TI 809-26
APPENDIX D
1. VISUAL TESTING (VT).
a. Method Description. Visual inspection, as a form of nondestructive testing, is the visual observation
the first nondestructive testing method applied, and if the inspected item fails to meet visual criteria,
more extensive nondestructive testing should not be conducted until the visual criteria is satisfied.
and other enhancements. Such instruments tend to distort the perception of the inspector. When surface
discontinuities such as cracks are suspected, the use of magnifying devices to further investigate the
(2) Visual inspection includes the measurement of the work, which may include the smoothness of
thermally cut edges, and the measurement of root openings, groove angles, weld size, convexity and
such as weld gauges are required.
b. Advantages and Disadvantages.
arc strikes, excessive convexity, overlap, toe cracks, undersized welds, undercut, seams and laminations
at exposed edges. Not all listed discontinuities are structurally significant, but they may provide indication
(2) Visual inspection cannot reveal subsurface discontinuities such as cracks, incomplete fusion,
slag inclusions, incomplete penetration, buried laminations or lamellar tearing. See Table D-1.
surrounding heat-affected zone (HAZ).
(4) The cost of visual inspection is usually less, per unit length of weld, that the other methods of
rather than simple verification measurements and recording of unsatisfactory workmanship.
D-1
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