What is SNT-TC-1A?

SNT-TC-1A is an ASNT recommended practice, not a standard. It gives an employer the framework to write its own Written Practice covering training hours, experience, examinations and vision requirements for certifying NDT personnel. Because it recommends rather than mandates, auditors ask to see the employer's Written Practice.

ASNT SNT-TC-1A 2024 — Requirements, Levels & 30-Day Pass Plan

Comprehensive guide to ASNT SNT-TC-1A Certification Requirements. Explore principles, standards, and best practices for effective implementation.

By Anoop Rayavarapu, ASNT NDT Level III · · Certification & Career

ASNT SNT-TC-1A Certification Requirements: Complete Guide 2026

ASNT SNT-TC-1A is the foundational standard for NDT personnel qualification in the United States and globally. With certification required by OSHA, API, ASME, and virtually every major industry, understanding SNT-TC-1A requirements is essential for launching and advancing your NDT career.

What is ASNT SNT-TC-1A?

Overview

ASNT SNT-TC-1A (American Society for Nondestructive Testing - Recommended Practice for Qualification and Certification of NDT Personnel) establishes minimum qualifications for NDT technicians in six methods: ultrasonic (UT), radiography (RT), magnetic particle (MPI), liquid penetrant (PT), eddy current (ECT), and visual inspection (VT). It's the most widely recognized NDT qualification standard in North America.

Comparison: SNT-TC-1A vs. ISO 9712 vs. ACCP

Standard Geographic Focus Certification Body Levels Portability
ASNT SNT-TC-1A North America (USA, Canada, Mexico) ASNT (non-profit) Level I, II, III (3 levels) Limited (primarily North America)
ISO 9712 Europe, Asia-Pacific, Global National accredited bodies (e.g., TWI in UK) Level 1, 2, 3 (3 levels) High (internationally recognized)
ACCP (ASNT) North America (alternative to SNT-TC-1A) ASNT Level I, II, III Moderate (ASNT certified alternative)
PCN (UK) UK and Commonwealth countries PCN (Personnel Certification Scheme) 1, 2, 3 High in UK/Europe

SNT-TC-1A Certification Levels

Level I: Basic Technician

Purpose: Perform designated specific NDT tasks under direct supervision; capable of conducting routine inspections and basic measurements.

Training Requirements:

  • Formal classroom training: Minimum 40 hours (equivalent to ~1 week full-time course)
  • On-the-job training (OJT): Minimum 300 hours or 3 months equivalent
  • Total time to Level I: 3-4 months for full-time student

Exam Requirements:

  • Written exam: 75-150 questions depending on method (typically 75-100)
  • Practical exam: Demonstrate basic proficiency (probe handling, equipment operation, interpretation basics)
  • Passing score: 75% on written, successful practical demonstration
  • Exam cost: per the certifying body’s current schedule per method

Certification Validity: 3 years from date of certification

Typical Level I Salary: $35,000-$50,000/year

Career Path: Entry-level inspector for basic inspections, technician work in labs, manufacturing QC departments

Level II: Intermediate Technician

Purpose: Plan and conduct NDT examinations; set up equipment; perform calibration; interpret results; evaluate acceptability; work independently on routine inspections

Training Requirements:

  • Formal classroom training: Minimum 120 hours (3-4 week course)
  • On-the-job training: Minimum 2,400 hours OR Level I + 1 year OJT
  • Total time to Level II: 1-2 years from entry

Exam Requirements:

  • Written exam: 150-200 questions (more difficult than Level I)
  • Practical exam: Demonstrate advanced skills including equipment setup, calibration, interpretation of complex indications
  • Passing score: 75% written + successful practical
  • Exam cost: per the certifying body’s current schedule per method

Certification Validity: 3 years from certification date (can be extended by demonstrating current experience)

Typical Level II Salary: $55,000-$80,000/year

Career Path: Lead inspector on most projects; inspection authority for non-API/ASME work; consulting; training roles

Level III: Expert/Inspector

Purpose: Develop and approve NDT procedures; train and certify NDT personnel; make final determination of acceptability; serve as inspection authority for critical inspections

Training Requirements:

