Arab Metrology Programme ARABMET Mass...

ARABMET-M.S. 1 - Nov. 2011_103E38 Page 1 of 21.......................................................................

Arab Federation for Metrology (A F M)Technical Support Unit

Arab Metrology ProgrammeARABMET Mass Intercomparison*

M.S. 1 – November 2011

Instructions and Technical Protocol

* Note: at the moment, a proposal is being made to register this comparison as anAFRIMETS Supplementary Comparison

Contents

1. Introduction ........................................................................... 22. Organization ........................................................................ 3

2.1 Requirements for Participation ..................................... 32.2 Participants................................................................... 42.3 Time Schedule ............................................................. 52.4 Transportation .............................................................. 62.5 Unpacking, Handling, Packing...................................... 62.6 Financial Aspects, Insurance ....................................... 7

3. Description of the Standards ................................................ 74. Measurement Instructions .................................................... 75. Annexed Papers and Forms ................................................. 8

5.1 Transportation protocol (arrival), contact person of the laboratory 95.2 Transportation protocol (departure), contact person of the laboratory 105.3 Calibration results 115.4 Uncertainty budget 125.5 Details of the balances 125.6 Details of the instruments used for air density determination 135.7 Traceability description 145.8 Data of the Artefacts 155.9 Record of the surface of the transfer standards 16

6. Formulas for the calculation of true mass and conventional mass 217. Remarks 21



1. Introduction:

The Arab Metrology Programme ARABMET, a programme established to work underthe umbrella of the Arab Federation for Metrology AFM, extends its invitation to theNational Metrology Institutes, NMIs to participate in measurement comparisonprogrammes in different metrological fields. The comparison programme is designedand organized by ARABMET under technical support of the National Institute forStandards NIS of Egypt being an active member of both the Programme and theFederation. The comparison programme is open for NMIs of the member and nonmember states of the Federation. The comparisons will be conducted followingappropriate measurement protocols. The objectives of the comparison programmesare to provide the participating laboratories with the means for comparing theirmeasurement results, opportunities for technical capability improvements andrecognition of CMCs.

It should be noted that the initial purpose of this intercomparison is to provide Arabcountries' NMIs an exercise in conducting and participating in an intercomparison.Later on, however, it was suggested to have this intercomparison registered as asupplementary AFRIMETS comparison; AFM being an Observer Member ofAFRIMETS.

The decision whether to register this intercomparison as an official AFRIMETSsupplementary comparison or not is still being discussed with the AFRIMETS TCMChairperson.

Regardless of the AFRIMETS TCM decision whether to register this as asupplementary comparison or not, it is decided to carry out the comparison for thewell fare of the participating NMIs. The procedure outlined in this document isprincipally intended to allow for a clear and unequivocal comparison of themeasurement results ensure the harmonization of mass measurements throughoutthe participating Economies.

The procedure is based on the protocol for the APMP.M.M-K6 (SUB)MULTIPLESMASS KEY COMPARISON programme designed and organised by APMP.DC andpiloted by Vietnam Metrology Institute (VMI.) with participation from Mass lab - NIS.Particular attention must be attributed to the availability of the laboratory carrying outthe calibrations, to transportation and to customs problems. By their declaredintention to participate in this comparison, the participating laboratories accept thegeneral instructions and the technical protocol written down in this document andcommit themselves to follow the procedure strictly.

A common way of evaluating and expressing the uncertainty of measurement isparticularly important to demonstrate the degree of equivalence between theparticipating laboratories.

One set of weights, with nominal values 100 mg, 2 g, 20 g, 500 g, 1 kg is chosen asthe artifacts for the comparison. The procedures and instructions are given below.INTERNATIONAL RECOMMENDATION OIML R 111-1 Edition 2004 (E) “Weights of



classes E1, E2, F1, F2, M1, M1–2, M2, M2–3 and M3 Part 1: Metrological andtechnical requirements” to be used in the non defined instruction.

The comparison programme is to be of the Round Robin scheme.The measurement results obtained will be evaluated and reported to the participatinglaboratories by NIS. Participants should note that it is their responsibility toarrange and bear costs of transport, Custom clearance of the artifact to thenext participating laboratory.

2. Organisation

The comparison will follow as closely as possible the rules set up by the BIPM. Theco-ordinating laboratory will be the Mass, Density and Pressure Lab – NIS , andMass and related Quantities Lab of the National Metrology Institute of South Africa(NMISA) will act as an invited lab. in case of AFRIMETS registration. Thechairperson of the AFRIMETS TCM will act as an observer of the comparison andwill regularly be informed about its progress.

