Acoustic Emission

Detect Flaws and Stress Corrosion Cracking at Early Stages with Acoustic Emission Testing

Giant Indo's Veritas Pvt Ltd

If you need to detect flaws in metallic pressure equipment , acoustic emission testing is one of the most reliable ways to detect the early stages of stress corrosion cracking. When a material undergoes stress or a series of internal changes such as corrosion, it generates energy from localized sources which produces sound waves. Acoustic emission testing is a non-destructive testing method designed to monitor sound waves emitted during material stress or failure. This condition monitoring method enables inspectors to examine metal deformation under stress and detect the sound of cracks and failures growing within the material.

Unlike other non-destructive testing methods, AE testing does not send energy into the inspected pressure vessel, but rather detects the energy emitted by the equipment itself. This technique is therefore time-effective because it can be performed during material operation. Acoustic emission testing enables you to monitor and inspect your entire pressure equipment, from tanks to welds. It provides immediate results and early warning of possible damage or failure in pressure equipment as well as solutions to determine the appropriate pressure level. GIV offers you acoustic emission testing services to help you detect, prevent and implement measures against any failure in your pressure equipment.

Benefits of Our Acoustic Emission Testing Services at a Glance

Using the acoustic emission testing service from GIV, you benefit from:
  • Early detection of flaws and corrosion cracking.

  • Inspection and testing of your equipment while in operation.

  • Significant cost savings for vessels with complex geometries.

  • Integral non-destructive testing and monitoring of your pressure equipment.

  • GIV exclusive one-stop-shop services.

Acoustic Emission Testing Approach

Unlike conventional NDT, acoustic emission testing is a non-destructive testing method which monitors the global area of pressure equipment structures, not only a localized area. This technique pin-points the active defect or stressed area, significantly developing within the structure which could endanger equipment integrity or safety.

Acoustic emission testing requires a minimum of three acoustic emission sensors installed on the structure via rope access to locate expanding defects by triangularly detecting acoustic waves being emitted. This method of monitoring is therefore non-invasive, since sensors are attached outside of the pressure vessel. Also, because the detected defect has to be active or progressive, acoustic emission testing can occur while equipment is in operation.

Instrumentation such as acoustic emission sensors are used in acoustic emission testing to detect, measure and record any structural degradation of the pressure equipment. Prior to testing, an attenuation survey is performed to plan the positioning of the sensors. Sensor responses are checked and collected data is recorded in order to provide a complete and understandable evaluation. Upon completion of the data evaluation, the client is provided a report listing the specific areas requiring follow-up non-destructive testing.

Advantages of the Acoustic Emission Testing

The acoustic emission testing services from GIV present many advantages:
  • No need to get into the pressure equipment, all tests are conducted from outside.

  • No interruption of the activity since equipment can be tested while in operation.

  • No shutdown or decommissioning.

  • No need for a rinsing process or refilling of the pressure equipment.

  • No corrosion through the introduction of water.

  • No time wasted on inactive defects AE testing can detect growing defects and in-service deterioration.

  • Benefit from our expertise and years of experience in conventional and advanced non-destructive testing to ensure the safety of your pressure equipment.

Acoustic Emission Testing vs Hydro-Test

A Hydro-test or hydrostatic test is another testing method for pressure vessels. It consists of filling the tested vessel with a liquid to help detect leaks and determine vessel pressurization at a specific temperature. This NDT method is often compared to acoustic emission testing. Yet, AE testing presents more advantages:
  • The hydro-test alone can only detect damage on existing leaks, but not on propagating cracks not yet breaking the surface of the pressure vessel.

  • The hydro-test may propagate defects in the vessel through the appearance of delayed hydrogen cracking.

  • Acoustic emission testing enables inspectors to detect material problems.

  • Acoustic emission testing is often performed parallel to the hydro-test to ensure that no significant damage, crack or leak exists in the pressure vessel before it is put into service.

Areas of Application of Acoustic Emission Testing

Acoustic emission testing is a method which can be applied to a wide range of areas and pressure equipments:
  • Tubes

  • Tanks

  • Spherical reservoirs

  • Fiber-reinforced materials

  • Gas station tanks and containers

  • Gas and hydrogen reservoirs

Applicable Standards for Acoustic Emission Testing

EN 15495:2007

Published in 2007, this standard applies to the zone location of the sources of acoustic emission during the examination of metallic pressure equipment while being proof tested.

EN 14584:2005

Published in 2005, this standard applies to the planar location that is, a plain surface - of the sources of acoustic emission during the examination of metallic pressure equipment being proof tested.