Heath Consultants Aqua-Scop - Manual (Page 32)

F. Practical Examples
Test probe measurement at valve 1 is .40 units; at valve 2, .90 units;
at valve 3, .10 units, and at hydrant 4, zero units. This indicates the
leak should be between points 1 and 2. Using the Ground Microphone,
point 5 is the strongest test. A sewer is present at point 5. This noise
could be the sound of water flowing in the sewer. If this is the case,
tests at 6, 7, and 8, the other sides of the sewer, the same intensity of
sound should be found. The comparatives show at point 5, .60 units
and the other points (6, 7, and 8), a decrease. This confirms the leak
is at point 5. The combination of the acoustical and numerical tests is
conclusive in this instance.
(Figure 17)
Houses without curb valves in a leakage area should be tested with
the Direct Contact Microphone directly on the service line in the
basement.
Checking with the Ground Microphone at point 2 gives a very strong
test. At point 1 a weak test is noted. The leak is at point 1. This is caused
by surface proximity and increased pipe turbulence sound at a bend
in the pipe. It is necessary to know the location of bends, as they will
cause an error in pinpointing if they are not taken into consideration.
Difference in pipe location will influence the measurement. In case of
doubt, drawings of local situations or a pipe locator should be used.
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