Ground Penetrating Radar

[kayssupply]

Does anyone have any experience with GPR? My son and I are researching it to see about starting a business using it to locate for excavators. It can "see" plastic pipe,rebar,voids,old ditch lines, sewer taps down to 15'. Does it sound like something any of you would like to have done for you? Any feedback would be appreciated

 

[Bird]

I read an article in The Dallas Morning News a few months ago (June 12, 2002) about the ground penetrating radar, and the FCC trying to prohibit its use. It seems that a lot of money had been invested by the state in the equipment and then the FCC was going to prohibit its use. The last article I saw was that they were going to be able to continue using it, at least in some areas. I think you'll be interested in and you might want to look at <A target="_blank" HREF=http://tti.tamu.edu/product/ror/gpr.stm>this link if you haven't already.

 

[Darren]

We looked into using it to locate graves in an old cemetery. An expert told us there was quite a bit of interpretation involved. He wouldn't guarantee results. That was probably two years ago.

Unless the equipment has substantially improved I would expect there's still a certain amount of "art" involved in being able to understand the results.

If it was really accurate, I'd expect most larger contractors would be using them. Is that the case?

 

[kayssupply]

At this point there is only 3 that have been sold in Illinois by the leading manufacture in the country. All are being used by government agencys. I haven't found one being used commercially , so far. The $20000+ price tag might be a reason.

 

[Darren]

For the average Joe, $20,000 is big bucks. For a contractor with hundreds of thousands of dollars worth of equipment and multi-million dollar contracts, $20,000 while not exactly pocket change isn't much when you consider the difficuty of underground construction in built up areas and liquidated damages.

I've seen many contractors get in trouble because they ran into more obstacles than they estimated when they started digging. Around here the feeling is that as long as they've called Miss Utility and the owners of the underground lines have marked them, it's not the contractor's problem. And the damage to an underground line isn't legally their problem when it wasn't located accurately.

I ran a 2" water line recently which involved getting the local utilities out to do their thing. We still wiped out the phone line. It was marked wrong. We did miss an unmarked 3" gas line by about 6" with the drill. The locals knew one was there, no one could pin point it. To find it later about 50' foot of trench had to be hand dug. It would have been nice if a GPR had been available and would have found the plastic line. It was about 3' down.

The idea has potential. I'd want a company rep to actually demonstrate the equipment so I would be real comfortable about the abilities. It might be interesting to find out what the premium would be for the liability insurance. If a contractor damages something you didn't locate, who pays?

Underwriters get real weird when they're not dealing with a well known risk. Either they won't write the coverage or the premium is stratospheric. Liability insurance is currently one of those areas the insurance companies are trying to make up their stock market losses.

 

[kayssupply]

Insurance is one of our concerns. We have a 5 day class available before we lay down our bucks. The utilities locators won't go on private ground. We are going to research this as in depth as we can. So far it sounds like a very useful service if the costs don't make it impractical.

 

[Anonymous Poster]

I think I'd certainly take the 5 day tour, and ask a lot of questions. Radar frequencys tend to be a tad nasty on the human body, so I'd be questioning that.
I'd also be doing some looking into the situation regarding underground location in your area. Aspelunth is one of the biggest in the country, and seems to be trying to become a monopoly. There is a board for locators, that is quite active, but I've lost the URL.
If the vendor offers the demonstration only at their chosen site, I'd run like he!!. If they let you choose a site, they might have a real product to offer.
Locating tends to be a business of contractors and sub contractors, all of whom seem to feel they are underpaid and overworked. Insurance costs are huge because when the locator screws up costs go into orbit, particularly when fiber is involved. Carriers get to bill not only for damage, but loss of potential income as well. If a better piece of equipment is available at $20,000, a lot of locators would be lining up to buy it, locating equipment is hardly cheap, and new generations seem to come along every few years.
I'd certainly want all my ducks lined up before I bought such a piece of equipment, the uses I've seen of such left a lot to be desired.

 

[clifst2310]

I used a GPR while in the Army. It was used to locate buried munitions like unexploded bombs, and interpretation is required. All the radar told us is that there was some abnormality, but it couldn't ID what the it was. With training and quite a bit of practice you should be able to learn the radar signiture that the buried cables, pipes, etc. produce.