A Quantitative Assessment of Historical Nondestructive Evaluation (NDE) Probability of Detection (POD) Data for Railroad Tank Cars

Abstract

This paper discusses a comprehensive analysis and quantitative assessment of two decades of nondestructive evaluation probability of detection (NDE POD) data collected using the Code of Federal Regulations’ (CFR)-approved NDE methods for railroad tank cars. The results obtained from this research demonstrate that these methods were not capable of achieving or approaching a 90-percent POD with 95-percent confidence (90/95 POD) for fatigue cracks in the butt weld (BW) test panels from the operators who participated in this research. The evaluation of the fillet weld (FW) data showed mixed results, but only the magnetic particle testing (MT) method reached 90/95 POD. Also, excessive false calls were observed in both the BW and the FW inspection results. These results indicate the variability in 1) NDE tests and calibration procedures, 2) operator variance, and 3) the influence of human factors on the application of the NDE inspection processes.