Replies

1. 
   rnsykes | Oct 09, 2006 07:16pm | #1

   I've never seen PVC used.  CPVC is pretty common though.  Not my first choice, but is perfectly acceptable.

2. 
   DanH | Oct 09, 2006 07:20pm | #2

   PVC or CPVC? Plain PVC is not supposed to be used for hot water, but CPVC is OK.

   CPVC "seems" flimsy, and must be protected from damage more than copper, but otherwise is an "acceptable" product. It's used in some new construction.

   The bigger question, in an old house, is whether there is other DIY work that is even more suspect. Don't go about doing unnecessary minor fixes when you may need to rip it out again for major fixes.

   If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
3. 
   IMERC | Oct 09, 2006 07:25pm | #3

   PVC (white) for cold..

   CPVC (light yellow) for hot..

   use PVC for hot and the water's heat will weaken the pipe and bursting will result....

   it it's the correct plastic for the application.. no problem..

    

    

   Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming

   WOW!!! What a Ride!

   Forget the primal scream, just ROAR!!!

4. 
   davidmeiland | Oct 09, 2006 10:02pm | #4

   My house had PVC for cold and CPVC for hot. I tore it all out while remodeling and while it's a little bit brittle it's actually kind of a bitch to break it apart. I wouldn't do anything unless you need to make a change. We use PEX or copper for all new work, although the yard has a full assortment of the C/PVC stuff for the budget minded.

1. 
   paperhanger | Oct 10, 2006 01:56am | #5

   they are starting to use the pex here in southeastern mass. the lines are color coded, red for hot and blue for cold and they are using the brass fittings for connections. looks pretty fast to install. wonder what the savings are to the HO.

5. 
   Matt | Oct 10, 2006 02:17am | #6

   My plumber installs CPVC as an upgrade to PEX.  The CPVC we get is kind of a light yellowish tan color.

1. 
   plumbbill | Oct 10, 2006 04:35am | #11

   My plumber installs CPVC as an upgrade to PEX.

   Really?

   I don't think I ever met anyone who thought cpvc was an upgrade to pex---- except the floguard salesman that took me to lunch.When asked why is there four engines on a 747------ "cause we couldn't fit six" a Boeing engineer

1. 
   Matt | Oct 10, 2006 02:43pm | #12

   That's right.  I talked to him about it.  He says that the CPVC is more expensive to install but gives better flow rates.  He does a lot of PEX houses too.  They specialize in new construction - if that matters...  He and his partner have been doing it for 30+ years - each...

    

1. 
   plumbbill | Oct 10, 2006 03:33pm | #14

   I only have limited experience with cpvc.

   I had a job a few years ago that had a food court in it. I came out of my office to help plumb the kitchen---- no copper was aloud downstream of the filters, so we were using cpvc.

   I told my guys "I'll do this wall", after about 30 min of cussin & swearin my main plumber came up to me & said " You don't do much cpvc do you"

   I said nope.

   He told me to quit trying to make it look good. That stuff bows & sags, & ya gotta have expansion loops in it.

   I'm mainly a copper guy & when we run pex --- well that would like trying to run romex straight so we don't even bother.

   But back to which is better, I don't like cpvc cause of the limitations on what can come in contact with the pipe.

   Now on the flow part----

   If your plumber is using floguard¯ or a competitor they are sized CTS so the pipe is pretty damn close to the same ID as pex.

   Now the fittings is where the restrictions come into play cpvc have external fittings & pex has internal fittings---- so cpvc will have a better flow at those points, but you generally have less fittings with pex than you do with cpvc.

   & with the flow restrictors on faucets pipes are oversized compared to what ya need.

   But opinions vary :-)When asked why is there four engines on a 747------ "cause we couldn't fit six" a Boeing engineer

6. 
   DougU | Oct 10, 2006 02:33am | #7

   I had/have CPVC water pipe in a house that  we have in TX and if I was going to keep the house I would rip it all out.

   I hate that crap! Very brittle.

   Doug

1. 
   DanH | Oct 10, 2006 02:48am | #8

   But in many areas (and likely parts of Texas) the water is corrosive and will eat through copper in no time.
   If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison

1. 
   DougU | Oct 10, 2006 03:44am | #9

   Yea I understand that and it probably makes sense but I've always like copper and how easy it is to work with that I just didnt like having to do any work on CPVC.

   Doug

7. 
   WayneL5 | Oct 10, 2006 04:08am | #10

   To expand on what someone else said, either PVC or CPVC are acceptable for cold water.  Only CPVC is acceptable for hot.  PVC is rated for use up to 140°F, CPVC to 180°F.

   On hot water lines you'll sometimes get leaks where plastic and metal are threaded together, such as a plastic male adapter into a brass valve or into a water heater.  The thermal cycling can eventually distort the plastic.  When connecting plastic to metal on hot water especially you should use an adapter fitting that is made for the purpose.  It looks somewhat like a dielectric union but is not.

   (C)PVC pipe are not bad materials and have a successful history, but like anything else can suffer from sloppy installation practices.  Until PEX came along it, along with PB, were the only materials that would work with certain aggressive water.  PB got a bad reputation after a manufacture produced some substandard fittings that failed.  The failures were so widespread it killed the market and the product was no longer made.

   Nowadays the market is shifting away from both copper (because of price) and (C)PVC to PEX because of ease of installation and PEX's greater resistance to physical damage.

1. 
   gtmtnbiker | Oct 10, 2006 03:28pm | #13

   What about kitchen sink drains? I've seen many houses where they use PVC for drains but in the kitchen, you might occasionally dump a pot of boiling water into the sink. Is this a concern? Or because it's a small amount on an infrequent basis, it's not really an issue?

1. 
   plumbbill | Oct 10, 2006 03:36pm | #15

   Then you're talking gravity verses pressure

   PVC can handle some pretty hot temps, but when the temp goes up the pressure rating drops.

   Hot tubs & spas are run in pvc all the time & they have temps upto 115 degrees, but there pressure is very low, usually no more than 25psi.When asked why is there four engines on a 747------ "cause we couldn't fit six" a Boeing engineer

2. 
   WayneL5 | Oct 11, 2006 12:19am | #16

   Sink drains are fine because the are under no pressure and the exposure is intermittent.  PVC's rating of 140°F means that it can be exposed to full rated pressure up to that temperature.  Above that temperature the pressure rating is derated.  Manufacturers provide charts of the amount to derate for each temperature.