2.1 Requirements for participation

The participating laboratories should be part of the countries NMIs and offer thismeasurement as a calibration service.

2.2 Participants

NMI Contact Person Contact address

National Institutefor Standards; NIS

EGYPTPilot Lab.

Dr. Alaaeldin A. Eltawil;Tech. Manager; Mass,Density & PressureLab

Mass and Force MetrologyDivision;National Institute for Standards;Tersa street, El Haram Giza;EGYPTel: +33889744Fax: +33867451e-mail: [email protected] Site: www.nis.sci.eg

National Standardsand Calibration

Laboratory; NSCL -SYRIA

Eng. Mazen El Rashed;Head of PrimaryMechanicalDtandards Lab.

National Standards and CalibrationLaboratory;Prefabricated Buildings; BerzaResidence; P.O.Box 30116Damascus;Arab Republic of SyriaTel.: + 963 11 2216760Fax.: + 963 11 5117539e-mail: [email protected] Site: www.nscl.sy



(cont. Participants List)

NMI Contact Person Contact address

Jordan NationalMetrology Institute;

JNMI - JORDAN

Eng. Mariam Bishtawi;Calibration Engineerand Head of Mass &Balances Lab.

Jordan National MetrologyInstitute;Royal Scientific Society;P.O.Box 1438 – Al-Jubaiha 11941;Amman – JordanTel.: + 962 6 5344701 Ext. 2300Fax.: + 962 6 5348796e-mail: [email protected] Site: www.jnmi.gov.jo

Central Laboratoryfor Testing and

Analysis-MetrologyCenter;

LCAE-CME -TUNISIA

Ms. Mouna Makhlouf;Head of Unit Mass andrelated Quantities.

Central Laboratory for Testing andAnalysis-Metrology Center;23, Rue Jawaher Lel Nehry;Montfleury 1008;Tunis – TunisiaTel.: + 71 958 404Fax.: + 71 958 424e-mail: [email protected] Site: www.lcae.nat.tn

CentralOrganisation forStandardisation

and Quality Control;COSQC - IRAQ

Ms. Hanan Abdel JalilAbdel Lateef;MechanicalMeasurements Officer.

Central Organisation forStandardisation and QualityControl;Ministry of Planning;P.O.Box 13032; Al- Jaderiya;IQ – BaghdadTel.: + 964 1 776 19 80Fax.: + 964 1 776 19 81e-mail: [email protected]

[email protected] Site: www.cosqc.gov.iq

National MetrologyInstitute of South

Africa;NMISA;

SOUTH AFRICAInvited Lab.

Mr. Benjamin van derMerwe;

AFRIMETS LTM Chair;Manager: NMISAMechanical MetrologyLab

National Metrology Institute ofSouth Africa, Private Bag X34,Lynnwood Ridge,0040,Tel: +27 12 8414340Fax : +27 12 8412131e-mail:[email protected] Site: www.nmisa.org

2.3 Time Schedule

The comparison will be carried out in a loop format (Round Robin Scheme). Eachlaboratory has one month for calibration and one month for transportation. With itsconfirmation to participate, each laboratory has confirmed that it is capable ofperforming the measurements in the limited time allocated to him. It guarantees, thatthe standards arrive in the country of the next participant on time. If for some



reasons, the measurement facility is not ready or customs clearance takes too muchtime in a country, the laboratory has to contact the coordinator immediately.

Laboratory Country Date Remark

NIS EgyptNovember 2011December 2011

Pilot Lab; AFM Member,AFRIMETS Member(NEWMET), APMP AssociateMember and EURAMETCorresponding Member

COSQC IraqJanuary 2012February 2012

AFM Member

NSCL SyriaMarch 2012April 2012

AFM MemberAPMP Associate Member

NMISA South AfricaMay 2012June 2012

Invited Lab. – AFRIMETSMember (SADCMET); APMPAssociate Member

LCAE TunisiaJuly 2012August 2012

AFRIMETS Member(MAGMET)

JNMI JordanSeptember 2012October 2012

AFM Member

NIS EgyptNovember 2012December 2012

Pilot Lab; AFM Member,AFRIMETS Member(NEWMET) and EURAMETCorresponding Member

2.4 Transportation

The transportation case is a metallic container with contents as described in theContents List. It is the responsibility of the participating laboratory, when it hasthe traveling standards, to organize and make all necessary arrangements totransport the case containing the travelling standards, to the next participatinglaboratory- preferably by hand-carrying, but air freight is acceptable, andensuring that all necessary customs and importation documents are in order.

You are kindly asked to inform the Coordinator and the pilot laboratory by e-mailimmediately after receiving the set of weights using the e-mail addresses given inthe annex.

