Measurement traceability

From SI to traceable flow metering14 Februari 2019 – Botlekstudiegroep @Euroloop Rotterdam

Erik Smits

Manager metrology services / Senior metrologist liquid flow & volume

This PowerPoint presentation is for educational purposes only!

Content

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1 The new International System of Units (SI) 3 – 8

2 The Global Measurement Infrastructure 9 – 11

3 VSL the National Metrology Institute (NMI) of the Netherlands 12 – 16

4 Measurement traceability in flow metering systems 17 – 25

5 Proven traceability 27 – 29

6 Questions 30

The new SIInternational System of Units

The kilogram is dead; long live the kilogram

20 May 2019 World Metrology Day

A vote for the future

4

OGSB, Kaliningrad, RU

Paris, 16 November 2018

The new International System of Units

5

e

h

NA

kB

cKcd

ΔvCs

Redefining the SI: from base units to defining constants

▪ 3 definitions based on constants

▪ 3 definitions based on atom/material properties

▪ 1 definition based on an artefact

▪ 6 definitions based on fundamental (or

conventional) constants

▪ 1 definition based on atomic property

6

c

µ0

Kcd

MIPK

ΔvCsm(12 C)

TTPW

cd

kg

m

s

AK

mol

kg

AK

mol

mcd

s

The revised SI

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The core is 7 defining constants:

By stating the fixed values of the 7 constants,

the whole system is defined.

The 7 base units are maintained for continuity

and unit analysis

Credit: Stoughton/NIST

LEGO Watt balance or (Brian) Kibble balance

NIST D.I.Y. Watt Balance

Am.J.Phys. 83, 913 (2015)

“In conclusion, the LEGO watt balance

combines three important ingredients:

science, technology, and fun”

(for less than 600 $)

The Global Measurement Infrastructure

BIPM, OIML, ILAC and ISO

VSL, NMi-Certin, RvA and NEN

Global Measurement Infrastructure

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Traceability to

the SI system

Legislation & Trade

Competent laboratories

Standardization

Metrological traceability

3 Recommendation

BIPM, OIML, ILAC, and ISO endorse the following recommendations:

▪ In order to be able to rely on their international acceptability, calibrations

should be performed

− in National Metrology Institutes which should normally be signatories to the

CIPM MRA and have CMCs published in the relevant areas of the KCDB or

− in laboratories accredited to ISO/IEC 17025 by accreditation bodies that are

signatories to the ILAC Arrangement;

▪ measurement uncertainty should follow the principles established in the GUM;

▪ the results of the measurements made in accredited laboratories should be

traceable to the SI;

▪ NMIs providing metrological traceability for accredited laboratories should

normally be signatories to the CIPM MRA and have CMCs published in the

relevant areas of the KCDB;

▪ within the OIML-CS, accreditation should be provided by bodies which are

signatories to the ILAC Arrangement and the above policies on metrological

traceability to the SI should be followed.

The above principles should be used whenever there is a need to demonstrate

metrological traceability for international acceptability.

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VSL the National Metrology Institute (NMI) of the Netherlands

Tasks, responsibilities and services in the (inter)national

measurement infrastructure

VSL tasks, responcibilities and services

▪ Research and Development

− Development and maintenance national

measurement standards

− International traceability assurance

− Research in metrology and measurement systems

▪ Calibration and Reference materials

− Calibrations of instruments (CIPM MRA and RvA K999)

− Reference materials (CIPM MRA and RvA P002)

− Proficiency testing / comparisons (RvA R006)

▪ Customized Applied Metrology

− Consultancy

− R&D Contracts

− International projects, training

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National Metrology InstituteAt the top of the metrological pyramid

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BIPM

VSL

Manufacturers

End users

Metrological traceability requires an established calibration hierarchy

VSL and/or

Calibration

LaboratoriesSI

SI

National/

Primary

Standards

Secondary / Working

Standards

Instruments in the

field

Calib

ratio

n H

iera

rchy

sm

all to

hig

her u

ncerta

inty

Calibration Chain

High pressure natural gas flow (traceability)

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Dit is de voettekst 16

VSL’s LNG

Calibration facility for

flow meters and

sampling systems

Measurement traceability in flow metering systems

Focus on liquid flow

Metrological traceability JCGM 200:2012

▪ Metrological traceability (2.41)

property of a measurement result whereby the result can be related to a reference through a documented

unbroken chain of calibrations, each contributing to the measurement uncertainty.

▪ Calibration (2.39)

operation that, under specified conditions, in a first step, establishes a relation between the quantity values

with measurement uncertainties provided by measurement standards and corresponding indications with

associated measurement uncertainties and, in a second step, uses this information to establish a relation for

obtaining a measurement result from an indication.

▪ Measurement uncertainty (2.26)

non-negative parameter characterizing the dispersion of the quantity values being attributed to a measurand,

based on the information used.

▪ Measurand (2.3)

quantity intended to be measured.

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19

Traceability for the liquid passing through the metering system

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Calibration of the flow meter – What to consider?

