UK’s first LEDRig Lite cure in London cemetery
About the project
Camberwell Old Cemetery in London was suffering from flooding, owing to a storm sewer evidently being damaged by tree roots.
Key aims and challenges
Southwark Council called on Danaher & Walsh APS to provide a permanent solution to the flooding issue. Another contractor had been mobilised to carry out high pressure jetting and a CCTV condition survey. The 300mm clay pipe was suffering from severe root intrusion – leading to a near total blockage - and was badly fractured in multiple locations.
To add to the challenge, the upstream manhole was located down a narrow path, 200m from an access road, and the downstream manhole was in a remote wooded area with difficult access. Excavation was out of the question, but immediate repair works were necessary.
How did we do?
Danaher & Walsh APS dismissed the recommendation of the previous contractor to carry out localised patch repairs then line the pipe using a hot-cure liner. We decided that the internal pressure generated by the patch repair process, as well as the possible movement created by using a standard inversion liner, would have carried a very high risk of total pipe collapse.
A pipe collapse would make excavation necessary, in an area of the cemetery which had a high probability of containing paupers’ graves from the 19th century.
We determined that the optimum solution was to use a winched-in, UV-cured liner. First, we used a remote-controlled precision robotic cutter to fully clear the pipe of roots and debris. We then dragged in the 47m x 300m x 6mm thick liner through the pipe using a winch.
The liner was cured using the revolutionary Sewertronics LEDRig Lite UV LED system – the first time this has been done in the UK. This ultra-compact system uses a ‘light train’, which drives through the pipe curing at speed of up to 1.3m per minute.
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