Quality in non destructive testing is first of all reliability of information, received in the process of control that is based on the following blocks:

• level of normative documentation where the requirements to the quality factors and techniques for their evaluation are specified;

• proper choice of inspection means and their technical state including materials and specimens for flaw detection;

• level of knowledge and qualification of NDT personnel;

• level of job organisation and motivation.

These blocks define, in their turn, the main activities of departments that implement non destructive testing and therefore they may be considered as leading components of the infrastructure of the System for NDT quality assurance.

Every of these components has specified requirements, id est, it is standardized.

Techniques, procedures and operations are defined in normative documents on products and methods, id est for the control implementation the quality factors, acceptable defects and procedures for their evaluation with stipulated error must be regulated.

Means for non destructive testing, auxiliary equipment and materials for flaw detection must ensure reliable evaluation of quality factors with stipulated accuracy. The requirements to the NDT means and materials for flaw detection are specified by standards and/or specification.

The requirements to the personnel qualification and assessment of its competence level in a proper NDT method for a specific industry sector are specified also by standards, particularly ISO 9712 and EN 473. The latter is adopted in the Republic of Belarus by direct use.

Organisational factors are defined by the quality assurance system of the department that implements non destructive testing and are specified in International Standards ISO 9001, ISO 9002, ISO 9003 and ISO/IEC Guide 49.

If there is standardization for defined factors and conditions, there is, of course, a system to evaluate their conformity to specified norms. The forms and methods of evaluation may be different.

In world practice this is resolved by accreditation in compliance with EN 45002 of inspection department that must meet EN 45001.

These European standards specify clear requirements to the entity seeking accreditation. Among these requirements:

• well-defined organisational structure and documented quality system;

• high qualification and competence of personnel that organise and implement control and testing;

• availability of inspection and measuring techniques that ensure reliability of control results being received;

• traceability of control results and operations of technological processes control.

Full coincidence with components of the infrastructure of the system for NDT quality assurance is clear and it means that assurance of quality in non destructive testing is possible through accreditation of department carrying out this testing.
In addition accreditation permits to cover requirements specific for the non destructive testing of all these four components.

It is exactly this approach that is adopted in the Republic of Belarus in implementing accreditation of laboratories for non destructive testing and technical diagnostics in the system for testing and calibration laboratories accreditation in the Republic of Belarus.