Hydro Excavation / Vacuum Excavations / Non-Destructive Digging—regardless what you call it, it all pretty much means the same thing.
Basically it’s a safe form of digging, which offers the least chance of cables, pipes, tree roots and pretty much anything else that is buried underground from being damaged when you need to dig in their vicinity, compared to the damage that could be caused by the teeth of an excavator or even just a crowbar (if you’re digging by hand).
Differences between Hydro Excavation / Vacuum Excavation / Non-Destructive Digging?
Now, there are slight differences between Hydro Excavation, Vacuum Excavation and Non-Destructive Digging. These differences relate to the level of water pressure being used, and whether it is in fact water that is being used to dig up the dirt. However, on this page we won’t go into all those details, as the majority of people reading this probably don’t really care what the difference is, so long as the process being used minimises the risk of damage to underground infrastructure.
For the record, the main service we offer at Geelong Cable Locations is Non-Destructive Digging, and as such we will refer to it as NDD for the rest of this page.
What is Non-Destructive Digging?
The process of NDD is to use high-pressure water from a lance or gun (similar to what you’d use when you wash your car at a commercial car wash centre) but with a lot higher water pressure. We use the water from the lance to actually dig up the dirt and turn it into mud.
Then, with a high-velocity vacuum, we suck up all the mud that’s just been created, which leaves us with a hole.
Click on the video below to see us out on a job site and see the NDD truck in action to give you a better guide to how it all works.
Should you use an NDD truck?
Deciding on whether or not you should use an NDD truck will depend on the project you are working on, your budget, and the level of risk you’re willing to take on.
NDD trucks are more expensive per hour than a backhoe/excavator and cannot move as much dirt as quickly as they can.
NDD is, however, faster than someone using a shovel.
So let’s go through it:
- If there is no risk of damaging underground services in the area you are working, then it would make sense that you would use an excavator.
- If there are underground services in the area and you are not paying wages, then you should use a shovel to dig down by hand and either expose the services—so you know exactly where they are—or just dig your whole job by hand.
- If there are underground services in the area and you don’t have time to dig it all by hand, or you can’t afford to have staff digging it all by hand, then you should use an NDD truck.
Another benefit of the NDD truck is that we can get into tight spots where you can’t get an excavator in—be it that you are too close to a building, or that you have overhead power cables, or that the site’s up against the back of a property.
There are also a range of other scenarios in which you can’t get an excavator into a site, but you can get a 100mm hose into the area—again this is where NDD would be beneficial to you.
Lastly, preserving tree roots would be another reason why NDD would be used over an excavator. If you have to work in the vicinity of tree roots and you need to make sure the roots don’t get cut or damaged, then NDD would be the way to go.
Why use Geelong Cable Locations’ NDD truck?
So the next question you’ll probably be asking is why should you use Geelong Cable Locations’ NDD truck over any other one that you might find on Google.
Well, we’re one of the only companies that offer a combined service of cable locating and non-destructive digging all in one vehicle.
Our NDD truck comes out equipped with all the basic cable and pipe locating equipment as well as a fully-qualified cable locating technician, who has experience in not only locating underground services, but exposing them as well.
He will know exactly what you can and cannot do around the underground assets as well as how they feel and look when you are exposing them.
This is an ideal situation if you’re wanting to locate where the underground services are on your site and then have them exposed.
**Please note: when we say “basic locating equipment”, this does not include ground penetrating radar or acoustic locating. If either of these are required, then it is recommended that you get a service locating vehicle to come out to site as well.
Why is it an advantage to use someone that can do both locating and NDD?
An issue we hear on some sites and within the construction industry, is that the client will get a locator out to site, then he’ll walk around and mark out where the underground cables and pipes are. The client will then call in an NDD truck, and its operator will dig down on those marks to try and expose them. Sometimes it will all go as planned and be not an issue, but other times he won’t be able to find the utility that should be in the area.
And then you have the issue of both guys blaming each other. The locator says it’s the NDD truck’s fault because he should dig deeper, or move over to the left or to the right. The NDD truck operator blames the locator and says he should have told the client that there was an issue with that locate, so that when he was on the NDD truck he would know that the underground installation might not be where the locator says it is.
This causes uncertainty, doubt, mistrust, and a level of scepticism between the NDD truck operator, the locator and the client—with each questioning the other and then questioning the rest of the work that the locator has performed.
Whereas if we go out with all the gear, it means that even if the client knows where the services are, when we dig down and if we can’t find it, then we can just hook onto it and get confirmation of how much deeper we need to go and whether or not we are digging in the right area.
Those of you with experience of working around underground services will know the dreaded feeling when you’re digging down and can’t find a service and you then have to decide: do you move over left, right, or is it just a little deeper?
If you keep going deeper, then chances are that what you’re looking for is just over to the side and you’ve already passed it. If you move over to the left, it’ll probably be on the right-hand side. If you move to the right, it’ll be on the left. And, of course, when you dig one meter either side and still can’t find it, you generally find it just another 100 or so millimetres lower at the spot where you started digging initially. It can all be very frustrating—especially if you’re doing it all by hand.
But instead, if you have us out to the site then we can just grab the locator and within 7 minutes we’ll know if we are on target or not.
What sort of jobs can we do?
Other companies may offer bigger trucks that are flashier and have all the bells and whistles, but you’ll have to be the one that is holding the operator’s hand as you explain to them what you need them to do and how you want it done.
Don’t get us wrong: on some projects this is perfectly fine and, especially on some of the bigger projects, you’ll probably have staff that are assigned to look after all the NDD trucks onsite.
But if you’re wanting someone that can think for themselves, has good general knowledge, and who doesn’t need full-time supervision, then we’re the ones for you.
Our truck has been designed for service proving, as in (a) locating where the pipe or cable is, and then (b) digging down and exposing it.
We can work a full day locating and exposing services without having to worry about filling up with water or finding somewhere to dump the dirt.
We can also do other jobs—like digging trenches or sucking pits out, and as you can see from the photos we’ve done this and a range of other jobs in the past.
We also have good working relationships with several other contractors so we can get the use of bigger trucks when needed, and we’ve had more than one truck on sites many times before, so that we can get the job finished without holding up the project.
If you do have a big project that you think might require multiple trucks on site, probably the best bet is to get in touch with us and we can go through it in more detail with you.