Aug. 25, 2011
-- One of four large water distribution mains that run through the south-west London borough, the Kew to Hampton main spans the four kilometres from Hampton Water Treatment Works to Kew Bridge Works. Originally constructed in the 1890s, the main has failed in several locations during the past few years causing localised flooding and disruption. Indeed, a major burst in Brentford in September 2010 caused severe flooding and disruption and was one of two bursts to happen within the space of just a month.
To address this issue, MGjv (the joint venture between Morrison Utility Services and Galliford Try) was contracted by Thames Water to re-line the existing 33” main and selected 710mm Excel (PE100) SDR17 pipe from GPS. The highly durable pipe provides the 10bar operating pressure required for the installation and was supplied with a number of fittings including mitred bends in three different angles and over 50 Frialen® couplers for electrofusion of pipe joints.
MGjv inserted the new pipe into the existing Victorian pipe to form a hardwearing replacement main which is structurally supported by the host pipe. Unusually for slip-lining installations, only one welding pit was allowed to be open at a time to minimise disruption during the works. This meant that butt-fused pipe strings were pushed forward (rather than pulled, as in typical slip-lining installations)
until they encountered a bend or other obstacle. Sections were then electrofused together using Frialen® couplers to provide a strong and water-tight bond. The starting pit was then backfilled and a new pit was dug at the end of each re-lined section.
Explains Peter Birbaumer from MGjv: “The integrity of the pipe and performance of each of the joints is extremely important in a project of this nature because it’s essential to minimise any potential for leaks and bursts. It was for this reason that our operatives underwent special training to install the 710mm electrofusion fittings as this method of jointing sections of the main is the most effective approach provided that the task is performed correctly. We have now successfully installed all 3.5km of PE pipe and completed 54 Frialen coupler joints ensuring that, with a little help from modern technology, the Victorian main will be good for another century.”