We’re very pleased to have our air excavation technology profiled in the Dec/Jan issue of Contractor magazine, including the behind-the-scenes story of how we found our AirX trucks and what kinds of jobs they particularly excel in.
Excavation using air as well as water is becoming a popular and cost-cutting alternative in civil construction.
You’d think that with 20 hydro-excavation trucks and 16 years in the business, working up and down the country with big names in construction, HydroVac would have looked no further than hydro-excavation.
The clue is in the name, after all.
However, it didn’t. That was until Andrew Williams, one of HydroVac’s directors, saw an air-excavation and vacuum truck in action and his head was turned.
“I instantly knew it was a great product for us. When I saw what it could do, I knew our customers would love it and that it would solve a lot of problems for them. It was a natural service to add to our offerings,” he says.
Using air instead of water means an operator can excavate and suck up product without adding any water (and weight) to it.
This has three main benefits.
Because it’s not a soggy mess, the contractor can handle their own excavated soil by reusing it on site or stockpiling it to take away at their leisure later.
Without the need to run dump trips, the truck can remain on site continuously, focused on completing the job.
And, if the contractor does choose to dump it, it costs less as a dry material, without the water adding weight.
HydroVac’s trucks are fitted with a unique filtration system that doesn’t emit dust to the atmosphere when they operate. Zero dust/carryover is especially helpful in residential work, or when working alongside a motorway with cars flying past.
As well as cutting back time and running costs, all of those factors have environmentally friendly benefits.
“These trucks are total high performers,” says Cat Woollams, HydroVac’s Project manager.
“They offer very high vacuum – 25000 CFM (compared to 1800-5000 CFM of hydro) – and a generous 10-inch boom which allows you to suck very big product without getting boom blockages. It can air excavate rocks the size of bowling balls.”
While the vacuum may be powerful, the excavation is comparatively gentle. Instead of aggressively cutting through dirt, it just loosens up the rocks and dirt and then allows the vacuum to do all the work.
For one of its recent tree jobs, HydroVac excavated six mature Pohutukawa trees for transplanting, without affecting any of the roots – even the fine-hair-sized ones.
“This is a game-changer for utility companies needing to do work underground – it means there’s no chance of damaging the network or high-voltage wires and there’s no water in the mix to cause issues,” says Cat.
HydroVac’s three air-X trucks have found favour with many HydroVac’s customers, including the Motorway Alliance, Fulton Hogan, Auckland Council and Vector – working on notable projects including the Central and Northern Interceptors and the City Rail Link, as well as smaller jobs like residential home builds and historical digs.
Director Andrew Williams has been in the vacuum and excavation business for 35 years, starting with one pump truck back in 2004.
These days, HydroVac has over 50 specialist vehicles, a passionate team of 60, head offices in Auckland and Christchurch, the ability to service pretty much the entire country, and a large and loyal customer base.
The company’s diverse service offering includes hydro and air excavation, CCTV, drain maintenance, grease traps, spill and flood response, and stormwater, septic and wastewater systems.
Andrew says he gets a thrill out of finding, or developing, new innovations and being among the first contractor here to offer air excavation was right up his alley.
Working closely with Frontline Machinery, he says he carefully researched the three main air-excavation and vacuum truck options, visited the factory of the front-runner, and ended up ordering two German-made Scania air-X trucks in 2017.
Frontline had them manufactured to suit our regulations for weight and safety, including a custom cab chassis.
“I was overwhelmed with the quality and how committed they were to building the best product,” he says. “The after-market service has been exceptional – the truck is always talking back to the supplier in Germany so at any time they can go online and fault-find the problem remotely.”
There’s been a lot of consideration of operator and pedestrian safety in the design he adds, and, as a result, if the operator does something that’s not correct, the truck will shut off and stop functioning.
“It doesn’t allow you to do anything stupid,” he says. The boom is operated by remote control, so there’s no need for operators to lug heavy hoses around and potentially hurt themselves.
“It’s night and day to what it was awhile back,” says Cat Woollams. “Ten years ago they were a compressor on a truck, long and slow, and would billow out clouds of dust causing a nuisance.
Now, the technology in them means they’re like a large computer on wheels.”
Air excavation may be in its infancy here, but overseas it’s a mature and recognised market, he adds.
“They use it a lot overseas in Europe, the UK, Malaysia, Australia … we’re just catching up. Internationally they use it a lot on rail networks – it’s a very efficient way of removing the ballast, the stones they pack around the rails to hold the sleepers up.”
Because air excavation can be used for rubble and anything dry, it is also used overseas for disaster cleanup and on demolition sites. When fitted with the right specialist filtration system, it can also be used for asbestos removal, which is something HydroVac is looking into.
Andrew Williams admits that hydro excavation still has its place in civil contracting, especially when working with clay.
“And all our hydro trucks are still busy but for some jobs, you just can’t beat air, mainly those where it’s very rocky and stony. For example, for re-excavation jobs, air excavation absolutely kicks ass – there’s nothing faster.
“Air-x comes with air spades and air breakers so we can break up the road ourselves, cut through the tops of the road ourselves, break up the top layer of the road and start air excavation without engaging another contractor.
“Our guys are in and out; the air-x can just smash through jobs like that,” says Andrew. “We’ll always offer hydro, but air-x will become a main contender in our industry, no doubt about it.”