  • Formal classroom training: 150+ hours
  • On-the-job training: Minimum 10,000 hours total NDT work (5 years minimum)
  • Level II certification in minimum 3 NDT methods
  • Total time to Level III: 5-7 years minimum

Exam Requirements:

  • Written exam: 150-200 questions (comprehensive, difficult)
  • Practical exam: Develop procedures, analyze complex defect scenarios, mentor scenarios
  • Passing score: 75% written + successful practical
  • Exam cost: per the certifying body’s current schedule per method
  • Total Level III cost: a modest cost+ if obtaining multi-method

Certification Validity: 5 years (longer validity than Level I/II)

Typical Level III Salary: $90,000-$150,000/year (consulting: $200-$400/hour)

Career Path: Inspection authority for critical projects; Level III consultants; procedure developers; expert witness testimony

Experience Requirements by Level

Certification Level Training Hours OJT Hours Time Required Experience Path Options
Level I 40 hours minimum 300 hours or 3 months 3-4 months Entry-level; no prior experience required
Level II 120 hours minimum 2,400 hours OR Level I + 1 year 1-2 years Option A: 2,400 OJT hours; Option B: Level I + 1 year experience
Level III 150+ hours minimum 10,000 hours total (5 years minimum) 5-7 years Level II in 3+ methods + 5 years total experience

Six NDT Methods Covered by SNT-TC-1A

1. Ultrasonic Testing (UT)

Difficulty Level: Moderate to High

Industry Demand: Very High (used by 95%+ of inspection companies)

Salary Premium: Highest demand = premium pay (+$5K-$15K above baseline)

Course Duration: 40 hours (Level I), 120 hours (Level II)

Career Focus: Thickness measurement (corrosion), weld inspection, flaw detection

2. Radiographic Testing (RT)

Difficulty Level: High

Industry Demand: Moderate (used in aerospace, power, nuclear heavily; oil & gas spotty)

Salary Premium: High (+$10K-$20K) due to licensing requirements and specialization

Course Duration: 40 hours (Level I), 120 hours (Level II)

Career Focus: Weld radiography, defect interpretation, safety officer roles

3. Magnetic Particle Inspection (MPI)

Difficulty Level: Moderate

Industry Demand: High (aerospace, forging, automotive)

Salary Premium: Moderate (+$3K-$8K)

Course Duration: 40 hours (Level I), 120 hours (Level II)

Career Focus: Ferrous material inspection, crack detection, manufacturing QC

4. Liquid Penetrant Inspection (PT)

Difficulty Level: Moderate

Industry Demand: Very High (works on all material types)

Salary Premium: Moderate (+$3K-$8K)

Course Duration: 40 hours (Level I), 120 hours (Level II)

Career Focus: Surface defect detection, aerospace, repair verification

5. Eddy Current Testing (ECT)

Difficulty Level: Moderate to High

Industry Demand: Moderate to High (aerospace, power generation, tube inspection)

Salary Premium: Moderate to High (+$5K-$12K)

Course Duration: 40 hours (Level I), 120 hours (Level II)

Career Focus: Tube/pipe inspection, surface crack detection, material characterization

6. Visual Inspection (VT)

Difficulty Level: Low

Industry Demand: Extremely High (required for all inspections as baseline)

Salary Premium: Low (baseline credential)

Course Duration: 20 hours (Level I), 60 hours (Level II)

Career Focus: Borescopy, weld visual assessment, general condition evaluation

Recommended Certification Pathway

Strategy for Career Progression

Year 1: Build Foundation

  • Get ASNT Level I in Visual Inspection (easiest, fastest, 4-6 weeks)
  • Get ASNT Level I in Liquid Penetrant (6-8 weeks after VT)
  • Total investment: modest against the salary uplift (courses + exams)
  • Salary position: Entry-level technician, $35K-$45K

Year 1-2: Add Capability

  • Get ASNT Level I in Ultrasonic Testing (8-10 weeks)
  • Begin Level II pursuit in VT and PT (2,400 OJT hours)
  • Total investment: modest against the salary uplift
  • Salary progression: $45K-$55K

Year 2-3: Specialize

  • Get ASNT Level II in UT (primary method)
  • Get ASNT Level II in PT or MPI (second method)
  • Total investment: modest against the salary uplift
  • Salary: $60K-$75K
  • Now qualified for API 510/570/653 prerequisites

