PEX tubing health risks?
July 25, 2012 10:01 AM Subscribe
Does anyone have information on using PEX tubing for residential use, particularly regarding long term health risks?
We are renovating an old house and the plumber suggested using PEX tubing instead of copper for the piping that will run up to the new bathroom. We have some concern about potential health risks as we drink tap water from the bathroom faucet often. Any information would be appreciated. Thanks.
We are renovating an old house and the plumber suggested using PEX tubing instead of copper for the piping that will run up to the new bathroom. We have some concern about potential health risks as we drink tap water from the bathroom faucet often. Any information would be appreciated. Thanks.
Agreed. My impression from people I've worked with in the past is that you have much more to worry about from your old pipes than from new PEX pipes. If anything they should be more stable than PVC, which is safe enough that we still use it extensively but which does have some chemical leeching problems.
There has been concern about the potential for PEX to have similar problems, and some research has been done into the matter. Here is an article in Plumbing and Mechanical magazine which mentions that leeching of MTBE into the pipes from contaminated soil was a concern, but that it was ruled out. Here's another article from Reuters which cites unanimous approval by the State of California to allow PEX piping (California was the most cautious about this and the last state to permit PEX) in response to a favorable environmental impact report.
I would not be worried about using PEX from a health standpoint, certainly no moreso than other forms of piping. I think it's a good product and one of the few cases where a plastic product is actually functionally superior to its non-synthetic predecessors.
posted by Scientist at 10:30 AM on July 25, 2012 [1 favorite]
There has been concern about the potential for PEX to have similar problems, and some research has been done into the matter. Here is an article in Plumbing and Mechanical magazine which mentions that leeching of MTBE into the pipes from contaminated soil was a concern, but that it was ruled out. Here's another article from Reuters which cites unanimous approval by the State of California to allow PEX piping (California was the most cautious about this and the last state to permit PEX) in response to a favorable environmental impact report.
I would not be worried about using PEX from a health standpoint, certainly no moreso than other forms of piping. I think it's a good product and one of the few cases where a plastic product is actually functionally superior to its non-synthetic predecessors.
posted by Scientist at 10:30 AM on July 25, 2012 [1 favorite]
We had our nasty corroded basement galvanized pipes replaced with PEX and functionally they are great. Our water quality and pressure improved significantly. I can't speak to health risks but I guess the consensus is that there are no indications of any problems. Compared to the stuff the plumber showed us our water was filtering through in the galvanized pipes, I think I'll take my chances with PEX.
posted by rocketpup at 10:39 AM on July 25, 2012
posted by rocketpup at 10:39 AM on July 25, 2012
A project in my old office (that I didn't work on) had a number of non-health issues with installation of PEX - can you guys offer insight on that?
The issues:
1. the piping is really easy to kink, and once the tube is kinked, the entire section must be discarded. There are obviously methods to prevent this, like bending the tubes while they're encased in a more rigid material, but have either of you had many problems with this in the field?
2. If you mistakenly cut a piece to short, it has to be discarded and a new one cut, since you can't readily connect on tube to another like you can with copper. Is this really an issue?
3. I though I heard something about every supply line essentially having to be a "home run" or that branching one smaller supply line off another one is very difficult. Any truth to that?
The guy working on the project in our office ended up feeling that PEX wasn't all it was cracked up to be. The main reason for going with it is for the lower material cost, but you apparently have to put more piping in (which conflict with other things), and there was a lot of waste material (can't recycle PEX as easily as copper) and wasted labor. This was in California, and it was certified only a year or two ago, so it might be an issue of contractors not being familiar with how to work the material yet. I'd be interested in any information other posters might have about these issues, though.
posted by LionIndex at 10:45 AM on July 25, 2012
The issues:
1. the piping is really easy to kink, and once the tube is kinked, the entire section must be discarded. There are obviously methods to prevent this, like bending the tubes while they're encased in a more rigid material, but have either of you had many problems with this in the field?
2. If you mistakenly cut a piece to short, it has to be discarded and a new one cut, since you can't readily connect on tube to another like you can with copper. Is this really an issue?
3. I though I heard something about every supply line essentially having to be a "home run" or that branching one smaller supply line off another one is very difficult. Any truth to that?
