This method involves both direct and indirect visual inspection techniques, direct inspection is where the material is inspected directly by the human eye with no additional visual aids, indirect inspection may involve the use of magnifying glass, mirror, borescope (mini camera), closed-circuit TV etc. Visual inspection is a crucial NDT method which is too often overlooked, this should be the basis for inspectors starting out in the NDT industry, for example, a visual examination of an operational plant can often reveal obvious problem areas, such as leaks, excess vibration, corrosion or misalignment, this inspection is a very cost effective exercise and can be used to identify areas that require further NDT applications.
Visual Testing- Level II
- Definitions
- Vision
- Lighting
- Environmental factors, direct and indirect methods of visual assessment
- Visual inspection equipment
- Surface conditions
- Inspection and testing criteria
- The reporting of results
- Codes and standards
- Preparation of a written instruction
- Product technology (welds, castings, wrought), in-service and secondary process defects