Visual testing is the most used and least respected method in NDT. It is also the one that finds the most defects, and the first examination every other method depends on.
Training covers what makes visual examination a formal method rather than an opinion: lighting levels measured at the surface, viewing angle and distance requirements, direct versus remote visual examination, magnification limits, and the vision acuity and colour-differentiation requirements the examiner must personally hold and re-verify.
Level I performs the examination to a written instruction and records what is present. Training focuses on systematic coverage, the measurement tools — weld gauges, profile gauges, depth measurement — and on recording rather than judging.
Level II evaluates against acceptance criteria, which for welds means AWS D1.1 or ASME acceptance applied consistently to undercut depth, reinforcement, profile, porosity and cracking. This is where the method becomes technical: undercut acceptance turns on fractions of a millimetre and on whether the connection is statically or cyclically loaded.
Level III approves procedures and qualifies personnel, and typically owns the interface with welding inspection qualifications such as CWI where the employer holds both.
Under ASNT SNT-TC-1A the employer sets training hours and documented experience hours per method and level in its own Written Practice, so the requirement you must satisfy is your employer's — not a universal number. Under ISO 9712 a central body examines and certifies, and the certificate travels with you between employers. Either way the pattern is the same: classroom or structured theory, supervised practical work, then general, specific and practical examinations. Training hours and experience hours are separate requirements, and candidates most often stall on the experience log rather than the coursework. Start documenting hours before you need them. How employers run the programme · the certification pathway in full.
The practical examination tests measurement rather than impression — candidates who eyeball undercut fail. It also tests coverage discipline and the discipline of recording what is there before deciding what it means.
ASME Section V Article 9, AWS D1.1 visual acceptance for structural welds, and API 510, 570 and 653 in-service visual requirements.
Every sector — VT is the first examination in almost every inspection programme, and in-service inspection under the API codes is substantially a visual discipline supported by volumetric methods.
VT sits alongside, not inside, welding inspection certification. A CWI qualification covers welding process knowledge and code application beyond NDT method certification, and many employers want both. CWI certification · visual inspection services.
Programmes are built and taught by practising ASNT Level IIIs. For companies, delivery is on-site at your facility — the practical work uses specimens representative of what your people actually examine, which is the single biggest difference between training that transfers to the job and training that does not. For individuals, scheduled cohorts and blended delivery combine structured theory with supervised practical. We are straightforward about the model: Atlantis does not operate walk-in training centres, and we will tell you when a local provider is the better answer for a single candidate.
It depends on the level and on how quickly you accumulate documented experience hours, which is usually the binding constraint rather than the coursework. A candidate already working under supervision progresses considerably faster than someone starting cold, because the experience accrues while they work.
Yes for Level I — it is designed as an entry point. Level II requires documented Level I experience in the method, so the sequence matters. The Level I route · Level II requirements.
Under SNT-TC-1A, no — employer-based certification lapses when you leave, though your documented experience travels with you and the new employer can certify you against their Written Practice. Under ISO 9712 the certificate is yours. This distinction is worth understanding before choosing a route. The comparison in full.
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VT is a certified NDT method, not an informal look. ASNT SNT-TC-1A recommends 8 training hours and 70 VT experience hours for Level I, and 16 further training hours with 140 cumulative VT hours for Level II — more classroom time at Level II than any other surface method. ASME BPVC Section V Article 9 governs the examination.
Visual testing is the method every other method depends on, and the one US employers most often assume needs no certificate. The codes disagree. ASME BPVC Section V Article 9 requires a written procedure, and direct visual examination performed with the eye within 24 inches of the surface at an angle no less than 30 degrees, under a minimum of 100 foot-candles — roughly 1,000 lux — measured at the surface. SNT-TC-1A's recommended table lists VT Level I at 8 training hours, 70 VT hours and 130 total NDT hours, and VT Level II at 16 further training hours, 140 cumulative VT hours and 270 total NDT hours. Every level requires a documented near-vision acuity examination, Jaeger No. 1 at not less than 12 inches or an equivalent, repeated annually, plus colour-contrast differentiation. For structural steel, AWS D1.1 Clause 8 supplies the acceptance criteria a VT Level II applies.
