By Tanner Vandenberg, CEO, FlexPak Leak Detectors Inc.
Production leak testing is the check that catches a seal defect while the product is still on your floor rather than at a customer’s. The question is not whether to run it. It is where in the line it goes and how often.
What production leak testing is
Production leak testing samples sealed packages off the line and checks each one for a seal breach. A package goes into a chamber, the chamber pulls a vacuum, and gas inside the package escapes through any defect as a visible stream of bubbles. Leak detection on a production floor is a sampling discipline before it is a piece of equipment.
It is a destructive-sample check on most formats, not a 100% inline inspection. That shapes everything about how you deploy it: you are sampling to catch a drifting sealer, not screening every unit.
Where it belongs on the line
Immediately after the sealer, and before the product is cased. That placement is the whole point.
A seal defect has one cause you can actually act on, which is the sealing operation itself: temperature, dwell, pressure, contamination in the seal area, film tracking. Testing right after the sealer means the sample you fail is still traceable to a machine setting that is still on screen. Testing at the end of the line means quarantining a pallet.
The cost of moving that check later is not the test. It is the volume of product between the defect and the detection.
How often to sample
There is no universal number and anyone who gives you one has not seen your line. What decides it:
- Sealer stability. A machine that drifts needs a tighter interval than one that holds.
- Changeover frequency. Every film change, format change and sealer adjustment is a reason to test, because that is when settings move.
- What a miss costs. A recall on a sterile or a chilled product is a different number from a dry-goods complaint, and the sampling rate should reflect it.
- Audit requirement. If a customer or an auditor has specified a frequency, that is the floor, not the target.
The pattern worth copying: test at every startup, at every changeover, and at a fixed interval in between. Startup and changeover are where defects actually cluster.
Production QA
Catch the seal defect before the pallet ships.
A FlexPak chamber gives a pass or fail in about 30 seconds, at the line, with no consumables to reorder.
What the test costs you in time
About 30 seconds per unit on a bubble emission chamber, plus handling. That number matters because it is what makes a tighter sampling interval affordable, and it is the figure to ask about when you compare package leak testing equipment.
A package leak detector uses water and vacuum, so there are no consumables to reorder and no reagent to run out of mid-shift. Vacuum range is roughly 0 to 27 in. Hg (0 to 90 kPa).
If your packages are vacuum sealed or liquid filled, a standard bubble test cannot make them bubble because there is no headspace inside to escape. The VAC attachment injects air so those formats become testable.
What production leak testing does not tell you
It gives you a pass or fail on seal integrity. It does not tell you how strong the seal is, and those are different questions that get confused constantly.
A package can pass a leak test and still peel open too easily. Seal strength testing is the measurement for that, and a program running only one of the two has a blind spot.
It also does not condition the package for transit. If your product flies, altitude conditioning under ASTM D6653 is a separate test and it does not detect leaks on its own.
Recording the result
A result nobody can retrieve is not evidence. If your QA program will face an audit, the run needs to be recorded against the unit, the batch and the sealer settings at the time.
The fully automatic controller (FPFA-T) holds 24 setpoints and logs each run, which is the difference between saying you test and showing that you did.
Frequently asked questions
Where should leak testing sit on a packaging line?
Directly after the sealer and before casing, so a failed sample is still traceable to the sealer settings that produced it.
How often should we sample?
At every startup, every changeover and a fixed interval between. Startups and changeovers are where seal defects cluster, because that is when settings move.
How long does one test take?
About 30 seconds per unit on a bubble emission chamber, plus handling.
Is production leak testing a 100% inspection?
No. On most formats it is a destructive sample check, so it is designed to catch a drifting sealer rather than screen every unit.
Can we test vacuum-sealed packages this way?
Not with a standard bubble test, because there is no headspace inside to push out through a defect. The VAC attachment injects air so those packages become testable.
About the author
Tanner Vandenberg is CEO of FlexPak Leak Detectors Inc., which builds the equipment described here at its St. Catharines, Ontario facility. Connect with Tanner on LinkedIn.