The Visual Testing (VT) has always applied, because it is based on the sight perceptions during various human activities, and in this sense is the N.D.T. forerunner.
Generally, the visual inspection has the aim to get a qualitative and dimensional analysis of the item according to specific acceptability criteria, whose evaluation must imply measurement instruments for an accurate sizing of the imperfections.
The examination can be direct (at naked eye and/or by means of magnifying lenses) or remote (with the aid of mirrors, endoscopes, fiber optics and cameras), depending on the accessibility of the surfaces to be inspected or according to the registration need.
The VT often precedes or is carried out together with other tests, and it is fundamental for the correct interpretation of results.
Although it seems to be the simplest of the N.D.T., at least with regard to the equipment used, it requires a solid experience, continuous training and recognized certification of personnel.
Visual tests are carried out by Metalprove S.r.l. with the greatest expertise, according to European standards (EN ISO 17637, EN ISO 5817, EN 1370, EN 13100-1, etc.) and to American codes (ASME Sec. V, ASME Sec. VIII, ASME B16.5, API 617, API 618, etc.).