▪ Calibration method

− Gravimetric

− Proving tanks

− Pipe prover

− Master meter

▪ Location of calibration

− In the system at actual conditions

− In a calibration laboratory (fluid properties,

pressures and temperatures)

▪ What kind of uncertainty / accuracy is needed

▪ Time between calibration

(Stay in control of your measurements)

▪ Traceable calibration certificates and reports

(National Metrology Institute or ISO/IEC17025)

▪ Etc….21

Calibration flow meter in system with pipe prover method

▪ Pipe prover

− Base (reference) volume at reference conditions

between detectors

− Mean temperature in prover (inlet and/or outlet)

− Mean pressure in prover (inlet and/or outlet)

▪ Flow meter

− Counted pulses representing the volume at

actual conditions

− Mean temperature in meter (outlet)

− Mean pressure in meter (outlet)

▪ Other

− Flow computer (time interpolation)

− Density

− I/O’s

− Calculations to reference conditions?

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Base Prover Volume proverBPVP = 1.8922 m3

Combined Correction Factors Prover

CCFP = CTSP x CPSP x CTLP x CPLP

Indicated Standard Volume Meter

ISVM = IVM x CCFM

Correction Pressure Liquid Prover

CPLP = 1 / (1 - ((PP + Pba - PeP ) x FP ))

Use: API MPMS 11.1 for FP

Gross Standard Volume prover

GSVP = BPVP x CCFP

Correction Pressure Steel Prover

CPSP = 1+((PP - Pbg x ID)/(E x WT)

Pressure ProverPP = 6.21 bar(g)

Temperature ProverTP = 17.1 °C

Correction Temperature Liquid ProverCTLP = VCFP

Use: API MPMS 11.1 for VCF

Correction Temperature Steel Prover

CTSP = 1+((TP - Tb) x GP)

Meter PulsesN = 10401

Indicated Volume MeterIVM = N / NKF

Itermediate Meter FactorIMF = GSVP / ISVM

Pressure MeterPP = 5.83 bar(g)

Temperature MeterTP = 17.0 °C

Correction Temperature Liquid MeterCTLM = VCFM

Use: API MPMS 11.1 for VCF

Correction Pressure Liquid Meter

CPLM = 1 / (1 - ((PM + Pba - PeM ) x FM ))

Use: API MPMS 11.1 for FM

Combined Correction Factors Meter

CCFM = CTLM x CPLM

Meter Factor vs Pipe Prover API MPMS 12.2.3

Mass balance used for measurement (metrological) traceability

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𝑉𝑎𝑐𝑡−𝑚 =

𝑉𝑝−𝑟𝑒𝑓 × 𝜌𝑝 ×1

1 − 𝛽 × 𝑝𝑝× 1 + 𝛾𝑝 × 𝑡𝑝 − 𝑡𝑝−𝑟𝑒𝑓 × 1 +

𝐷𝑝 × 𝑝𝑝𝑑𝑝 × 𝐸𝑝

𝜌𝑚 ×1

1 − 𝛽 × 𝑝𝑚

▪ What influences the mass balance of the volume passing through the flow meter and the

pipe prover it is calibrated with?

− Calibrations of all the instruments

− Changes between calibrations like shift, drift etc..

− Incorrect values of constants used like for example the expansion of steel

− Incorrect equations for expansion of the liquid based on a reference condition

− System components that are not in the equation like leakage of valves, failing detectors

− Etc…

How certain are we all about measurement performance of the system?

Example

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OGM, Belgarod, RU

Balancing measurement uncertainties

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▪ Top left: Original calculation

▪ Top right: Temperature shift between

calibration from normal 0.1 to 0.5 °C

▪ Bottom right: Prover volume shift between

calibration from normal 0.02 to 0.05%

Proven traceability and accreditation (focus on ISO/IEC17025)

Proven traceability

▪ Use the following documents:

− RvA T018 (revision 4)

− ILAC P10:01/2013

▪ Visible in calibration certificates

− CIPM MRA (NMI’s and DI’s like VSL, NEL)

− ISO/IEC17025 accredited laboratories

▪ Also check the claimed CMC’s on BIPM

website or the scope of work on the website of

the accreditation body

▪ Other traceability is possible!

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What can you expect from an accredited company

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▪ Audited by an accreditation body on a regular basis. This includes the management and technical

aspects

▪ The accreditation body is audited by colleague accreditation bodies

▪ Instruments, standards and reference materials used are proven traceable to SI units

▪ Calibration results and its measurement uncertainty can be assumed to be within the set confidence

levels (k=2 ± 95%)

▪ The used calibration methods are fit for purpose

▪ The competence of staff is evaluated

▪ Takes part in comparisons (preferable according ISO 17043) to show competence

▪ Etc…

Euramet.M.FF-K4.1.2016

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+31 15 269 15 00

+31 15 261 29 71

info@vsl.nl

www.vsl.nl

fsmits@vsl.nl

VSL

PO Box 654

2600 AR Delft

The Netherlands

T

F

E

I

Erik Smits

E

Measurement traceability

From SI to flow metering14 Februari 2019 – Botlekstudiegroep @Euroloop Rotterdam

VSL training courses 2019

▪ Algemene Metrologie

− 1 dag

− 26 maart of 17 september

▪ Onzekerheidsrekening

− 3 dagen

− 18 t/m 20 juni of 19 t/m 21 november

▪ Gas Flow Metrology

− 5 dagen

− 11 t/m 15 november

▪ Calibration Liquid Flow Meters

− 3 dagen

− september

− Optioneel: 1 dag Introduction Uncertainty Calculation in flow

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