By agreement a t the 10th WGFF meeting , the international comparison , for Volume of Liquids at 20 L and 100 mL, was performed during 2012 - 2014. Specially designed stainless steel pipettes were used as transfer standards for 20 L, whereas commercially available pycnomet ers were used for 100 mL. Only one measurement result, out of 39, was qualified as non - consistent. The average degree of equivalence ? ? , ? , for artifacts at 20 L (TS 710 - 04 and 710 - 05) resulted in 0.000 1 % and 0.000 44 %, respectively. As for the 1 00 mL artifacts, the average degree of equivalence ? ? , ? , for artifacts TS 03.01.12, 03.01.16 and 03.01.17 resulted in 0.000 54 %, 0.000 17 % and 0.001 1 %, respectively

Malengo, A

MALENGO, ANDREA

Archivio istituzionale della ricerca - INRIM

   9th ISFFM                                                                                                                                 Arlington, Virginia, April 14 to 17, 2015 Results of the second round of International Comparison for volume of Liquids at 20 L and 100 mL  Roberto Arias: Centro Nacional de Metrología (CENAM) John Wright: National Institute of Standards and Technology (NIST) Christian Lachance: Measurement Canada (MC) Elsa Batista: Instituto Português da Qualidade (IPQ) Erik Smits: Dutch Metrology Institute (VSL) Olle Penttinen: Technical Research Institute of Sweden (SP) Andrea Malengo: Instituto Nazionale di Ricerca Metrologica (INRIM) Wang Jintao: National Institute of Metrology (NIM) Dominic Ondoro: Kenya Bureau of Standards (KEBS) Dalni Malta: Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO) Corresponding Author: rarias@cenam.mx   Abstract By agreement at the 10th WGFF meeting, the international comparison, for Volume of Liquids at 20 L and 100 mL, was performed during 2012 – 2014. Specially designed stainless steel pipettes were used as transfer standards for 20 L, whereas commercially available pycnometers were used for 100 mL. Only one measurement result, out of 39, was qualified as non-consistent. The average degree of equivalence ?̅?𝑖,𝑗, for artifacts at 20 L (TS 710-04 and 710-05) resulted in 0.000 1 % and 0.000 44 %, respectively. As for the 100 mL artifacts, the average degree of equivalence ?̅?𝑖,𝑗, for artifacts TS 03.01.12, 03.01.16 and 03.01.17 resulted in 0.000 54 %, 0.000 17 % and 0.001 1 %, respectively.  1. Introduction Back in 2003, the first version of the International Comparison for Volume of Liquids at 20 L and 100 mL (under the umbrella of the International Committee for Weights and Measures) included 8 institutes, from eight economies; including participants from SIM, EURAMET and APMP. This second version of the International Comparison included 10 institutes, from 10 economies; six of which had already participated in the first round (CENAM/Mexico, NIST/USA, MC/Canada, SP/Sweden, INRIM/Italy and INMETRO/Brazil.  The transfer standards that were used for the second version of the Volume of Liquids at 20 L and 100 mL were the same as those for the first version. This time however, instead of using three artifacts for 20 L, only two stainless steel pipettes (FV-04 and FV-05) were used; similarly, three 100 mL pycnometers (03.01.12, 03.01.16 and 03.01.17) instead of the six pycnometers used back in 2003. Of course, all artifacts were re-manufactured in order to slightly change its corresponding volume (ether to contain or to deliver).  It is intended that at least one participating institute from each Regional Metrology Organization could, in the near future, lead the corresponding and subsequent, RMO Key Comparison; using the same, but slightly modified, transfer standards. These RMO Key Comparisons will allow linking any RMO participant to the KCRV.    9th ISFFM                                                                                                                                 Arlington, Virginia, April 14 to 17, 2015 Measurements from KEBS were not included into the calculation of the Reference Value because of the lack of the uncertainty statements for all of the artifacts.  