Use of Acoustic Monitoring Data for PCCP Condition Assessment

Abstract

Acoustic monitoring of PCCP is not new. Research on acoustic monitoring began in the late 1980's and early 1990's by the Bureau of Reclamation. Results up to this point have focused on "listening" for large distinctive acoustic anomalies using sensors placed at some distance from the anomalies, with suitable equipment for relatively short periods of time, typically a few months to one year. When wire break activity was detected, in most cases, only a few acoustic events were recorded. Improvements in technology have lead to longer monitoring times and the recording of literally thousands of wire break acoustic events with very high fidelity from pipes with a wide variety of conditions. This relatively new plethora of high quality data provides the opportunity to "mine" more useful information from acoustic data. This work presents analysis of acoustic emission data in the time domain and other transformed domains for a pipeline from the onset of installation of a permanent fiber- optic acoustic monitoring system through rupture of the pipe. The overall characteristics of the acoustic events are discussed along with progression and changes in the events as the pipe approaches rupture. Once the overall characteristics are understood, the details of the each acoustic event are mathematically investigated and characterized as the pipe approaches rupture. The goal is to develop analytical methods which allow condition assessment from condition monitoring data.