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A Practical Guide
For Underground Services Location and CCTV Drainage Surveys
Water
Water mains are either plastic
or metal and the method of tracing these two types are different.
Plastic Main
In order to trace this main it is necessary that it is live and that run-off
is allowed. See Acoustics
If a trace wire is incorporated when the pipe is laid radiodetection can
be used.
What can go wrong
A. Trace limited to 100 metres from transonde
B Sound signal corrupted by ground density (concrete etc.)
C. Sound signal corrupted by traffic and construction plant
Metal Main
A transmitter is attached to a conductive surface of a SV, FH FH, WO etc.
or exposed pipe. The active signal is then traced above ground.
What can go wrong
A. Plastic repair incorporated into pipe terminates signal.
B. Ground density corrupts signal
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