2.  Participants # Participant Date Contact Remarks 1 CENAM, México 03/2012 Roberto Arias Pilot 2 NIST, USA  05/2012 John Wright SIM participant 3 MC, Canada 06/2012 Christian Lachance  SIM participant 4 IPQ, Portugal 07/2012 Elsa Batista EURAMET participant 5 VSL, Netherlands 08/2012 Erik Smits EURAMET participant 6 SP, Sweden 09/2012 Olle Penttinen EURAMET 7 INRIM, Italy 10/2012 Andrea Malengo EURAMET pivot 8 NIM, China 01/2013 Wang Jintao APMP pivot 9 KEBS, Kenya 04/2013 Dominic Ondoro AFRIMET participant 10 INMETRO, Brazil 02/2014 Dalni Malta SIM participant  Table 1.  List of participants for Comparison on Volume of Liquids at 20 L and 100 mL.   3. Conditions selected Each laboratory was responsible for receiving the Transfer Packages, testing and sending them to the next participant according to the schedule. The participating laboratories determined the volume of water that each of the two Transfer Standards (TS) of 20 L is able to deliver after a 60 second period of dripping-off at a reference temperature of 20 °C; as well as to determine the volume of water that each of the three 100 mL TSs - glass pycnometers of the Gay-Lussac type – is able to contain, at a reference temperature of 20 °C. The transfer package for 100 mL did not include a temperature measurement system. It was up to the participating laboratories to measure water temperature according to their own facilities and procedures.  4. the transfer packages 4.1 Transfer Package for 20 L (two items) Each transfer standard (TS) consists of: a) the 20 L pipette, b) a hand held digital thermometer, c) fittings for assembling and disassembling.      9th ISFFM                                                                                                                                 Arlington, Virginia, April 14 to 17, 2015  Fig. 1.  Image of the 20 L transfer standard  The 20 L pipette (see Fig. 1), which is made of stainless steel, has been designed to:  a) Minimize the contribution of the meniscus reading to the volume uncertainty, b) Minimize the quantity of water drops attained to the inner surface after drainage. c) Provide a leak-free metal to metal seal between the two parts of the container, d) Minimize the risk of volume changes, and e) Keep the air/liquid interface as small as possible.  These features were intended to produce repeatable and reproducible volume measurement values on the order of 0.005 %, or better. Temperature of the water inside the TS was measured by a hand held digital thermometer coupled with 4-wire Pt-100 temperature sensor. A torque wrench was supplied with the transfer package to provide repeatable and reproducible torque values while assembling the transfer standard. Based on experience and on reference data, CENAM, as the Pilot Laboratory, selected (47.7 ± 2.0) × 106 ºC1 as the cubic coefficient of expansion for the stainless steel used to make the TS; uncertainty is expressed as standard uncertainty. 4.2 Transfer Package for 100 mL (three items) The Transfer Standards for volume at 100 mL are commercially available glass pycnometers (Gay Lussac Type, see Fig. 2). Made out of boro-silicate glass, they were manufactured according to ISO 3507. A set of three pycnometers of 100 mL were calibrated and results given    9th ISFFM                                                                                                                                 Arlington, Virginia, April 14 to 17, 2015 for a reference temperature of 20 °C.  