Papers by Author: Peter Tscheliesnig

Abstract: The TÜV Austria (formerly TÜV Vienna) has been testing different structures, mainly pressure equipment, since 1977 with Acoustic Emission. I will not enumerate all the different tests, which are more than 20.000 till today, but I will point out, how the test method has changed on some typical tests over the years. I will also remind you on the different possibilities, which have been offered by the rapid development of the electronic data acquisition and treatment, especially during the last 10 – 15 years.

Abstract: Acoustic emission testing (AT) is in Europe an already well established non-destructive testing (NDT) method. Qualification requirements as well as certification of testing personnel are laid down in European standard EN 473. A widespread application of AT deals with testing of unfired pressure vessels for re-qualification after a certain period of service (repetition test). The advantages of applying AT compared to the traditional procedure of hydrostatic test plus visual inside inspection are numerous. Just to name the most important: reduction of downtime, omitting of residual humidity and no risk of product contamination with water. It is a fact that AT provides much more useful information concerning the condition of the pressure vessel under test than a simple ‘passed’ or ‘not passed’ obtained usually by a hydrostatic test. This contribution gives two examples of practical experience, where severe corrosion defects have been detected by AT. The defects have been found in both cases on the vessel’s shell under the thermal insulation, where they have been hidden undetected for years. It can be assumed that even the vessel with the most severe damage (loss of more than 50% of the nominal wall thickness) would have passed the traditional repetition test procedure and that failure within the following service period would have occurred. In contrary to this scenario, AT enabled the vessel operator to perform appropriate repair in time.