Industrial equipment operating under positive or negative pressure conditions is very suitable for the application of acoustic emission technology. These items of plant can include structures of many different sizes and applications, including pressure vessels, piping, couplings, valves and tubes, to mention a few. They can also be operated at cryogenic and elevated temperatures. The correct use of acoustic emission technology can monitor any structure while under operating pressure and conditions, and can detect any material activity associated with the applied load. Analysis of these acoustic emission pulses can discriminate between such noise sources as mechanical noise, vibration, insulation movement, bubble formation and material deformation/degradation. There are various instrument accessories which allow specific problems, such as very high temperature, very low temperature, corrosive atmosphere, and access problems associated with monitoring pressure equipment to be overcome. They still allow a valid acoustic emission test to result and provide an accurate Structural Integrity Index value and classification of the monitored structure for continued use, while providing a basis for maintenance scheduling of such equipment, prior to failure. Metacoustics has developed techniques which allow the remnant life of pressure equipment to be estimated from acoustic emission data.
Repaired pressure vessels such as this steam locomotive boiler behind the restored steam engine 5910, is a good and enjoyable application of acoustic emission technology.
Acoustic emission monitoring during the Manufacturing stages is a wise use of acoustic emission techniques. It is possible to evaluate the quality of manufacture and highlight any stress concentrations which is invaluable knowledge during future vessel operation.
Metacoustics pioneered the use of acoustic emission in leu of the long used hydro-test as a proving and operational verification test. There are many serious problems associated with hydro-tests. The use of acoustic emission techniques instead of the hydro-test was an essential part of the commissioning of a new chemical plant. For the first time, a new plant was commissioned with Metacoustics using acoustic emission techniques instead of the conventional hydro-test. This approach was both technically and economically advantageous and successful.