All monitors are not created equal

The forthcoming Europen Standard on the Quality Assurance of Automated Monitoring Systems will have a significant impact on the monitoring of certain industrial emission sources in the UK. Beverly La Ferla reports.

On 1 May, while costumed rioters were protesting throughout London, the atmosphere was considerably hotter in a workshop to discuss the Draft European Standard on the Quality Assurance of Automated Monitoring Systems (AMS), CEN/TC 264, which has been produced as a Draft by CEN Working Group 9.

Quality assurance
The Draft Standard describes procedures that must be carried out "to cover quality assurance of automated measuring systems installed on industrial plants for the determination of the flue gas components and other flue gas parameters". These procedures are for determining the uncertainty of the values measured by an AMS, for ensuring that the quality of the measured results is maintained, and for performing annual surveillance tests on the AMS.

Importantly, the Draft Standard is limited to the quality assurance of the AMS and does not include the quality assurance of the data collection and recording system of the plant, even though this can be as important as the performance of the AMS in determining the quality of the data obtained. The reason given is that different countries require data to be presented differently, thus making it unfeasible to draw up universal guidelines.

In response to this, delegates at the workshop expressed concern because the data processing system will be used to report the measurements to the EU and is often the cause of faulty data.

Three different Quality Assurance Levels have been defined in the Draft Standard:

  • QAL 1 : ensures the suitability of the AMS and its measurement procedure is evaluated. MCERTS (the Environment Agency's Monitoring Certification Scheme) currently covers this.
  • QAL 2 : ensures an AMS is validated and calibrated.
  • QAL 3 : ensures ongoing quality assurance during the operation of the AMS.

Annual surveillance tests are also required to test the validity of the measured data using a series of functional tests.

Queries were raised about the necessity to carry out QAL 3 measurements where the measured emissions are well below the required emission limit value. There also appears to be no justification within the Standard for performing the QAL 3 tests every seven days.

Concerns were also raised over water vapour and dry hydrogen chloride (HCl) on the basis that cross interferences cannot be determined on site for water vapour and dry HCl can take up to three hours to reach one tenth of its final concentration value.

Finally, after a run through of the statistics required to fulfil data requirements, delegates immediately petitioned for simple worked examples.

Costs to increase
A major concern, brought up by instrument manufacturers, was that the maintenance and running costs of monitoring systems will be several fold higher than the initial capital outlay of monitor units themselves. Dr Richard Gould, MCERTS Project Manager at the Environment Agency, comments, "The UK industry does not spend relatively as much as similar industries in some other EC States, so the cost argument is likely to be deflected by the CEN standard. However, extra requirements for monitoring do mean extra costs. The Agency is working on researching the optimum number of reference tests needed to keep costs down."

On interaction with MCERTS, Dr Gould said, "The draft standard will be supported by MCERTS by meeting the requirements of QAL 1 and will also influence a new MCERTS standard entitled 'Operator's monitoring arrangements'."

The Agency is currently reviewing the Draft Standard to make it "more reasonable" and take into account the practicality of the proposed measures.

The current framework in the UK and abroad
MCERTS (Monitoring Certification Scheme) is a UK certification scheme for environmental instruments and monitoring services brought into play by the Environment Agency in 1998 to assure the installation, performance and maintenance of pollution monitoring equipment and to provide quality monitoring data.

MCERTS was specifically founded to ensure that both equipment and services are accredited to national standards in line with forthcoming EC directives. Sira Certification Services is the certification body which manages the scheme and is itself accredited for product certification.

Product certification requires an instrument manufacturer to demonstrate that the manufacturing process is controlled under a quality management system and produces instruments that deliver consistent performance. Manufacturers are audited each year.

The Umweltbundesamt (UBA) scheme, commonly referred to as T†V after the main test organisation which evaluates the instruments, is the German approval scheme for monitoring instruments.

The UBA's scheme has been in existence for over 25 years and is similar to MCERTS in that the instruments must go through laboratory testing and a three month evaluation.


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