Source: ASME BPVC Section V, Article 9; AWS D1.1/D1.1M Structural Welding Code — Steel, Clause 8 visual inspection acceptance criteria; ASNT SNT-TC-1A (2020 edition), vision examination and recommended training requirements; API 510, API 570 and API 653 in-service visual requirements.
| Parameter | Requirement | Governing document | Who verifies and records it |
|---|---|---|---|
| Illumination, direct visual examination | 100 foot-candles (about 1,000 lux) minimum, measured at the surface being examined | ASME BPVC Section V, Article 9 | VT Level II, with a calibrated light meter; source and meter recorded |
| Eye position, direct visual examination | Within 24 inches (600 mm) of the surface, at an angle of 30 degrees or greater to it | ASME BPVC Section V, Article 9 | VT Level II, recorded on the examination report |
| Remote visual examination | Resolution at least equivalent to direct visual examination, demonstrated on the system in use | ASME BPVC Section V, Article 9 | VT Level III on the written procedure, with the demonstration retained |
| Examiner near-vision acuity | Jaeger No. 1 type at not less than 12 inches, or an equivalent, one eye or both, natural or corrected | ASNT SNT-TC-1A, examined annually | Employer, documented per person on the certification file |
| Examiner colour-contrast differentiation | Ability to distinguish and differentiate the colours used in the method | ASNT SNT-TC-1A | Employer, documented per person on the certification file |
| Undercut, statically loaded structural weld | 1/32 inch maximum, with 1/16 inch permitted for an accumulated 2 inches in any 12 inches of weld | AWS D1.1 Clause 8 | VT Level II or CWI, measured with a gauge |
No, and the reverse is also false. A CWI covers welding processes, procedure and welder qualification, and code application. A VT Level II is an NDT method certification issued under the employer's Written Practice, which is what ASME BPVC Section V Article 9 work calls for. Employers running both structural and pressure-equipment work hire people holding both credentials.
A minimum of 100 foot-candles, roughly 1,000 lux, measured at the surface being examined — not at the workbench, and not estimated. The light source and the calibrated meter used are recorded on the examination report. Remote visual examination using borescopes, mirrors, fibrescopes or cameras is demonstrated to have resolution at least equivalent to direct visual examination.
Near-vision acuity is examined annually under SNT-TC-1A: the candidate reads Jaeger No. 1 type at not less than twelve inches, or an equivalent such as Times Roman N-4.5, with one eye or both, natural or corrected. Colour-contrast differentiation is documented separately. Failing the vision examination suspends the certification regardless of how many experience hours are logged.
Yes, unless the contract documents specify otherwise. AWS D1.1 requires visual inspection of all welds and makes additional NDT applicable only where the contract designates it. That places the whole acceptance decision on a VT-qualified examiner measuring undercut, reinforcement, profile, porosity and cracking against Clause 8 criteria with gauges rather than by eye.
Direct visual examination places the examiner's eye within 24 inches of the surface at an angle of 30 degrees or greater. Remote visual examination substitutes mirrors, borescopes, fibrescopes or cameras where access prevents that, and the system is demonstrated to have at least equivalent resolution. Internal examination under API 510, 570 and 653 relies heavily on remote visual.
A VT Level II performs the examination, evaluates against the acceptance criteria and signs the examination report. Final acceptance of the completed vessel rests with the Authorized Inspector, who signs the Manufacturer's Data Report. The distinction matters on audit: NDT personnel certify examinations, and the Authorized Inspector certifies code compliance of the finished item.
Tell us the methods and levels you need and how many technicians. We reply with available dates, the delivery options that fit, and what your written practice requires — usually the same working day.
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Training scopes are quoted from the national visual testing service: direct and remote visual examination against named acceptance criteria, with the evidence chain written to survive an audit.
VT is where trade welders enter inspection — the full welder-to-NDT route explains why it comes first and what follows.