The honest answer depends on what 'trained' means for your role: aware, competent to witness and review, or certified to perform and sign off.
First decide what 'trained' means
A plant engineer who must review NDT reports and challenge a contractor's technique needs a different depth of training from a technician who will perform ultrasonic scans and sign reports. Mixing the two up wastes budget in both directions: inspectors sent to theory-heavy appreciation courses, and engineers sent to multi-week certification programmes they will never use.
Three practical levels cover most industrial needs: method appreciation (2–5 days), technique competency for review and witnessing (1–2 weeks), and formal certification under SNT-TC-1A or ISO 9712 (weeks of training plus months of documented experience).
Typical durations by method
Certification-level course lengths are set by the certification scheme's recommended training hours. As a working guide for Level I or Level II preparation:
- Visual testing (VT): 1–2 days of formal training
- Liquid penetrant (PT): 2–3 days
- Magnetic particle (MT): 3–4 days
- Radiographic testing (RT): 5–10 days, plus radiation safety requirements
- Ultrasonic testing (UT): 10–15 days for welds — the longest of the common methods
- Radiographic film interpretation: 3–5 days as a standalone skill
Training hours are only half the requirement
Under both SNT-TC-1A and ISO 9712, classroom hours alone do not certify anyone. Each level also requires documented industrial experience in the method — measured in months, not days — plus a vision examination and general, specific and practical exams administered by the employer or a certification body.
That is why a realistic certification plan spans 6–18 months: initial training, supervised on-the-job experience logged against the written practice, then examination. Employers who plan for only the course dates are surprised by the experience gap at exam time.
A practical planning rule
If the goal is better report review and acceptance decisions, a structured 3–5 day methods and interpretation course is usually sufficient and far cheaper. If the goal is certified in-house capability, budget for the method courses, the experience period and the exam logistics as one programme — and start with the methods your plant actually uses.