Glossary

Fluorescent Penetrant Inspection

floo-res-uh nt pen-i-truh nt

noun

Definition

Fluorescent Penetrant Inspection (FPI) is a Non Destructive Testing (NDT) technique where a fluorescent dye is applied to the surface of an impermeable material to clearly identify surface defects. The basic steps include cleaning or preparing the surface to be inspected, applying the penetrant, removing the excess penetrant, and then documenting the remaining “highlighted” surface defects. Only tiny cracks or chips will be found. While one of the cheaper NDT methods, the disadvantages include the small amount of materials that can be inspected, the rigorous cleaning and preparation, and that the method is limited to external surface defects.

Related terms: predictive maintenance