LAWR

5 Annual Guide 2015 | SOURCE TESTING ASSOCIATION regulated with a daily ELV that is used when applying the QA requirements described below. e reduction in the absolute value of the daily ELV is the main regulatory impact on the QA requirements, as discussed below. Overview of EN14181 is section provides an overview of EN 14181 which de- fines three Quality Assurance Levels – QAL1, QAL2 and QAL3 – and an Annual Surveillance Test (AST). e basic structure of the QA process is shown in Figure 1. e operator has the following general responsibilities: • Installation of compliant equipment (QAL1) • In-situ calibration of AMS using an accredited test l aboratory (QAL2) • Performing ongoing quality assurance based on regular zero and span checks (QAL3) • Submission of QAL2, QAL3 and AST reports and on- going maintenance of records • Annual check of the in-situ calibration using an accre- dited test laboratory (AST) • Checking of hourly averages against the valid calibration range (weekly) QAL1 requires an assessment of the suitability of the AMS equipment. New analysers should be certified and the certification field trial should be carried out on a similar process to that under consideration. e monitoring equipment must be placed so that representative readings can be obtained. QAL2 requires calibration of the monitors against ana- lytical methods – Standard Reference Methods (SRM) – applied by a test laboratory accredited to ISO 17025. e straight line calibration relationship between the AMS and the SRM test data is established by taking at least 15 pairs of measurements obtained across at least three days of op- eration. Any scatter in the data comparison is assumed to be caused by the plant monitor and this scatter (variability) must be below a threshold in order to pass. Prior to a QAL2 calibration, various functional tests must be performed. As a minimum, the test laboratory must audit the functional tests. e operator must also per- form a weekly check of the reported emissions data to determine if this lies outside the Valid Calibration Range (VCR) established during the test campaign. QAL2 is intended to take account of any bias caused by the specific monitoring equipment or the sampling location and must be conducted every five years or following a sig- nificant change to the process, the fuel mix or the AMS. AST are intended to validate the calibration established under QAL2 by, again, employing an accredited test laboratory to take a reduced number of parallel measure- ments. e tolerance applicable to the data scatter is widened and an additional test compares the mean devia- tion from the calibration line with the 95% confidence interval mentioned above. QAL3 is intended to provide an audited check of on- going performance by conducting regular zero and span checks of the monitors and comparing the measured drift against pre-defined warning and action limits using a control chart approach. Changes to the revised EN 14181 General provisions: Appendix K of EN 14181:2014 describes the main tech nical changes between the first and second editions of the Standard. e main purpose of the amended Standard remains the same, that is, the AMS meets the regulatory uncertainty requirements, now specified in the Industrial Emissions Directive for combustion and incineration plant. e IED confidence interval, evaluated at the daily ELV, is now referred to as the Maximum Permissible Uncertainty (MPU) within EN 14181:2014. All of the uncertainty requirements within the Standard are replaced by the MPU. As an example, for a plant with a daily ELV of 100 mg/m 3 NOx, MPU is 20% of 100 mg/m 3 , i.e. 20 mg/m 3 . All QAL2/AST testing shall be conducted by a test labo- ratory that is accredited, under ISO 17025, to make the measurements or one that is approved directly by the competent authority. e measuring range of the AMS can now be selected to match the anticipated maximum short term (hourly or half-hourly) ELV. Quality Assurance Level 1 A normative reference to the EN 15267 series of Standards [5,6,7] for the certification of CEMs has been added. is means that new AMS installations must be certified to EN 15267 as demonstration of QAL1 compliance. For large combustion plant, the certification range should be below 2.5*ELV and for incinerators below 1.5*ELV. e QAL1 uncertainty should be less than 75% of the IED con- fidence interval. In the above example, less than 75% of 20 mg/m 3 , i.e. 15 mg/m 3 . Existing uncertified AMS installations may be approved by the competent authority, e.g. on the basis that the re- Table 3: IED Confidence Intervals Species Confidence interval (95%) SO2 20% NOx 20% Dust 30% CO 10% TOC 30% HCl 40% HF 40% » Figure 1: Quality Assurance Levels (QAL) EN 14181 made simple EN14181 Suitable equipment Set-up correctly Stays working correctly QAL1 QAL2 QAL3 Annual Surveillance Test

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