Underground Pipe Locating and Inspection

[BronYrAur]

Any recommendations on how to best locate and inspect underground piping? I have been asked to perform a wellness study of a mill water system that sends river water into a plant to cool various machines. The piping is very old and the plant would have to shut down in the event of a failure. There are a couple of valve boxes, but other than that I have several miles of buried pipe. I think it's ductile iron, but I'm not sure. The mains start out at 24" diameter, but reduce down along the way as branches take off. I read about the "pigs' used in oil pipelines, but I don't see how I could use them here. The piping may be as deep as 12'. Any ideas for locating and inspecting would be appreciated.

 

[BigInch]

Pigs will be difficult with reducing diameters and without a means to catch them.

If you're really not sure where they are, you could try locating them either via metal detection, or ground penetrating radar.

Have you thought about using an internal remote cable TV inspection?

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[ndeguy]

Ground penetrating radar would probably locate the pipes if you can access directly above the run. A link to a leading companies website:

http://www.georentals.co.uk/gpr_main.htm

Without a pig launcher/catcher you wont be able to use pigs. Once you have located the exact pipe course by GPR, if you are able to excavate at regular intervals of about 30 metres metres, you could have guided wave ultrasonics carried out for cracks and wall thickness loss > 5% of cross-sectional area.

Here is a website link:

http://www.guided-ultrasonics.com/index.html

Good luck



Nigel Armstrong
Karachaganak Petroleum
Kazakhstan

 

[rconner]

I don't work specifically in the condition assessment field but I would think maybe a good place to start would be to ask if there are any "as built" or earlier plans/specifications or soil surveys etc. in existence for the pipeline. If the pipe is indeed metal, I would think you may be able to "locate"/confirm its and/or its appurtenances locations at least in plan view at some depths with a good metal (pipe) locator/detector or the other methods talked about in this thread. Also, you could inquire if there are any maintenance logs or other incident accounts in existence for the pipeline, and also where and when there have been any tapping or "cut-in" (valves, tees, etc.) or flow testing etc. operations performed at any location of the pipeline since it was originally constructed. If so, you might want to see if any coupons or pipe pieces were removed and retained in these operations (then plan on taking a look at same inside and out, and perhaps even to test/confirm material type, condition at least at the time of the operation, the presence of any coating/lining system, etc.) I guess you could even talk to any old hand inspectors or constructors who may have been around when the pipeline was constructed, in an effort to learn as much as possible about it. Beyond these things, you may wish to consult with reputable experts in the field of condition assessment and equipment for doing same, once you know and could relate to them exactly what you have and as far as you know its history (to allow knowledgeable consultation). Only other comment I'd make is in general (particularly if there have been no problems with the line) one probably doesn't want to be any more invasive than necessary or create problems or damage to the pipeline that don't exist at the present time.

 

[nackra]

http://www.entech-ndt.com

another GPR and infrared possibility

 

[wfn217]

See API Standard 1615.

 

[BigInch]

I don't have a copy, but according to its scope, there appears to be little information in API RP 1615 of relavence to this thread.

1.2.2 This recommended practice applies to underground storage tank systems (see 1.3.48) that are used to store petroleum products at retail and commercial facilities.

Would you care to elaborate?

Going the Big Inch!

http://virtualpipeline.spaces.msn.com