Year 4-7: Advance to Level III

  • After 5 years NDT experience, pursue ASNT Level III in UT (most critical)
  • ASNT Level III in PT/MPI/ECT (specialize in 2+ methods)
  • Total investment: modest against the salary uplift
  • Salary: $90K-$150K+
  • Becomes inspection authority; can sign off on procedures and inspections

SNT-TC-1A Exam and Certification Process

Exam Structure (Using UT Level II as Example)

Written Exam: 150-200 multiple-choice questions

  • Equipment operation and setup: 20-25%
  • Principles and physics: 20-25%
  • Procedures and techniques: 30-35%
  • Defect detection and interpretation: 15-20%
  • Calibration and standards: 10-15%

Practical Exam: Hands-on demonstrations

  • Equipment setup and calibration (30 minutes)
  • Perform inspection on practice piece (45 minutes)
  • Interpret results and make accept/reject decisions (30 minutes)
  • Evaluator observes and scores on competency checklist

Passing Criteria: 75% on written + successful practical demonstration

Certification Timeline

  • Training Course: 1-4 weeks depending on level and method
  • OJT/Experience: Can occur in parallel with training
  • Exam Scheduling: Usually 2-4 weeks after course completion
  • Certification Issuance: 2-4 weeks after passing exam
  • Total: 2-8 weeks from course start to certification

Cost Summary for Common Certifications

Certification Path Training Cost Exam Cost Total First-Time
Level I (single method) a modest cost a modest cost a modest cost
Level II (one method, from scratch) a modest cost a modest cost a modest cost
Two methods (VT + PT Level II) a modest cost a modest cost a modest cost
Level III (after 5 years, per method) a modest cost a modest cost a modest cost per method

Recertification and Maintaining Credentials

Recertification Interval

  • Level I & II: Recertify every 3 years OR demonstrate current employment in NDT field within past 3 years
  • Level III: Recertify every 5 years OR demonstrate equivalent experience and continued professional development

Recertification Options

Option 1: Retake Full Exam

  • Cost: varies with specification per method
  • Time: 1 day (4-5 hours)
  • Requirement: Continue employment in NDT field

Option 2: Maintain through Experience

  • Cost: varies with specification (administrative fee)
  • Requirement: 50+ hours of field work in past 3 years; documented experience
  • Advantage: No need to retake full exam

SNT-TC-1A vs. Other Certifications

When SNT-TC-1A is Required

  • OSHA regulated industries (construction, shipbuilding, aerospace)
  • Most inspection companies (baseline credential)
  • Manufacturing and QC environments
  • Non-API/ASME work
  • General NDT career foundation

When ISO 9712 is Preferred

  • International work (Europe, Middle East, Asia)
  • Multinational companies
  • Global project contracts
  • Export to regulated countries

When API Certifications are Required

  • API 510 (Pressure Vessels) — signature authority role
  • API 570 (Piping)
  • API 653 (Storage Tanks)
  • Note: All three require ASNT Level III in ≥2 methods as prerequisite

Frequently Asked Questions (FAQ)

Q1: Do I need SNT-TC-1A certification to work in NDT?

A: Not legally required to perform NDT work, but it's industry standard. Most employers require it; many clients mandate it; career advancement is severely limited without certification. Bottom line: Get certified if you want a real NDT career.

Q2: What's the easiest NDT method to certify in first?

A: Visual Inspection (VT). Shortest course (20 hours Level I), lowest exam cost (a significant capital item), fastest to pass. Then add Liquid Penetrant (PT) or Magnetic Particle (MPI) — both moderate difficulty. Save Ultrasonic (UT) and Eddy Current (ECT) for when you have more experience.

Q3: Can I do Level II without doing Level I first?

A: Yes, if you meet the experience requirements. SNT-TC-1A allows you to skip Level I IF you have 2,400 OJT hours. However, almost everyone does Level I first (it's faster and cheaper as a foundation).

Q4: How long does ASNT certification take?

A: Level I: 3-6 weeks. Level II: 3-12 months (depends on your OJT hours). Level III: 5-7 years minimum. Most companies fast-track qualified candidates through Level I-II in 1-2 years if they have solid OJT experience.

