Performance Estimation of a Remote Field Eddy Current Method for the Inspection of Water Distribution Pipes

Abstract

Remote Field Eddy Current (RFEC) technology allows the in situ inspection of metallic water distribution pipes. RFEC tools provide the location and magnitude of corrosion defects on the inspected pipes. The capacity of an RFEC tool to detect corrosion defects is evaluated in this paper by comparing its results with those obtained from the analysis of computed tomography (CT) scan images of the inspected pipes. Localization and characteristics of defects identified with the RFEC tool and from the CT scan images were compared for six cast iron pipes. An original method is proposed for the analysis of the CT scan images from which wall thickness losses were estimated by using the basic principle that the attenuation coefficient of X-rays in a homogenous material is a linear function of its density. The results show that the RFEC tool is able to localize most of the defects identified from the analysis of CT scan images. These findings reveal that the tested RFEC probe provided reliable information on the main corrosion defects, and thus on the general structural integrity of the inspected pipes.