Contaminants can enter the packaging through leaks, or conversely, the product can be lost through these same leaks. These leaks often occur at the sealings between packaging components, whether they are made of similar or different materials. In addition, the entry or exit of gas or moisture through these leaks can degrade the sensitive contents of the packaging. There is no general consensus regarding the level of leakage that would be detrimental to a particular packaging. However, these tests are designed to detect any leakage, and therefore, components showing an indication of leakage may be rejected. These procedures are suitable for checking and locating leak sites. However, they are not quantitative, meaning that no indication of the size of the leak can be inferred from the test. Therefore, this method is used as a pass/fail test. It should be noted that these tests are destructive, meaning that no test package or component sample exposed to a dye penetration test can be used for the final product packaging.
Method A of this standard defines a procedure for detecting and locating a leak equal to or larger than that formed by a 50 µm wire in the seals of a nonporous package. Furthermore, Method B describes a procedure for detecting and locating a leak of at least 10 µm in diameter in a flat nonporous sheet. For both methods, a penetrating dye solution is applied to the seal or surface to be tested. After minimal contact with the penetrating dye, the site is inspected for dye penetration or preferably placed against an absorbent surface to detect coloration by the dye. These test methods are used for nonporous, transparent, and opaque surfaces and require that the penetrating dye has good contrast with the tested materials and/or the absorbent surface.