What Is Leak?
The leak test determines whether a sealed package maintains its integrity. Methods used include bubble observation in water under vacuum, bubble observation under applied internal pressure, dye penetration, and pressure-decay monitoring. The method's sensitivity sets the smallest leak size that can be detected.
Purpose of Leak
The purpose is to verify the package fulfils its function of protecting the contents and isolating them from the outside environment. In sterile medical packaging and modified-atmosphere food packaging, a leak is directly a product-safety issue.
Which Products Is Leak Applied To?
- Modified-atmosphere food packaging
- Sterile medical device packaging
- Liquid food and beverage packaging
- Blister and stand-up pouch packaging
- Chemical and hazardous substance packaging
In Which Sectors Is Leak Used?
Standards Related to Leak
- ASTM D3078 (determination of leaks in flexible packaging by bubble test)
- ASTM F2096 (detecting gross leaks in packaging by internal pressurization — bubble test)
- ASTM F1929 (detecting seal leaks in porous medical packaging by dye penetration)
- TS EN ISO 11607-1/-2 (packaging for terminally sterilized medical devices)
- TS EN 868 series (packaging materials for terminally sterilized medical devices)
- ISTApackaging transport performance test series test
Leak Conditions
- Vacuum/pressure level
- Defined in the standard; selected per packaging type
- Dwell time
- Observation time defined in the standard
- Sensitivity
- The smallest leak size the method can detect is reported
Equipment for Leak
- Vacuum leak test chamber
- Pressure bubble test rig
- Dye penetration test materials
- Pressure-decay monitoring system
Sample Requirements for Leak
- Sealed package as offered for sale
- Specimen produced with real fill and seal parameters
- The number of specimens is determined by the statistical evaluation
- If sterilisation is applied, specimens both before and after are required
Duration of Leak
Testing a single specimen is short; duration is set by the number of specimens. If assessment after sterilisation and transport simulation is required, total duration extends markedly.
Leak Procedure
- 1The method is selected per packaging type and expected leak size.
- 2The specimen is immersed in a water bath or pressurised.
- 3The defined vacuum or pressure is applied.
- 4Bubble emission is monitored for the observation time.
- 5If there is a leak, its location is marked and recorded.
- 6Results are reported per specimen.
Leak Acceptance Criteria
The acceptance criterion is no leak detected at the sensitivity of the chosen method. For sterile barrier systems, ISO 11607 requires packaging integrity to be maintained after transport and sterilisation too.
Evaluation of Results
The method's sensitivity determines what the result means: bubble methods find gross leaks, not micron-scale channels. For sterile packaging, when a sensitive method is required, non-destructive techniques are preferred, and the justification for the method chosen is stated in the report.
Leak Report
- Package identification and sealing parameters
- Method applied and its sensitivity
- Vacuum/pressure level and observation time
- Number of specimens and number found leaking
- Leak locations and photographs
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- (EU) 2017/745 Medical Device Regulation
- (EC) 1935/2004 Regulation on Materials Intended to Come into Contact with Food
Ambalaj Testleri — What Does This Testing Field Cover?
The section below describes the field that the Leak test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Packaging testing examines two different functions separately: does the packaging protect the product during transport, and does the packaging material transfer harmful substances into its contents? These two questions require different laboratory infrastructure and must not be confused.
On the protection side, distribution simulation is carried out: drop, vibration, compression, stacking and, where needed, low pressure tests are applied in sequences representing the real shipping chain. These tests are meaningful as a SEQUENCE rather than individually; in real life too, packaging is exposed to successive loads and each load builds on the damage left by the previous one. Specifications such as ISTA and ASTM D4169 define these sequences by shipment type.
The shipment type determines the sequence itself. The exposure of a palletised load differs from that of a parcel shipped individually: the latter sees far more handling, more drops and impacts in a wider variety of orientations. The growth of e-commerce has brought this second scenario to the fore and turned parcel shipping simulation into a specification group of its own.
On the food contact side, MIGRATION is what counts: the amount of substance passing from the packaging material into the food is compared against overall and specific migration limits. For plastic packaging the list of permitted substances and the limits are defined in separate legislation; the declaration of conformity (DoC) rests on this assessment and is a document that every link in the supply chain must carry.
In a migration test the choice of SIMULANT is critical. Because testing with real food is not practical, liquids representing food are used: different simulants for aqueous foods, for fatty foods and for acidic foods. Choosing the wrong simulant invalidates the result; the choice depends on which food type the packaging will contact and at what temperature.
Barrier properties are a third axis. Oxygen and water vapour permeability directly determine the shelf life of the product; in pharmaceutical and food packaging these values are a design input. Barrier performance is sensitive to temperature and relative humidity, so the measurement conditions are part of the report.
Sterile medical device packaging is the most tightly regulated sub-body of this family. Here the packaging is a barrier maintaining sterility; seal strength, leak testing, distribution simulation and shelf-life studies run together as a validation package.
The packaging legislation side is becoming rapidly more demanding. Recyclability, recovered content ratio, packaging reduction and reuse targets must now be measurable and declarable; this turns packaging design from a material selection exercise into a conformity exercise.
Method groups in this field
Distribution simulation
Drop, random and fixed frequency vibration, compression, stacking, low pressure; as ISTA and ASTM D4169 sequences.
Mechanical strength
Edge crush (ECT) in corrugated board, bursting strength, box compression strength, tape peel adhesion.
Barrier measurements
Oxygen transmission rate (OTR), water vapour transmission rate (WVTR), permeability in film and sheet materials.
Migration
Overall and specific migration tests; simulant and temperature conditions are chosen according to the use scenario.
Seal and integrity
Seal peel strength, leak detection by dye penetration, bubble test, headspace analysis.
Shelf life
Real-time and accelerated ageing; part of the validation package in sterile packaging.
Commonly confused in this field
- A single drop test is not a distribution simulation; the tests are applied as the sequence defined in the specification.
- A migration test carried out with the wrong simulant or the wrong contact temperature is invalid.
- Accelerated ageing does not replace real-time ageing; a shelf life claim is supported by real-time data.
- Barrier values are valid together with the measurement temperature and relative humidity; an OTR/WVTR value given without conditions cannot be compared.
- A packaging change (film supplier, seal parameter, box design) may require the validation to be repeated.
- A food contact declaration of conformity is not a test report; it is a document that rests on reports but summarises a broader assessment.
Which decisions these results support
- Reducing shipping damage and verifying the packaging design
- Declaration of conformity for food contact packaging
- Supporting the shelf-life claim
- Validation of sterile device packaging
- Recyclability and content declarations under packaging legislation
Related Tests
Frequently Asked Questions About Leak
No bubbles appeared — is the package leak-tight?
It only means leak-tight at the sensitivity of the method applied. Bubble methods do not show very small channels. For critical applications such as a sterile barrier, a more sensitive method should be chosen.
Is retesting needed after transport?
Yes, for sterile packaging. ISO 11607 requires showing the packaging retains its integrity until it reaches the end user; an integrity test is therefore performed after transport simulation.