REPORT Calibration of industrial platinum resistance ... - BIPM

COOMET.T-S2 Page 1 of 65

REPORT

of

COOMET Supplementary Comparison

COOMET.T-S2 (COOMET project No 642/MD/14)

Calibration of industrial platinum resistance

thermometers in thermostats

at temperature range from -40 °C to 420 °C

Prepared by

Constantin Bordianu (coordinator)

National Institute of Metrology (INM)

28, E. Coca str., MD 2064, Chisinau, Republic of Moldova,

Phone: + (373) 22 903 103

Fax: + (373) 22 903 111

E-mail: [email protected]

[email protected]

2018

mailto:[email protected]



INDEX

1 Introduction ....................................................................................................................................... 3

2 Participants of comparison ................................................................................................................ 3

3 Comparison schedule ........................................................................................................................ 4

4 Description of thermometers ............................................................................................................. 4

5 Measurement procedures ................................................................................................................... 4

6 Characterization of thermometers ..................................................................................................... 5

7 Calibration method and instrumentation used ................................................................................... 7

8 Analysis of results ............................................................................................................................. 7

9 Uncertainty calculation of the reference values ................................................................................ 8

10 Standardized Deviation Coefficients calculation .............................................................................. 8

11 Results ............................................................................................................................................... 9

12 Conclusions ..................................................................................................................................... 21

ANNEX 1. Participant laboratories uncertainty budgets .......................................................................... 22

ANNEX 2. Equipment used ...................................................................................................................... 53

ANNEX 3. Comparison protocol .............................................................................................................. 55


1 Introduction

The object of this report is to present the results of the comparison of calibration of 100 Ω platinum

resistance thermometers. These comparisons are supplementary COOMET comparisons.

The purpose of the comparison is to determine the metrological equivalence of the participant

laboratories (see Table 1) in the calibration of platinum resistance thermometers by direct comparison

method in the range from (-40) ºC up to 420 ºC. The results of the comparison may be use by

participants for the confirmation of calibration and measurement capabilities and publications of CMCs

in this range.

The comparison runs from August 2015 to February 2018. INM has acted as the pilot laboratory also

providing the two thermometers used, whose characteristics are shown in table 3. The artifacts were

platinum resistance thermometers (PRTs), which were tested and characterized by INM, the

coordinating laboratory, before circulation. The protocols (given in Annex 3) provide guidance for

preparation, annealing criteria and the measurement sequence.

2 Participants of comparison

Participant details, name and e-mail address of the contact person are listed as follows:

Table 1. Participants of comparison

NMI Address Contact

person

e-mail address

phone, fax

1 National Institute of Metrology

(INM)

28, E. Coca Str., Chisinau,

Republic of Moldova MD-

2064

Constantin

Bordianu

(coordinator)

Phone: (+373) 22 903 103

Fax: (+373) 22 903 111

[email protected]

[email protected]

2

Center for standardization and

metrology under the Ministry of

economy of the Kyrgyz Republic

(CSM under MoE KR)

197 Panfilov Str., 720040

Bishkek, Kyrgyz Republic

Denisova

Marina

Phone: +996 (312) 66 02 38

Fax: +996 (312) 66 13 67

[email protected]

3

Kazakhstan Institute of

Metrology

(KazInMetr)

Center of Measurement

Standards, Left bank of the

river Ishim, Orynbor Str., 11,

010000, Astana, Republic of

Kazakhstan

Naryman

Kadyrov

Phone: +727 303 91 26

+7 701 666 59 29

[email protected]

[email protected]

4

State Metrology Service (SMS)

under the State Committee for

Standardization, Metrology and

Patent of the Republic of

Azerbaijan (AZSTAND)

124, Mardanov gardashlary

str., AZ 1147, Baku,

Republic of Azerbaijan

Azer

Baghirov

Phone:

(+994 12) 449-99-59/127

(+994 55) 507-08-45

Fax: (+994 12) 440-63-16

[email protected]

5

Georgian National Agency for

Standards and Metrology

(GEOSTM)

Chargali Str., 67, 0178

Tbilisi, Georgia Celidze Iurii

iurichelidze.geostm@yahoo

.com

6

Institute of Metrology of Bosnia

and Herzegovina

(IMBiH)

Augusta Brauna 2, 71000

Sarajevo, Bosnia and

Herzegovina

Nedzadeta

Hodzic

[email protected]

.ba

7 TUBITAK National Metrology

Institute (UME)

Barıs Mh. Tubitak Gebze

Yerleskesi P.K.54, 41470

Gebze/Kocaeli, Turkey

Alev Çorman [email protected]













3 Comparison schedule

The planned comparison schedule, artifact transport and handling, and instructions to participants

was reproduce in Annex 3. The final circulation scheme was as follows:

Table 2. Comparison Schedule

NMI Country Final of measurements

INM Republic of Moldova 07 August 2015

CSM Kyrgyz Republic 02 December 2015

AZSTAND Republic of Azerbaijan 28 March 2016

GEOSTM Georgia 30 June 2016

IMBiH Bosnia and Herzegovina 31 October 2016

UME Turkey 30 March 2017

KazInMetr Republic of Kazakhstan 22 December 2017

INM Republic of Moldova 28 February 2018

All temperature values are referred to the International Temperature Scale of 1990 (ITS-90).

