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 lowest 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.
What is Non-Destructive Digging (NDD) ?
The process of NDD is to use high-pressure water from a lance/gun, similar to what you’d use when washing 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 an excavated hole.
Click on the video below where we’re 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?
Now, let’s be honest. Unlike what some of our competitors may tell you, Non-Destructive Digging really doesn’t need to be used on every single job you do.
Deciding on whether or not to use an NDD truck will depend upon:
- 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 per hour as an excavator can.
NDD is, however, faster than someone digging by hand with a shovel.
So let’s go through it and break it down for you.
- If there’s no risk of damaging underground services in the area where you’re working, then it would make sense for you to use an excavator.
- If there are underground services in the area and you’re not paying wages, then you should use a shovel to dig down by hand and either expose the services in the area—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 by hand, then you should use an NDD truck.
In addition, when you’re working in areas of underground services a further benefit of using the NDD truck is that it will work in areas that excavators can not. Maybe:
- you’re working too close to a building, or
- there are overhead power lines, or
- the works are in the backyard of a house and you can’t get an excavator in there.
There are also a range of other scenarios in which you won’t be able to get an excavator onto a site, but where 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 example of where NDD would be an improvement over using an excavator. If you have to work in the vicinity of tree roots and those roots must be left intact and can not be cut or damaged at all, then NDD would be the way to go.
Why use Geelong Cable Locations’ NDD truck?
So the next question you’re probably asking is: why should you use Geelong Cable Locations’ Non-Destructive Digging truck over any other one that you might find through Google.
Well, we’re one of the few companies that offers a combined service of cable locating and non-destructive digging all in one vehicle. Our NDD truck comes equipped with all the basic cable and pipe locating equipment* as well as a fully-qualified cable locating technician—who has experience not only in locating underground services, but in exposing them as well.
He’ll know exactly what you can and can’t do around the underground assets, as well as how they should feel and look when you’re exposing them with the NDD truck.
This is an ideal situation if you want to locate where the underground services are on your site and then have them exposed.
*Please note: when we talk about “basic locating equipment”, this mainly means we don’t have access to the full range of locating tools that we carry in our service locating vehicles, particularly our ground penetrating radar or acoustic locating equipment. If either of these are required, then we recommend that we come out with a service locating vehicle as well as the NDD truck.
Why is it an advantage to use someone that can do both locating and NDD?
An issue we sometimes hear—both on some sites we’ve worked at, and also within the construction industry when the topics of Non-Destructive Digging and service locating comes up—is that the client will get a locator out on to site, who’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 the utilities that have been located. Sometimes everything will all go as planned and there’s no issue. But other times, the NDD operator won’t be able to find a cable/pipe that should be in the area the locator marked up.
When this happens, you get issues out on site—with both guys blaming each other.
The locator says it’s the NDD truck operators fault because he should dig deeper, or move over to the left or right. The NDD truck operator blames the locator, saying he should have told the client that there was an issue with that locate, so that when he fired up the NDD equipment he would have known that the underground installation might not be exactly where the locator had marked on the ground.
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 come out with all the gear it means that, even if the client knows where the services are and tells us exactly where they want us to dig, if we can’t find the utility that should be there when we dig down, we can just simply hook up the locator and go along and check whether or not we’re digging in the right spot. If we are, then we can check how much deeper the service is. And if we’re not, we can see if we need to move over more to the left ot the right.
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. You then have to decide: do you move over towards the left, or to the right, or is it just a little deeper?
- If you keep going deeper, then the chances are that you’ve already passed it and it is just to the side.
- If you move over a bit 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’ll generally find it’s just another 100 or so millimetres lower at the spot where you originally started digging.
It can be very frustrating—especially if you’re doing it all by hand.
Whereas if you call us out to site, then we can just grab the locator and within a couple of minutes we’ll know whether we’re on target or not.
What sort of jobs can we do with the NDD truck?
Other companies may offer bigger trucks that are a bit flashier and come with all the bells and whistles, but you’ll have to hold 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 bigger projects, you’ll probably have staff who can be assigned just to look after the NDD trucks onsite.
But if you want someone who can think for themselves, has good experience, common sense and 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. As you can see from the photos on this page, we’ve done this and a range of other jobs in the past.
We also have good working relationships with several other NDD companies, so we can get the use of bigger trucks when needed. We’ve had multiple trucks on sites many times before—mostly when we’ve needed to get the job finished in a tight deadline, without holding up the bigger project.
If you have a big project and you think you might require multiple trucks on site, the best bet is to get in touch with us first so we can go through it with you in more detail, rather than just booking online as you would if you were booking in a standard job.
Click the play button below to watch another video of a job site we worked on in which we used Non Destructive Digging.
Non-Destructive Digging isn’t what you want after all?
So, if after reading all of this you’ve worked out that NDD is not what you actually want after all, then don’t worry too much about it. Unless you have dealt with this sort of stuff before, all the terminology we use could get a little confusing.
If you just want someone to come out and mark on the ground where all the underground cables and pipes are, then what you need is called ‘Service Locating’.
What we do in those circumstances is come out with a service locating vehicle that carries every piece of locating equipment we have, and then use the relevant equipment to locate the services in the area where you’re working.
To find out more about service locating, you can head to this page. It’ll walk you through what it is and how it can assist you on your site.
NDD is what you are after—but you need that and more?
So you do need Non-Destructive Digging, but you’re also after someone who can handle the rest of works associated with the underground utilities in the area?
Well, we can help you with that as well!
That’s called project management—and we can do everything from arranging permits and obtaining traffic control, to surveying the depths of the services we locate and plotting them on a plan, to backfilling the holes after we’ve exposed the utilities for you.
To find out more details about what we can do to help you, then go to the project management page, which you’ll find here