Each participating laboratory measured water temperature using its own instruments and procedures. The linear coefficient of expansion for the boro-silicate glass is provided by the manufacturer as 3.3 × 106 °C1; this value is transformed to a cubic expansion coefficient of (9.9 ± 1) × 106 °C1.    Fig. 2.  Image of the 100 mL transfer standards  5.  Experimental procedures  Weighing* Water** De-aerated water? Density formula 20 L 100 mL CENAM DS DR IE + O No Tanaka et al1 NIST DR  O No Patterson & Morris2 MC SS  1D No Tanaka et al IPQ SS SS IE + O No Tanaka et al VSL DS DS DM+2D No Bettin & Spieweck3 SP DS SS IE Yes Bettin & Spieweck INRIM SS SS IE + 2D No Tanaka et al NIM ABA SS IE No Tanaka et al INMETRO ABA DR DI No measured  Table 2.  Summary of the experimental procedure employed at the different NMIs  *Weighing: DS: Double substitution; DR: direct reading; SS: single substitution; ABA: substitution weighing **water: IE: Ion exchange; O: Inverse osmosis; 1D: single distillation; 2D: double distillation, DM: demineralized     9th ISFFM                                                                                                                                 Arlington, Virginia, April 14 to 17, 2015 No mathematical expression was provided or suggested in the technical protocol to evaluate the measurand; each participant made use of its own methods to determine the volume of water from mass and density determinations.  6.  Results 6.1 Stability of the TSs CENAM as the pilot laboratory tested all artifacts before and after the comparison. The results of the testing are given in tables 3 and 4. Initial tests values correspond to the official measurements results of CENAM and are taken for the calculation of the KCRV.  20 L date initial date final |∆V|/mL (xi ± u(xi))/mL, k = 2 (xi ± u(xi))/mL, k = 2 TS 710-04 03/2012 19 990.75 ± 0.80 06/2014 19 990.76 ± 0.80 0.01 TS 710-05 19 993.50 ± 0.80 19 993.41 ± 0.80 0.09  Table 3.  Stability of the 20 L TSs, according to the measurement results obtained at the pilot laboratory.   100 mL date initial date final |∆V|/mL  (xi ± u(xi))/mL, k = 2 (xi ± u(xi))/mL, k = 2 TS 03.01.12 03/2012 99.642 0 ± 0.002 6 06/2014 99.643 6 ± 0.002 6 0.001 6 TS 03.01.16 103.090 8 ± 0.002 6 103.092 5 ± 0.002 6 0.001 7 TS 03.01.17 100.596 8 ± 0.002 6 100.596 9 ± 0.002 6 0.000 1  Table 4.  Stability of the 100 mL TSs, according to the measurement results obtained at the pilot laboratory. No substantial drift was observed either on the 20 L TSs nor on the 100 mL TSs; the initial and final measurements at the pilot NMI showed to be consistent with each other, within the uncertainty. Therefore, no additional contribution of uncertainty due to drift will be included when calculating degrees of equivalence. It is to be noted that neither NIST nor MC tested the 100 mL artifacts, the technical contacts noted that they are not including calibration services of glassware in their corresponding CMC list. Therefore, 20 L TSs were tested by 10 participants, whereas 100 mL TSs by 8 NMIs.    9th ISFFM                                                                                                                                 Arlington, Virginia, April 14 to 17, 2015  6.2 Results reported by the participants Tables 5 and 6 show the results and standard uncertainties as reported by the participants. 