The guy working on the project in our office ended up feeling that PEX wasn't all it was cracked up to be. The main reason for going with it is for the lower material cost, but you apparently have to put more piping in (which conflict with other things), and there was a lot of waste material (can't recycle PEX as easily as copper) and wasted labor. This was in California, and it was certified only a year or two ago, so it might be an issue of contractors not being familiar with how to work the material yet. I'd be interested in any information other posters might have about these issues, though.
posted by LionIndex at 10:45 AM on July 25, 2012
LionIndex writes "If you mistakenly cut a piece to short, it has to be discarded and a new one cut, since you can't readily connect on tube to another like you can with copper. Is this really an issue?"
You can get PEX unions which are functionally the same as copper unions. One of PEX's great benefits is the lack of joints so generally you try to avoid them but there isn't really anything wrong with them and they are used for repairs when a length of pipe is damaged.
LionIndex writes "I though I heard something about every supply line essentially having to be a 'home run' or that branching one smaller supply line off another one is very difficult. Any truth to that?"
This is a design decision. Because PEX is fairly cheap and easy to pull the advantages of home runs (IE: every fixture fed from it's own line from a central manifold) are easier to take advantage of then they are with copper. But it is still just a piece of pipe; there isn't any physical reason to treat it exactly like copper as far as layout goes.
posted by Mitheral at 11:09 AM on July 25, 2012 [1 favorite]
You can get PEX unions which are functionally the same as copper unions. One of PEX's great benefits is the lack of joints so generally you try to avoid them but there isn't really anything wrong with them and they are used for repairs when a length of pipe is damaged.
LionIndex writes "I though I heard something about every supply line essentially having to be a 'home run' or that branching one smaller supply line off another one is very difficult. Any truth to that?"
This is a design decision. Because PEX is fairly cheap and easy to pull the advantages of home runs (IE: every fixture fed from it's own line from a central manifold) are easier to take advantage of then they are with copper. But it is still just a piece of pipe; there isn't any physical reason to treat it exactly like copper as far as layout goes.
posted by Mitheral at 11:09 AM on July 25, 2012 [1 favorite]
To answer LionIndex's questions, I replaced all the plumbing in my house with PEX myself (not a pro), and this was my experience:
1. If a piece gets kinked, then you're probably have to cut that part out...but in all my hundreds of feet of PEX in put in my house, I never came close to having a kink. You can buy elbow joints and crimp them into the PEX if you need to turn a very tight corner, but usually there's enough room to allow a larger, looping bend.
2. Not really an issue. You can easily connect two pieces using a union, just crimp them together. But if you measure twice, and leave a little extra, it's not hard to avoid being short.
3. Nope, the layout design is independent of the plumbing material used. You can use branch or homerun layouts with both PEX and copper. I used a hybrid approach myself - a big loop that went through every room, and short branches to the faucets in those rooms, with two separate master loops for each half of the house.
Overall, PEX was cheaper than copper in both cost and labor (I've installed copper plumbing too), and was much nicer to work with. There's not any more material used/wasted nor wasted labor in my experience, and in fact there's less labor involved (and it's faster too).
The leftover PEX "scraps" that I have are actually the remainder of the large rolls that I bought - I don't have a pile of 2ft pieces like what happens when you're done with a copper plumbing job.
Here's a pic of some PEX branches coming off the main line (and the rest of that set shows a few more - I connected the PEX lines to copper standoffs that entered the house for durability during the construction, but you can bring PEX directly into the house too if you wish).
posted by jpeacock at 11:10 AM on July 25, 2012
1. If a piece gets kinked, then you're probably have to cut that part out...but in all my hundreds of feet of PEX in put in my house, I never came close to having a kink. You can buy elbow joints and crimp them into the PEX if you need to turn a very tight corner, but usually there's enough room to allow a larger, looping bend.
2. Not really an issue. You can easily connect two pieces using a union, just crimp them together. But if you measure twice, and leave a little extra, it's not hard to avoid being short.
3. Nope, the layout design is independent of the plumbing material used. You can use branch or homerun layouts with both PEX and copper. I used a hybrid approach myself - a big loop that went through every room, and short branches to the faucets in those rooms, with two separate master loops for each half of the house.
