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Thread: Locating gas lines

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    Default Locating gas lines

    Today, after locating an underground water leak, I was asked to locate a gas line in the same area. This was the one utility on the property that the one-call locators were not responsible for. The gas line was steel, as far as I could see. I made a direct connection just above ground level. I could not achieve a strong signal and then could not follow the gas line with any confidence. I tried various frequencies, none with much success. Is there anything about the construction of a steel gas line that might make it difficult to trace? Could this line to turn plastic below grade? There was not tracer wire present.

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    Default Re: Locating gas lines

    An insulated fitting is probably the culprit. It could go from steel to plastic also. My guess is an insulated fitting not letting your signal go through. Was this a private gas line?

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    Senior Member underground quester's Avatar
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    Default Re: Locating gas lines

    Quote Originally Posted by testtech View Post
    Today, after locating an underground water leak, I was asked to locate a gas line in the same area. This was the one utility on the property that the one-call locators were not responsible for. The gas line was steel, as far as I could see. I made a direct connection just above ground level. I could not achieve a strong signal and then could not follow the gas line with any confidence. I tried various frequencies, none with much success. Is there anything about the construction of a steel gas line that might make it difficult to trace? Could this line to turn plastic below grade? There was not tracer wire present.
    A couple of things I can think of other than what Golden has correctly stated:

    1) If it is a steel line there may be a welded joint on the line near where the riser comes out of the ground. Scrape down to bare metal, perhaps use a file, then connect your positive lead to the bare metal below that welded joint.

    BETTER YET, get a pair of vice grips and loosen them a bit , place them around the pipe just below the weld (if there is a weld) and snap them shut, just snug. You do not want to crush the line. Move the vice grips up and down until you are at clean bare metal. Then connect your positive lead to vice grips and ground out away from suspected run of gas service. This was recommended to me by Frosty and works like a hot damn!!!

    2) If it is a steel riser and PE (polyethylene) service line you of course would not get a tone. If there was no tracer wire, then during construction or whatever, the wire has been cut off. Or, some lazy bastard forgot to/did not put a tracer wire in there.
    You may want to try digging down a small ways around the riser to see if there is a tracer wire. On occasion, I have had to dig down about a foot or so to find the damned tracer wire that the customer had inadvertently buried making a flower bed or whatever.

    On occasion, I have had to phone the local gas utilitys' "construction" or "graphics" (aka:auto cad) departments to get them to advise me what the line is constructed of. I would imagine they would then want to know why you need to know, but just throwing things out there.

    In some of the older areas of my territory the local gas utility used PVC pipe for a short time AND the A holes did not use tracer wires. Go figure... So tracing them is impossible.
    Last edited by underground quester; November 4th, 2008 at 10:29 PM.
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    Default Re: Locating gas lines

    The difference between a steel service and a plastic service is often difficult to see above ground and without viewing a service card/record. All risers are steel (at least all that I have seen) and if the services changes to plastic it is usually at the bottom of the riser where it makes a 90 degree bend.

    This is where you need to put your trouble-shooting skills to work. If you are unable to get a good signal check the usual - good lead contact, good ground, change frequency up/down, etc. Still nothing consider digging shallow around base of riser and look for a tracer wire. Chck hook-up point to make sure you attach leads at the lowest point possible and metal to metal. If the line is steel at some place on the meter set will be an insulator to stop their own cathodic protection from being wasted on the customers in-house gas lines and water lines.

    If all else fails, try to induce starting with your transmitter on the ground about 2-3 feet out from the point where the riser enters the ground. If you have no luck inducing from the riser try locating the main (direct or inductive) and following it back to the service.

    Gas and water give me more trouble than any other utilities and they have taught me about patience as much raising teenagers.

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    Default Re: Locating gas lines

    [QUOTE=dirt painter;9535] If you have no luck inducing from the riser try locating the main (direct or inductive) and following it back to the service.

    Yes, good point dirt painter, do on occasion drop the box on distribution mains to trace back the steel service line.

    On occasion I have additionally hooked to a neighbours house who has a PE service line with tracer wire that direct connects to steel mains. You can connect to the neighbours and providing the service line you want is steel, it will carry a signal to the riser. A bit tricky though when you are new to it.
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    Default Re: Locating gas lines

    I would guess it probably turns to plastic. Next time I will dig below the surface to check for a tracer. Tracers are required on plastic now. I don't know if they were decades ago when that place was built. I hooked up below a gasketed coupling. I tried frequencies from 512 to 200 k. I used a plastic grinding wheel on a drill to get to bare metal. Inducing is not an option because the line was pretty well surrounded with every utility known to man. I did get signal to leak onto other objects, probably through the building grounds. Thanks for the info. Today they will dig carefully, assuming they are near the gas line. They know they are near telephone, cable and power.

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    Default Re: Locating gas lines

    If you are unsure about the tone and it is a private line anyway, do not paint it in yellow. ?I would always paint that in orange or red, or other color and tell the contractor if I trusted him that I had "bled onto it" when I was locating the other utility. Just in case it was wrong.

