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Copper Repiping

20 years ago

Hi everyone,

I have a few galvanized pipes i need to replace. They are both very easy to get at as my basement is just a hole in the dirt (my house is 98 years old). Now I know I need to replace them with copper pipes, but I guess when I picture copper plumbing it's the small stuff running to my taps. The pipes I need to replace come straight off my water meter and up to my kitchen sink. This pipe is at least (guessing) 3/4" O/D. So what I'm wondering is, is there a certain type of copper piping I need? Also if you have any tips for me that would be great! :)

Thanks so much.

~FOX~

Comments (9)

  • 20 years ago

    Some use dielectric fittings between copper and steel, some don't. Unless you use alot of water you should be able to use 1/2" copper, but it's no big deal to use 3/4" either. Make sure it is "L" rated for plumbing.

    If your water is acidic you can use "K" copper or install an acid neutralizer because it will eventually eat through the copper. Sometimes you'll have a hint by the blue stains in the sinks or inside the used copper pipe.

    I use copper unions wherever I might have to make repairs in the future and I don't skimp on shut-off valves.

  • 20 years ago

    To correct a couple point of Bayme's statement:

    "Some use dielectric fittings between copper and steel, some don't. Unless you use alot of water you should be able to use 1/2" copper, but it's no big deal to use 3/4" either. Make sure it is "L" rated for plumbing."

    1. All the plumbing codes strictly prohibit directly coupling copper to iron pipe. You are required to transition by means of a dielectric union, dielectric nipple or a 6" hardened bronze nipple between the copper and iron pipe. Failure to do so will result in electrolosys and premature failure.

    2. The code minimum size for a residential water supply line is 3/4" and that same 3/4" should be maintained inside the structure until it reaches the Hot & Cold junction at the water heater. While it was eluded that this is not a big deal, it is in fact a very big deal because a 3/4" line has more than twice the volume capacity of a 1/2" line, thus reducing the line to half inch reduces the volume of flow to less than 50% of the rated system design.

    When comparing pipe capacity we cannot use diamter but rather we must us a formula that compares cross sectional area, therefore the formula is Large Diameter Squared divided by small diameter squared.

    Comparing 3/4" to 1/2" we get:

    (3/4 x 3/4) / (1/2 x 1/2) =
    (.75 x .75) / (,5 x .5) =
    0.5625 / 0.25 = 2.25

    This means a 3/4" line carries 2.25 times the volume of a 1/2" line.

    While type "L" copper is the preferred material for residential distribution piping, the codes do permit types M, L & K (both roll pipe and rigid tempered pipe) for distribution piping above grade inside the structure.

    Type "M" may not be used below grade.

    Unions are required on both the hot and cold water lines within 12" of the top of a water heater.

    While additional unions may prove somewhat handy for future maintenance it is also very easy to just cut the pipe and rejoin it with a sweat coupling. Unions are mechanical fittings and MAY NOT be installed in concealed locations.

  • 20 years ago

    Hi,
    man you guys are awesome! But i'm not sure i was clear on what i am doing. Basically from my water main (meter) it starts as copper at the meter but then quickly changes to galvan. after that. It goes to a junction, with one side going to my kitchen and outside taps (galvan.) and the other going into plastic tubing and onto the rest of the house. I have attached a link for photos so you can see what i mean. Thanks so much for the information! let me know what you think.

    ~FOX~

    Here is a link that might be useful: Watermain/Meter

  • 20 years ago

    Thank you so much for posting the photos as it made assessing your situation much easier.

    For the record, everything in the water meter photo meets code approval.

    On the lower left side of the photo we can see the handle from a 3/4" ball valve. That is your main water shutoff valve and it designates the point of division between the supply piping (line from the well or municipal main to the structure) and the distribution piping (lines within the structure used to distribute the water to the load demand points.) The code requires that the main water supply valve MUST BE a full bore type valve and a ball valve is a full bore valve.

    On the right hand side of the water meter there appears to be a 2" hardened bronze nipple between the water meter union and the galvanized iron pipe. While this union is less than the code minimum 6" it must be understood that the watermeter body is also hardened bronze so the combined lenght of hardened bronze material from the copper to the galvanized iron pipe far exceeds the required code minimum of 6".

    There is a problem with the juction where the plastic pipe joins the iron pipe. The plastic is connected by means of a copper MIP x Barb adapter and there should be a dielectric union, dielectric nipple or 6" hardened bronze nipple between the iron pipe and the copper fitting.

    The plastic pipe also appears to be Polybutelene pipe. PB piping systems have a very high incidence of failure, not from the pipe itself, but from fitting problems. PB pipe has been prohibited under the Uniform Plumbing Code but it is still listed as approved for both supply and distribution piping under the International Residential Code.

  • 20 years ago

    lazypup:
    Thank you so much for the information, since I am changing the galvanized pipes I won't have to worry about the special fittings mentioned right? You have been very helpful, thank you.

    ~FOX~

  • 20 years ago

    You are correct, the dielectric transition fittings are only required when joining copper pipe to iron pipe or vessels. Once you remove the iron pipe you will no longer need a dielectric transition except when joining a copper line to an Iron water heater vessel, an iron or steel expansion tank or an iron or steel heating system.

  • 20 years ago

    Hi lazypup,
    I got it done today, just thought I'd post the after pictures for you to see...I'm no pro, but there were no leaks :) so that's a good thing. Thanks again for all your help, made the job much easier.

    Cheers.

    ~FOX~

    Here is a link that might be useful: Plumbing

  • 20 years ago

    Overall it looks great.

    The only thing i see that might need correcting is the electrical grounding bond around the water meter. I cannot tell from the photo but you may even have it already.

    In the photo we can see an electrical ground cable clamped to the copper pipe on the right hand side of the meter near the main water shutoff valve. The should be another wire clamped to the pipe at that point then going around the meter and clamped to the pipe on the house side of the meter. This is to insure there remains a continuity to ground from the house piping to the house ground in the event the meter is pulled out for service.

    Both the Plumbing codes and the National Electrical code no prohibit grounding appliances or devices to water pipes but there are numerous electrical devices in the home that are directly connected to the piping system, such as pumps, electrically operated solenoid valves, electric water heaters and HVAC boilers. If one of those devices should happen to develope an internal short it can potentially energize the copper pipes and in that scenario if someone were to remove the meter they could be electrocuted, therefore we are required to install the bonding wire.

    I looked at your solder joints and they look very good. Although it is not a requirement i did notice something that is sort of a personal pet peive of mine. Those d@#& skew labels that all the big box stores put on the fittings. I like to remove all tape or labels from the fittings before soldering so you don't end up with that unsightly amatuerish burnt paper hanging on the fitting when your done.

    It is also a good idea to keep a moist rag handy when soldering. After you apply the solder you use the rag to wipe the joint. This will remove any excess beads of solder and flux that remains on the exterior of the pipe. If flux is left on the pipe it will turn green in a few months and can result in premature corrosion on your pipe.

    Years ago soldered copper joints were called "Wiped joints" for that reason and some inspectors will look for it.

  • 20 years ago

    great, thank you for the tips!

    ~FOX~