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tore and vac' Oafs help National Grid to achieve a 90% success rate
Page 17
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NATIONAL GRID IS using a pair of specially modified Daf LF45s to reduce disruption caused by essential road repairs. Designed to be used back to back to protect the crews, the trucks operate a technique known as 'core and vac' to access damaged utility services. First, one truck removes a 650mm diameter plug of the top layer of asphalt and concrete, then the second loosens and vacuums out the earth above the fault. It can handle 35 of the most common underground faults, and is able to reduce a previous five-day job to just five hours.
National Grid says that in its East Midland region alone, the new technique is suitable for 1,500 of the 5,000 annual leaks it has to attend, and that it has a 90% firsttime success rate in finding the fault location.