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Developments in Metrology

Ed W.B. de LeerNMi Van Swinden Laboratorium

The Netherlands

UNECE WP.6 Presentation 24 november 2004

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Secondary Standards

SI

Measurand

MeasurementResult

Measurement Process

PrimaryStandard

Calibrated Instrument

s

PrimaryProcedure

Validation,Measurement Uncertainty

Traceability

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Traceability to the SI

Harmonizedlegal regulations

ValidatedMeasurement Methods

Competence of conformity assessment bodies

World Measurement System

NMI´sNMI´s

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Metre Convention

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BIPM

Scientific centre for metrology: custodian of the kilogram and the time

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EUROMET

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CIPM MRA

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Mutual recognition

Mutual recognition of calibration certificates is based on

1. Results obtained in BIPM or regional key comparisons

2. Successful implementation of a quality system based on the principles of ISO/IEC 17025 and, where relevant, ISO Guide 34.The recognition of the QMS can be based on accreditation, peer evaluation or self declaration.In EUROMET, the quality system must be presented in a QS Forum.

Key Comparisons of National Standards

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1 kg Key Comparison

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KCDB

kcdb.bipm.fr

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KCDB

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KCDB

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“High Accuracy” comparisons

All laboratories send a standard to the pilot laboratory

Preparation errors can now be Preparation errors can now be “randomised”“randomised”

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GC-TCD results

GC-TCD Results for 50,000 umol/mol CO in nitrogen

0,93

0,94

0,95

0,96

0,97

0,98

0,99

1,00

1,01

1,02

1,03

47000 47500 48000 48500 49000 49500 50000 50500 51000 51500 52000 52500

Concentration (umol/mol)

Rat

io t

o C

on

tro

l

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GLS for GC-TCD versus Gravimetry

• Conclusions for 50,000 mol/mol– Std dev of residuals is 1mol/mol (0.002% rel)-

after excluding two outliers– At 50,000 mol/mol, the gravimetric values are

very consistent within their stated uncertainties.

-80

-60

-40

-20

0

20

40

60

BAM CENAM CSIRO IPQ KRISS LNE NIST NMIJ NPL

Re

sd

iua

l De

via

tio

n (

um

ol/m

ol)

k=2k=2

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Cu in soil and sediment

0

5

10

15

20

25

30

35

40

45

50

0 5 10 15 20 25 30 35 40 45 50

Cu (mg/kg dw, certified value)

Cu

(m

g/k

g d

w,

measu

red

valu

e)

intercept: 0.55 ± 1.28 mg/ kg (k=2)slope: 0.969 ± 0.064 (k=2)

Validation of CRMs with IDMS

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Publication of draft VIM revision

• International Vocabulary in MetrologyApril, 2004

• Revision is based on the Uncertainty Approach (UA) from the GUM. Old version is based on the error concept, which is called the Classical Approach (CA)Conflict with VIML?

• The comments from ISO are approximately 60 text pages

• Uno was not accepted as a new SI unit

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Metrology in short

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GUM revision ?

• No revision of the GUM will be published

• Measurement result = value + measurement uncertainty + unit

• 4 extensions to the GUM are in preparation

• First extension on Monte Carlo calculation of measurement uncertainty published as a draft version

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Metrology and Standardization

• ISO– ISO 17000 (problem: definition of

conformity assessment activities)– ISO 17010 (problem: impartiality question)– MU concept is fully integrated in many new

standards

• CEN– MU concept is fully integrated in many new

standards

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Metrology and Accreditation

• BIPM – ILAC• Certified reference materials are the link to

the SI for most chemical measurements• Accreditation of RM producers is now possible

against ISO/IEC 17025 and ISO Guide 34 in combination

• Special calibrations of NMIs (very low uncertainties)

• Harmonization BMC and CMC• Linking key comparisons to proficiency tests

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From Cooperation to Coordination?

• European Research Area in Metrology (MERA)• Implementing the European Research Area in

Metrology (iMERA)• The metrology dilemma is budget driven:

– Do we serve the national needs in calibration?– Do we manage a profitable business?– Do we serve the future needs in metrology?

• The answer could be in coordination

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Thank you

for your attention