ADS Environmental Services Mikron QR 775014 A0 - Manual (Page 5)

ADS Mikron User Manual
2
Principle of Acoustic Leak Listening
The principle of leak noise listening is to determine the location with the
greatest leak noise. The path of the pipeline under investigation must be
known and other potential sources of noise interference must be
acknowledged.
Because sound travels much better through the pipe, the first step involves
listening directly at each accessible fitting (e.g., valve or hydrant) along the
pipe. This enables the operator to identify the pipe section where the leak
noise is greatest.
The next step involves using the ground microphone to listen to the leak noise
transmitted through the ground, taking measurements at regular intervals
along the ground surface above the selected section of the pipe. This method
should enable the operator to identify the location with greatest leak noise.
Filters are used to reduce the effects of noise interference and maximize the
reception of leak noise. Harder materials generally transmit sound better.
Therefore, iron and steel pipes coupled with paved surfaces tend to transmit
higher frequencies and higher levels of noise. Plastic pipes and soft ground
give poorer performance.
Listening on 3 hydrant/valve positions