9: Non-destructive Examination
API ICP Self Study Materials
API ICP Self Study Materials
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9.3 VISUAL EXAMINATION (VT)<br />
9.3.1 General<br />
Visual examination is the most extensively used NDE method for welds. It<br />
includes either the direct or indirect observation of the exposed surfaces of<br />
the weld and base metal. Direct visual examination is conducted when<br />
access is sufficient to place the eye within 6 in. – 24 in. (150 mm – 600 mm)<br />
of the surface to be examined and at an angle not less than 30 degrees to the<br />
surface as illustrated in Figure 12. Mirrors may be used to improve the angle<br />
of vision. Remote visual examination may be substituted for direct<br />
examination. Remote examination may use aids such as telescopes,<br />
borescopes, fiberscopes, cameras or other suitable instruments, provided<br />
they have a resolution at least equivalent to that which is attained by direct<br />
visual examination. In either case, the illumination should be sufficient to<br />
allow resolution of fine detail. These illumination requirements are to be<br />
addressed in a written procedure.
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