CML Optimization: Effective and Efficient Coverage and Placement

Inspectioneering Journal, May/June 2017 Issue 

A best in class Mechanical Integrity (MI) program is comprised of numerous components, including Risk-Based Inspection (RBI), Integrity Operating Windows (IOWs), inspection strategies, and more. Inspection strategies, including Condition Monitoring Location (CML) selection, are critical in ensuring program effectiveness, as their results drive key decisions and continuous program improvement. Effective CML coverage and placement enables owner/operators to better understand and mitigate potential risks in a cost-effective manner. It also inspires confidence in the data used to make informed decisions, which ultimately maximizes the value of an MI program.

Consider a piping circuit subject to localized thinning requiring CML placement. One may choose to place spot UT CMLs on every single elbow, tee, and reducer, and one or more on each straight run, in an attempt to detect localized asset degradation (see Figure 1). Not only does this have a lower probability of confirming anticipated damage due to the selected inspection technique, but it may even cost more than a targeted inspection of likely locations by UT scan or profile RT.