What is the first NDT method that is typically used by NDT personnel?

What is the first NDT method that is typically used by NDT personnel and many others but which only a limited number of people hold certification in? The answer is visual testing (VT). One of the first things that is checked during an inspection will be the identification of the component and this is often followed by a quick ‘once over’ to see if there are any obvious flaws and restrictions that may affect subsequent testing.

What happens if there appeared to be an obvious flaw/defect that should probably have been investigated and reported but the tester did not hold an appropriate VT qualification and they were there to employ a different NDT method? If the tester did not have either the appropriate VT certification or ‘Operating Authorisation’ (a written statement issued by the employer, based upon the scope of certification, authorising the individual to carry out defined tasks (BS EN ISO 9712)) covering VT, can there be a meaningful report generated that would stand up to scrutiny in a court of law? If the tester did not report the visual flaw(s), would they be following an incorrect course of action? Would an untrained tester be aware of all the variables in visual testing and know what equipment is required and how it should be maintained and calibrated?

A small sample of the syllabus areas covered in ISO/TR 25107, which are covered in the approved training courses, include: visual perception: what the eyes see, what the mind sees and what others perceive; detection ability: covering flaw size, shape, orientation/position, flaw types, surface condition effects, equipment limitations and lighting effects; classification and assessment of observations as per acceptance criteria from the codes, standards or written instructions or by specific reference to a Level 3 where no codes or standards exist; and by comparison, by measurement or by automated evaluation, for example pattern recognition.

In conclusion, if you are involved in any visual testing it would appear that you should be trained specifically for it and if you are reporting the results of a visual test you should hold the relevant certification.

john.moody@bindt.org

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