From the magazine

Expanda – 20 years on and still evolving

In fact, Interflow estimates that approximately half of all pipes that have been renewed in Australia to date have been done with Expanda. Internationally Expanda has been used successfully in dozens of countries.

This remarkable Australian success story has come about through a relentless drive on behalf of Sekisui Rib Loc and Interflow to continue to improve the product and extend the range of situations in which it can be used. The product is still proudly called Expanda, but today’s Expanda is a vastly superior and diverse product compared to its humble beginnings.

Expanda is a PVC spiral wound product. The liner is spirally wound through a deteriorated host pipe at a smaller diameter than the host. Once the desired length is reached, an expansion process is performed that causes the diameter of the liner to increase until it is in contact with the host pipe. The key features of the product that make it so attractive to the market are:

  • It can be used in live flow without the need for bypass
  • It is non-disruptive to residents
  • It is quiet and takes up a relatively small footprint on site
  • It has no waste products or other negative environmental impacts
  • The process is safe
  • It is cost effective
  • The product is long lasting – in fact, the original pipelines installed almost 20 years ago are still intact and there have been no liners that have failed or needed to be replaced.

The success of Expanda has very much been due to the expertise developed both within Sekisui Rib Loc and Interflow. Only with this expertise has it been possible to respond to the ever-changing demands of the industry and deliver world-class solutions for its clients. Indeed to this day there are several people in both Sekisui Rib Loc and Interflow that have been continuously involved in the development of Expanda from day one. The table at left chronicles some of key developments that have occurred over the last 20 years.

Expanda is now routinely installed in every state of Australia and in New Zealand by Interflow. The product used for reticulation sewers is designed to be fast, nimble and streamlined. In the large sewers Interflow is capable of installing Expanda in pipes of up to 900 mm in diameter and in lengths of over 200 m. The equipment used for different pipe sizes is very different and is tailored for the specific needs of each part of the market.

A good recent example of the capability of Expanda and Interflow was the installation of a 220 m length of diameter 750 mm pipe (total weight 3.5 tonnes). In order to perform such a long installation, machinery with enough power needed to be designed and built. Furthermore, the PVC profile had to be capable of withstanding the torque imparted on it during installation. The installation took several hours and during this time the flows in the pipe had to be managed so that flotation forces were kept under control. This successful installation pushed the boundaries of spirally wound liners even further and new techniques were developed in the process. The experience and knowledge gained from this will be applied to meet even greater challenges in future.

Despite these developments the evolution of Expanda has not come to an end. Interflow and Sekisui Rib Loc are continuing to develop the product and have a list of exciting developments in the pipeline. As always these developments will focus on making Expanda more and more competitive, to cover a wider range of applications and ultimately to add greater value to its clients.

There have been, and will continue to be, other spiral wound products on the market, however Expanda and Interflow stand alone as the market leaders. With over 20 years of practical installation experience and with 27 years of research and development behind the product Expanda and Interflow are uniquely placed in terms of not only what they offer their clients today but also continuing the development of newer and more innovative solutions for the future.

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