Qualification and certification of NDT

One of the principal standards that governs third-party certification in NDT worldwide is ISO 9712:2012 Non-destructive testing – Qualification and certification of NDT personnel. The certification covers proficiency in one or more of the following methods: acoustic emission testing (AT); eddy current testing (ET); infrared thermography testing (TT); leak testing (LT); magnetic testing (MT); penetrant testing (PT); radiographic testing (RT); strain gauge testing (ST); ultrasonic testing (UT); and visual testing (VT). The sectors that are listed include product sectors, which include castings (c) (ferrous and non-ferrous materials); forgings (f) (all types of forgings: ferrous and non-ferrous materials); welds (w) (all types of welds, including soldering, for ferrous and non-ferrous materials); tubes and pipes (t) (seamless, welded, ferrous and non-ferrous materials, including flat products for the manufacturing of welded pipes); wrought products (wp) except forgings (for example plates, bars and rods); composite materials (p) or industrial sectors, sectors combining a number of product sectors including all or some products or defined materials (for example ferrous and non-ferrous metals or non-metals such as ceramics, plastics and composites); pre- and in-service testing, which includes manufacturing, railway maintenance and aerospace. Additionally, this does not preclude the development of additional sectors to satisfy national needs.

There is only limited guidance on techniques, including the definition of ‘NDT technique’ as ‘a specific way of utilising an NDT method’ (for example ultrasonic immersion technique). This definition can be found in Section 3: Terms and Definitions in ISO 9712:2012. The system specified in this international standard can also apply to other NDT methods or to new techniques within an established NDT method. With UT, the PCN Working Groups have elected to have separate certification for sectors including manual UT of welds, cast or wrought and additional certification for UT TOFD, UTPA, guided wave, etc. The current challenge is how to decide on the sectors and techniques relating to RT, as traditional film-type RT is being replaced in some situations with digital and computed RT. Additionally, computed tomography is being used more. The general theory syllabus for RT could be considered common to all, along with radiation safety, and the image acquisition process has many common syllabus areas. However, the processing of the acquired image is significantly different.

The next consideration is training, which simply states: The candidate shall provide documentary evidence, acceptable to the certification body, that they have satisfactorily completed training in the method and level for which certification is sought. Fortuitously, there is additional guidance. When creating industrial sectors as defined in Annex A, the certification body should consider whether the minimum training requirements in Table 2 are sufficient or should be increased. It does not mention techniques within a method in which there can be many, such as UT, manual, TOFD, UTPA, immersion testing, guided wave, etc. For the experience requirements there is a similar lack of clarity and the certification body has to decide what is appropriate in conjunction with the working groups. These situations will continue to manifest themselves as different techniques become accepted as ways of testing.

If you, as an end-user, are offered an ISO 9712 certificated person to perform inspections, you do need to understand what the person is certificated in and what the syllabus covers.

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