Collection and Discrimination of AE Signals from Tank Ships using an intrinsically safe certified AE Sensor System

Equipment for use in potentially explosive atmosphere is subject to particular requirements on safety and quality as determined by a number of Standards. For use in Europe, such equipment needs to conform to the EC directive 94/9/EC, also called “ATEX Directive”. The conformity must be certified by a socalled ATEX Certificate. In the frame of the EC-funded research project „Corrosion testing of tank ships“, AE-field tests on board large tank ships were executed. Intrinsically safe certified AE sensors were temporarily immersed through a potentially explosive atmosphere from the tank top through manholes into the liquid contents. Ship owners and involved classification societies insisted on the availability of a system certificate confirming intrinsic safety for the used sensors and isolation barriers. This paper summarizes basics of explosion protection and the ATEX directive, the safety requirements on Acoustic Emission field test equipment for use in potentially explosive atmosphere, and shows a realization of certified equipment and data acquired from immersed sensors on board of a tank ship and used for the location of a natural artificial AE corrosion source. Important Terms and Basics of Explosion Protection