A Rapid Scanning Inspection Method for Insulated Ferromagnetic Tubing

Abstract

Until the present there has been no effective way to rapidly scan thermally insulated refinery or process piping for corrosion or thin wall. Such defects, if left unattended, can lead to wasteful losses of time, energy and money. To date the most common means of locating such defects has been random spot measurement of suspect regions using ultrasonic or radiographic techniques. The obvious weakness of such an approach is the low probability of selecting the region of most severe corrosion in a long expanse of insulated piping. PA Incorporated has developed an electromagnetic inspection device which rapidly scans nearly 100 percent of an insulated pipeline (flanges and tees excluded) and provides a quantitative (2 percent) measurement of average wall thickness and qualitative evaluation of external and internal corrosion. The value of the device lies in its ability to quickly locate major problem areas through thermal insulation which can then be examined in more detail by removing insulation and using other techniques. This paper describes the device, the inspection results to date, and the unique advantages of this new inspection tool.