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  1. #1
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    Default Galvanized gas piping in soil

    Today, I found buried galvanized gas piping in the rear yard at an inspection. Ok, actually, the galvanized gas piping exited the soil, so I believe that it is reasonable to assume that at least some of the buried piping is galvanized. The plumbing contractor at the site told me that galvanized piping used for gas does not require additional corrosion protection. He actually said that it should not be wrapped with the black PVC tape.

    I looked through the UPC/CPC and found this:

    1211.1.3 Protection Against Corrosion. Gas piping in contact with earth or other material that could corrode the piping shall be protected against corrosion in an approved manner. When dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not be laid in contact with cinders. Uncoated threaded or socket-welded joints shall not be used in piping in contact with soil or where internal or external crevice corrosion is known to occur. [NFPA54: 7.1.3]

    As you can see, it does not specifically allow or exclude galvanized.

    I followed-up by looking at NFPA 54 (Fuel Gas Code 7.1.3) and ended up with essentially the same paragraph. No help there.

    I then looked at the IRC and found this:

    G2415.8 (404.8) Protection against corrosion. Metallic pipe or tubing exposed to corrosive action, such as soil condition or moisture, shall be protected in an approved manner. Zinc coatings (galvanizing) shall not be deemed adequate protection for gas piping underground. Ferrous metal exposed in exterior locations shall be protected from corrosion in a manner satisfactory to the code official. Where dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not be laid in contact with cinders.

    The IRC does not allow galvanizing on buried gas piping, that much is clear. My problem is that California does not recognize the plumbing portion of the IRC and uses the UPC. Is there anything in the UPC/CPC or NFPA 54 that states that zinc coatings are not good enough? I have been unable to find out what "an approved manner" is.

    Obviously, I cannot tell what is going on underground or whether the threads at the elbows were wrapped, and I am going to defer on that basis if I can find nothing else, but I had thought that all metal gas piping had to be wrapped.

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  2. #2
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    Default Re: Galvanized gas piping in soil

    Anyone? Anyone at all?

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  3. #3
    Join Date
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    Default Re: Galvanized gas piping in soil

    Quote Originally Posted by Gunnar Alquist View Post
    Anyone? Anyone at all?
    Hmmm, Anyone???

    First, you may have missed something in what you quoted: "Uncoated threaded or socket-welded joints shall not be used in piping in contact with soil." so it really doesn't matter what you cannot see, as much as what you can see regarding above the soil line.

    Secondly, related and responsive to your near closing assumption (thinking all underground metal piping having to be wrapped...) and implied question: and in general, familiarize yourself with these phrases:

    cathodic protection; and
    cathodic protection system.

    Third, we have pictured deteriorated, oxidized, corroding, zinc sacrificed, sun (uv) bleached, exposed to the outdoors, materials in contact with soil, in close proximity to other system materials, and rigid material in close proximity or encased in concrete/cementious foundation material in earthquake country.

    Fourth, we have an improper abandonment/out-of-service, assumedly still under pressure, valve & plug, non-capped stub end, dead-end; with no connection to an appliance or regulator/relief beyond closed valve. If exists an intermediate valve also off, we have additional concerns, as to bled or not (pressure, percentage ratio of gas present), condensation, corrosion, etc.

    Finally, you did invite Anyone? Anyone at all?!

    Last edited by H.G. Watson, Sr.; 12-02-2010 at 10:56 AM.

  4. #4
    Join Date
    Mar 2007
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    Default Re: Galvanized gas piping in soil

    HG,

    Thanks. And, yes I did invite anyone. This would seem to include you.

    I did not entirely understand your final paragraph, but it seems to me that I am essentially correct.

    As it turns out, the 2003 UPC excluded galvanized piping just as the IRC does. I wonder why the 2006 and 2009 UPC chose to omit that sentence.

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