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    Default Re: Locating gas lines

    in charlotte we have a lot of inserted lines. where steel lines start to go bad or have been damaged, they insert a plastic line inside of the steel. usually there is an anode wire on these. (they are a ground wire running from a white plug\stake buried under the meter up to the riser and is attached by a clamp) you need to unscrew the set screw that bonds the anode wire to the meter. ususally then you can hook to the steel line and it will run. anodes' are a pain here, but im not sure that they do it everywhere. a good way to tell steel svcs are they are usually 'wrapped' with a black tar paper below the cut-off valve. check for that and make sure your not connecting to that, make sure your on the steel. usually the tab on the valve is the easiest place to hook it.

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    Default Re: Locating gas lines

    Quote Originally Posted by paintitout View Post
    If you are unsure about the tone and it is a private line anyway, do not paint it in yellow. ?I would always paint that in orange or red, or other color and tell the contractor if I trusted him that I had "bled onto it" when I was locating the other utility. Just in case it was wrong.
    I wouldn't paint color on any line that I knew wasn't mine. Best bet if you want to is just paint it out black, then you can say "I didn't mark the gas, private line, whatever." Fact of the matter, as proved out in court, is if you put colored paint on it indicating it is a line you are responsible.

    Paint it black. I didn't mark a h2o main, private electric svc. Do you see any colored paint there? Didn't think so.

    CYA

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    Default Re: Locating gas lines

    I guess I take for granted that I locate gas every day here in Indy, and not everyone finds it as easy as me. Here in Indy we have access to great prints/service records, which give composition and measurements and depths. But we get good at recognizing PL or STL services based on what the look like at the meter... Tracer/tone wires buried w/ plastic services ARE sometimes hard to find. Often just under mulch, etc. But here in Indy there was a period where the gas company, for whatever reason, stopped the wire and wrapped it around the service near the bottom of the riser, sometimes 3ft. from where the service comes out of the ground. No clue why they thought THAT was a good idea. I've had to dig for a couple. Continued....

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    Default Re: Locating gas lines

    There was also a time where the gas company used as tracer wire some thin television antenna wire or something, which over decades has corroded/broken and won't locate.
    Other periods (1980s) the Indy gas company for some reason didn't tack tracer wires to the main, so you won't get continuity when sending signal down it. Not a huge problem, just bump up signal. Anyway, I find gas to be the easiest utility to locate. Mostly reliable depth, no crazy turns, good prints to work off of...

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    Senior Member AULupstate's Avatar
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    Default Re: Locating gas lines

    The biggest problem with locating steel and having wires to hook up to is they DO NOTHING but go to a cathodic protection anode bed (common mistake hooking up to them). Steel and Cast Iron being the 'hardest' gas lines to locate come with their own unique set of problems.

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    Default Re: Locating gas lines

    I don't think I have had the pleasure of locating a cast iron gas line. (sarcasm off now) As long as the locator realizes that the signal will always go towards an anode bed with steel mains, that can be used as a great way to manage your signal. It takes alot of hook up points. Personally, I hate inserted gas lines. Those are the hardest I have come across. Crap signal on anything but highest of power.

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    Senior Member sprayandpray's Avatar
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    Default Re: Locating gas lines

    Here in Texas the powers that be are requiring all gas companies to replace the underground elbows that tie the riser to the service. Now this only involves a certain type of poly connection but still affects approximately 800,000 services statewide.
    Here's the catch -the contractors doing the replacements are also replacing the tracer wires at each meter from the top down to the elbow, however, if there was no previous tracer wire they are placing a dummy piece of wire, making it seem like everything is updated.
    The Utiliquest locators are going nuts! They had become familar with their neighborhoods and knew which tracer wires worked(basically they snipped off any that wouldn't carry a signal). This knowledge had been gained thru many years of trial and error.
    I'm really glad that our only gas client is relatively new to the business and we don't have any of this happening.
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    Senior Member underground quester's Avatar
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    Default Re: Locating gas lines

    Quote Originally Posted by sprayandpray View Post
    Here in Texas the powers that be are requiring all gas companies to replace the underground elbows that tie the riser to the service. Now this only involves a certain type of poly connection but still affects approximately 800,000 services statewide.
    Here's the catch -the contractors doing the replacements are also replacing the tracer wires at each meter from the top down to the elbow, however, if there was no previous tracer wire they are placing a dummy piece of wire, making it seem like everything is updated.
    The Utiliquest locators are going nuts! They had become familar with their neighborhoods and knew which tracer wires worked(basically they snipped off any that wouldn't carry a signal). This knowledge had been gained thru many years of trial and error.
    I'm really glad that our only gas client is relatively new to the business and we don't have any of this happening.

    Just a quick question Spray:

    Is the service line from the gas main to the elbow steel or poly?
    If steel, why are they not simply clamping the tracer wire to the steel service line? Laziness?

    Who the heck knows in this business, but I cannot imagine poly service lines from a poly or steel main, not having a tracer wire run with it on the original install.

    Having said that, up here for a few years, the gas utility used PVC some with NO tracer wire. PVC incidently breaks down rather quickly because of a reaction with the gas. They have now seen the errors of their ways!
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