Increased requirements on the quality of emission measuring devices and systems
Basically 2 major facts result from the amendments of related ordinances and directives. On the one hand, there are new benchmarks for the plant availability and on the other hand quality requirements for the used measuring systems and their continuous operation have tightened.
The requirements resulting from the common immission protection acts are fulfilled in principle with erection, commissioning and calibration. However, during continuous operation a pollutant monitoring being as complete as possible has to be ensured. The following table shows the new requirements on availability during continuous operation (according to the uniform practice in monitoring emissions):
|Continuous emission measuring systems||at least 95 %|
|Measuring systems for oxygen||at least 98 %|
|Electronic evaluation systems||mind. 99 %|
Further requirements on availability of emission monitoring technology result from country-specific regulations:
„Each day having 6 invalid half-hourly average values due to error or maintenance of the continuous measuring system is invalidated. If more than 10 days per year are invalidated in consequence of such circumstances, the responsible authority has to oblige the operator to improve reliability of the continuous monitoring system." (see annex II of 13th federal immission control ordinance in Germany)
In order to determine a valid daily average value not more than 5 half-hourly average values of any day must be considered due to non-working or maintenance of CEMS. Per year not more than 10 daily average values must be considered due to non-working or maintenance of CEMS (Directive 2000/76/EG concerning waste incineration)
1.2. Increased quality requirements according to DIN-EN 14181
The DIN EN 14181 stipulates 3 so-called quality assurance levels (QAL) and an annual surveillance test (AST).
The QAL 1 requires the use of suitability-tested automated measuring systems (the test is done according to DIN EN ISO 14956) and addresses to device manufacturers.
The QAL 2 demands the installation of the automated measuring system (AMS), its calibration with the standard reference measuring method (SRM), the calculation of the measurement's uncertainty/variability of the AMS as well as the inspection of the compliance of defined measuring uncertainties. That refers to accredited measuring institutes (in Germany according to § 26,28 Federal Immission Control Act)
QAL 3 stipulates the on-going quality assurance to be done by the operator consisting of regular drift checks of the AMS during operation.
That is completed by the AST determining that an annual surveillance test incl. SRM measurements has to be done by accredited measuring institutes in order to check the uncertainty of the AMS values.