Bubble Leak Test, Water bath, Bubble leak emission etc.
How it works:
- Partially fill the pouch with a consistent sized filler or air (this is a must do step)
- Submerge pouch 25mm under water level
- Apply vacuum to chamber (15 Hg for standard 20 Hg for liquid packaging)
- Watch for a stream of bubbles from the leaking area
Best for:
- Seal channel leaks
- Gross defects
Watch out for:
- Operators get very comfortable with this test and assume it will also detect weak seals. This is a leak test only; in extreme cases it may expose a weak seal. I have seen several weak seals pass the leak test but then fail when probed or subjected to additional tests.
Limitations:
- Only capable of detecting leaks greater than 250 microns
Vacuum Decay Testing
This method was employed for some pouches containing powder bound for the International Space Station.
How it works:
- Place pouch in a vacuum sealing chamber with filler material
- Vacuum seal the pouches
- Observe over 24hr period for changes
Why it matters:
- Detects very small leaks consistently
- Removes operator subjectivity
Best for:
- Food, medical, high-value products
- Validation and QA testing
Dye Penetration Test
This is excellent as a diagnostic tool to determine where the pouch is leaking.
How it works:
- Apply dyed liquid along seal edges on the interior of the pouch (cut pouch in half if needed)
- Seal the pouch so you can apply pressure to try to force the dye out of any potential failure points
Best for:
- Finding channel leaks in heat seals
- Dialing in sealing parameters
Burst / Creep Testing
You’re not just looking for failure—you’re looking at how it fails. This test is most effective for detecting delamination issues.
How it works:
- Pressurize pouch until it bursts (burst test)
- Or hold pressure and watch for slow failure (creep)
Why it’s useful:
- Weak seals often correlate with micro-leaks
- Helps you understand margin, not just pass/fail
Helium Leak Testing
This is what medical and pharma use when failure is unacceptable. Personally, I have rejected the suggestions and requests for this type of testing, but depending on what you consider “micro-leaks” maybe this is for you!
How it works:
- Fill pouch with helium
- Detect leakage with a mass spectrometer
Pros:
- Extremely sensitive
Cons:
- Expensive, slow, not practical for most production floors
Feel free to submit an inquiry or comment on your experience with pouch leaks in the comments section. Thanks Tom C. from Canada for submitting your question.
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