Q5: Can I become Level III in NDT?

A: Yes, but it requires: (1) 5+ years total NDT field experience, (2) Level II in minimum 3 methods, (3) 150+ hours formal training, (4) Successful exam passing. It's a long process, but Level III inspectors earn $100K-enterprise tier+.

Q6: Is SNT-TC-1A recognized internationally?

A: Recognized in North America (USA, Canada, Mexico). For international work, ISO 9712 is more portable. Many companies train for both SNT-TC-1A and ISO 9712 simultaneously.

Q7: What happens if I fail the ASNT exam?

A: You can retake anytime after your course. No waiting period. Retake cost: a modest cost per attempt. Most candidates who fail and study their weaknesses pass on the second try (85%+ second-attempt pass rate).

Q8: Do I need to maintain ASNT certification while holding API certifications?

A: API certifications require maintaining ASNT Level III (which implies you maintain lower level certifications too). So yes, you must keep your ASNT active to keep API 510/570/653 valid.

Q9: What salary increase can I expect with ASNT Level II vs. Level I?

A: Level I technician: a modest cost. Level II: a modest cost. That's a potential a modest cost annual raise — easily justifying a modest cost training investment that breaks even in 1-2 months.

Q10: Can I combine SNT-TC-1A with other certifications (API, ISO)?

A: Absolutely. Multi-certified inspectors (e.g., "ASNT Level III UT + API 510 + ISO 9712") are most valuable and highest-paid. Career strategy: Establish SNT-TC-1A first, then layer API, then add ISO 9712 for international mobility.

Conclusion

ASNT SNT-TC-1A certification is the foundation of any professional NDT career. With systematic progression through Level I → Level II → Level III across your preferred NDT methods, you can build a six-figure career with global opportunities. Start with VT and PT/MPI at Level I, advance to Level II in UT for highest demand and pay, then pursue Level III and API certifications for expert authority and consulting roles.

New to SNT-TC-1A entirely? Start with our SNT-TC-1A certification overview — what the document is, why it is an employer-based (not ASNT-issued) qualification model, and how it compares to CP-189, ISO 9712, ACCP, and Canada's CGSB-derived scheme.

Ready to start your NDT career? Explore our complete NDT training guide to find courses in your area, or review NDT salary data to understand your earning potential at each level.

For the people managing everyone else’s certifications

Tracking one certification is easy; tracking two hundred across five methods, with vision exams, on-the-job hours and client-specific approvals, is where inspection companies lose client audits. Certification tracking and the wider inspection management software guide cover how currency is enforced at dispatch so a lapsed technician simply cannot be assigned to a job. There is also a free qualification and calibration register you can start using today.

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ASNT SNT-TC-1A is a recommended practice, not a standard, and not a certificate ASNT issues. It tells a US employer how to write its own Written Practice covering training hours, on-the-job experience, examinations, vision testing and recertification for NDT Level I, II and III personnel. The employer certifies its own people, and the credential is valid inside that employer's programme.

Under ASNT SNT-TC-1A the employer, not ASNT, is the certifying body. The employer publishes a Written Practice naming the responsible NDT Level III, the training and on-the-job experience hours required for each method and level, the examination structure and grading rule, the near-vision and colour-perception testing regime, and the recertification interval. An auditor at a US refinery, fabrication shop or inspection company does not ask to see SNT-TC-1A itself; it asks for the Written Practice and the personnel files proving the practice was followed. Level I performs set-ups and records data under supervision. Level II sets up, calibrates, interprets, and owns the accept or reject call. Level III writes and approves procedures and examines and certifies Level I and II personnel. Because the document recommends rather than mandates, an employer may impose requirements more stringent than SNT-TC-1A, and must justify any deviation in writing. ANSI/ASNT CP-189 is the mandatory-standard sibling; ISO 9712 is the third-party alternative.

