Importance of Non-destructive Testing Education, Training and Certification
Education of personnel engaged in non-destructive inspection, including formal training, and certification, is probably the greatest single factor affecting the quality of non-destructive inspection. The objective of most (NDT) methods is to detect internal defects with respect to their nature, size and location. This is done by different methods, depending upon their inherent capability or sensitivity for flaw detection. The sensitivity of flaw detection for different NDT methods depends upon a number of variable factors which usually include type of specimen, its geometry and surface condition; nature, type and location of defects; characteristics of NDT equipment and parameters of relevant NDT methods and operator's eyesight, qualifications, experience and integrity.
Looking at the numerous variable factors influencing the sensitivity and quality of non- destructive testing, as listed above, the factor common to all the NDT methods is the operator, the person responsible for executing the tests and reporting the results. It is through the operator that the results of NDT tests are compiled for further consideration and critical decisions about the fate of the tested part. In many cases he himself holds the responsibility of passing a judgement on the acceptance or rejection of the part. It is the operator through whom the results of NDT can be falsified. If the operator is not properly knowledgeable, trained and experienced he might totally misjudge the results of NDT and reject the parts which are sound and capable of performing in service. On the other hand he might send the faulty parts into service which may become a source of premature failure. In both the cases the consequences are going to be adverse. In the first case the organization is going to suffer undue production losses while in the second the premature failure may lead to even bigger losses. Of no less importance is the integrity of the operator in view of his ability to falsify the results intentionally.
Non-destructive testing, in radiography, uses hazardous radiation sources. There is a danger of undue radiation exposures to the radiographers as well as to the general public if the radiographer is either ignorant or careless about these hazards. It is therefore essential to properly train all the radiographers in the use of radiations, and the radiation monitoring and handling equipment. All such persons should be properly certified and such certificates in fact should be cancelled in case their holders are found to be indulging in any malpractices or negligence regarding the safe use of radiation sources.
With the advent of new space-age materials and complex systems, engineers will be able to pursue structures and systems that require lower weight, greater strength, higher performance, less maintenance, and greater reliability to meet the competitive engineering and social challenges of the future. Each step of this scenario requires quality-control usually through NDT procedures and applications. Recognizing that NDT expertise is a key resource for the current and future needs of industry, industrialists are becoming more aware and concerned that such expertise is not taught to every undergraduate science and engineering student.
These same individuals in industry perceive that it is not just the technical discipline of NDT that is missing; it is the whole philosophy of NDT, which must become a part of the new engineering curriculum. This then brings out the need for making NDT a part of the entire educational programme in addition to training the operators for specific jobs.
The need for effective qualification and certification schemes has been recognized as a significant part of the technology since the early 1960s. Over the last few decades, international organizations including IAEA, ISO and ICNDT have dedicated considerable efforts to designing systems for credible and harmonized systems of qualifying the individuals who carry out the tests. Many product standards, codes of construction and contract documents recognize that the human element is critical to the reliability of the test and mandate formal certification of the NDT personnel performing the test.