Level I and II qualification and certification per SNT-TC-1A, with ASNT Level III authority across all six methods.
NDT personnel qualification per SNT-TC-1A is the process by which a company demonstrates, documents, and formalizes the competence of its inspectors to perform nondestructive testing. SNT-TC-1A is ASNT's recommended practice and is recognized by codes such as ASME BPVC, API 1104, AWS D1.1, and ASTM.
Unlike ISO 9712, where an independent body certifies the inspector, under SNT-TC-1A responsibility rests with the employer. The Level III oversees the entire process — develops examinations, evaluates results, and recommends certification to the employer. SimpleNDT acts as that Level III for companies that do not have one on staff.
The complete qualification process follows a well-defined sequence that meets all SNT-TC-1A requirements:
1. Prerequisites verification: the candidate must meet the minimum requirements for formal training (classroom hours) and supervised practical experience defined in the company's Written Practice. Minimums vary by method — ultrasonic and radiographic testing require 40 hours of training for Level 1 and 80 hours for Level 2, while liquid penetrant requires 8 and 24 hours respectively.
2. General examination (40 questions): evaluates knowledge of the method's basic principles — physics, equipment, terminology, and technique fundamentals. Questions are developed by the Level III based on ASNT's Body of Knowledge for the method.
3. Specific examination (20 questions): evaluates knowledge of operating procedures, examination techniques, codes, standards, specifications, and acceptance criteria applicable to the employing company. This examination is customized — not generic — as it must reflect the procedures and standards the inspector will actually use.
4. Practical examination: the candidate demonstrates familiarity and ability to operate equipment, perform the examination, and evaluate results. At least one sample containing a discontinuity must be tested. The Level III evaluates both technique and interpretation.
5. Visual acuity examination: mandatory annual test — near visual acuity sufficient to read Jaeger number 1 at 30.5 cm (natural or corrected). For radiography, a gray-shade discrimination test is also required.
6. Recommendation and certification: if the candidate passes all examinations and prerequisites are met, the Level III recommends certification to the employer. The employer issues the certificate, valid for 5 years.
The qualification generates a complete set of documentation meeting audit requirements under ASME and other codes:
Qualification certificate: formal document issued by the employer identifying the inspector, method, level, certification date and expiry, signed by the responsible Level III.
Examination records: copies of the general, specific, and practical examinations administered, with the candidate's responses and scores. The minimum passing criterion is typically 70% on each examination (or as defined in the Written Practice).
Training record: documentation of formal training hours completed by the candidate, including dates, content, and instructor.
Experience record: documentation of supervised practical experience, with dates, type of work performed, and responsible supervisor.
Visual acuity record: result of the Jaeger examination and, where applicable, color vision test (Ishihara) and gray-shade discrimination.
SimpleNDT qualifies Level 1 and Level 2 inspectors in the following methods:
VT — Visual Testing: fundamental method, mandatory under most codes. Includes weld inspection before, during, and after welding, dimensional verification, and surface finish evaluation.
PT — Liquid Penetrant Testing: detection of surface-open discontinuities in non-porous materials. Applied to welds, castings, and forgings. Per ASME Section V Article 6 or ASTM E165.
MT — Magnetic Particle Testing: detection of surface and near-surface discontinuities in ferromagnetic materials. Techniques with AC/DC yoke, prods, and coils. Per ASME Section V Article 7 or ASTM E709.
UT — Conventional Ultrasonic Testing: detection, location, and sizing of internal discontinuities. Includes pulse-echo and through-transmission techniques. Per ASME Section V Article 4 or ASTM E164/E2375.
RT — Radiographic Testing: volumetric inspection with X-rays or gamma rays. Includes conventional film, computed radiography (CR), and digital radiography (DR) techniques. Per ASME Section V Article 2.
The Written Practice is the central document of the personnel qualification program. It is the employer's responsibility, developed or reviewed by the Level III, and must be available for audit. SimpleNDT develops complete Written Practices or reviews existing documents to ensure compliance.
A well-developed Written Practice clearly defines the minimum training and experience requirements for each method and level, describes the types of examinations administered and passing criteria, establishes the recertification process (every 5 years), defines the responsibilities of each personnel level (I, II, and III), and documents the use of an external Level III where applicable.
SNT-TC-1A certification is valid for 5 years. Recertification may be accomplished by evidence of continuing satisfactory performance or by reexamination, at the Level III's discretion. For companies holding an ASME stamp, a technical performance evaluation is mandatory before recertifying Level I and II personnel — simply renewing the certificate without verifying competence is not sufficient.
How SNT-TC-1A works: structure, personnel levels, Written Practice, examinations, recertification, and the role of Level III — complete guide.
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