6 ms·

I’m less convinced. Copper is susceptible to its own failure modes. Water moving too fast in a copper pipe can erode the pipe, and “too fast” is quite slow, esp

by amluto 4y ago

I’m less convinced. Copper is susceptible to its own failure modes. Water moving too fast in a copper pipe can erode the pipe, and “too fast” is quite slow, especially for hot water. If you want hot water quickly, you want the fastest practical speed, which means the smallest practical pipe, and you can easily run into the limitations of copper. PEX and CPVC tolerate considerable higher water velocity. (I think this is because copper’s passive layer can be scoured away, whereas plastic pipes don’t need a passive layer.) If you have well water or water from anywhere other than a utility that controls the chemistry correctly, the water can dissolve your pipes. The rainwater from my roof makes copper instantly shiny, which is a bad sign for the copper.

themitigating 4y ago
Solder doesn't last forever right? When did we start using it over iron?
- SoftTalker 4y ago
  I had iron pipe in my first house. Water was rusty when we got home after a weekend away. Got tired of rust stained sinks and laundry. Ripped it all out and replaced it with CPVC (this was before PEX was really widely available). Never had trouble after that.
r3trohack3r 4y ago
Not to mention water itself is horribly corrosive. Pure water will strip copper pipes. That’s the real reason fluoride was added to tap water: 1) it was cheap 2) it was safe to drink 3) it kept the water from eating the city’s pipes. We had a city in Illinois do whole city RO and advertise the cleanest water in the country. Well it was the cleanest water going into the pipes, but if you own a house in that city the water coming out of your tap is full of old pipe!
- alfor 4y ago
  Where did you get the info about fluoride?
  - r3trohack3r 4y ago
    From an ex-well driller - which I yield isn’t the most reliable source. I haven’t been able to find a source since posting this. I may have my facts backwards! The closest I have is this CDC report saying it reduces corrosiveness: https://www.cdc.gov/fluoridation/engineering/corrosion.htm https://www.cdc.gov/fluoridation/engineering/corrosion.htm My understanding is that, if you take fluoride out of the water, you’ll need to replace it with something or the water will replace it itself (aka eat the pipe). That obviously doesn’t mean fluoride was originally added for that reason though.
    - alliao 4y ago
      I recall reading somewhere the massive underground water container project in Qatar ran into issues with RO water eating pipes everywhere
    - mbreese 4y ago
      I doubt most freshwater sources have enough minerals in them to not be corrosive enough to need to add anything to reduce corrosiveness (ground water wells, rivers, etc...). The only purpose for adding fluoride would be to add fluoride for dental purposes. The only thing I could think of that might have corrosive issues would be desalination water that was overly purified like the sibling comment mentioned. But even then, they should be adding some kind of minerals back before distributing it to people's homes. Ultrapure water tastes horrible and likely isn't safe for drinking long term.
- jahewson 4y ago
  So much wrong here I don’t know where to start.
  - r3trohack3r 4y ago
    > Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something. I’m totally open to being wrong. I’m eager to learn - which is generally why I share information. If I don’t readily share what I know to be true, like in this case, nobody will ever correct me and I’ll spend the rest of my life being incorrect. On HN you generally start by telling someone why they’re wrong and supporting that in some way. I.E. if you know/believe fluoride was added for another reason - that’s a good place to start. Or if you know/believe purified water is not corrosive, that would be a good place to start.
- lazide 4y ago
  That's complete bullshit. Only acidic water (and strongly so) will damage copper pipe. Most copper pipe will easily last 50-100 years, if not more. Flouride isn't added in any sort of concentration that would measurably change water Ph. And more.
  - r3trohack3r 4y ago
    Your statement is at odds with what I know about water. Your saturation index is what drives water’s interaction with the surfaces it touches, not just pH. If the index is too high it will deposit what it’s carrying (scale) and if it is too low it will pick up material from the pipe it’s flowing through (corrosive). These are used in swimming pools, but originally the saturation index was developed by Langelier to protect city pipes from corrosion: https://en.m.wikipedia.org/wiki/Hard_water#Langelier_saturation_index_(LSI) https://en.m.wikipedia.org/wiki/Hard_water#Langelier_saturat... IIRC most cities try to run a high saturation index to intentionally lay down scale that further protects the pipes from corrosion. It may be true that fluoride isn’t in sufficient quantity to impact the saturation index, but that is distinct from pH.
