scope:

This standard describes procedures to determine the uncertainty of results of quantitative chemical and physical measurement methods. The standard is restricted to measurement methods for laboratory samples.

The principle of uncertainty determination is in accordance with NVN-ENV 13005.

In this standard the emphasis lies on the use of performance characteristics and the results of internal and external quality control in quantifying the measurement uncertainty. This standard follows the terminology and quantification procedures of NEN 7777+C1 on performance characteristics of measurement methods.

This standard pays limited attention to the determination of measurement uncertainty based on the uncertainty of influence variables. This approach has been developed for chemical analysis methods and examples provided in the EURACHEM/CITAC Guide Quantifying Uncertainty in Analytical Measurement (QUAM) [1].

If the measurement uncertainty is determined in accordance with NEN-EN-ISO/IEC 17025, then this measurement uncertainty shall be reported in cases where:

a) the uncertainty affects compliance with a specification limit (limit value) and/or decision-making rule;

b) the client's instructions require this;

c) it is relevant for the validity of application of the measurement results.

Targeted standards are available for scopes with specific characteristics. In particular for air quality surveys NEN-EN-ISO 20988 and for radiochemistry the NEN-ISO 11929 series (under development) apply.

NOTE The determination of the measurement uncertainty of quality measurement results is not the subject of this standard.