Product Manual

Figure 4-1 Sound Intensity vs. Water Pressure Graph
Metal pipes, such as iron mains, copper services, and steel pipes, transmit water
leak sounds that are louder and higher in frequency than do PVC pipes or asbes-
tos-cement pipes. Thus, knowledge of the pipe material is important (see Figure
4-2).
Figure 4-2 Filtered Frequencies Graphs
If the LD-12 user knows that the leak is small, with pressure of 60 psi or more,
and in an iron main or copper service, then the user knows the sounds should be
in a high frequency range, perhaps 400 Hz to 1200 Hz. If the LD-12 user knows
that the leak is large, with a pressure of only 30 to 40 psi, and in a PVC pipe,
then the user knows the sounds should be in a lower frequency range, perhaps
200 Hz to 600 Hz.
4-2
15 30 45
Water Pressure (psi)
Sound
Intensity
(Amplitude)
60 75
Leak noise range
for PVC Pipe
Hertz600200
Leak noise range
for Cast Iron Pipe
1000 Hertz400