20 L TSs TS  710-04 TS 710-05 xi/mL u(xi)/mL xi/mL u(xi)/mL CENAM 19 990.75 0.40 19 993.50 0.40 NIST 19 990.92 0.58 19 993.39 0.58 MC 19 990.45 0.75 19 993.24 0.75 IPQ 19 990.69 0.85 19 992.97 0.69 VSL 19 990.53 0.34 19 993.25 0.34 SP 19 990.62 0.25 19 993.45 0.25 INRIM 19 990.73 0.19 19 993.55 0.19 NIM 19 990.45 0.30 19 993.14 0.30 KEBS 19 978.13  20 007.64  INMETRO 19 991.05 0.20 19 993.81 0.20  100 mL TSs TS 03.01.12 TS 03.01.16 TS 03.01.17 xi/mL u(xi)/mL xi/mL u(xi)/mL xi/mL u(xi)/mL CENAM 99.642 0 0.001 3 103.090 8 0.001 3 100.596 8 0.001 3 IPQ 99.643 8 0.000 77 103.092 0 0.000 8 100.597 3 0.000 8 VSL 99.643 9 0.001 9 103.091 9 0.001 9 100.595 4 0.001 9 SP 99.644 7 0.001 5 103.094 0 0.001 5 100.597 5 0.001 7 INRIM 99.643 6 0.000 83 103.092 1 0.000 83 100.595 7 0.000 83 NIM 99.639 1 0.001 4 103.091 1 0.001 1 100.593 8 0.001 7 KEBS 100.407 0  100.955 1  100.017 3  INMETRO 99.643 3 0.000 48 103.091 9 0.000 46 100.595 5 0.000 44  Tables 5 & 6.  Reported results for 20 L and 100 mL TSs.   7. Computation of the key comparison reference values  The KCRV for volume of liquids at 20 L and 100 mL has been calculated by applying the “weighted mean” method as suggested by Cox4. Tables 7 – 11 show the calculations.    9th ISFFM                                                                                                                                 Arlington, Virginia, April 14 to 17, 2015 TS 710-04 xi/mL u(xi)/mL xi/u(xi)2 1/u(xi)2 (xi  xref)2/u(xi)2 CENAM 19 990.75 0.40 124 942.17 6.25 0.000 NIST 19 990.92 0.58 59 426.04 2.97265161 0.093 MC 19 990.45 0.75 35 538.58 1.77777778 0.152 IPQ 19 990.69 0.85 27 668.78 1.38408304 0.003 VSL 19 990.53 0.34 172 928.46 8.65051903 0.390 SP 19 990.62 0.25 319 849.89 16 0.248 INRIM 19 990.73 0.19 553 759.75 27.700831 0.007 NIM 19 990.45 0.30 222 116.10 11.1111111 0.960 INMETRO 19 991.05 0.20 499 776.14 25 2.292          2016005.9 100.846974 4.145    xref/mL 19 990.74 20.05,8  = 15.5    u(xref)/mL 0.10 pass  TS 710-05 xi/mL u(xi)/mL xi/u(xi)2 1/u(xi)2 (xi  xref)2/u(xi)2 CENAM 19 993.50 0.40 124 959.40 6.25 0.000 NIST 19 993.39 0.58 59 433.37 2.97265161 0.040 MC 19 993.24 0.75 35 543.55 1.77777778 0.118 IPQ 19 992.97 0.69 41 993.21 2.10039908 0.600 VSL 19 993.25 0.34 172 951.95 8.65051903 0.568 SP 19 993.45 0.25 319 895.18 16 0.045 INRIM 19 993.55 0.19 553 837.95 27.700831 0.065 NIM 19 993.14 0.3 222 146.03 11.1111111 1.428 INMETRO 19 993.81 0.17 691827.2 34.6020761 2.678          2222587.84 111.165366 5.996    xref/mL 19 993.53 20.05,8  = 15.5    u(xref)/mL 0.095 pass   Tables 7 & 8.  Consistency check and computation of KCRV for TSs 710-04 and 710-05    9th ISFFM                                                                                                                                 Arlington, Virginia, April 14 to 17, 2015   Figs. 3 & 4.  Measurement results for 20 L artifacts.    9th ISFFM                                                                                                                                 Arlington, Virginia, April 14 to 17, 2015  TS 03.01.12 xi/mL u(xi)/mL xi/u(xi)2 1/u(xi)2 (xi  xref)2/u(xi)2 CENAM 99.642 0 0.001 3 58959745 591715.976 0.929 IPQ 99.643 8 0.000 77 168061722 1686625.06 0.553 VSL 99.643 9 0.001 9 27602178.6 277008.31 0.114 SP 99.644 7 0.001 5 44286511.1 444444.444 0.906 INRIM 99.643 6 0.000 83 144641605 1451589.49 0.209 NIM 99.639 1 0.001 4 50836278.4 510204.082 8.645 INMETRO 99.643 3 0.000 48 432479774 4340277.78 0.060          926867815 9301865.14 11.418    xref/mL 99.643 22 20.05,6  = 12.6    u(xref)/mL 0.000 33 pass  Table 9.  Consistency check and computation of KCRV for TS 03.01.12.   TS 03.01.16 xi/mL u(xi)/mL xi/u(xi)2 1/u(xi)2 (xi  xref)2/u(xi)2 CENAM 103.090 8 0.001 3 61000480.5 591715.976 0.711 IPQ 103.092 0 0.000 80 161081205 1562500 0.006 VSL 103.091 9 0.001 9 28557299.6 277008.31 0.001 SP 103.094 0 0.001 5 45819555.6 444444.444 1.945 INRIM 103.092 1 0.000 83 149647431 1451589.49 0.062 NIM 103.091 1 0.001 1 85199265.9 826446.281 0.524 INMETRO 103.091 9 0.000 46 487201828 4725897.92 0.000          1018507065 9879602.42 3.249    xref/mL 103.091 91 20.05,6  = 12.6    u(xref)/mL 0.000 32 pass   Table 10.  