“De-zincification” with Zurn PEX Fittings
I happened to read an old article yesterday about a serious problem with Zurn pex fittings. Apparently, over time they can lose their zinc, become corroded and weakened and fail. They call it ‘dezincification.’ During this process, the fittings can actually give off lead which leaches into the water. There was a class action lawsuit that came and went unknown by me, in my ignorant bliss.
We plumbed our home with pex in 2007 and have been so happy with it, no complaints. However, after reading this article I thought I had better check the condition of the fittings. Some of them are visible in the utility closet and they do, indeed, look like they are corroding.
Has anyone else had this problem and, if so, how did you handle it? Zurn has replaced their brass fittings with plastic ones, which don’t inspire a lot of confidence.
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I’m not sure how loosing zinc would also release lead. How old are these fittings? Lead-free solders, for example, have been required for decades now. Whether or not any metal will leach out of a fitting into the water depends on the water chemistry. The widely publicized water issues in Flint were due to the water authority there switching water sources (from the Detroit river to the flint river), and then cheaping out and not treating the water properly which resulted in lead leaching into the water in certain areas that had old pipes. I think the treatment they cheaped out on resulted in too-low phosphate levels but I may not be remembering correctly on that part.
It is entirely possible your fittings are only corroded on the outside and are fine inside the pipe. I have this problem at work with very large chilled water systems. The corrosion inhibitors work great inside the pipe where they are not exposed to air, as soon as they leak out they seem to become corrosion enhancers on the outside of the pipe where exposed to air.
The only way to be sure would be to cut one of the fittings open to inspect it. You may find that they’re fine, in which case you don’t need to worry about the others. If one is corroded, they probably all are due to them all being exposed to the same water chemistry. I can tell you that my mechanical contractors love PEX, but they only trust the compression type fittings that are installed with a big crimp tool. I don’t trust the push-in fittings long term.
Bill
Thanks, Bill, I sure hope you're right. My fittings are from 2006. Here's a few links on the subject:
http://www.plumbingfittingsettlement.com/FAQ.aspx
https://inspectapedia.com/plumbing/PEX_Brass_Fitting_Leaks_De_Zincification.php
https://www.nace.org/Corrosion-Central/Corrosion-101/Dezincification/
Here's an example of a fitting I am worried about. It really looks like it's about to let loose, to me (the crimp ring, at least).
That connection looks just fine to me, a little surface discolouration is all I see. The right hand one is asymmetrical, but it started out that way with a poor angle on the crimper when they installed it, not because it has shifted at all. As long as it held then it was first pressure tested, I can't see why it would let go now. As Bill said, it might be worth taking one out and looking at the inside to reassure yourself.
Thanks, guys, this has taken a load of worry off my mind. I would like to take one off and get a better look at it but sounds like it's not terribly urgent.
One question maybe one of you might know the answer to, I have a water softener in this utility closet and wondering if dumping the salt into it may get into the air and corrode things faster?
Yes, I have had this happen. Some type of coating (like LPS3) might help.
Those are not exposed to water so unless metal is migrating through the plastic you should be okay.
That said they would be corroding by contact with air so they are likely corroding from the outside in.
Also they should have no lead in them to leech, or do they?
The fitting in the pic you posted looks fine. It just shows the usual petina grass gets as it ages. Corrosion would usually be a blue/green color and would have a crusty look to it.
Your fitting is older than the date lead-free fittings were mandated. I wouldn’t worry about that though, any lead content will be very small and you’re unlikely to have any signfitidant leaching unless you have strange water chemistry (acidic).
Regarding the salt in your water softener, that could be a concern, but it’s easy to minimize any risks. Usually either high-quality pelletized salt, or block salt. With block salt you’ll have no dust but they’re more difficult to handle. Pellets have minimal dust. Don’t use rock salt, it’s dusty and the dirt in it will gradually clog your softener.
Bill
I know it's been a while since this post was opened, but I wanted to make a remark here. Those fittings don't look fine to me. Well, the fitting itself does (almost), but the crimp rings don't. And I do see what could be indication of a little zinc escaping on the fitting (the white coloration). I have fittings that I buried underground, wrapped in Silicone and the whole bit... on 1.5" PEX. Did the install 3 years ago. Unfortunately we have about 50 fittings 5 feet underground in 20 different areas (don't ask but it was necessary short of running 400% more pipe), and now they are starting to fail left and right... on number 4 failure now in the last couple of months... just cracking right at the joint. I thought maybe because they where stressed when backfilled, but when I was repairing one, I put just a little stress on another trying to straighten the pex pipe a little, and it snapped like a toothpick. Not a good situation. My fittings do not display any white residue, just a blue/green discoloration which I find concerning. That's all I know for now, but if these are all defective it will be a $20,000 repair job when all is said and done, as I have to use a $60 union plus the regular fittings for each repair, since the pipe is too inflexible to allow for the insertion of both ends of the new joint. Even worse, I've been replacing with the same types of brass fittings because I can't find any other options for 1-1/2 PEX. If anyone knows of a source for 1-1/2" PEX Stainless Steel (SS) fittings, please, by all means, post a reply here. Thanks!
