TPi January 2012

products & developments

Pipe exhumation shows performance of pipe lining

Removal of a section of pipe

Once a length of pipe had been exposed to reveal a jointed section, the pipe was cut either side of the spigot and socket joint to enable recovery of the joint section. A sledgehammer was then used to remove the cast iron pipe

3M’s fast-setting polymeric pipe lining products are used for optimising water quality and minimising the risk of failure of ageing iron drinking water pipes. Their performance was demonstrated following a routine pipe exhumation in Northern England. Once lined, returned-to-service mains are routinely exhumed to sample the effectiveness of the lining application, and the results are added to the lining records for that area. In this instance a 125mm (5") diameter cast iron water main, estimated to have been in service for around 50 years, had been treated two years previously with 3MScotchkote rapid setting polymeric lining 169HB in order to address significant water quality issues. A section of this main, buried underneath a grass verge adjacent to a main highway, was selected for retrieval so the lining could be inspected and its condition assessed. The water supply to the main was turned off, but the main remained charged with water during excavation.

No defects were found within the pipe, even after the aggressive recovery process, showing the strength and suitability of the product for in situ water pipe lining. Carl Bradley of 3M’s corrosion protection products division explained, “After many years and even decades in service, the insides of cast iron pipes can become clogged with minerals and other contaminants, with potentially major impact on water quality. They are also more prone to physical failures as they age. In situ lining has become very much established as a reliable and cost-effective alternative to excavation and replacement of entire mains – and this example clearly shows how modern lining equipment and products are able to deliver effective, consistent, robust and long-lasting protection – mitigating against issues of both water quality and pipe failure.” 3M Scotchkote rapid setting polymeric lining 169HB is a spray-applied, semi- structural lining for the rehabilitation of drinking water distribution pipelines between 75 and 300mm in diameter. It provides a high build lining that will remain intact in the event of pipe fracture due to ground movement. Its rapid curing characteristics allow the start of return-to-service procedures within 60 minutes of application. 3MCorrosion Protection Products – UK roofing.cpp.uk@mmm.com www.3m.co.uk/scotchkote

between the cut sections and expose the lining. Despite the aggressive nature in which the pipe was removed, the lining survived intact, and there was also no evidence of water having permeated the lining. The removed section of lining showed that the original application process, using specialist lining equipment to treat the pipe in situ, had been successful in creating a smooth internal layer with an even material thickness which faithfully followed the internal geometry of the pipe.

Inspection revealed a smooth internal layer with an even material thickness

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Tube Products International January 2012

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