Every incident when the artefacts may have been polluted or damaged should bedocumented and immediately communicated to the pilot laboratory. Also if there isany delay or required change in the time schedule, the pilot laboratory should beinformed in appropriate time



2.5 Unpacking, Handling, Packing

When the set of mass standards arrives at the participating laboratory the case and itscontents should be checked for any damage and missing items. The full set of itemshas been described in the Contents List provided within the case.

The standards should only be manipulated with the supplied tools. They shouldnot be touched with bare hands.

A visual inspection of the surfaces of all the masses should be made and observationsnoted on the corresponding paper sheet. The pilot laboratory should be informed afterthe arrival of the set of masses and the results of the visual inspection of the massesand other relevant items as soon as possible by e-mail or fax message. On departurethe pilot laboratory should also be informed as soon as possible.

The mass standards should be stored in well-controlled environmental conditions andthey should be protected from dust, aerosols and vapors whenever they are not insidethe balance before use.

2.6 Financial Aspects, Insurance

Each participating laboratory covers the costs for the measurements, transportationand eventual customs formalities as well as for any damages that may haveoccurred within its country. The overall costs for the organisation and for the devicesare covered by the organising pilot laboratory through the financial support from AFMTechnical Support Unit. The pilot laboratory has no insurance for any loss or damageof the standards during transportation.

3. Description of the Standards

The package contains 5 Masses of the OIML design without adjusting cavity. Theyhave been acquired with the following nominal mass values:

Normal value1 kg

500 g20 g2 g

100 mg

The serial nos. of the sets is 5060911. The weight of the set in its carrying case isapproximately 5 kg.

Immediately after having completed the measurements, the pack has to be sentto the next participant. It is advisable to prepare and organize this transportationbeforehand. Please inform again the coordinator and the next laboratory by faxor e-mail about date of shipment, Transportation Company and possibly flightdetails.



4. Measurement Instructions

The participating laboratory shall determine the mass of every standard in the set.Before determining the mass of each standard, dust particles should be removed fromthe surface of the standard using a soft brush. No washing or wiping should beperformed. All weighing should be performed in air. If the buoyancy correction isused, the air density should be determined using the laboratory’s standard procedurespecified on the annexed form.

Measurement should be done only after an appropriate acclimatization time asspecified in OIML R111 .

The final results should be sent by e-mail and also by conventional post to thecoordinator and the pilot laboratory. The measurement results, data of the ambientconditions, instruments used and traceability of the participating laboratory should beentered in the enclosed forms and should be sent to the coordinator and the pilotlaboratory within one month after completing the measurements as time schedule.

5. Annexed papers and forms

5.1 Transportation protocol (arrival), contact person of the laboratory5.2 Transportation protocol (departure), contact person of the laboratory5.3 Calibration results5.4 Uncertainty budget5.5 Details of the balances5.6 Details of the instruments used for air density determination5.7 Traceability description5.8 Data of the Artefacts5.9 Record of the surface of the transfer standards



5.1 Transportation Protocol (arrival) Laboratory

Laboratory Date

Arrival of the mass standards Date Form

Conditions of the Mass standards on arrival

Transportation box:

Surface conditions:(use record sheets)

Other remarks

Contact person of the LaboratoryName

Full mailing address

Telephone:

Telefax

e-mail



5.2 Transportation Protocol (departure)

Laboratory Date

Arrival of the mass standards Date Form

Conditions of the Mass standards on departure

Transportation box:

Surface conditions:(use record sheets)

Other remarks

Contact person of the LaboratoryName

Full mailing address

Telephone:

Telefax

e-mail



5.3 Calibration results

Measurement results:

Laboratory Date

Normal value Mass m Standard uncertaintyu c

No. of measurementscycles*

1 kg (true) (true)(conv.) (conv.)

500 g (true) (true)(conv.) (conv.)



100 mg (true) (true)(conv.) (conv.)

* If the calibration was made by other procedures than one-to-one comparison (e.g. subdivisionusing a system of weighing equations), give the degrees of freedom of this procedure.

Environmental data during calibration (state the maximum and minimum values of temperature,humidity and pressure during measurements for all individual artifacts)

Nominalvalue

Temperaturet/°C

Pressurep/pa

Relativehumidityh/%

Dew pointtemperature*t/C

*(CO2conc)

Airdensityρa/kgm-3

1 kg

500 g

20 g

2 g

100 mg

* if not measured an assumed value can be taken



5.4 Uncertainty Budget

The uncertainty shall be estimated and combined following the ISO Guide to the Expression ofUncertainty in Measurement.