Consistency check and computation of KCRV for TS 03.01.16.           9th ISFFM                                                                                                                                 Arlington, Virginia, April 14 to 17, 2015 TS 03.01.17 xi/mL u(xi)/mL xi/u(xi)2 1/u(xi)2 (xi  xref)2/u(xi)2 CENAM 100.596 8 0.001 3 59524759.2 591715.976 0.538 IPQ 100.597 3 0.000 80 157183295 1562500 3.149 VSL 100.595 4 0.001 9 27865770.1 277008.31 0.058 SP 100.597 5 0.001 7 34808823.5 346020.761 0.898 INRIM 100.595 7 0.000 83 146023625 1451589.49 0.067 NIM 100.593 8 0.001 7 34807531.9 346020.761 1.558 INMETRO 100.595 5 0.000 44 519604700 5165289.26 0.909          979818505 9740144.56 7.177    xref/mL 100.595 89 20.05,6  = 12.6    u(xref)/mL 0.000 32 pass   Table 11.  Consistency check and computation of KCRV for TS 03.01.17.     Fig. 5.  Measurement results for 20 L artifacts.    9th ISFFM                                                                                                                                 Arlington, Virginia, April 14 to 17, 2015     Figs. 6 & 7.  Measurement results for 100 mL artifacts.    9th ISFFM                                                                                                                                 Arlington, Virginia, April 14 to 17, 2015 8.  Conclusions  i. The International Comparison for Volume of Liquids at 20 L and 100 mL was conducted during 2012 – 2014; its execution was affected by the fact that the transfer package remained at the Brazilian Customs for nearly 8 months; despite this fact, the artifacts did not change their metrological properties, and the KC was completed successfully.  ii. The comparison project was piloted by CENAM. Ten institutes tested the two 20 L transfer standards, whereas 8 tested the three 100 mL pycnometers.  iii. No discrepant measurements were distinguished on the 20 L artifacts. The largest difference between two participants was 0.004 2 %; whereas the average degree of equivalence ?̅?𝑖,𝑗, for artifacts 710-04 and 710-05 resulted in 0.000 1 % and 0.000 44 %, respectively.  iv. Only one participant produced anomalous results for 100 mL measurements; NIM´s result for TS 03.01.12 was inconsistent with IPQ, VSL, SP, INRIM and INMETRO. However, results for artifacts 03.01.16 and  03.01.17 were all fully consistent with each other. The average degree of equivalence ?̅?𝑖,𝑗, for artifacts 03.01.16 and 03.01.17 resulted in 0.000 17 % and 0.001 1 %, respectively.   9.  Acknowledgments This section is intended to thank all metrologists that either performed the measurements or collaborated in the results analysis. From CENAM: Mrs. Sonia Trujillo and Manuel Maldonado; from VSL: Jos Rath and Erik Smits; from SP: Per Wennergren and Peter Lau; from IPQ: Nelson Almeida and Elsa Batista; from INRIM: Davide Torchio.                                                            [1] Tanaka, M., et. al; “Recommended table for the density of water between 0 °C and 40 °C based on recent experimental reports”, Metrologia, 2001, 38, 301-309. [2]  Patterson, J. B. and Morris, E. C., "Measurement of Absolute Water Density, 1C to 40C”, Metrologia, 31, 1994, 277-288. [3] Bettin, H., and Spieweck, F., "Die Dichte des Wassers als Funktion der Temperatur nach Einfuehrung der Internationalen Temperaturskala von 1990", PTB-Mitteilungen, 100, 1990, 195-196. [4] Cox M., "The evaluation of key comparison data"; Metrologia, 2002, 39, 589-595.  

Results of the second round of International Comparison for volume of Liquids at 20 L and 100 mL

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Results of the second round of International Comparison for volume of Liquids at 20 L and 100 mL

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