Liquid penetrant testing (LPT) is one of the most widely used non-destructive testing methods.
Liquid penetrant testing (LPT) is one of the most widely used non-destructive testing methods. LPT is based on capillarity or capillary attraction, where a liquid is able to flow into narrow spaces without the assistance of – or even in opposition to – external forces such as gravity. The materials processes and procedures used in liquid penetrant testing are designed to make the results of this capillary action visible and capable of interpretation. Liquid penetrant testing is an effective means of locating and determining the severity of surface discontinuities in materials, including those that are not visible to the naked eye.