in order to seal to the pipe. You freeze them, they explode. Pipe can handle freezing.
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So how I believe pipe bursts happen is when 2 locations of water freeze very near one another. The ice expands laterally in the pipe and exerts pressure towards each other. Since water does Not compress at domestic working pressures the energy has to go somewhere.. the weakest link is the seam or sidewall of the copper pipe or as we're seeing, the weakest point in those elbows.
I use a pipe freezing machine to create frozen water inside of pipe frequently when I need to shut off a line or splice in a tee. The instructions state to place the freeze plugs 24" apart from each other. It doesn't explicitly say its to avoid pipes bursting... but it is my assumption that if I did them too close to one another, I'd have a burst pipe.... hmmm... me thinks I have a fun experiment and video idea now.
I use a pipe freezing machine to create frozen water inside of pipe frequently when I need to shut off a line or splice in a tee. The instructions state to place the freeze plugs 24" apart from each other. It doesn't explicitly say its to avoid pipes bursting... but it is my assumption that if I did them too close to one another, I'd have a burst pipe.... hmmm... me thinks I have a fun experiment and video idea now.
A glass milk bottle will handle freezing if the stopper can lift out. The ice can flow and extrude out of the top. I think that enough pex pipe near each side of the fitting would make EP (engineered plastic) survive too.
Next time you will have really cold weather, try putting a whisky bottle with water in it outside. Use no stopper. Bet the bottle does not break. Expect a cylinder of ice above the neck of the bottle.
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That makes sense. If the PEX expands on either/both sides of the fitting, it might very well let the fitting survive. The PEX might look like a snake that swallowed a rat, but eventually it will reshape as it thaws. I'll have to try putting together an experiement.
John
Uponor specifies a minimum cut length of pipe of 2" (1/2" pipe) or 3" (3/4" pipe). But they state this is to ensure that the expander head does not damage the fittings. I think that they should update their documentation to discuss the effect that the distance between fittings has on freeze protection.
With that said - one of the benefits of PEX-A is that you can avoid fittings in many cases because of the flexibility of the pipe.
It rarely gets below freezing here, and if it does, it is just barely below freezing for a few hours. Whenever it is forecast to get to freezing here (maybe once or twice per season), we get a lot of emails and local warnings about leaving the water running to avoid burst pipes.
Due to the Texas issue, I think it will be wise for me to build for freeze protection in the next couple of months when I install new hose spigots and run a new main line from the street to the house. It will be nice to not have to worry about freezing temperatures anymore.
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