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Understanding Acoustic Emission Testing- Reading 1 Part B-A

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On site inspection results<br />

The results obtained over a sample of 4820 km of water distribution network<br />

in different Italian cities that have been surveyed using the cross-correlation<br />

technique in the last ten years are now outlined.<br />

During the systematic survey concerning the above mentioned networks -<br />

about half consisting of cast and ductile iron pipes and the other half of steel<br />

pipes and asbestos cement pipes (only 33 km of plastic pipes have been<br />

inspected) - a total of 3450 water leakages have been detected.<br />

Out of the detected leaks, 3312 (96%) have been located exactly and have<br />

undergone repair. Some of the remaining 174 leaks have been located during<br />

the repair excavation at distances greater than 3-4 meters. The location<br />

errors are essentially due to the uncertainty of the used distance between<br />

sensors.<br />

Charlie Chong/ Fion Zhang<br />

http://www.ndt.net/article/wcndt00/papers/idn183/idn183.htm

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