The ultrasonic crack technology using piezo electric transducers has proven good detection capabilities for several types of cracks and crack like defects in liquid lines globally. Within the last 20 years only minor developments and improvements in this area were offered to pipeline operators. The most significant enhancement was most probably moving from bucket sizing to absolute depth sizing some few years ago. Nevertheless, several technology related limitations remain for some types of defects with regards to sizing capabilities, e.g. the geometry of the defects such as hook cracks has a direct relationship with the response of the pulse-echo measurements..

Recent developments in NDT Global allowed overcoming and solving several of these limitations, e.g. by utilizing higher resolution tools, specialized sensors or special measurement configurations. These enhancements addressed several aspects, e.g. depth sizing accuracies, extended maximum crack depth sizing of the formerly known maximum crack depth of typically 4mm to through wall defects and less sensitive measurement capabilities to skewed or tilted defects.

The authors will discuss these technological limitations and developed solutions, initially investigated within a highly sophisticated modeling and simulation environment, followed by small scale laboratory testing and finally applied to NDT Global's test facility. Furthermore, the authors will share results from commercial inspections gathered in different pipelines showing the advantages of high-resolution tools (UCx) for detection, identification and sizing.Finally, the paper will provide a summary on interacting crack and deformation features gathered in a test setup and a commercial pipeline.