The award was presented at the International ISTT No-Dig 2010 gala dinner held in Singapore on 9 November. ISTT Chairman Dr Sam Ariaratnam announced that the Interflow and Sekisui Rib Loc joint submission was selected as the winner from many impressive entries from all over the world.
The International No-Dig Project of the Year award is awarded annually and judged by members of the ISTT. The award recognises excellence in completed trenchless projects from all around the world. The No-Dig awards raise the profile and status of the industry by promoting the science, practice and advancement of Trenchless Technology worldwide.
Interflow produced the world’s largest and longest spiral wound pipe ever made measuring at least 2,400 mm in diameter and 706 m in length. The achievement has resulted in a ‘step change’ in the advancement of spirally wound Trenchless Technology, and was accomplished with the support of Sekisui Rib Loc.
The spirally wound pipe was produced as part of the North Georges River Submain (NGRS) sewer rehabilitation project in Sydney, Australia for Interflow’s client, Sydney Water.
Sydney Water awarded Interflow a contract to reline and renew sections of this 2,520 mm diameter sewer trunk main totalling 5,438 m in length. The project commenced in June 2008 and was completed in May 2010.
The major engineering challenges associated with this project were:
This demanding criteria was the catalyst that ultimately led to Interflow and Sekisui Rib Loc developing a world leading solution.
The technology developed to meet the above challenges was based on the Ribline product from Sekisui Rib Loc. Ribline is a spiral wound polyethylene/steel composite pipe that has an extremely high strength to weight ratio.
To achieve the projects’ minimum diameter requirement with a liner of thickness 31 mm, the liner needed to be installed with an annular space no greater than 58 mm. This was a significant reduction in the typical allowance that is made when attempting to spiral wind liners of this size.
Up until this project the practical limitation for the maximum length and size of pipe that could be produced using this spirally wound technique was governed by the torque of the winding machine and its ability to overcome the weight and frictional forces of the newly wound pipe as it rotates inside the host pipe. In order to produce a 706 m length of pipe liner at 2,400 mm internal diameter with an annulus of only 58 mm in a single shot, these limitations had to be overcome.
The key to meeting this challenge was Interflow’s development of an innovative flotation technology. The use of flotation to assist spiral wound liners is not new; however, controlling the flotation forces in situations where the flows in the pipe are highly variable presents a more complex challenge.
Interflow’s goal was to develop a flotation technology that was capable of controlling the flotation forces by diverting flows between the inside of the liner and the annular space. In doing this, the volume of water inside the newly formed pipe and the amount flowing between the new pipe and the host pipe was able to be distributed to enable the newly formed pipe to have neutral buoyancy at all times, irrespective of the changing flow conditions in the sewer system. The frictional limitation on the maximum length of pipe that can be produced was then eliminated.
In fact, even with 706 m of pipe continuously rotating (a mass of over 120 tonnes) the torque levels on the winding machine were very low, indicating that a much greater length than the 706 m would have been possible. Interflow believes that this technology has made a significant advance to these limits which will in-turn open up new opportunities for the industry.
This latest worldwide recognition for Interflow comes on the back of receiving widespread accolades for the same project from within the industry and the greater public in Australia. The project was awarded the Australasian Society for Trenchless Technology (ASTT) Project of the Year Award in 2009, and has also been recognised within the wider engineering community, having been a finalist in the State Engineering Excellence Awards and a finalist in the State Civil Constructors Federation for Project of the Year.
One of the most significant credits bestowed on this project was its selection as one of six examples of Australian Engineering Excellence to be put on display at Sydney’s Powerhouse Museum of Technology and Design, a popular museum in Australia.
Interflow’s interactive display showcases the science and technology of producing the 706 m long pipe at 2,400 mm and is on show to the public until February 2011. Interflow’s exhibit exposes the Trenchless Technology industry to the greater public and is the first example in Australia of exposure in a public museum.
Interflow has been at the forefront of the trenchless industry in Australia and New Zealand from the beginning. Along the way it has pioneered the introduction and development of many world-leading and award-winning products and construction methods. Most recently Interflow was awarded the ASTT 2010 Project of the Year for the renewal of a 3,000 mm siphon.
One of Interflow’s most significant areas of expertise is the know-how developed to rehabilitate large diameter pipelines. Over the last ten years, Interflow has continually pushed the barriers in this area and now has a dedicated division employing over 50 people devoted to large diameter pipeline rehabilitation.
Capabilities include the ability to reline circular and non-circular pipes at diameters over 3,000 mm, operate in built up areas, operate deep underground, work in live flows, and offer a wide range of solutions to meet the needs of the contract.
Interflow’s know-how is not only applicable and available to the Australasian market; the company believes it has a great deal to offer in many markets around the world by partnering with organisations that have a desire to enhance the outcome of projects by leveraging off of the know-how Interflow has to offer.
Interflow has also developed a number of innovative products for the Australasian market. One of these is the Interfit product for sealing lateral connections in pipes from 150 mm to 300 mm. Interfit is a patented product and winner of an Australian Engineering Excellence award.
Over the last seven years there have been over 40,000 lateral seals installed by Interflow using this method. The company believes that there is opportunity to offer this product to the wider market and in the near future expects to begin exporting the technology to the European, Asian and US markets.
Interflow is recognised as a leader in the trenchless industry in Australasia and is well positioned to bring some its know-how and products to the industry globally.
