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Acoustic Emission Testing
Hazardous conditions or events must be avoided. For this purpose, recurring inspections must be carried out in process engineering plants in accordance with the BetrSichV( Ordinance on Industrial Safety and Health).
Pressure gas containers for the transport and storage of hydrogen, for example, are also subjected to inspections using Acoustic Emission Testing.
However, while CRAs offer high performance, they are not immune to damage. Welds, flanges, and load-bearing zones can experience fatigue, stress corrosion cracking, or microstructural deterioration— often in ways that are difficult to detect visually. AT provides an ideal monitoring solution by capturing high-frequency signals generated by material distress. AT sensors are mounted externally on equipment surfaces and detect even subtle discontinuities or shifts in structural integrity. Additionally, inspections can be performed without disrupting operations or exposing sensitive surfaces to contaminants that could compromise the passive oxide layers critical to CRA performance.
Real-world example: Cost reduction in practice
A typical polymer resin production facility can provide a compelling case for the benefits of AT. Traditionally, such a plant conducted annual hydrostatic testing at a cost of approximately € 1 million. By transitioning to AT, the operator would achieve measurable savings across several categories. Breakdown of annual savings:
•• Avoided two-day production stoppage: EUR 160,000
•• Eliminated fluid-based inspection process: EUR 200,000
•• Avoided gasket and seal replacements post-inspection: EUR 25,000
•• Reduced unplanned maintenance by 80 %: EUR 40,000
•• Enabled simultaneous testing of multiple pressure circuits: EUR 100,000
•• Limited follow-up inspections to high-risk areas: EUR 50,000
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Extended lifespan of key components: EUR 10,000
Total potential savings: EUR 585,000 annually Conservative implementation( 70 %): EUR 410,000 annually The switch to AT not only cut direct inspection costs but also allowed for smarter allocation of maintenance resources. Labour and material use were reduced, and the asset health insights gained from AT enabled better long-term investment planning.
Within these same operational environments, heat exchangers present a complementary challenge. Though they may be constructed from the same corrosion-resistant materials, they function as thermal control systems used to condense vapours, recover waste heat, or cool process fluids. Exchangers are often subjected to intense thermal cycling, high flow velocities, and chemically reactive conditions. This makes them susceptible to tube cracking, joint fatigue, and erosion, especially in designs like shelland-tube or plate exchangers, where internal access is limited. Here, too, AT offers a significant advantage. It allows operators to monitor the structural health of exchanger units in real time, identifying subtle signs of internal failure long before they escalate into system outages or compromised thermal performance. Because AT works without dismantling the equipment, it supports a shift toward conditionbased maintenance, reduces unnecessary downtime, and extends service intervals for these critical subsystems. While CRA-based infrastructure and heat exchanger assemblies differ in function, they often operate side by side— subjected to similar environmental stressors and degradation mechanisms. AT enables both to be assessed under a single, non-invasive methodology, offering a unified approach to asset integrity in demanding process conditions.
Optimising inspection cycles The value of Acoustic Emission Testing extends beyond fault detection. By capturing real-time
34 Heat Exchanger World October 2025 www. heat-exchanger-world. com