In-line inspection - is sufficient data being collected?

When it comes to the in-line inspection of pipelines, the term 'high resolution' is often used. This term is not quantifiable and is of little use to the pipeline operator who requires to know the area of metal loss that will not be detected or will be inaccurately sized by an in-line inspection tool. It is not enough that the factors affecting the detection and sizing capability of an in-line inspection tool be considered, but also, the inspection tool must collect sufficient data in order to produce a satisfactory performance. Finally, the pipeline operator should consider that any area of metal loss that has a dimension in the circumferential direction of less than the pitch between two circumferential sensors is unlikely to be detected and sized correctly.