Pack Integrity and Closures

Gas leak detection systems are used to "sniff" for a test gas which has been earlier introduced into the package.

Pira use a Qualitek leakmeter 120 electron capture detector. The leakmeter 120 responds to SF6 and other electron capturing compounds and can detect leak rates as low as 1x10-7 ml/sec SF6.

The gas is injected into the test package and the injection point sealed with tape. The leakmeter fitted with a miniature "sniffer" probe is used to locate any leakage routes.

The technique is easily capable of detecting microleaks in non-porous medical device packaging and modified atmosphere (MAP) food packaging. In the latter application it is often used to identify leakage routes after a high oxygen content has been determined.

The technique is similar to helium leak detection which uses a mass spectrometer detector. One advantage of sulphur hexafluoride as a test gas is that it has a higher molecular weight that helium and less likely to give a false "leak" result from gas permeation through the packaging material.

Closure release torque

Pira use a Mecmesin Orbis digital closure torque tester for measuring application and removal closure torques, calibrated in accordance with ASTM D3474.

Applicable standard test methods include:

ASTM D2063, "The torque retention of continuous thread closures on containers, with matching finishes, for predetermined environmental conditions over time" and ASTM D3198, "Standard Test Method for Application and Removal Torque of Threaded or Lug-Style Closures".

Leak resistance of closures

Closures applied to nominal application torque are routinely tested for resistance to leakage after storage at elevated temperature, simulated transit vibration or vacuum testing as detailed in ASTM D4991 "The testing of empty containers for resistance to leakage under differential pressure conditions such as those which can occur during air transport".

The causes of leakage can be investigated by dimensional analysis of the container and closure thread dimensions with the aid of a non-contact optical measuring stage.

Sports closure testing (BSDA Code of Practice)

The BSDA "Code of Practice for Sports Closures" sets out the tests needed to demonstrate due diligence for sports closures.

Pira are able to test closures to all aspects of the code, including the rotational opening force test which was developed by Pira.