Source: ASNT Recommended Practice No. SNT-TC-1A (2024 edition), with ANSI/ASNT CP-189 as the mandatory-standard equivalent and ISO 9712 as the third-party alternative

Technically reviewed by Anoop Rayavarapu — ASNT NDT Level III (UT, RT, MT, PT, VT, ET) · API 653 · ISO 9001:2015 Lead Auditor
What SNT-TC-1A actually requires in an employer's Written Practice — element by element
Written Practice elementWhat SNT-TC-1A asks the employer to defineWho owns itMost common audit finding
Training hoursMinimum classroom hours stated per method and per level, following the recommended-practice tables (40 hours for UT Level I)Employer, delivered by employer or training providerHours claimed with no attendance record and no instructor qualification on file
Experience hoursDocumented on-the-job hours per method and level, performed under supervision and signed offEmployer, verified by the responsible Level IIIHours reconstructed retroactively at exam time instead of logged as the work was done
ExaminationsGeneral, specific and practical examinations per method, with the composite grading rule fixed in the Written PracticeResponsible NDT Level IIIQuestion banks and answer keys not access-controlled or not retained for audit
Vision testingNear-vision acuity checked annually and colour perception on the stated cycle, both recordedEmployerAnnual near-vision test lapsed, putting every report signed in that window in question
RecertificationInterval stated in the Written Practice, satisfied by examination or by evidence of continuing work in the methodEmployerExpiry tracked in a personal spreadsheet, so a lapsed technician is dispatched to a job
Level III authorityA named Level III responsible for the programme, either employed or contracted from outsideEmployerOutside Level III named on paper with no evidence of involvement in examinations or procedure approval
SNT-TC-1A is a recommended practice: the auditable requirement is the employer's own Written Practice, not the ASNT document it was written from.

Is SNT-TC-1A a standard or a recommended practice?

SNT-TC-1A is a recommended practice. It sets out what an employer's NDT personnel qualification programme should contain rather than imposing binding requirements, which is why an employer may write requirements more stringent than the document but must justify anything less. ANSI/ASNT CP-189 is the mandatory-standard version, used when a client specification calls for a standard rather than a recommended practice.

Who issues an SNT-TC-1A certificate — ASNT or my employer?

Your employer. Under SNT-TC-1A the employer administers the examinations under its responsible Level III's authority and issues the certificate against its own Written Practice. ASNT does not hold your file or issue the certificate. ASNT's own central programmes, the NDT Level III certificate and ACCP, are the ones ASNT examines and issues directly to the individual.

Does my SNT-TC-1A certification transfer if I change companies?

No. An employer-based certification is valid within the Written Practice that issued it and lapses when you leave. A new employer may credit your documented training and experience hours toward re-certifying you, which is usually fast, but it must examine and certify you under its own practice. Central schemes such as ASNT NDT Level III, ACCP, ISO 9712 and PCN travel with the individual.

What is the difference between SNT-TC-1A and CP-189?

SNT-TC-1A recommends; ANSI/ASNT CP-189 requires. CP-189 is written as a mandatory standard, so its qualification and certification requirements are fixed rather than adjustable in an employer's Written Practice, and it is what a specification names when the client will not accept employer discretion. Many US employers run SNT-TC-1A as the baseline and add CP-189 for contracts that demand it.

How often does SNT-TC-1A require a vision test?

Near-vision acuity is checked annually, using a Jaeger No. 1 chart or equivalent at the distance the work requires, and colour perception is checked on the longer cycle stated in the Written Practice. A lapsed annual vision test is one of the cheapest findings to prevent and one of the most damaging to receive, because it calls into question every report the technician signed in the lapsed period.

Can an employer use an outside Level III to run its SNT-TC-1A programme?

Yes. SNT-TC-1A allows the responsible Level III to be a contracted outside Level III rather than an employee, which is how most small and mid-size inspection companies run a compliant programme. The Written Practice must name that person, and the audit test is evidence of real involvement: procedures actually signed, examinations actually administered or approved, and personnel files actually reviewed.

The requirements above describe what the recommended practice asks for. Running the programme as a US employer covers the operational side — the Written Practice, the Level III authority, the examination records, and why competent technicians still fail audits.

The document versus the comparison

This page owns the document: what SNT-TC-1A actually requires, section by section. Two adjacent questions have their own pages and are deliberately not repeated here — how the recommended practice differs from its mandatory sibling is SNT-TC-1A versus CP-189, and how the employer-based model compares with central certification is ISO 9712 versus SNT-TC-1A.