A guide to EN 14181: quality assurance of AMS

EN 14181 (UNI EN 14181 in Italy) is the European standard that defines quality assurance procedures for continuous measurement of emissions to air carried out with automated measuring systems (AMS), often also referred to as CEMS (Continuous Emission Monitoring Systems).

It applies mainly to plants covered by the Industrial Emissions Directive 2010/75/EU (IED) and by national legislation on industrial emissions; in Italy it is referenced in Annex VI to Part Five of Legislative Decree 152/2006.

The aim of the standard is to ensure that data collected by AMS are accurate, reliable and legally valid for environmental compliance purposes. To achieve this, it sets out three quality assurance levels (QAL1, QAL2 and QAL3) and an annual surveillance test (AST).

The three quality assurance levels

QAL1 - Suitability of the system

The first level (QAL1) verifies, before installation, that the measuring system consists of instruments suitable for the intended application. This stage includes:

QAL2 - Calibration

QAL2 is the calibration procedure that compares the readings of the installed AMS with results obtained using standard reference methods (SRM). It includes:

It must be carried out within 6 months of commissioning and then at least every 5 years, or more often if required by legislation or the competent authority. It must also be repeated after significant changes to plant operation or to the AMS, or if an AST fails.

QAL3 - Ongoing quality assurance by the operator

The third level, carried out by the plant operator, ensures that performance is maintained over time through:

The annual surveillance test (AST)

Every year the AST verifies that the AMS is working correctly and that the calibration function determined in QAL2 is still valid. It includes a functional test and at least 5 parallel measurements with the reference method, together with the variability test.

Putting it into practice

For an industrial plant, implementing EN 14181 requires:

Conclusions

Compliance with EN 14181 is not just a regulatory obligation: it ensures reliable data for the plant's environmental management and for reporting to the competent authorities.