MB Inspection Ltd. now offers Acoustic Emission (AE) testing in addition to their already broad range of specialised inspection services.
AE testing quickly assesses the condition of vessels and piping and identifies any areas in need of attention. This is achieved with widely (2-6m) sensors that detect high frequency stress waves (acoustic emission) from defects responding to the applied load (internal pressure, liquid fill and so forth).
Recorded AE signals are evaluated to determine whether follow-up inspection is needed and where. Cost savings are often large because in many cases, vessels need not be shut down for the test and even large vessels or systems may be tested in days rather than weeks.
Test Procedures We have procedures in place for testing a broad range of pressure vessels, tanks and piping including:
Aboveground storage tanks
Spheres
Refrigerated tanks
PSA vessels
Absorbers and reactors
Multilayer or plywall vessels
Double walled or jacketed vessels and tanks
Process piping
High energy (steam) piping
Materials Tested with AE These include most metals and composites:
Capabilities Acoustic emission testing uses high frequency sound (stress) waves generated by sharp discontinuities (cracks) under load. These signals are detected by externally mounted sensors either during a discrete load test (in-service pressurisation, hydrostatic test) or on-line, without a planned loading sequence. The benefit of a planned load test is that it can be done over a short time frame, on-line monitoring is suitable for equipment in cyclic service or where long-term monitoring is a more desirable option.
Interpretation of AE signals determines approximately where cracking or other damage is present. Follow-up inspection with another NDE method is usually needed to determine the exact nature and location of an AE source. The benefits and capabilities of AE testing are:
Provides 100% coverage of a vessel or section of piping. However, attachments or areas not stressed during the test need to be inspected by other means.
Sensitive to process related damage. Fabrication defects and other blunt, structurally insignificant flaws will generally not produce AE at operating loads.
Avoids the need to remove large sections of insulation. Relatively small cutouts (100mm) are needed to mount AE sensors.
Testing may be done on-stream or off-line with product: no need for shut-down and cleaning.
Benefits
Cost savings by avoiding vessel entry or the time and cost of external (UT) examinations.
Provides 100% coverage of the pressure boundary or other load bearing elements. Can detect defects or damage beyond the weld zones.
Sensitive to ID, OD and embedded defects.
Permanent record of test data, ability to monitor and evaluate remotely.
