Has anyone tried using a Sub Surface AML+ or AML Pro to locate underground PVC? I'm looking at GPR but it doesn't work much in this region; Sub Surface is making some impressive claims on their web site but if it's really all of that I would think I'd have heard more about it.
Go ahead and slap me, now. Just gotta say it.
We find backhoes are exceptionally well suited to finding jagged, broken pieces of PVC pipe.
On occasion, a 1/2- inch by 24-inch or longer piece of rebar will find a buried piece of PVC with a hole in the top of it.
I always wanted to submitt a plan for trenches 10' apart and 10' deep going north - south and east - west on a site where One Call Refuses to locate for design surveys. They actually did a locate for a monument for us last year. I had to explain that the monument was going to start in a 4' deep hole with a 12" Helix driven to refusal. The Helix went down 17' before it twisted the shaft.
Just to mention the basics.
I have two nice probing rods. One fiberglass and the other stainless steel with extensions. For Louisiana soils they work and by experience one gains proficiency in their application. They are not for the feint of heart or for office trained personnel. It is work.
Other than that, I have seen some of the pvc locators work but were verified with by probe.
Or the discussion of dowsing can rear itself again here for the umpteenth time. :whistle:
Robert Hill, post: 327034, member: 378 wrote: Just to mention the basics.
I have two nice probing rods. One fiberglass and the other stainless steel with extensions. For Louisiana soils they work and by experience one gains proficiency in their application. They are not for the feint of heart or for office trained personnel. It is work.Other than that, I have seen some of the pvc locators work but were verified with by probe.
Or the discussion of dowsing can rear itself again here for the umpteenth time. :whistle:
We are quite familiar with probing, we do it daily. We are also quite familiar with what happens to a 3" gas line when it is struck by said probe.
I'm going to get all old and gray on you all, but here goes...
We have a couple of sub-surface locators. I can't remember their names (because I've never used them), but a couple of my guys are pretty good with them. I think they've come a long way in the last 10 years with locating equipment. We have even had good luck with the dreaded nemesis, pvc rural water lines. Our biggest problem is the iron content of the red clay and our sometimes non-existent subsurface moisture. This apparently screws with the inductive locators.
However, I am a tried and true probe user. We call it the iron hoobajoo...Having spent my entire adult life being outdoors, watching jobs of all sorts and paying attention, I've gotten really good at "seeing" trench lines that were put in years ago and have healed. The trick to probing for shallow (+/- 3') buried lines is in the eyes and knowing where to start. I bet there's a lot of you out there that know what I'm talking about.
This product looks interesting. I definitely would like to see an on site demo. If it can truly be used in wet conditions, it would have some advantage over GPS. My first thought is that it could be another tool in the tool box. The main question is how deep can you detect what size object? As it appears to detect everything (wood, metal and pvc), the unit is detecting all dissimilar materials. This could be an issue in congested areas. Would have to use it a while to determine just how useful it could be.
Do you commonly have PVC gas lines without tracer wires or tape? Usually in this area, the wire or tape is damaged and sometimes can be located with radio frequency equipment in sections using the conductive mode.
I was looking at a job where the AML would be a possible solution. The job would be about 4 hours from home and I found a dealer about 2 hours further from the job. The dealer said he would do a demo on the line in question if necessary and gave me the name of someone who purchased one. I called that person and he said the AML was one more tool in his box that was available to him. He has gotten great results at times while other times not so much.
The job was canceled so I never got the demo.
Interesting. It seems to be some variation on ground penetrating radar.
" AML utilizes high-frequency radio waves that penetrate the ground to detect buried PVC pipes and other objects that magnetic locators canÛªt find."
Lee D, post: 327039, member: 7971 wrote: We are quite familiar with probing, we do it daily. We are also quite familiar with what happens to a 3" gas line when it is struck by said probe.
I wasnÛªt trying to make a ÛÏdigÛ at you. When you have a hard surface cover, it was SOL
Yes, I almost witnessed a rebar being driven into a domestic gas line in a quiet residential neighborhood. Close call and a spike was set with an offset cross in the sidewalk.
Two toughest locates that I had was the LP&L facility in Algiers Point across from the ferry landing. Brought in the pros to do it since they wanted perimeter and site locates. The other was for new security entrances at Felicity St, Nashville and Napoleon Ave at Tchoupitoulas St. for the Port of New Orleans (post 9/11). It helped to have contact names/#s of Homeland Security to drop. BTW, it was interesting to see how the fiberglass witness post/signs differed from the actual locations and how they looked like they were laid out by an inebriated crew. They had hit countless conflicts in construction.
Levee crossing for COE are the toughest manual probes when they wanted depths. Sweaty work at the toe of levees.
I worked for GSE and I know the surveyor who was porbing under an Live Oak on Little Bayou Black and thought that he hit a root but really knocked out a 1/3 of the Houma phone lines that day. OOPS
Do you commonly have PVC gas lines without tracer wires or tape? Usually in this area, the wire or tape is damaged and sometimes can be located with radio frequency equipment in sections using the conductive mode.
We're running into some lines that are poorly marked or not marked at all. We typically use a Radio Detection RD8000 and if there is tracer wire or tape that works well, but it's not always there. I'm just trying to make sure I'm covering all my bases.
The utility locator we use has located PVC sewer cleanout lines by snaking the line with a metal tape and inducing the signal. Not sure this would work with pressurized water or gas lines, though.
It's been a while but one manufacturer (Schostedt?) made a unit that installed on a hydrant (opened) and sent pulses through the water line that was "heard" by a receiving unit. Dagnab it I wish I could remember who it was.
Andy
Lee is correct the company he works with knows how to locate pipe, they have some people that have the "gift" Great bunch of guys, I am talking about probing for 8 hours non stop, 6 days a week. Any new technology would be a blessing. blood blisters on hands thru gloves by 11:00am because the crew is cheaper than a hydro-vac. Good times.
witching does not not work for anyone but I was surprised when instructor on pipelocating course shown it to us, I tried and it worked for me. not legitimate method of course but it works. 2 steell wires bent at 90 deg keep horizontally parallel, when crossing a line they will cross. verified with pipelicator - bang on. works on pvc pipes as well.
Andy Bruner, post: 327151, member: 1123 wrote: It's been a while but one manufacturer (Schostedt?) made a unit that installed on a hydrant (opened) and sent pulses through the water line that was "heard" by a receiving unit. Dagnab it I wish I could remember who it was.
Andy,
It is called a thumper. The last one I bought was from Metrotech. Using it is a little scary as the seals on the hydrants will start to leak. One time we hooked it up to an outside facet on a Wal-Mart. This set off an alarm and caused us much grief. Another problem with this process is that the range is limited and in noisy areas the signal is hard to hear. It is another tool in the box that I will only use as a last resort.
