ASNT VT Level III case studies
ASNT VT Level III · Put your knowledge to work in context.
The ASNT NDT Level III designation in Visual Testing (VT) is a professional certification offered through ASNT Certification Services, the certification arm linked from the American Society for Nondestructive Testing website. Level III is the highest of the three NDT qualification levels, and in practice it is pursued by experienced VT personnel who interpret and apply standards, write and review procedures, and take responsibility for method quality. The ASNT VT Level III case studies are 5 cases and about 3,108 words.
1Resolving a Disputed Indication on a Pressure-Vessel Weld Under Poor Illumination
A Level II inspector reports a linear indication about 6 mm long on a 12 mm fillet weld joining a nozzle to a shell. The work is performed in a fabrication shop at 07:00 with ambient illumination measured at 150 lx at the weld surface.
690 words, about 3 min2Selecting and Qualifying a Borescope for Internal Tube Inspection
A heat-exchanger tube bundle (tube ID 25 mm, length 4 m) must be visually examined for pitting and erosion at the tube-to-tubesheet transition and along the first 300 mm. Access is from the channel head only.
644 words, about 3 min3Technique Sheet Conflict: Viewing Distance and Angle for a Critical Weld
A written VT procedure for structural welds specifies: viewing distance not greater than 600 mm, viewing angle not less than 30° to the surface, and surface illuminance of at least 1000 lx. A Level II inspector examining a 25 mm thick complete-joint-penetration groove weld finds that a stiffener plate blocks direct viewing of one weld face.
575 words, about 3 min4Interpreting a Weld Toe Line: Undercut, Mismatch, or Crack?
During visual examination of a circumferential butt weld in 8 mm stainless steel pipe, the inspector notes a continuous dark line along the upper weld toe for about 40% of the circumference. The line is uniform in width, follows the toe contour closely, and appears on the side where the pipe sections show a slight step (about 1 mm) at the joint.
613 words, about 3 min5Qualification and Certification Boundaries for a New VT Inspector
A technician has completed a 40-hour VT training course and passed an in-house written examination. Management wants to assign the technician to perform visual examination of pressure-retaining welds and to sign inspection reports, citing the training certificate as evidence of qualification.
586 words, about 3 min