Application Notes / Case Studies

Overview

One of the significant advantages of using Veriteq's validatable temperature and relative humidity data loggers is that they can radically minimize the need for frequent calibration.

The benefits of being able to use longer calibration intervals are obvious: fewer trips to verify accuracy, less paperwork, and peace of mind that equipment is operating within spec.

Challenge

A challenge of using equipment that requires less calibration than existing methods is how to reconcile it with long-accepted calibration norms. For example, many standard operating procedures call for calibration checks before and after every deployment, a process commonly called “closing the loop.”

In fact, one validation manager of a major pharmaceutical company described the pre-cal/post-cal process as “so deeply in-grained in the culture of the company that to consider omitting it” could not work.

Another challenge is the risks associated with extended calibration intervals. What happens if a data logger used for a critical temperature study has, for some reason, drifted out of calibration — potentially invalidating the work it has been involved with prior to that time?

With such a possibility, what can be done to minimize the chances of a calibration problem ocurring between calibration intervals — without resorting to frequent full calibrations?

Solution

For companies who require frequent calibration checks, or who otherwise want to minimize the risks of using any equipment that might have drifted out of calibration, there are several possible procedures they can follow to regularly check calibration. Each of these methods is designed to fuflill a company's needs for closing the loop.

First, there are obvious signs of problems to know when calibration is required. For example, when measurement readings vary widely from the norm. If it is known that the controlled environment has been stable, then look for chemical contamination that would corrupt sensor measurements.

Or if the logger sees high impact force, physical gamge in the form of a broken circuit may be the cause.

For calibration issues that are less obvious, users can perform
accuracy checks without going to a full lab for calibration:

• Comparing them to other calibrated (NIST-traceable) Veriteq data loggers or to a "control" (or "gold standard") data logger whose sole purpose is as a calibration refererence;

• Comparing them to a different NIST-traceable reference instrument;

• Comparing them to an accepted reference standard (such as a ice bath or saturated salt solution environment).

Veriteq is an A2LA-accredited calibration laboratory.

For more information on procedures you can use that involve the above calibration checks, please contact Veriteq.