Can't help you with stainless but you can look at F1960 fittings. Some of the ones with the plastic expansion rings are compatible with both types of PEX and come with plastic fittings. The expansion tool is pretty pricey though.
If this won't work, I don't think it will be all that costly to have a machine shop turn you the 50 or so fittings out of thick wall stainless pipe.
Also watch for pex rings, lot of them are now copper coated steel.
Hi Akos, thanks for the reply. As far as I understand it, you can't use the expansion rings on Pex B for various reasons (damage, won't contract back to shape the same). Regarding the PEX rings, that's for the tip... All the ones I've cut are solid copper... from SupplyHouse.com. Lastly, I will call and check, but I'd suspect a machine shop would be cost prohibitive cuz they'd have to make a separate mold for each fitting as probably $1000 for each.
You can get stainless steel T's, 90s, and hose barbs, they're all commonly used for water well applications with PE pipe. You might be able to find some that will fit your PEX, then you can assemble the fittings you need from those basic components. That might be an option for you.
Akos is right about the crimp rings. The steel ones will rust out over time underground. You need the "old school" ones, which should still be available. If you go to a commerical plumbing supply house instead of a box store, you should be able to specify what you want.
BTW, if you have to run underground pipe over a good distance outside, try using HDPE pipe and thermal fusing the sections together. This avoids the need for couplers, and you can make sweeps instead of 90s. All the utilities use HDPE pipe these days, and it's thermally fused which is much more reliable than any type of fitting. It's probably too late on your "already done" project that just needs repairs, but it's something for others to consider if they have large-scale outdoor plumbing projects. You can run water and gas lines this way, just use the proper type of HDPE pipe for each application. The same goes for electrical and communications conduits.
Bill
Hi Bill, thanks. I have not been able to find any SS hose barbs that will fit the ID of my PEX. Do you know of any that are compatible? Have you had experience with this? My understanding is that those barbed connectors, are a very different size than the PEX ID. All my PEX rings are good... it's the fittings that are snapping. Thanks for the tip on thermal fusing. Obviously, as you stated, too late for this project... and we did "sweep" everywhere. No 90's underground... just lots of Tee's. I'm assuming PEX can't be heat fused. Do you know of any PEX repair fittings so I don't have to add the repair union in addition to the new fittings like i've been doing (see my prior pic), cuz by doing this, I'm just adding even more underground fittings to those that I already have.
I would suggest a mechanical supply house, which is not quite the same as a plumbing supply house, for the fittings. You’ll have to ask, but you might get lucky. It’s worth a shot. Btw, regarding Akos suggesting a machine shop, the shop won’t make “molds”, they will turn the fittings on a lathe from rod or tube stock. All they have to do is drill or ream the center bore, then cut the threads and the barb on the exterior. It’s not even precision work, so it would go faster than you’d think. I do think it would still be fairly expensive though, so I’d hunt around for factory made fittings first.
I don’t see any reason why PEX couldn’t be thermally fused, but you’d need someone with the fusion rig and the right die set for the pipe you have. If you can find someone with that equipment, and I’d check with utility contractors that do directional drilling work, then you could at least avoid unions and splices. You’d still need the tee fittings though. I suspect some kind of metal embrittlement, which might be due to your soil chemistry. Try coating the fittings with epoxy paint before hiring them to help with this. I’ve had some luck using epoxy paint to stop deterioration of old cast iron drain pipe and fittings in the past, so it might help here too.
If you have a machine shop make your fittings, ask that they make them from 316 stainless (that is an alloy spec number). 316 is the most corrosion resistant of the common stainless alloys. It’s more expensive than 304, but it should last forever in your application.
I’ll try to remember to ask my directional drilling contractor if they have ever fused PEX before. I have them bidding a job tomorrow. Normally they work with HDPE pipe, but I’ll try to remember to ask if they’ve ever tried anything else in their fusion rig. I’ll reply back if they know anything.
Bill
Another benefit of getting them machined is you can modify the design so you don't need a coupler.
Have them make the coupler without the stop in the center and with longer barbs (overall maybe 1.5" longer). Cut back the pex to take out the section that was crimped, slide the new fitting mostly into one side, line up the two pipes and slide the fitting into the other one. Won't be fun with 1.5" pex but I think it should be doable.
T fittings would be pretty pricey to machine though, so a better option is to have them make PEX to NPT and thread those into a stainless T. Again, make the barb on the PEX extra long.
Akos, you sound like an engineer :-) I like to tell customers sometimes that when you start thinking as an engineer, you can start thinking "I can't find what I want in the catalog, but I can DESIGN what I NEED and make it custom" :-)
Bill
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De-zincification caused a big problem here in NZ some years ago with Dux brand PEX fittings. The fittings would corrode where the plastic pipe is crimped to the barb section and then leak. To my (limited) knowledge the problem has since been cured with a change of alloy.
Have a read here...
https://www.canada.ca/en/conservation-institute/services/conservation-preservation-publications/canadian-conservation-institute-notes/dezincification-brass.html