Successful and consistent application of nondestructive testing techniques depends heavily on personnel training, experience and integrity. Personnel involved in application of industrial NDT methods and interpretation of results should be certified, and in some industrial sectors certification is enforced by law or by the applied codes and standards. NDT professionals and managers can join NDTMA, a member organization of NDT Managers and Executives who work to provide a forum for the open exchange of managerial, technical and regulatory information. Their annual conference is at the Golden Nugget in Las Vegas.
Certification schemes There are two approaches in personnel certification: •
Employer Based Certification: Under this concept the employer compiles their own
Written Practice. The written practice defines the responsibilities of each level of certification, as implemented by the company, and describes the training, experience and examination requirements for each level of certification. In industrial sectors the written practices are usually based on recommended practice SNT-TC-1A of the
American Society for Nondestructive Testing. ANSI standard CP-189 outlines requirements for any written practice that conforms to the standard. For aviation, space, and defense (ASD) applications NAS 410 sets further requirements for NDT personnel, and is published by AIA – Aerospace Industries Association, which is made up of US aerospace airframe and powerplant manufacturers. This is the basis document for EN 4179 and other (USA) NIST-recognized aerospace standards for the Qualification and Certification (employer-based) of Nondestructive Testing personnel. NAS 410 also sets the requirements also for "National NDT Boards", which allow and proscribe personal certification schemes. NAS 410 allows ASNT Certification as a portion of the qualifications needed for ASD certification. •
Personal Central Certification: The concept of central certification is that an NDT operator can obtain certification from a central certification authority, that is recognized by most employers, third parties and/or government authorities. Industrial standards for central certification schemes include ISO 9712, and ANSI/ASNT CP-106 (used for the ASNT ACCP scheme). Certification under these standards involves training, work experience under supervision and passing a written and practical examination set up by the independent certification authority. EN 473 was another central certification scheme, very similar to ISO 9712, which was withdrawn when CEN replaced it with
EN ISO 9712 in 2012. In the United States employer based schemes are the norm, however central certification schemes exist as well. The most notable is
ASNT Level III (established in 1976–1977), which is organized by the
American Society for Nondestructive Testing for Level 3 NDT personnel.
NAVSEA 250-1500 is another US central certification scheme, specifically developed for use in the naval nuclear program. Central certification is more widely used in the European Union, where certifications are issued by accredited bodies (independent organizations conforming to ISO 17024 and accredited by a national accreditation authority like UKAS). The
Pressure Equipment Directive (97/23/EC) actually enforces central personnel certification for the initial testing of
steam boilers and some categories of
pressure vessels and
piping. European Standards harmonized with this directive specify personnel certification to EN 473. Certifications issued by a national NDT society which is a member of the European Federation of NDT (EFNDT) are mutually acceptable by the other member societies under a multilateral recognition agreement. Canada also implements an ISO 9712 central certification scheme, which is administered by
Natural Resources Canada, a government department. The
aerospace sector worldwide sticks to employer based schemes. In America it is based mostly on the Aerospace Industries Association's (AIA) AIA-NAS-410 and in the European Union on the equivalent and very similar standard EN 4179. However EN 4179:2009 includes an option for central qualification and certification by a
National aerospace NDT board or
NANDTB (paragraph 4.5.2).
Levels of certification Most NDT personnel certification schemes listed above specify three "levels" of qualification and/or certification, usually designated as
Level 1,
Level 2 and
Level 3 (although some codes specify Roman numerals, like
Level II). The roles and responsibilities of personnel in each level are generally as follows (there are slight differences or variations between different codes and standards): •
Level 1 are
technicians qualified to perform only specific
calibrations and tests under close supervision and direction by higher level personnel. They can only report test results. Normally they work following specific work instructions for testing procedures and rejection criteria. •
Level 2 are
engineers or experienced technicians who are able to set up and calibrate testing equipment, conduct the inspection according to codes and standards (instead of following work instructions) and compile work instructions for Level 1 technicians. They are also authorized to report, interpret, evaluate and document testing results. They can also supervise and train Level 1 technicians. In addition to testing methods, they must be familiar with applicable codes and standards and have some knowledge of the manufacture and service of tested products. •
Level 3 are usually specialized engineers or very experienced technicians. They can establish NDT techniques and procedures and interpret codes and standards. They also direct NDT laboratories and have central role in personnel certification. They are expected to have wider knowledge covering materials, fabrication and product technology. ==Terminology==