Utilizing Pulsed Eddy Current to Inspect Insulated Piping

Abstract

A wide range of Oil & Gas plants is subjected to periodic inservice inspection in order to ensure continued safe and economic operation. The catastrophic failure of a component in a process plant may result in costly business interruption and also it endangers plant personnel. If an explosion or fire occurs, or a hazardous chemical is released widespread fatalities or undesirable environmental consequencies may result. Premature failure of plants can hapeen as a result of variety of different causes, and these include design deficiencies, manufacturing defects, fabrication or erection defects, service related deterioration and operating deficiencies. In order to prevent the sudden upset and resultant catastrophic failures, regular inspections most suitable for the anticipatory failures has to be identified and executed. The inspections are often performed by traditional NDT methods such as Radiographic testing and ultrasonic testing. These can be highly sensitive, but the rate of coverage is relatively very low and extensive preparation for inspection often required, eg. Like insulation removal or composite wraping removal often required for the inspection of substrate. There are also many situations where access or geometry prevents the use of conventional inspection methods. Over recent years a wide range of advanced NDT technques has evolved. These techniques provide large area screening of a component for significant degradation. Some of the techniques can be rapidly applied and they also provide means of inspecting areas which would be uninspectable. PEC or pulsed eddy current is one among this and this inspection technique is most suitable and best approach for insulated and composite wrapping applied section of piping. ZK site have many critical piping components applied with pressure / non pressure containment composite wrapping and the recent survey on these piping concluded many affected by corrosion under wrapping. PEC inspection is a solution for the inspection and condition monitoring of substrate under the wrapping, and which has proven and established.