Supply line preference

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Viking, Feb 5, 2011.

  1. Viking

    Viking New Member

    Joined:
    Feb 3, 2011
    Location:
    Wisconsin
    Can I get opinions on supply line preference? I have install copper a number of times, but would like opinions on PEX and CPVC. PEX appears quite a bit less expensive, and easier/faster to install, but copper seems so much more durable. And CPVC just seems cheep.

    I live in southeastern Wisconsin, in an area with very hard water.

    Thanks for any info you can provide.
     
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    Pex can be a lot faster to install. The fittings are more expensive than copper, and it can look funky (not as big a deal, since most of it ends up behind walls). Both pex and cpvc expand and contract more than copper, so you have to account for those changes in length. Transitioning to solid conversion pieces to mount things with pex can cost more, but if something isn't used much you may not need it. To use a compression shutoff valve, you must buy the ferrules to reinforce it. Depending on the type of system you use (expansion verses cinch), pex may have more restriction at a fitting, but you use fewer (the Uphonor expansion has the least restrction compared to the cinch versions). Not all pex is created equal - it has three different manufacturing methods (called -A, -B, and, -C). -A is the most expensive, and is the only one that can have a kink repaired without cutting it out and splicing in a joint. It is also the most flexible and has the tightest bend radius.

    Plastic pipe can last longer in some parts of the country. Copper generall can last a very long time, but some water just eats holes in it...then a plastic pipe will be better. Pex is much less prone to blowing out if it freezes, but a joint or fitting is still the weakest point. If I was going to do a job with it, I'd either solder copper or use pex. CPVC wouldn't be in my choice list. If you use the expansion system (primarily Uphonor's -A stuff), the expansion tool is fairly expensive, and the manual version will give you a workout. On either of the pex systems, crimping or expanding in a tighte area can be a pain, but the crimp is probably easier. An expansion joint is (in my opinion) more reliable. Pex has shape memory, and always wants to return to the original shape. So, an expanded joint always wants to get tighter, whereas a crimped joint always wants to get looser. Fail to crimp properly or the tool out of calibration, and it may not be a good joint. On the expansion system, if you get the fitting in all the way, and the reinforcement ring is positioned properly, the joint will be good. The only way to get an expanded joint apart is to cut it off and start over. You have a chance of cutting the crimp ring and taking a crimped joint apart.

    Both pex and cpvc have a smaller ID than copper, so if max volume is a criteria, you may need to upsize the pipe. WIth many of today's flow restricted valves, this may not be an issue, but is a consideration. The ability to run without fittings with pex is a major consideration, but also can be a pain with the friction of pulling a run through all of the possible holes along the way. Rodents can chew on any pipe, but will make a hole quicker in pex or cpvc verses copper. The plastic pipes need to be covered up and protected from direct UV within a certain timeframe, or they can be compromised. This normally isn't an issue, but could be if construction was delayed and the walls open for awhile. With either plastic pipe, you shouldn't run the risk of burning the house down while soldering! But, if you transition, it's still possible. Neither pex nor cpvc is recommended for things like a tub spout...first, it is not rigid, and second, it will produce too much backpressure and water will back up to the showerhead, regardless of the divertor position.

    I've probably left some things out, as I've only done a little bit. Others will have their preferences and experiences. There are lots of threads discussing this, so a little search here will bring up numerous opinions.
     
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  4. gator37

    gator37 Retired prof. engr.

    Joined:
    Nov 10, 2009
    Occupation:
    Retired prof. engr.
    Location:
    Alabama
    I agree with Jad... I put in ~400 feet of PVC (not CPVC) to the house as service water (allowed by code) supply in 1987, deep enought not to freeze and never had a problem with it.
    The only question I would have is where was the plastic pipe stored before you purchase it. (in the sun, or protected?)
    Dave
     
  5. Tom Sawyer

    Tom Sawyer In the Trades

    Joined:
    Nov 29, 2010
    Location:
    Maine
    Go with pex, expecially if you have hard water. Pex is rapidly becoming the de-facto standard. CPVC is OK and pretty cheap and requires few tools to install but Pex is more durable in the long run.
     
  6. Viking

    Viking New Member

    Joined:
    Feb 3, 2011
    Location:
    Wisconsin
    Thanks guys. Do any of the plumbers have an opinion?
     
  7. hj

    hj Master Plumber

    Joined:
    Aug 31, 2004
    Occupation:
    Plumber
    Location:
    Cave Creek, Arizona
    Yes, I do NOT use PEX or CPVC.
     
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