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Thread: Burried Natural Gas Pipe

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    DIY Junior Member jamiedolan's Avatar
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    Smile Burried Natural Gas Pipe

    Hello;

    I'm running a new gas line to my outdoor grill, 24" deep. I've never buried gas pipe before. I've installed quite a bit of black iron inside, and am completely comfortable with laying and fitting the pipe, including pressure testing the system. It is also legal here to perform the work on your own property.

    The AHJ here said they don't require black iron to be protected with any type of extra coating or wrap before it's buried. However, I am concerned about it rusting out, I've read of a several people that have had black iron rust out after several years in ground.

    Does a wrap significantly extend the life of buried black iron? Is there a particular wrap material you recommend?

    I can get CSST if it would be significantly better than black iron for a direct burial application.

    Thanks
    Jamie

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    Plumber jimbo's Avatar
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    Black iron would not last a year underground, in wet soil. Cast iron soil pipes are deep, and are in fact CAST IRON, not steel. What is commonly called black iron pipe is steel, NOT cast iron. They used to use galvanized here, but that also rusts out after several years. Today, around here, they use a lot of epoxy coated steel pipe, with heavy mil pipe wrap tape applied to primered joints.

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    DIY Junior Member jamiedolan's Avatar
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    Quote Originally Posted by jimbo View Post
    Black iron would not last a year underground, in wet soil. Cast iron soil pipes are deep, and are in fact CAST IRON, not steel. What is commonly called black iron pipe is steel, NOT cast iron. They used to use galvanized here, but that also rusts out after several years. Today, around here, they use a lot of epoxy coated steel pipe,
    Now that you say that, I am quite sure this is not really iron and I am using the wrong terminology. I am sure the pipe I use is the epoxy coated steel pipe.

    Quote Originally Posted by jimbo View Post
    with heavy mil pipe wrap tape applied to primered joints.
    Do you apply something to the joints beyond a thread compound(retorseal, / harvyseal) prior to applying the pipe wrap?

    Thanks

    Jamie

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    Master Plumber nhmaster's Avatar
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    you can't direct bury either steel or galvanized.

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    Plumber jimbo's Avatar
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    This is the type of product I am referring to. Others, such as Oatey and Rectorseal make similar.

    The primer is usually yellow, and around here, the inspector will fail the job if he can't see the yellow primer.

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    DIY Junior Member jamiedolan's Avatar
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    Quote Originally Posted by nhmaster View Post
    you can't direct bury either steel or galvanized.
    I must be confused or they approve of using different materials here for some reason.

    When my dad built his detached workshop about 5 years ago, he used the standard black epoxy coated pipe that you see at all the home centers, he buried that in the ground, doing nothing special to the joints, beyond using Harveyseal on the threads. This was done WITH a permitted and approved. I wasn't sure it was correct, but this is being approved here by the AHJ. Hence my confusion as to the proper kind of pipe to bury.

    Is it proper per national code to bury the expoy coated black steel but not the un-coated black steel?

    What I am trying to ask, what is the proper gas pipe to use for direct burial? I would like this done properly so it will last, even if a lesser method would be approved by the AHJ.

    Thanks,

    Jamie

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    DIY Junior Member jamiedolan's Avatar
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    Hello again;

    The pipe you see that comes through the concrete is my main gas line that comes into the house, this is direct buried. It looks more like galvanized to me. It is wrapped on the outside. It was installed in 1963. I'm not trying to argue that it is correct by any means, just showing you what I am familiar with. I would honestly like to know the correct and legitimate way to do this. If you see anything that looks wrong with my workmanship, please let me know.

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    This is the pipe, and fittings I use inside, you can see the yellow Harveyseal compound on all my joints. I clean the male and female threads, check the pipe to make sure the threads are not cut too deep (which I have found once in a while from the factory), I evenly and throughly apply the Harveyseal all the way around the Male threads, apply nothing to the female threads. I then tighten with 2 14" Ridgid pipe wrenches.


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    Jamie

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    Plumber jimbo's Avatar
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    In 1963, they were probably using galvanized. But when it is in soil shallow enough to have a lot of moisture, it will also rust out. I have dug up a lot of galv. the was just half-round....top half of the pipe looked good, bottom have more or less not existent.

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    DIY Junior Member jamiedolan's Avatar
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    Quote Originally Posted by jimbo View Post
    In 1963, they were probably using galvanized. But when it is in soil shallow enough to have a lot of moisture, it will also rust out. I have dug up a lot of galv. the was just half-round....top half of the pipe looked good, bottom have more or less not existent.
    That pipe is less than a foot underground, do you think it should be dug up and replaced or at least inspected?

    What kind of pipe is it that feeds the gas meter from the gas co? Here it is some kind of metal pipe that comes straight out of the ground that is normally painted grey or the color of the house.

    Jamie

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    Master Plumber nhmaster's Avatar
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    There are over a hundred pages in the National Fuel Gas code that cover piping and fittings that can and can not be used for gas piping. I suggest you get a copy.

  11. #11
    I&C Engineer (mostly WWTP) Lakee911's Avatar
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    Why not use a plastic pipe?

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    I see specific plumbing information for nearly all types of plumbing projects...except gas. I recently replaced a leaking supply line from the meter, which was underground and after a lot of searching, I found the specific info for a proper installation here. Epoxy Wrapped Black Pipe (Green Pipe) is used for direct burial. All joints must be assembled with yellow mastic pipe thread compound and tripple wrapped with a heavy mil tape suitable for burial. Regular black pipe and fittings may be used 6" above the finished grade. Then ofcourse, The system must hold a minimum of 10 p.s.i for atleast 15 minutes.

    Of all the info I gathered, these were the most important because this is what the inspector looked for. And yes, he waited the whole 15 minutes before approving the pressure test. He signed off and notified the utility company and the gas was turned on just in time for a much needed hot shower. I live in central California.

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    This thread goes back to last August, I suspect the job has been done ( rightly or wrongly ) for quite some time now.

  14. #14
    Moderator & Master Plumber hj's Avatar
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    Black or galvanized pipe cannot be direct buried, unless they have a protective wrap, (I would not use black pipe even then). The epoxy coated black pipe is not much better than having paint on it, because the epoxy coating can be damaged during assembly or installation, and if the spot is not protected it can rust out in a couple of years. I once saw a section that was so bad it looked like a piece of Swiss cheese. Unless it is a very short run, I use polyethylene plastic. CSST has to be "sleeved" for underground installation.

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    And the sleeve has to be ventilated. Very expensive

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