    - lazide 4y ago
      1) That isn’t distinct from PH, it’s a refinement of it? 2) There is theory, and there is practice in the field. What you’re referring to is the equivalent of ‘wet bulb temperature’ for temps. Which is a thing, but water conditions for a given area rarely vary like temperature will - and are in control of the local water treatment plant. What you’re referring to was specifically made to measure and help control these conditions. If copper piping is allowed by local code, they’ll know - and keep it within these ranges. Areas with water that is not easy to keep within these ranges will also corrode galvanized pipe (commonly used for water in most areas), and will likely also corrode brass fittings and valves (including back flow valves) commonly used in many areas, leaching lead, copper, etc. among other things. Those areas prohibit them by code for that reason. Copper piping will generally not corrode unless PH is < 6.5 or > 8.5, which is significantly outside what most would consider reasonable water quality. I personally have a well in an off grid location with 6.2 PH, and use only CPVC for that reason. Where I live, I’ve done some retrofits and replaced 75 year old copper pipe that was good as new inside.
- bostik 4y ago
  > water itself is horribly corrosive Funnily enough, this is technically true, but would only manifest in a warped reality. In the acidic/caustic scale, regular water is just slightly on the caustic side of neutral. (pH 5.5 or thereabouts?) - It won't strip the pipes it runs in. But that's not the kind of water we're talking about here. That would be pure distilled water. It's the near-universal cleaning agent. Because of the complete lack of impurities, distilled water has the ability to absorb fair amounts of almost anything it gets in contact with. It also tastes really bad. (The taste of "nothing" for regular water is our calibrated baseline with various minerals and other impurities. If you take all of that out, the perceptual difference between expected and experienced is quite stark.) For what it's worth, cavitation and turbulence are much more likely culprits to eat the plumbing material. Also: shoddy quality will always cause problems, regardless of your choice of materials.
Spooky23 4y ago
That’s pretty uncommon, generally the joints fail before pipes do. PEX with compression fittings is the closest thing to copper in terms of durability, but exists because of labor savings. Appropriately installed copper is the most durable interior water service and will comfortably outlast the life of the structure.
- l1tany11 4y ago
  They say all it takes is not de-burring the pipe to create the turbulence. We have a lot of problems in my county with copper pipes leaking. There are entire plumbing companies dedicated to finding the leaks and repairing them. There are still more companies dedicated to repiping. I know of developments where they epoxy coated all the piping because they were getting so many leaks. You can read about the huge class action lawsuits going on involving the local water utility (who is being blamed for water chemistry causing the issues. They point fingers elsewhere, obviously). I’ve seen a copper pipe where in the middle of the pipe there is a pinhole leak on the top side of the pipe (too far for turbulence, can’t be cause by sediment). If you want the most durable, I would think it would be either pex-a or perhaps 316 stainless steel (which is a valid code compliant option). But no one really knows, and it’s probably water chemistry dependent. It’s being argued in the courts now (for whatever that’s worth).
  - amluto 4y ago
    > perhaps 316 stainless steel Stainless steel is awesome! Unfortunately the connections are not so easy. Stainless steel-to-brass threaded connections are probably safe under most circumstances but are dubious per the code. Push-to-connect fittings often use little stainless teeth to hold the tubing in, and this may work less well when the pipe is nearly as hard as the teeth. (John Guest makes special fittings for stainless steel tubing.) You can’t sweat stainless steel pipes. Obviously everyone should plumb their houses with swagelok fittings! :)
    - cto_of_antifa 4y ago
      The other option would be brazing with jewelry silver at like $60/oz. Yikes.

