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Not only is trenchless works typically more time efficient than open cut alternatives, meaning that machinery is operated for shorter periods, but traffic fuel consumption is lowered by trenchless methods.

By avoiding traffic disruptions, trenchless projects prevent the delays and detours associated with conventional underground infrastructure projects. This lowers the amount of petrol consumed, and subsequently reduces carbon emissions.

In addition, according to a study conducted for the North American Society for Trenchless Technology (NASTT) by the University of Waterloo, located in Ontario, Canada, it found that trenchless job sites produce fewer emissions.

They require minimal construction machinery and equipment as there is no need for excavation, compaction, backfilling and re-paving, dramatically reducing fuel consumption.

With the industry focused on preserving the environment and reducing emissions, the ASTT created a Carbon Calculator to promote innovation in the trenchless technology sector.

The purpose of the ASTT is to advance the science and practice of trenchless technology for the public benefit, while promoting education, training, study and research and practice for the public benefit and to publish the useful results of the same.

With this in mind, paralleled with the global goal of reducing carbon emissions, the ASTT formed a Special Interest Group (SIG) of leading industry professionals to create a solution that supports the mitigation of climate change impacts.

ASTT Councillor Matthew Boyle says the ASTT embarked to create a SIG to look at the impact trenchless technology has in reduction carbon generation in construction projects. “The SIG’s purpose was to provide members with access to a Carbon Calculator to quantify, and therefore promote, trenchless technology as a lower carbon emissions alternative to Excavate and Lay,” he says.

“The primary focus of the SIG was to provide members a tool to compare greenhouse gas emissions using comparative approaches in the capital delivery of services.”

As a result, the SIG approached the market for the development of the calculator and selected the Moata Carbon Portal from Mott MacDonald in August 2020.

At the time of release, it was the first carbon calculator capable of measuring the capital and operational carbon footprints of building information modelling (BIM) designed assets.

Boyle says following Mott MacDonald agreeing to be on board with the ASTT, the SIG moved into trial phase where asset owners were selected to use to the tools in their businesses for best use practices in Australia.

However, it was here where the process stalled and the use of the calculator in the trial was limited, little feedback was submitted, and the pandemic hitting Australia.

Boyle says the SIG has currently been suspended until further legislation and member support.

“We went with Mott McDonald because in New Zealand there is a legislative requirement to monitor carbon emissions, but until there is something in place like this in Australia, the SIG has come to a halt.”

In December 2021 the Australian Government released the June 2021 quarterly update of Australia’s National Greenhouse Gas Inventory.

Australia’s greenhouse gas emissions fell by 2.1 per cent in the year to June 2021, and have fallen by 20.4 per cent since 2005

Boyle says he sees the awareness of carbon emissions driving the trenchless community to look deeply into its supply chain to innovate and come up with new techniques and products to drive zero emissions further into the future.

“I see the specification of low emitting trenchless technology by asset owners and government organisations to be the standard across Australia and New Zealand,” he says. “I believe this will be backed up by legislation and the trenchless community will be well placed to help deliver on a low carbon future.”

With the trenchless community already doing its part to reduce emissions, Boyle says the rehabilitation process for overall asset installation can be measured, quantified, and improved into the future.

This is where the Carbon Calculator could demonstrate how the use of trenchless technology can reduce project carbon emissions.

“This is great evidence for asset owner members, contractor members and supplier members. It could also be used to see what part of the process emits more carbon, allowing innovation to occur to effect overall emission reduction,” Boyle says.

The ASTT says its Carbon Calculator is not to be relied on to make commercial decisions nor is it a tool that will accurately define Capital Carbon Baselines, noting that there is no specific, quantified carbon goal that the calculator aims to reach.

Rather, the tool will be used to promote best practices across the industry.

The three steps the calculator aims to take is:

1. Reduction – reduce the carbon impact of infrastructure.

2. Behaviours – improve the behaviours of designers, constructors, and entire supply chains to reduce infrastructure carbon.

3. Union – create a common way of working to calculate carbon reductions across the industry, setting the narrative.

Boyle says with the ASTT’s overall goal being to advance the science and practice of trenchless technology for the public benefit and to promote education, training, study and research and practice for the public benefit, it is hoped the calculator will be used on individual projects and tested across various areas, with the onus on contractors and client organisations to use the tool and consider their own impacts.

“With this as our goal, we will support all measures that our members are taking to reduce emissions and promote to educate the greater community into the advancements and benefits of trenchless technology,” he says.

Located in regional Victoria, local utility GWM Water discovered that one of the network drains had been badly damaged by an external source. The drain had a diameter of 375 mm, and damage was only the top third of the pipe.

The repair proposal offered up several different options with varying cost and different degrees of difficulty accompanying each.

It was important to work through the different scenarios with the client and look at what was going to deliver the best value for money, cause the least disruption, and generate the greatest long-term outcome.

There was the option of setting up a bypass line over a train line, which instinctively brings with it a complete set of complications that must be worked through, as well as the planning process and time restraints.

By using this methodology, there were options to restore the line by either cutting it out and replacing it in its entirety or installing a new top section of host pipe and then patching the area using a bladder in the network.

The second option of patching also brought its own challenges around formation of the patch, managing the host pipe repair under inflation, and the team would still have the bypass line to work through.

The suggestion was made to rebuild the line using Smart Lock. This was something the utility had not seen or used before on its network. Smart Locks can be installed to rebuild the line under flow, in this case removing the requirement of bypassing and managing the bypass across a train line.

Once GWM Water saw the way that Smart Lock works, the client realised this was the best option on this desperately needed repair. GWM Water was impressed by how the stainless-steel banded together with the silicate impregnated fibreglass to restore the pipe’s shape and build structural integrity back into the line.

Work commenced and the damaged pipe was rebuilt using 5 Smart Locks, each locking into the previous one by managing the pressure used to blow out the packer. Once all the Smart Locks were joined together under live flow, CCTV footage of the drainage system was taken, and the outcome was demonstrated to be successful. The section of the pipe was covered in concrete to alleviate the same mistake happening again.

The finished product came up extremely well with little interference to the network and definitely a great saving to the client.

How it works

The Smart Lock is an innovative solution that is quick and easy, completed in three simple stages: load, lock and leave. By wrapping the stainless-steel sleeve with fibreglass and silicate resin and sending the packer down the pipe and into position, the Smart Lock solution is loaded before being locked into place by the innovative ratchet system to complete the repair.

With an average installation time of only 20 minutes, the installation team can leave to get to the next job as the resin impregnated fibreglass matting is left to cure behind the stainless-steel sleeve.

Smart Lock is ideal for localised defects such as cracks and holes, root infestation, water infiltration, displaced joints and redundant lateral connections. All can be repaired by installing a Smart Lock directly at the location. The solution provides a cost-effective alternative to excavation, relining or pipe replacement and is a permanent and structural repair.