I would think a "One Call", "Miss Dig", ... to the utility companies would be your starting point. I believe they are compelled to locate all of their facilities, even by easement on private property. On private property for what is considered a "private utility", this becomes more challenging. I've seen many drillers place that burden back on the owner and exculpate liability for striking unknown utilities. Basically Mr. Owner, if you can't find it, then how can I?
I'm unaware of a magic wand device that will sweep an area clear, nor would I think you want to get bogged down doing this unless you are getting paid for it. SUE (Subsurface Utility Engineering) would help define the deliverables for this type service. Even in that case, you are working with the owning utility for the location of their facility and mapping it to a defines class level of locate.
Thanks for the reply. I was just looking at a tool that can assist us on placing borings in safe locations. The owner can pay for this extra effort. Sometimes we have to drill within neighborhood areas where utilities are everywhere. We do have utilities maps but I think that an additional tool for checking "on the spot" it will be helpful as well.
I had a decent sized SUE project about a decade ago with an industrial client to map their mill water distribution. A previous consultant had tried GPR with little to no success. We mapped it with standard inductance locators, working it from known valve vaults and historic maps. I'm not saying GPR can't work, but it certainly wasn't a single sweep / "all-clear" device.
I also scoped out a large mapping project for an old historical cemetery which we looked at GPR for unmarked graves. Very expensive and we ended up adopting an alternate locating technique. Our firm is multi-national and we have the GPR equipment in-house.
I can tell you point blank there is NO magic wand out there that you jump out of truck with and start drilling. Scope your projects tighter and educate your client.
Thanks for the suggestions. I used GPR in the past but it took time to process the data and also the results were not too useful. I was looking for something more handy. I understand that there is no an equipment that can provide the exact underground data and most of the times is a judgement call based on available maps or what we can see at the site (manholes, pavement/sidewalks cuts-repairs, etc). Thanks again for your input...
If the utility in question has a tracer wire, other means of passing an electric current through it, or is an electric line that is how most 811 "one call" locators locate their respective utilities. Locating depth can be tricky as the 811 guys will tell you there is no guarantee that the tracer wire was installed at the approximate depth of the utility.
I would prefer to put the onus on the 811 guys than take that responsibility in my own hands typically though. Apparently this type of location request is free of charge at least in the USA.
See link for examples of this type of locators. These locators do have a function to approximate the depth of the electric charge they locate.
dik, I was searching for hydrovac and looks like it uses a large vacuum truck to expose the buried lines? It was not clear to me how it works. If you can share any links about this method it will be appreciated.
sam74, thanks for the locators examples. These handy locators is what I have been seen. I will take a look more closer at that link.
WORK TO BE UNDERTAKEN IN ACCORDANCE WITH ALL RELEVANT SAFETY CODES
PROVIDE SAFETY BARRIERS AS REQD
PROVIDE ‘WARNING/DANGER’ SIGNAGE AS REQ'D
ALL LOCATE DOCUMENTATION MUST BE CURRENT AND MUST BE WITH THE PERSON DOING THE EXCAVATION AT ALL TIMES
ASSUME ALL CABLES TO BE EXPOSED DURING THE HYDROVACING ARE ENERGIZED. SAFE WORK PRACTICES SHALL BE DEVELOPED BETWEEN THE OWNER THE CONTRACTOR TO ENSURE SAFETY WHILE WORKING AROUND LIVE CABLES. CONTRACTOR TO ENSURE ALL EQUIPMENT AND CABLES ARE NON-ENERGISED AT ALL TIMES INCLUDING PERIODS OF INACTIVITY
HYDROVAC TRUCK SHALL BE SUITABLY GROUNDED INTO THE EQUIPOTENTIAL ZONE. PROVIDE GROUNDING PADS FOR ALL WORKERS AS REQUIRED
CONTRACTOR TO ENSURE ALL EQUIPMENT AND CABLES ARE NON-ENERGISED AT ALL TIMES INCLUDING PERIODS OF INACTIVITY
HYDROVAC AS REQD TO EXPOSE ALL BURIED UTILITIES. TAKE CARE TO PREVENT OVER EXCAVATION
ABSOLUTELY NO MECHANICAL EXCAVATION WITHOUT PERMISSION
REMOVE EXCAVATED MATERIAL AND DISPOSE AS DIRECTED BY OWNER
HYDROVAC EQUIPMENT SHALL HAVE SUITABLY SIZED WATER RESERVOIR AND DISCHARGE TANK FOR THE WORK
WAND TIP SHALL BE EQUIPPED WITH A HIGH PRESSURE NOZZLE WITH A SINGLE JET OSCILLATING HEAD. DIRECTION OF WAND SHALL BE ACROSS CONDUCTORS AND NOT PARALLEL TO THEM. DIRECT HIGH PRESSURE NOZZLE IN A CIRCULAR PATTERN TO AVOID PROLONGED CONTACT WITH CONDUCTORS.
VACUUM NOZZLE SHALL HAVE A SOFT TIP (NEOPRENE OR EQUAL) TO PREVENT DAMAGE TO THE CONDUCTOR
WATER TEMPERATURE FOR HYDROVAC OPERATION SHALL NOT EXCEED 40%%CC. WATER PRESSURE SHALL NOT EXCEED 1500 PSIG
IF DAMAGE OCCURS TO CONDUCTOR, STOP WORK, AND PROCEED AS DIRECTED BY OWNER
Check with a local operator; this may not be suitable for some soils
Thanks dik for the link. The hydrovac method looks interesting, however it is too disruptive for the purpose of verifying utilities just for soil boring explorations. For earthwork in construction projects it will be a nice option. I am in Japan and have not seen this method, but it is interesting. Problem here is that disposal costs for sludge are quite high...
Used lots of times for high voltage cables subject to damage (not energised) and buried piping. even with congested sites. The volume of 'sludge' is not great... and is essentially the same type of soil and volume to be excavated and should not entail large costs for disposal. Substantial money can be saved in the event a conductor or pipe is cut using other mechanical means.
IR... that's what it essentially is. We also use hydrodemolition... much higher pressure to remove concrete...
Hi dik, are the hydrovac and hydrodemolition methods common/popular in the US? They appears a good option, but I have not heard about these methods, that's why I am asking. Thanks again.
We do a lot of industrial stuff... and hydrovac is quite common for exploratory work. An opportunity for someone in Japan...
Hydrodemolition is also common... under very high pressure it is possible to remove a couple of inches of concrete; I've got a couple of projects where I'm using it to remove deteriorated concrete to attach a WWM reinforced 'patch'.
I work in the electrical utility industry at the moment and perform a lot on 811 calls or "one calls". Typically each utility or pipeline owner will mark the approximate location of all utilities using the type of utility locator I mentioned above for information purposes only These locations will a lot of times be surveyed to include on a base survey for new projects so one would have an idea of what is out in the field that is not visible and could cause conflicts. When actual construction takes place most of these guys will require a crossing to be hydrovaced in the field with their representative on site to insure no damage will take place. And if the potential for a costly conflict exists the hydrovacing might also take place in the design phase as well to establish elevations for design purposes. So I would say it is very common as well.