by amluto 4y ago

themitigating 4y ago

Solder doesn't last forever right? When did we start using it over iron?

SoftTalker 4y ago
I had iron pipe in my first house. Water was rusty when we got home after a weekend away. Got tired of rust stained sinks and laundry. Ripped it all out and replaced it with CPVC (this was before PEX was really widely available). Never had trouble after that.

r3trohack3r 4y ago

Not to mention water itself is horribly corrosive. Pure water will strip copper pipes. That’s the real reason fluoride was added to tap water: 1) it was cheap 2) it was safe to drink 3) it kept the water from eating the city’s pipes. We had a city in Illinois do whole city RO and advertise the cleanest water in the country. Well it was the cleanest water going into the pipes, but if you own a house in that city the water coming out of your tap is full of old pipe!

alfor 4y ago
Where did you get the info about fluoride?
- r3trohack3r 4y ago
  From an ex-well driller - which I yield isn’t the most reliable source. I haven’t been able to find a source since posting this. I may have my facts backwards! The closest I have is this CDC report saying it reduces corrosiveness: https://www.cdc.gov/fluoridation/engineering/corrosion.htm https://www.cdc.gov/fluoridation/engineering/corrosion.htm My understanding is that, if you take fluoride out of the water, you’ll need to replace it with something or the water will replace it itself (aka eat the pipe). That obviously doesn’t mean fluoride was originally added for that reason though.
  - alliao 4y ago
    I recall reading somewhere the massive underground water container project in Qatar ran into issues with RO water eating pipes everywhere
  - mbreese 4y ago
    I doubt most freshwater sources have enough minerals in them to not be corrosive enough to need to add anything to reduce corrosiveness (ground water wells, rivers, etc...). The only purpose for adding fluoride would be to add fluoride for dental purposes. The only thing I could think of that might have corrosive issues would be desalination water that was overly purified like the sibling comment mentioned. But even then, they should be adding some kind of minerals back before distributing it to people's homes. Ultrapure water tastes horrible and likely isn't safe for drinking long term.
jahewson 4y ago
So much wrong here I don’t know where to start.
- r3trohack3r 4y ago
  > Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something. I’m totally open to being wrong. I’m eager to learn - which is generally why I share information. If I don’t readily share what I know to be true, like in this case, nobody will ever correct me and I’ll spend the rest of my life being incorrect. On HN you generally start by telling someone why they’re wrong and supporting that in some way. I.E. if you know/believe fluoride was added for another reason - that’s a good place to start. Or if you know/believe purified water is not corrosive, that would be a good place to start.
lazide 4y ago
That's complete bullshit. Only acidic water (and strongly so) will damage copper pipe. Most copper pipe will easily last 50-100 years, if not more. Flouride isn't added in any sort of concentration that would measurably change water Ph. And more.
- r3trohack3r 4y ago
  Your statement is at odds with what I know about water. Your saturation index is what drives water’s interaction with the surfaces it touches, not just pH. If the index is too high it will deposit what it’s carrying (scale) and if it is too low it will pick up material from the pipe it’s flowing through (corrosive). These are used in swimming pools, but originally the saturation index was developed by Langelier to protect city pipes from corrosion: https://en.m.wikipedia.org/wiki/Hard_water#Langelier_saturation_index_(LSI) https://en.m.wikipedia.org/wiki/Hard_water#Langelier_saturat... IIRC most cities try to run a high saturation index to intentionally lay down scale that further protects the pipes from corrosion. It may be true that fluoride isn’t in sufficient quantity to impact the saturation index, but that is distinct from pH.
  - lazide 4y ago
    1) That isn’t distinct from PH, it’s a refinement of it? 2) There is theory, and there is practice in the field. What you’re referring to is the equivalent of ‘wet bulb temperature’ for temps. Which is a thing, but water conditions for a given area rarely vary like temperature will - and are in control of the local water treatment plant. What you’re referring to was specifically made to measure and help control these conditions. If copper piping is allowed by local code, they’ll know - and keep it within these ranges. Areas with water that is not easy to keep within these ranges will also corrode galvanized pipe (commonly used for water in most areas), and will likely also corrode brass fittings and valves (including back flow valves) commonly used in many areas, leaching lead, copper, etc. among other things. Those areas prohibit them by code for that reason. Copper piping will generally not corrode unless PH is < 6.5 or > 8.5, which is significantly outside what most would consider reasonable water quality. I personally have a well in an off grid location with 6.2 PH, and use only CPVC for that reason. Where I live, I’ve done some retrofits and replaced 75 year old copper pipe that was good as new inside.
bostik 4y ago
> water itself is horribly corrosive Funnily enough, this is technically true, but would only manifest in a warped reality. In the acidic/caustic scale, regular water is just slightly on the caustic side of neutral. (pH 5.5 or thereabouts?) - It won't strip the pipes it runs in. But that's not the kind of water we're talking about here. That would be pure distilled water. It's the near-universal cleaning agent. Because of the complete lack of impurities, distilled water has the ability to absorb fair amounts of almost anything it gets in contact with. It also tastes really bad. (The taste of "nothing" for regular water is our calibrated baseline with various minerals and other impurities. If you take all of that out, the perceptual difference between expected and experienced is quite stark.) For what it's worth, cavitation and turbulence are much more likely culprits to eat the plumbing material. Also: shoddy quality will always cause problems, regardless of your choice of materials.

Spooky23 4y ago

That’s pretty uncommon, generally the joints fail before pipes do. PEX with compression fittings is the closest thing to copper in terms of durability, but exists because of labor savings. Appropriately installed copper is the most durable interior water service and will comfortably outlast the life of the structure.

l1tany11 4y ago
They say all it takes is not de-burring the pipe to create the turbulence. We have a lot of problems in my county with copper pipes leaking. There are entire plumbing companies dedicated to finding the leaks and repairing them. There are still more companies dedicated to repiping. I know of developments where they epoxy coated all the piping because they were getting so many leaks. You can read about the huge class action lawsuits going on involving the local water utility (who is being blamed for water chemistry causing the issues. They point fingers elsewhere, obviously). I’ve seen a copper pipe where in the middle of the pipe there is a pinhole leak on the top side of the pipe (too far for turbulence, can’t be cause by sediment). If you want the most durable, I would think it would be either pex-a or perhaps 316 stainless steel (which is a valid code compliant option). But no one really knows, and it’s probably water chemistry dependent. It’s being argued in the courts now (for whatever that’s worth).
- amluto 4y ago
  > perhaps 316 stainless steel Stainless steel is awesome! Unfortunately the connections are not so easy. Stainless steel-to-brass threaded connections are probably safe under most circumstances but are dubious per the code. Push-to-connect fittings often use little stainless teeth to hold the tubing in, and this may work less well when the pipe is nearly as hard as the teeth. (John Guest makes special fittings for stainless steel tubing.) You can’t sweat stainless steel pipes. Obviously everyone should plumb their houses with swagelok fittings! :)
  - cto_of_antifa 4y ago
    The other option would be brazing with jewelry silver at like $60/oz. Yikes.