1. Reliability : Trouble free service given by any product may be termed as Reliability.2. Destructive testing are usually Quantitative measurements.3. NDT tests are qualitative measurements.4. Even though a component is to be inspected using other NDT methods, a good visual inspection

should be carried out first.5. Procedure for Visual: Illumination of the test specimen with light usually in the visible region.

The specimen is then examined with eye or light sensitive devices such as photocells.6. The most valuable NDT tool is human eye.7. Human eye is most sensitive to yellowgreen light which have a wave length of 5560 Angstrom.8. For VT adequate lighting i.e. 800-1000 lux is of prime importance.9. While doing VT, it is limited to no more than 2 hours on continue basis to avoid error due to

decrease in visual reliability and discrimination.