Acoustic Emission & Advanced NDT

Usage and benefits of acoustic emission testing:

• 100% testing (integral testing) of the structural integrity of pressure-bearing components such as pressure vessels and pipes
• Testing of small as well as extremely large plant components
• Final assessment at the manufacturer according to EN 13445-5 (harmonized standard for the Pressure Equipment Directive)
• Application in the course of periodic testing (in-service inspection)
• Replacement of inside inspection of pressure equipment
• Minimal system downtime during execution
• Early warning system for possible failure and for timely maintenance
• Information benefit with regard to the actual condition of the test object compared to conventional testing (hydrostatic test, pneumatic test, etc.)
• Detection of active degradation mechanisms such as local plastic deformation, crack propagation, corrosion and erosion
• Real-time monitoring of plant components
• Non-invasive detection method that records the dynamic response of the material to the applied stress (pressure, load, temperature, etc.)
• Support for safe and efficient plant operation

Usage and benefits of acoustic emission testing:

• Applicable for tanks of nearly any size - testing of tanks with diameters of 100 meters and more
• Detection of corrosion
• Early warning system for possible leaks
• Significant spatial reduction for subsequent tests and inspections in the case of corrosion or leakage indications
• Leak and strength tests after construction and periodic testing of the tank bottom for corrosion and leakage
• Non-invasive test methods using the stock product under conditions most similar to the operation
• Minimal static operationion of the tank (no removing from and returning of storage product for one to two days)
• Information on the actual condition of the tank bottom with regard to corrosion and leakage without opening and cleaning the tank
• Support for safe and efficient system operation

Leak testing with "ALARM" (Acoustic Leakage Announcement and Registration Module):

• In-house development in cooperation with OMV AG
• Completely self-contained and needs no external power or communication cable
• Travels with the transportation fluid through the pipeline
• Suitable for pipelines with diameters from 100 mm till to 450 mm (4" - 18")
• ALARM has almost neutral buoyancy within the liquid medium
• Low operational noise and therefore highly sensitive to leakage
• Detectable leakage rates in the range of 10 l/h
• Possibility to record the pressure and temperature along the total lenght of the pipeline
• Inserting and removing of ALARM can take place at the pig trap for maintenance/cleaning
• Pipeline systems of 100 km and more may be inspected

In addition to existing acoustic emission testing applications, TÜV AUSTRIA also provides solutions for customized testing tasks. Through the research and development of new test methods as well as the use of advanced non-destructive test methods (NDT methods), even complex technical problems in industrial plants can be realized. The further development of test methods is based on cooperation with individual partners, universities, technical colleges as well as national and international research institutions.

Customer-specific solutions:

• Specific test programs tailor-made to the individual requirements
• Implementation of a monitoring program to safeguard ongoing operation
• Monitoring of critical plant components during operation

Advanced and traditional NDT methods:

• Phased array technique
• Time of flight diffraction (TOFD)
• Acoustical component testing
• Stress and strain measurements
• Acceleration measurements on components
• Classic NDT such as radiographic and ultrasonic testing

Research projects:

• CORFAT (EU research projects)
• HotConSens (international research project)
• Cooperation with research institutions and industry partners
• Internal research and development

The acoustic emission testing provides a qualitative assessment of actual conditions and organizes plant components into one of three categories (comparable to a traffic light system, red-yellow-green). This allows for maintenance priorities to be set for carrying out repairs in due time and thus prevent operational failure. Therefore, acoustic emission testing makes a significant contribution to safe plant operation. Typical test objects are:

• Hydraulic accumulators
• Gas cylinders
• Gas cylinder bundles and trailers
• Annealing ovens
• Sterilization autoclaves
• Pressurised operating chamber and decompression chambers
• Storage vessls for hydrogen and other technical gases
• Carbon dioxide storage vessls (cryogenic or under ambient conditions)
• Piping systems within refineries and chemical plants
• Aboveground and underground liquefied gas storage (LPG) tanks
• Very large LPG tanks (mounded LPG bullets) with capacity of more than 1000 m³
• Reactors, filters and storage tanks in air separation plants
• Drying and cooling cylinders in paper factories
• Long distance transport pipelines
• Pressure equipment made of austenitic steel
• Heat exchangers
• Flat bottomed storage tanks
• Offshore pipelines
• Components for steel and plant engineering
• Spherical and cylindrical natural gas tanks
• Spherical storage tanks for liquefied gases
• Reactors in the chemical and petrochemical industry
• Geometrically complex pressure equipment and pressure equipment with fittings (columns, absorbers, separation equipment, pressure swing absorbers, ...)

Acoustic emission testing is used in a number of different industry sectors. The following is a list of current sectors where acoustic emission testing is used:

• Chemical & petrochemical industry
• Oil & gas industry
• Power plants
• Energy sector
• Technology companies
• Pulp & paper industry
• Process industry
• Production plants
• Mechanical and plant engineering

Acoustic emission testing is used for test related to manufacturing (process controls and final inspections, acceptance test) as well as for testing in operation (in-service testing and continuous monitoring). The following phases of the lifespan of a product are covered:

• Material and construction optimization
• Production (quality assurance)
• Final assessment
• Initial pressure test
• Periodic tests
• Monitoring during operation/condition monitoring
• Detection of leaks
• Preventative maintenance
• Condition-based maintenance
• Risk-oriented maintenance