Abstract
Acoustic emission testing based on test procedure, database and evaluation criteria has been widely used as a standard method for testing bottom plate conditions in oiI storage tanks. More than 160 tanks have been tested in Japan on the basis of the test procedure since it was introduced to Japanese industry in 1999. After acoustic emission testing, tanks were opened and thickness data were collected. Good correlation has been found between acoustic emission activity and the corrosion risk parameter (ccrresponding corrosion rate) resulting from a statistical ana1ysis of the thickness data from discrete point thickness measurement. Ultrasonic bottom p1ate scan testing has been conducted to verify the reliability of the correlation. This paper presents some case studies, comparing the acoustic emission data with bottom plate scan testing resu1ts. The reliability of acoustic emission testing in terms of source location and thickness mapping is discussed with the aid of location figures. The case studies have been made partly as the research project of the High Pressure lnstitute of Japan, sponsored by the Japan Oil, Gas and Metal National Corporation.
