A common complaint from plant engineers and quality departments that are using air for leak testing is that the zero point will drift from zero during the course of the day. A drifting zero creates a quality control challenge. A common request is to find ways to minimize, or even better, eliminate any drifting zero and the need to constantly readjust the leak test instrument to compensate for drifts.

In the domain of industrial air leak testing for quality control, the “zero drift” phenomenon is accepted as a fact of life. “Zero drift” is when testing a non-leaking master device, the leak tester displays regularly a consistent non-zero reading and the leak test instrument needs to be readjusted. Changes in shop floor temperature are usually blamed for why a zero point will drift. This article is to help explain the reasons for why zero drift occurs and ways to mitigate or even eliminate it.