Additional Methods to the ASTM F1929 Dye Penetration Test
Two new dye application methods have been added to the ASTM F1929-12 Standard Test Method for Detecting Leaks in Porous Medical Packaging by Dye Penetration. Also, an appendix has been added for interpreting the test results.
The ASTM F02 Committee worked on these additions for quite some time to ensure definitive interlaboratory study results. Additionally, some minor editorial changes were made to offer a better interpretation of the often misrepresented 5-20 second dye dwell time. The good news is the same dye solution formula is used with the same test method sensitivity of 50µm channels.
The edge dip technique is one of the additions. Many of us have been using this method for some time, but now it is documented, standardized, and round-robin tested. This method involves dipping the side of the porous pouch, bag, or tray into the dye solution and allowing for capillary action to pull the dye up, detecting a seal channel. Since it does not require a syringe for injection, it is safer, much less messy, and uses less dye solution.
The other technique uses an eye dropper or pipette to apply the dye solution to the outer edge of the package seal. This method is especially useful for lidded trays with a stepdown flange or when the seal is set back from the edge. Chevron seals also work well with this method when the pouch is not trimmed for an edge dip test.
Guidance on false positive observations using the dye solution is another major revision to the standard. The appendix addresses wicking, oxidative sterilization (gas plasma), and bending/folding of materials that have caused confusion and misinterpretation of this method. Users will find interpretation of these issues to be easier to understand.
Users of the ASTM dye penetration test now have the flexibility of three proven and standardized methods to choose from when performing package seal integrity testing. The 2012 revision also has better guidance for interpreting seal integrity results. The committee is working on a new dye penetration test for nonporous packaging such as foil and film pouches. This test will involve a different dye solution formula with added surfactant to reduce the surface tension.
Hal Miller, President, PACE Solutions