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Visual Vacuum Bubble Leak Testing or Bubble Emission Testing

In this article we cover the leak testing method of visual vacuum bubble leak testing for use on product and food packaging containing headspace gas. This may also be referred to as bubble emission testing when packaging is immersed in water under atmospheric conditions.

The bubble emission test is used to determine package integrity. Issues such as packaging material compatibility, sealing machine setup, and seal reliability are crucial for high altitude trucking and airfreight shipments. Package integrity is also crucial to consumer safety since heat-sealed packages are designed to provide a contamination free and sterile environment to the product. Bubble emission leak testing can be a destructive testing method and just like with dye penetration manufacturers should expect to waste a certain amount of package material and products when using this method. Leak testing by bubble emission involves submerging the package under water and then looking for visual leaks. By applying a vacuum to the system, the external pressure on the package is reduced thus allowing for air/gas to leak out of the packaging–creating a stream of bubbles that can be easily identified and located.

Bubble to Leak Rate Conversion - Bubble Emission TestingVacuum bubble emission testing is performed by filling a test vacuum chamber with water–test product will be submerged in water. Next, the chamber lid is closed and vacuum is applied. Vacuum is slowly increased and the package begins to expand. The package is observed for a steady flow of bubbles from the flexible container, thereby indicating a leak is present. Once the vacuum is released from the system, the package is inspected for the presence of test fluid (water) inside the specimen. It should be noted that flexible packaging with little or no head space cannot be reliably evaluated with this test method. Parameters such as the vacuum level during test and the testing time will vary based on the various types of packaging methods and test requirements.

Bubble emission leak testing systems allow users to accurately set up packaging lines that are reliable and minimize downtime.


A major testing laboratory required a bubble testing chamber to perform ASTM F2096 and ASTM D3078 bubble testing to assess package integrity. LACO designed (X1P15805), an acrylic chamber, 24" W x 20" L x 15” H to hold approximately 31 gallons of water. The chamber included an integrated shelf attached to a shock assisted lid to hold packages submerged in the water.

Acrylic package integrity testing system - Vacuum Chamber for visual bubble leak testing

LACO Technologies offers a range of clear acrylic cylindrical and cube style vacuum chambers which are ideal for visual leak testing methods. LACO can customize a system with all necessary components for vacuum bubble leak testing.

Check out our visual vacuum bubble leak testing chambers: Clear Vacuum Chambers


  • ASTM D 3078-02: Standard Leak Test Method for Determination of Leaks in Flexible Packaging by Bubble Emission
  • ASTM F2096–04: Standard Test Method for Detecting Gross Leaks in Medical Packaging by Internal Pressurization (Bubble Test)
  • ISO 11607: Packaging for Terminally Sterilized Medical Devices
  • ASTM E 515-05: Test Methods for Leaks Using Bubble Emission Techniques 
  • ASTM Designation: Definition of Terms Related to Leak Testing