Laboratory Date

Uncertainty Contributions1 kg 500 g 20 g 2 g 100 mg

uAUm refubu∆mw(others)

ucEffectivedegrees offreedom

5.5 Details of the Balances used for the calibration

Laboratory Date

Manufacturer Type Maximumload Resolution Standard

Deviation*Manual /automatic

1 kg

500 g

20 g

2 g

100 mg

*Please indicate the weighing procedure and number of measurements



5.6 Details of instruments used for air density determination

Laboratory Date

Manufacturer Type Range Resolution Uncertainty(1σ)

Temperature

Pressure

Humidity

CO2*

* Applicable if measured

Description of air buoyancy determination

Description of the measuring room during the week of measurements

Mean temperature

Minimum, maximum temperature

Maximum change of temperature during 8 hours

Mean humidity

Minimum, maximum humidity



5.7 Traceability

(Insert the standards including additional weights used for the calibration and theirtraceabilities back to the international prototype of the kilogram)

Laboratory Date

1 kg

Identification Mass m Uncertaintyum(k=1) Volume V Uncertainty

uv (k=1) Cal. date

500g


uv (k=1) Cal. date

20 g


uv (k=1) Cal. date

2 g


uv (k=1) Cal. date

100 mg


uv (k=1) Cal. date



5.8 Data of artifacts:

Laboratory Date

Serial No.: 5060911Nominal

mass Identification Densitykg/m3

Uncertaintykg/m3

1 kg AE3 7960.66 + 0.20500 g AD2 7978.77 + 0.2020 g AFS 8043.6 + 1.52 g AUX 7987.7 + 10.5

100 mg ----- 8000 + 20



5.9 Record of the surface of the transfer standard5.9.1 Record of the surface of the transfer standard (p.1 of 5)

Laboratory Date

1 kg

Top surface

Rolled-out side surface

Base surface



5.9.2 Record of the surface of the transfer standard (p.2 of 5)

Laboratory Date

500 g

Top surface


Base surface




Laboratory Date

20 g

Top surface


Base surface




Laboratory Date

2 g

Top surface


Base surface




Laboratory Date

100 mg

Please describe the observations.



6. Formulas for the calculation of true mass and conventional mass of an OIMLmass and its uncertainty

For the evaluation of mass of a test standard and its uncertainty, calculation formulas for theone to-one comparison with a single reference standard or a sum of those are being given in:

INTERNATIONAL RECOMMENDATION OIML R 111-1 Edition 2004 (E)“Weights of classes E1, E2, F1, F2, M1, M1–2, M2, M2–3 and M3 Part 1:Metrological and technical requirements” to be used in the non definedinstruction.

Annex C : Calibration of a weight or weight set

Annex E : CIPM formula and an approximation formula

7. Remarks

7.1 If additional weights are used, their mass and volume shall be included. Data ofadditional weights with the test mass have negative sign.

The sensitivity of the balance may be determined with any measuring cycle or inlarger intervals depending on its change in time.

The air density ρ (shall be calculated using the Annex E : CIPM formula and anapproximation formula or using an other formula. This formula should be given inthe statement about the buoyancy calculation.

7.2 Uncertainty of the weighing process shall be determined from a significant number n ofrepetitions or from previous measurements using a “pooled” experimental standarddeviation with (see ISO Guide 4.2.4)

7.3 Uncertainty contributions for long-term stability of the reference standards should beconsidered.

Correlations between the masses of the reference standards and additional massesshould be included . If they are unknown, maximum correlation shall be given.Correlations between the volumes of the reference standards shall be considered in thesame manner .

7.4 In the case that, for determining the air density, the same instruments with the sameunknown systematic error (type B uncertainty) are used during the mass calibration ofthe test standard and that of the reference standards (correlated air densities), theuncertainty contribution of the air density contains co-varianceseven if the differencesin air density at the different calibrations are negligibly small. Only if the type Auncertainties of the instruments are much larger than the type B ones, can thecorrelation of air densities be neglected.



The volume of the reference standard is generally correlated with its mass , because ofthe buoyancy correction applied when the reference mass was calibrated (except for areference standard that is the international prototype). The difference between the airdensity during calibration of the reference standard and that during calibration of thetest standard is assumed to be negligibly small

7.5 Non-linearity of the balances shall be excluded by proper choice of the sensitivityweight, uncertainty contributions due to eccentric load or other systematic error of thebalance used should be included in repetablity of measurements. An importantsystematic error usually occurs with balances having an automatic weight exchangemechanism. The corresponding correction and its uncertainty contributions can beestimated by interchanging positions and its respective results.

7.6 The uncertainty contributions of corrections for different centers of gravity, temperaturedeviation from 20 o

reference weights are assumed to be negligibly small for comparisons.

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