In the early '80s high frequency AE sensors were developed for the detection of crack growth during the testing of pressure vessels. In the mid '80s a major oil company in the UK evaluated several portable leak detection systems and concluded that instrumentation using these AE sensors provided the best means of leak detection. The focus of the resulting follow-up work was refinery loss control and hence gaseous leakage from relief, vent and blowdown valves. From experimental and site work a method for quantification of the gas leakage from the measured AE signal, inlet pressure and the valve parameters was developed. Following this work commissioned existing manufacturer(s) to develop a new intrinsically safe instrument taking into account operating experience and incorporating newly available micro electronics. This instrument became available in 1992.
Subsequent to this groundwork, Score have developed a liquid leakage quantification for a range of valves aimed at those handling produced water, condensate and light crude oils. Score have also carried out work on behalf of major oil companies to extend the range of the predictive maintenance method to large ball valves (to 36" nominal bore) on both gas and liquid.