Requirements of EU Directives for Gas Analysis through ISO & Traceability to National Metrology Institutes Martin Milton, Peter Woods and David Nettleton* National Physical Laboratory, UK. NCSLI 2004

 UK’s National Metrology Institute  Prepare & maintain UK’s measurement standards: –ensure accuracy and comparability across the UK and with trading partners, –calibration and testing.  R&D into measurement technologies National Physical Laboratory, UK

Europe and its NMIs  EUROMET is Europe’s Regional Metrological Organisation  EUROMET is a collaboration of 31 National Metrology Institutes in Europe  EUROMET runs projects for R&D collaboration, consultation, comparisons, traceability  EUROMET structured into 11 technical fields  More information on EUROMET can be found at Booth 207

Overview  Why bother with traceability ? –Natural gas analysis –Vehicle emission testing –Air quality monitoring  Recent initiatives to demonstrate international comparability between the NMIs –e.g for vehicle emission gases

What is (Metrological) Traceability? “Property of a result of a measurement (or the value of a standard) whereby it can be related to stated references, (usually national or international standards), through an unbroken chain of comparisons all having stated uncertainties” International Vocabulary for Metrology  Traceability of measurement results is NOT an aim in itself!  Traceability is a means to provide: – –Comparability – –Stability – –National and International recognition

International Standard ISO  Title “General requirements for the competence of testing and calibration laboratories”  Scope “ This International Standard specifies the general requirements for the competence to carry out tests and/or calibrations, including sampling. It covers testing and calibration performed using standard methods, non-standard method, and laboratory-developed methods”

Worldwide  ISO “General requirements for the competence of testing and calibration laboratories” –requires traceable measurement standards – “where available”  Fields regulated by legal metrology –Evidential breath alcohol –Motor vehicle emissions testing Requirement for Traceable Gas Standards

In Europe  EU Directives on emissions monitoring: –Hazardous Waste Incineration, –Integrated Pollution Prevention and Control, –Waste Incineration, –Large Combustion Plant All include requirements for measurements with prescribed uncertainty  EU Directives on ambient air quality: –SO 2, ozone, NO x, CO –Benzene, 1,3-butadiene –Trace metals and PAHs in ambient air Requirement for Traceable Gas Standards

Accessing traceable gas mixtures - the European model  National primary or secondary standards from a National Metrology Institute  Commercial gas mixtures –Certified by a National Measurement Institute –Prepared under an ISO Calibration accreditation –Analysed by gas companies against traceable standards  Commercial gas mixtures – with traceability to units of mass –not accepted by ISO Technical Committee158

Primary Standard Gas Mixtures (PSM) Concentration uncertainty  0.02% - 0.1% at (95% level of confidence) Primary Reference Gas Mixtures Concentration uncertainty  0.1% - 0.4% at (95% level of confidence) Secondary Gas Standards Concentration uncertainty  0.4% - 1% at (95% level of confidence) Certified Reference Gas Mixtures Concentration uncertainty  1% - 3% at (95% level of confidence) Accuracy and cost to suit customers from industry, Government laboratories and regulators Traceable Gas Standards at NPL

But – how is traceability to National Metrology Institutes disseminated ?  Vehicle emission mixtures  Natural gas  Air quality and industrial emission

Traceability of Vehicle Exhaust Emission Tests in the UK Gas companies manufacture traceable standards to +/- 1% ISO accredited engineers calibrate test stations NPL certifies Secondary Standards to +/- 0.4% NPL prepares sets of Primary Standards to +/- 0.2% Exhaust emission tests performed to +/- 3%

Mutual Recognition of National Standards  In October 1999, the directors of the National Metrology Institutes (NMIs) of thirty-eight Member States of the Metre Convention and representatives of two international organizations signed a Mutual Recognition Arrangement (MRA) for national measurement standards and for calibration and measurement certificates issued by National Metrology Institutes.  These Mutual Recognition Arrangements are a response to a growing need for an open, transparent and comprehensive scheme to give users reliable quantitative information on the comparability of national metrology services and to provide the technical basis for wider agreements negotiated for international trade, commerce and regulatory affairs.

Mutual recognition of National Standards  The technical basis of the MRA is: –The results of Key and Supplementary Comparisons –Calibration and Measurement Capabilities (CMCs) of the National Metrology Institutes

CZ [CMI-CHMI] KR [KRISS] SA [CSIR-NML] PT [IPQ] FR [BNM-LNE] GB [NPL] CH [OFMET] CN [NRCCRM] DE (1) [BAM] DE (2) [PTB] SK [SMU] NL [NMi-VSL] HU [OMH] JP [NRLM] RU [VNIIM] US [NIST] IT [IMGC] PO [GUM] JP [NMIJ/CERI] TW [CMS/ITRI] SY [ERL-HIAST] CCQM-K3 EUROMET.QM- K APMP. QM-K3 Key Comparisons to ensure the international comparability of standards CO, CO 2 and propane

Key Comparisons – CO Results APMP.QM-K3EUROMET.QM-K3CCQM-K3

APMP.QM-K3EUROMET.QM-K3CCQM-K3 Key Comparisons – CO 2 Results

Key Comparisons – Propane Results APMP.QM-K3EUROMET.QM-K3CCQM-K3

Model for international comparisons  All laboratories receive a standard from the pilot laboratory  Analysis errors are “randomised”, but errors in the preparation of the standards are “systematic”

Experimental model for international comparisons  All laboratories send a standard to the pilot laboratory  Preparation errors can now be “randomised”

GC-TCD of Independent Primary Standards (50,000  mol/mol CO/N 2 ) –Fit is sufficiently good to support analysis of residuals

 Conclusions –Std dev of residuals is 1  mol/mol (0.002% rel)- after excluding two outliers –At 50,000  mol/mol, the gravimetric values are very consistent within their stated uncertainties. k=2 GC-TCD of Independent Primary Standards (50,000  mol/mol CO/N 2 )

Traceability in natural gas analysis  High value commodity  Industrial best practice is encapsulated in a series of technical standards from ISO 193 –Calorific Value (CV) and other physical properties by analysis  Traceability and ISO used to confirm the quality of laboratories and standards

UK Range for Natural Gas Analysis

Traceability of ambient air measurements in the UK Gas companies manufacture standards to fill tolerance of +/- 5% Calibration of field stations (under ISO 17025) NPL certifies commercial standards to +/- 3% NPL maintains Primary facilities to +/- 0.3% Automatic measurements performed hourly at 200 stations to 15 %

Limits on gaseous emissions to air  The EU Directives on waste incineration and large combustion plants state

Traceability of gas measurements in Europe - Conclusions   National Metrology Institutes provide the basis for the traceability of gas analysis, which can provide stability, comparability and international recognition for measurement results. These support industry in: –Meeting environmental regulation –Facilitating trade of instrumentation and commodities. –Verifying that products meet international standards   Partnership between National Metrology Institutes and special gas companies, using ISO accreditation can lead to efficient methods of dissemination  Mutual Recognition Arrangements between National Metrology Institutes is leading to the acceptance of standards and certificates between Europe, the USA and Asia.

Thank you for your attention  Questions?