What is the formula for ndt composite examination grade?

composite = (w_G·G + w_S·S + w_P·P) ÷ (w_G + w_S + w_P); equal weights: composite = (G + S + P) ÷ 3; pass requires: min(G, S, P) ≥ 70 % AND composite ≥ 80 %; practical needed = [ composite_min·(w_G + w_S + w_P) − w_G·G − w_S·S ] ÷ w_P. Composite grade from general, specific and practical examination scores, with the 70 % per-part and 80 % composite pass rules and the practical score still needed.

What should I check before relying on the result?

Both rules must be met: every part at or above the part minimum and the composite at or above the composite minimum. The employer's written practice is the governing document — it may set higher pass marks or weight the practical more heavily. The practical examination normally includes the candidate's written report on the specimens; a report that misses a required indication fails the practical regardless of the setup marks. Level III candidates sit a basic examination plus a method examination, each graded on its own pass mark rather than combined into this composite. Verify against the governing edition: ASNT SNT-TC-1A (2020), Section 8 — composite grade is the average of the general, specific and practical scores; minimum 70 % on each part and 80 % composite. ANSI/ASNT CP-189 applies the same pass rules..

NDT composite examination grade Calculator

Qualification examinations for Level I and Level II are marked in three parts. The general examination covers the principles of the method and is not tied to any one product. The specific examination covers the equipment, procedures and acceptance criteria the candidate will actually work to, so it is written around the employer’s own procedures and the codes in use. The practical examination puts the candidate on real hardware: set the equipment up, run the technique on specimens containing known discontinuities, and record the result on a report the Level III can audit.

The three marks are averaged into a composite grade, and there are two gates rather than one. Each part must reach 70 % on its own, and the composite must reach 80 %. The double gate exists because averaging alone would let a strong theory candidate hide a weak practical — and the practical is the part that reaches the weld. A candidate scoring 95, 95 and 55 averages 81.7 but is not certifiable, because the practical is below 70.

Because the composite is an average, the arithmetic works backwards usefully: with the general and specific results known, the practical mark needed to reach an 80 % composite is fixed, and it is often well above 70. Knowing that number before the practical is sat tells the candidate and the Level III whether more preparation is worthwhile.

Equal weighting of the three parts is the normal arrangement, but the employer’s written practice governs and some practices weight the practical more heavily, or set pass marks above the recommended minima. A failed examination has a waiting period and a re-examination rule set by the written practice, and only the failed part is normally re-sat.

Worked example

General examination score	82 %
Specific examination score	76 %
Practical examination score	85 %
Weight — general	1
Weight — specific	1
Weight — practical	1
Minimum for each part	70 %
Minimum composite	80 %
Composite grade	81 %
Lowest part score	76 %
Margin on composite	1 %
Margin on weakest part	6 %
Practical score needed to pass	82 %
Pass	1

Equal weights, so composite = (82 + 76 + 85)/3 = 243/3 = 81.0 %. Lowest part is the specific at 76 %, which clears 70 % by 6 points; the composite clears 80 % by 1 point, so the candidate passes. Working backwards, the practical needed was (80 × 3 − 82 − 76)/1 = (240 − 158) = 82.0 %, and the 85 % scored exceeds it.

Use at your own risk — verify before you act

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