Interflow Awards
A routine Expanda Pipe relining project in central Victoria looked to have become complicated when it was found that one of the lines to be renovated was a larger diameter than shown on the plans.
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The Problem:
Interflow were awarded a contract to reline sewers in a size range of 150mm to 300mm. The local Water Authority feared delays and complications when it was found that one of the pipelines had been incorrectly surveyed. Shown on the plans as having a diameter of 300mm, the largest size of pipe on the project, relining was about to commence when it was discovered that the actual diameter was 375mm.
The Solution:
Rib Loc Expanda Pipe is not pre-supplied in a range of specific diameters. It is 'made on site' by winding at a smaller fixed diameter and then mechanically expanded to fit the host pipe. A larger or smaller than expected pipe can be effectively relined by continuing to expand the liner until it makes contact with the pipe's internal wall. The host pipe diameter is not critical. The liner will have a circular cross section and constant wall thickness.
Other types of liners are 'factory made' to pre-determined diameters. An oversize or undersize pipe would stop the project until the specific diameter liner can be manufactured and transported to site. Additional costs would be substantial.
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The Project:
Lining of pipes with Rib Loc Expanda Pipe is carried out by winding a profiled strip of plastic to form a pipe inside the deteriorated pipe. Currently three ‘profiles’ of plastic strip are available to cover a pipe size range of 15Omm to 75Omm. The profiles have different dimensions to provide the required design stiffness.
For relining of pipes with a diameter of 300mm, profile designated as 85Ex is normally used. The same profile is commonly used for 225mm and 375mm diameter pipe.
On this project a liner with a fixed diameter of 280mm was first wound into the 300mm nominal size pipes before being mechanically expanded.
When it was discovered that one of the lines was actually 375mm size rather than 300mm, the same winding head was used to first install the fixed liner at 280mm diameter. It was then easily expanded up to match the larger diameter.
No delays were caused to the project and the only additional expense incurred by the Authority was for the additional profile used.