How does Cirrus’ calibration differ from anyone else? Part 3 of 6

When we calibrate an instrument, we are checking the performance to exactly the same standards as when the instrument was first manufactured.

We use the same test equipment, software and procedures so that when you get your equipment back, it will have exactly the same performance as when it was new. We will even clean your instrument before it comes back to you.

Are you sure that you know what you are getting?

Cirrus routinely monitors the validity of calibrations offered by third party test and calibration companies for Cirrus equipment.

Some of these laboratories are issuing certificates of calibration against Cirrus instruments without carrying out the full and proper range of checks required.

In a recent example, a £2,500 sound level meter was sent to a third party for calibration but the Leq and Peak(C) measurement functions of the instrument were not even checked.

These measurements are a basic and mandatory requirement under the Noise at Work Regulations and so it is essential that the instruments measure accurately.

The performance of the microphone was not verified and the checks that were carried out were made using an acoustic calibrator from a different manufacturer, a test that can only be done with a full and clear understanding of the complex issues of cross calibration between microphones and acoustic calibrators. This amounted to little more than a quick check.

In this example, the test lab failed to make even basic tests and even missed a fault with the instrument that would have made any measurements inaccurate.

Any measurements made with this instrument could be challenged which could lead to problems if the measurement information was used to meet any regulatory requirements. In addition to this, it was over 6 weeks before the instrument was returned.

Find out more about calibration of our noise measurement instruments and why calibration is important. You can call us on 0845 230 2434 in the UK or +44 1723 891655 from outside of the UK or you can email

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