Overall, PEX was cheaper than copper in both cost and labor (I've installed copper plumbing too), and was much nicer to work with. There's not any more material used/wasted nor wasted labor in my experience, and in fact there's less labor involved (and it's faster too).
The leftover PEX "scraps" that I have are actually the remainder of the large rolls that I bought - I don't have a pile of 2ft pieces like what happens when you're done with a copper plumbing job.
Here's a pic of some PEX branches coming off the main line (and the rest of that set shows a few more - I connected the PEX lines to copper standoffs that entered the house for durability during the construction, but you can bring PEX directly into the house too if you wish).
posted by jpeacock at 11:10 AM on July 25, 2012
Best answer: I recently went through the process of deciding on which plumbing system to install in our house to replace the old galvanized steel pipes which had started to fail, including looking at stainless options (our house is small, and we try to do everything for the 50 years or so that we expect is the outer limit of our remaining lifespan).
After doing all sorts of reading, including carefully dissecting the California EIR on the adopion of PEX regulations, we decided on PEX. The considerations we took seriously and eventually put to rest were:
There are 3 different PEX systems right now. The Upinor fittings require a fairly expensive tool to make the junction, there is apparently a hand-operated one but the one that the local plumbing supply place sold me cost $400. The big box stores have a system that works with a crimped metal band, there's a lot about how you have to check every joint with the gauge to make sure you made the joint correctly. In either of those first two situations, once you use a fitting it's used. You can use a junction, but cutting the tube off will damage the fitting. Hardware stores carry Shark Bite fittings, which push on the end without tools, and can be removed. Shark Bites are great for "It's 4PM on Sunday and I need to get this running tonight", but when we pressurized our house, the Shark Bite junctions were the ones that were leaking and we had to rework.
So, yeah: After looking at all the options pretty carefully, we went with the Upinor ProPEX for our house, because we decided that PEX really was the healthiest for both the inhabitants, and the environment generally. I ran ¾" PEX to manifolds underneath the kitchen and bathroom walls, and then ran ½" to the individual outlets. As mentioned above, if you kink it, either use a junction or throw away the section. It's cheap enough to do either.
I re-did the plumbing in our 1 kitchen, 1 bath, utility sink and laundry hookups in the garage in a weekend, with a bit of last-minute help from a friend on Sunday evening. I would have easily done it in less if I'd been smarter about yanking out the galvanized steel (Don't try to unscrew it, Sawzall from the beginning).
posted by straw at 1:30 PM on July 25, 2012 [1 favorite]
After doing all sorts of reading, including carefully dissecting the California EIR on the adopion of PEX regulations, we decided on PEX. The considerations we took seriously and eventually put to rest were:
- MTBE
- It has been acknowledged that MTBE has been discovered in water run through PEX plumbing. There were two potential sources for this: Manufacturing residue, and the fact that PEX can apparently leach small molecules in from surrounding soil. This has been addressed in two ways: The flushing protocol after PEX installation, and don't bury unprotected PEX.
- Bacterial growth
- There were some reports of bacterial contamination on PEX tubing. My conclusion, after reading all sorts of things, is that copper actively kills off microbes that PEX doesn't, because PEX is more benign. This is a reason to follow the flushing protocol on new PEX installations, and if you flush correctly you clean the pipes so that such things don't hold over from installation (they die anyway after a while because of lack of nutrients). This is also why the wetlands preservation folks are lobbying for PEX over copper: Less copper in the wastewater.
- Component failure
- Upinor had some bad brass fittings that caused some early failures of PEX systems, and some big recalls and lawsuits. They have fixed that. If you use metal crimp-on fittings, you need to make sure that you gauge every crimp.
There are 3 different PEX systems right now. The Upinor fittings require a fairly expensive tool to make the junction, there is apparently a hand-operated one but the one that the local plumbing supply place sold me cost $400. The big box stores have a system that works with a crimped metal band, there's a lot about how you have to check every joint with the gauge to make sure you made the joint correctly. In either of those first two situations, once you use a fitting it's used. You can use a junction, but cutting the tube off will damage the fitting. Hardware stores carry Shark Bite fittings, which push on the end without tools, and can be removed. Shark Bites are great for "It's 4PM on Sunday and I need to get this running tonight", but when we pressurized our house, the Shark Bite junctions were the ones that were leaking and we had to rework.
