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Copper pipe in a single line steam system

Jerry_8 Member Posts: 1
I am a home owner on Long Island with an 80 year old house. The house uses a single pipe steam system for heating. I am in the process of adding an extension
to the house. The plumbing contractor extended a steam line to the new space via 1½" copper pipe instead of steel pipe. The copper pipe he used was very thin walled and he used soldered fittings. As an engineer, I believe that steel pipe with threaded fittings should have been used
instead. There is the issue of corrosion with dissimilar metals at the point of contact along with anodizing of the cast iron boiler due to the condensate traveling along copper pipe on the way back to the boiler. Then there is also the issue of the solder joints withstanding the heat, pressure and expansion co-efficient of copper. I believe this set up will be prone to leaks in a few years. Does anyone have any documentation showing that only steel pipe should be used in single line steam systems? Whatever you have will be appreciated. Thank you!


  • If you

    go to the top of the page, click on "seach" and type in "copper steam pipe", you will bring up a few threads regarding the subject.

    It has been discussed many times here on The Wall. All the pros concur that the only place you can use copper tubing is on the wet returns.

    If you want some textbook documentation, maybe someone else can help you.

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  • Ken_8
    Ken_8 Member Posts: 1,640
    I'm not so sure we would suggest

    copper is even okay for wet returns!

    Naturally occurring acids form and would compromise the copper even faster than steel!

    The issue of dissimilar metals is NOT an issue in this application however.

    Insulation, size and pitch however were never mentioned. These are the larger issues to be considered IMHO.

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  • chuck_6
    chuck_6 Member Posts: 107
    Copper pipe

    I'm not an engineer, but in reading Wall comments for a while, you should always use black iron pipe instead of copper piping. The difference in temperatures of the two can cause corrosion, which can go back into your boiler, and of course ruin it.
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