Poll Question Analysis

Question

Which statement about EMAT technology is correct?

Response

As can be seen from the poll results, the question “Which statement about EMAT technology is correct” creates some uncertainty. Let’s shed some light on the subject by taking a closer look at the question and the possible answers.

As most of you know, EMAT (Electro-Magnetic Acoustic Transducer) is an inspection technology that can be used to inspect pipelines for cracks or coating defects. To this end, a rapidly fluctuating magnetic field creates ultrasound waves in the pipe wall. Material defects reflect these sound waves, which are then captured by the EMAT sensors. Contrary to conventional piezo-electric ultrasound, familiar to many from visits to the doctor or hospital, no liquid coupling agent such as water or oil is necessary. This makes EMAT technology especially ideal for gas lines. Some of you chose answer (c). However, we were able to trick you with this answer because EMAT works in gas AND liquid pipelines.

So what about answer (a) then? Yes, EMAT is able to detect cracks as well as laminations and distinguish between both. The focus of EMAT is on cracks, so laminations are usually not subject to reporting. Dents might cause sensor lift-off, but besides that, there is no way to further assess deformations. Our RoGeo XT service helps to identify dents and can be combined with the additional service of correlating dents with crack calls.

Nevertheless, the majority of respondents chose the correct answer, (b): EMAT data analysis covers assessment of coating type and condition as well as axial cracks. These are indeed the targets of the EMAT data analysis.

Find out more about our RoCD EMAT-C Service here.