Coated Gas Piping

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by MichaelBukay, Jan 14, 2013.

  1. MichaelBukay

    MichaelBukay Plumber

    Messages:
    54
    Location:
    San Diego, California
    I don't use this product. I usually opt for PE when gas piping goes underground. Long story short: outdoor tankless water heater quit firing. Trouble code said no gas supply. Confirmed by removing flex and opening valve. No gas. Supply coming from meter underground. Find water in the gas piping underground. Suck water out with wet/dry vac and when gas is turned back on, I find MANY holes in the piping underground. So my question is how many of you have find this before? This is my first time. Under the epoxy coating where there are pipe wrench teeth marks....the piping hollowed out. I read other older threads here about this piping being pretty crappy. I was under the assumption the piping under the epoxy was galv. Apparently not. The piping is only two years old. I'm just in shock really. PE pipe to the rescue tomorrow.... piping.jpg
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,255
    Location:
    Cave Creek, Arizona
    qquote;So my question is how many of you have find this before?

    Too many times. that material, even though it is code approved it is the poorest possible material for a buried gas line. The coating is not much more than a coat of paint, and the base pipe is black steel which should NEVER be buried undelground. ANY damage to the coating, such as wrench marks, or exposed pipe MUST be tightly covered with pipe wrap tape. IF moisture can contact the base pipe, it WILL corrode quickly. I have seen pipes, like yours, which looked like Swiss Cheese in a matter of a few years.
  3. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    The manufacturer, and code, require ANY spot on the pipe, such as exposed threads, wrench marks, scratches, etc. to be PRIMED ( primer is $20 a quart) and wrapped with 40 mils of tape ( = TWO wraps of the available 20 mil tape). How many installations do you think really achieve this? First off , most guys and ALL DIY skip the primer, because it is so expensive, and they think one wrap of tape is enough. And usually only tape the joints, not the scratches!
  4. bluebinky

    bluebinky Member

    Messages:
    408
    Location:
    Santa Clara, CA
    Not all DIY installs skip the primer. A few years ago, I put some buried coated steel underground (out to my new shop) at my place in Texas. I'm confident I did it right, but when I move back in a couple of years, I'm gonna tear it all up and pay someone who is licensed to put in plastic. The original install will never get to see any gas...
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,255
    Location:
    Cave Creek, Arizona
    The real reason for the primer is that it is a "second line of defense" against corrosion if the tape failed. If the tape is installed, with the proper overlap, it creates an inpenetrable "sheath" around the pipe, which does not necessarily depend on the tape's adhesion to the pipe.
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