For any measurement made, there is always a degree of uncertainty associated with the measurement.
When measurements are included in a quality-controlled system, it is required that the uncertainty of
measurement (or measurement accuracy) is known and documented in a satisfactory way for all significant
components. An accredited calibration procedure requires traceability of the calibration, monitored
by a public body with a recognition for international acceptance and trust. An accredited calibration
can also be seen as a regular health check of measurement equipment, performed by specialists in an
accredited laboratory.
Unfortunately, the word "calibration" has ended up having at least two meanings.
1: The use of a sound calibrator to verify the sound level meter reading
before and after a measurement.
2: To do a thorough periodic verification in a Calibration Laboratory.
It is recommended that this sound analyser is verified in a calibration laboratory every two years. Some measurement standards
may set other requirements to the verification interval.
This sound analyser was verified according to IEC 61672 (2013) when it was new.
The current calibrator standard is IEC 60942 (Ed. 3).