Penetrant Testing

First introduced at the end of the 19th century, penetrant testing is constantly undergoing new developments aimed at increasing the probability of detecting discontinuities, and improving hygiene, safety and environmental protection conditions. Penetrant testing materials, accessories and equipment are constantly being perfected to achieve a high level of performance, while taking into account operators' concerns in terms of ergonomics.

Penetrant testing is the most widely used non-destructive testing (NDT) method on metal alloys and a certain number of non-metallic materials for detecting and locating open to-surface and through-going discontinuities on the surface of the part to be examined.

Used in all industrial sectors virtually anywhere except underwater, on site or in the workshop, in manufacturing or maintenance, in environments at –25 °C or +50 °C, on parts up to 200 °C, penetrant testing offers a flexibility and versatility that few other NDT methods can claim. Like all other NDT methods, penetrant testing has its own limitations.

Penetrant testing, which some had predicted would disappear before the year 2000, remains the most widely used method (after visual inspection, however) compared to all other NDT methods.

UV-A lighting sources with light-emitting diodes (LEDs) have largely replaced those with mercury vapour bulbs, which are toxic to both humans and the aquatic environment.

One of the criticisms often raised about penetrant testing is the use of chemicals. If regulations on conditions of use and discharges (gaseous or liquid) are followed, operators' health and the environment are protected.