Why testing the same test specimen under the same test conditions, but the test results can still be different? Is the discrepancy caused by the specimen itself, laboratory conditions, or the difference in operation procedures? What are the common factors affecting barrier test results?

In general, laboratory apparatus is maintained and calibrated at least every 12 months. If I use the equipment daily, would it be necessary to calibrate it at a higher frequency? What’s the best frequency to calibrate your testing instrument?

One of the most prominent data comparison events is the global inter-laboratory barrier property test data comparison held by PIRA regularly. Labthink also organizes a round robin test for test data comparison across laboratories. What is inter-laboratory data comparison, and how can it help avoid data discrepancies?

Watch the playback of our ‘How to avoid test data discrepancies?’ webinar and find out more elaborate answers to these questions.

Key takeaways of this webinar:

What is the core reason for barrier testing discrepancies?

1. Barrier testing is a highly sensitive, microscopic test.
2. Discrepancies arise from numerous tiny, unavoidable deviations in procedure, material handling, and instrument settings.

What is an acceptable difference between two lab results?

1. A difference of 10% is considered normal.
2. For very high barrier materials (which are more sensitive), a difference of up to 20% might be the normal expectation.

What are the main factors influencing test results?

1. Material properties of the test specimen (specimen integrity, thickness uniformity, coating uniformity, etc.)
2. Direction in which the gas permeates the specimen
3. Humidity, concentration, and composition of test gas
4. Test conditions like temperature and humidity
5. Stop conditions and testingtime
6. Instrument calibration every 12 months, even 3-6 months if used daily
7. Laboratory configuration
8. Operation procedures

How to minimize test discrepancies?

1. Set test parameters consistently and maintain a stable laboratory environment
2. Do more tests and compare group data
3. Participate in inter-laboratory data comparisons to validate laboratory/testing instruments’ proficiency