Liquid Penetrant Testing Level 1 (PT-1) Practice Exam

Which is a common cause of false indications in penetrant testing?

1. Using the wrong type of penetrant

2. Incorrect lighting conditions

3. Contamination on the surface

4. Excessive cleaning before testing

The correct answer is: Contamination on the surface

In penetrant testing, false indications can arise from a variety of issues, but contamination on the surface is a particularly common cause. Contaminants such as oils, greases, rust, or dirt can create barriers that either prevent the penetrant from entering the discontinuities or trap penetrant on the surface. This can lead to misleading signals when the developer is applied, resulting in false positives that may suggest flaws where there are none. Understanding the nature of contamination is critical; for effective penetrant testing, the surface must be clean, well-prepared, and free of any substances that could interfere with the penetrant's ability to reveal defects. If the test surface is not adequately prepared, the quality of the inspection results can be compromised, leading to unreliable interpretations. While the other factors listed could also contribute to false indications, such as the wrong type of penetrant or incorrect lighting conditions, contamination remains a primary concern in ensuring accurate results during penetrant testing. Proper surface preparation is essential to mitigate this risk and to ensure that the penetrant can perform as intended.