So, yeah: After looking at all the options pretty carefully, we went with the Upinor ProPEX for our house, because we decided that PEX really was the healthiest for both the inhabitants, and the environment generally. I ran ¾" PEX to manifolds underneath the kitchen and bathroom walls, and then ran ½" to the individual outlets. As mentioned above, if you kink it, either use a junction or throw away the section. It's cheap enough to do either.
I re-did the plumbing in our 1 kitchen, 1 bath, utility sink and laundry hookups in the garage in a weekend, with a bit of last-minute help from a friend on Sunday evening. I would have easily done it in less if I'd been smarter about yanking out the galvanized steel (Don't try to unscrew it, Sawzall from the beginning).
posted by straw at 1:30 PM on July 25, 2012 [1 favorite]
WRT to your questions:
1. I've never heard of kink issues. Someone was in a hurry, the stuff is pretty rigid. Perhaps they were trying long-pulls through narrow traces or something? My experience has been mostly new construction though, so that's probably something to consider. I will, however, redo my house with pex when I finish rewiring it. (The house, not the pex. Subject-verb agreement isn't my forte.) I'll probably even use the insulated type for hot water runs.
2. They answered this. PEX joints are relatively expensive, but you use few. They are readily available, and pex can take a pretty hefty bend. (I've seen it bend within a wall with studs 16" on center, although I wouldn't recommend this.)
3. In my experience (which is limited, admittedly), homeruns to a manabloc type system have lots of advantages but are indeed purely optional. They're nice because you avoid at-location shut-offs, and because they make it super easy to do fun things like zonal radiant floor heating. They also mean you're only tying into supply one time.
posted by TomMelee at 6:01 PM on July 25, 2012
1. I've never heard of kink issues. Someone was in a hurry, the stuff is pretty rigid. Perhaps they were trying long-pulls through narrow traces or something? My experience has been mostly new construction though, so that's probably something to consider. I will, however, redo my house with pex when I finish rewiring it. (The house, not the pex. Subject-verb agreement isn't my forte.) I'll probably even use the insulated type for hot water runs.
2. They answered this. PEX joints are relatively expensive, but you use few. They are readily available, and pex can take a pretty hefty bend. (I've seen it bend within a wall with studs 16" on center, although I wouldn't recommend this.)
3. In my experience (which is limited, admittedly), homeruns to a manabloc type system have lots of advantages but are indeed purely optional. They're nice because you avoid at-location shut-offs, and because they make it super easy to do fun things like zonal radiant floor heating. They also mean you're only tying into supply one time.
posted by TomMelee at 6:01 PM on July 25, 2012
Oh, and the original question was about the health risks of PEX, not the installation risks, but I wanted to address TomMelee's point #2: That depends a lot on what fitting system you use. The Upinor ProPEX tool is pricey, but the fittings are cheap, I think ½" junctions were < $.50 each, Ts were under a buck. You need a plastic ring for each of those, but they're a few pennies a shot. The crimp-on PEX is a little more expensive, and the Shark Bites are several to many dollars each.
And yeah, it can take a bend, but buy a couple of spare 90° couplers, when you're trying to get that shower valve installed you'll thank me.
posted by straw at 2:18 PM on July 26, 2012 [1 favorite]
And yeah, it can take a bend, but buy a couple of spare 90° couplers, when you're trying to get that shower valve installed you'll thank me.
posted by straw at 2:18 PM on July 26, 2012 [1 favorite]
« Older Are WWE fans sufficiently well-behaved at live... | America Day Fun and Games for ESL Learners Newer »
This thread is closed to new comments.
That said, your "old house" almost certainly has leaded solder in existing copper pipes, and on the off chance you have cast pipes somewhere, they're almost certainly full of rust. Additionally, little pits and pockets at joints and along the pipe give fun places for things to build up. It's delightful.
Typically after a fresh PEX install you flush water through the system, so there shouldn't be anything to worry about. You also get colored pipe for temperature designation, you never have to learn to do a sweated joint or deal with PVC primer and cement, and you just simply don't have to worry about joints anywhere except unions and at terminal points.
posted by TomMelee at 10:13 AM on July 25, 2012 [1 favorite]