ASTM D4991 Explained: A Comprehensive Guide to Rigid Container Leakage Testing
Key Components of the ASTM D4991 Test:
- Immersion Fluid – To conduct this test, a solution of 50% ethylene glycol in water is recommended, as it is less likely to form bubbles at high vacuum levels, improving the accuracy and consistency of the test results.
- Preparation – The test method focuses on removing air dissolved in the immersion fluid by creating a vacuum of -950 millibars and maintaining it for 10 minutes. At least three products must be tested simultaneously, with the containers prepared under the same conditions as in the production process.
- Test Procedure – The test involves immersing the containers in the ethylene glycol-water solution, applying a vacuum, and observing for any leakage indicated by a continuous stream of bubbles. After the vacuum is released, the containers are examined for any fluid inside, which is also evidence of leakage.
- Reporting – A detailed report must be prepared, including information on the containers and closures, the number of specimens tested, test pressure requirements, test temperature, and results.