INFICON :: LEAK TEST - Best Practices for Leak Detection

How Do You Judge the Accuracy of a Leak Detector?

According to Six Sigma* guidelines, there are four different parameters that determine the quality of measurement equipment:

  • Repeatability
  • Reproducibility
  • Linearity
  • Stability

When applied to leak detection, what do these four characteristics mean?

Repeatability indicates the degrees of variation when measuring the same leak over and over again (by the same operator). You can determine this by simply measuring the same calibrated test leak several times under the same conditions. Repeatability is determined by the maximum and minimum detected leak rates: the smaller the difference between the two values, the better the repeatability.

Similar to repeatability, reproducibility considers the test results from different operators. To determine the reproducibility of a leak detector, different operators measure the same calibrated test leak several times. Again, the variation of the different leak rate measurements gives you reproducibility; the smaller the variations, the better the reproducibility of the leak detector.

Linearity in a leak detector shows the span of measurement error over a large measurement range. This is especially important when calibrating a leak detector with a leak rate value different from the trigger value used. This is determined by calibrating the leak detector with a small test leak and then testing this against larger test leaks (factor 100 to 1000), or vice versa.

Stability indicates the reliability of test results over time. To determine the stability of a leak detector, set the leak detector with a calibrated leak. Now let the leak detector run for many days, checking the leak rate reading in regular intervals; the smaller the deviation after time, the better your leak detector.

INFICON rigorously tests its leak detectors according to these four characteristics. We will share the results of these tests with you in our next issue.

* Six Sigma is a management strategy used to identify and remove the causes of defects and errors in manufacturing and business processes.


Forward to a Colleague
Subscribe | Contact Us | Visit INFICON
Spring 2009
Tech Talk
Tech Talk
Send Us Your Photos
Leak detection has many faces in many places. We are looking for your best leak detection photo. Send us a photo of you and/or your team in action with your INFICON leak detector, and you get a cool gift!
Leak Detection Tools Business Unit (LDT)
Represented by managing director:
Dr. Ulrich Döbler
Bonner Strasse 498, D-50968 Köln,
Registered Office: Cologne
Commercial Register: Local Court Cologne: HRB-Nr. 26659
VAT identification number: DE205 480 919
Ticona Information Service
Tel: +49.(0)221.347.40 (Germany)
Fax: +49.221.347.342414 (Germany)