4 Description of thermometers

The PRTs used as traveler thermometers, were intend to represent the normal platinum resistance

thermometers having, at the same time, enough stability to allow the comparison of the results. Two

different thermometers were used to increase the reliability of the comparison. Table 3 provides a

summary of the main features of the PRTs used.

Table 3. PRTs characteristics

Manufacturer VNIIM, Russia

Model ЭТС – 100/1

Serial Number 15 - 57 15 - 67

Temperature range of -200 °C to 661 °C

Resistance values at 0 °C 100 Ω

Metal sheath thermometer length 650 mm

Diameter 6 mm

The INM is the reference laboratory where the PRTs ware calibrated before and after circulation.

After receiving the PRTs, before calibration started, participating laboratories should complete the

preliminary work outlined below.

5 Measurement procedures

The protocol of the comparison (Annex 3) was prepared by INM and agreed with the participant

laboratories. It was approved by the CCT-WG7 in May 2016. The modifications introduced in the

protocol, following the CCT-WG7 requests, did not involve critical changes in the measurement

procedure so it was not necessary to repeat any measurements after the CCT-WG7 protocol acceptance.

It was agreed to make the comparison using the Wt of each laboratory at 1mA current. The Wt values

ware defined as the quotient between the resistance value of the thermometer at the calibration point and

the resistance value at the triple point of water.


In order to maintain as much control as possible over the travelling PRTs and check the influence of

transport, participants were requested to report to INM the PRTs measured resistance values at the triple

point of water or at the ice point prior to the calibration.

6 Characterization of thermometers

PRTs characterization were conducted by INM and consisted mainly of two studies:

- Heat conduction study

- Hysteresis study

6.1 Heat conduction study

A heat conduction study was done for two thermometers of the same model in order to determine the

proper immersion depth for each PRT. The study was conducted in the extreme temperatures of

calibration: (-40) ºC and 420 ºC, and consisted in full immersion of the PRT and then decreasing the

immersion depth centimeter-by-centimeter taking readings of the PRT resistance value in each position.

Below are two graphs (figure 1) with the results obtained.

Figure 1. PRTs heat conduction study

The results show that the optimum depth of immersion should not be less than 160 mm.

6.2 Hysteresis study

Both PRTs were subjected to five temperature cycles. At each cycle were performed:

- Cooling to -40 ºC for at least 10 minutes.

- Air heating to room temperature.

- Determination of Rt (at 0,01 ºC).

- Heating to 420 ºC for at least 10 minutes.

- Air cooling to room temperature.

- Determination of Rt (at 0,01 ºC).

This hysteresis study was performed twice, one before the first calibration at INM and the other one

before the last calibration at INM. Figure 2 shows the results obtained, where the odd-numbered points

are after cooling to -40 °C and even-numbered points are after heating to 420 °C.

Both thermometers have shown the overall stability within 3 mK along the whole hysteresis study.

However, it is difficult to distinguish clearly, if the causes of the instabilities are due to the thermometer

hysteresis. The differences observed are mainly due to short time stabilities of the thermometers.


Figure 2. Hysteresis study

6.3 Thermometers self-heating

INM performed measurements of the thermometers self-heating in an ice point during the initial and

the final calibrations. The self-heating was estimated by measuring the thermometers resistance at two

electrical currents: 1 mA and 2 mA. The self-heating was in all cases lower that 2 mK.

6.4 Stability of the thermometers

The stability of PRTs during the comparison was determined as the difference between the results

received by the INM at the beginning and end of the comparison.

Also, for the better study of PRTs stability, the results obtained by each laboratory were also

analyzed. The comparison protocols specified the measurement of R (0 °C) or TPW as receiving and

send the results immediately to INM. This data allowed the checking of the thermometer status after the

successive displacements and, if significant changes were detected, allowed the taking of appropriate

actions. R (0 °C) measurements were performing by the laboratories at the water triple point or at the ice

bath. In order to standardize the results and comparing them, the resistance values were extrapolated to

the water triple point temperature.

Table 4. Control measurements at the water triple point, PRT s/n 15-57

Laboratory Date Temperature,

°C

Measurement

resistance, Ω

Resistance in

TPW, Ω Uncertainty, °C

INM 07.08.2015 0,0100 100,0780 100,0780 0,006

CSM 02.12.2015 0,0000 100,0696 100,0736 0,02

AzMI 28.03.2016 -0,1350 100,0068 100,0647 0,04

GEOSTM 30.06.2016 0,0002 100,0720 100,0759 0,005

IMBiH 31.10.2016 0,0100 100,0780 100,0780 0,001

UME 30.03.2017 0,0100 100,0784 100,0784 0,01

KazInMetr 22.12.2017 0,3450 100,2160 100,0823 0,024

INM 28.02.2018 0,0100 100,0784 100,0784 0,006

Table 5. Control measurements at the water triple point, PRT s/n 15-67

Laboratory Date Temperature,

°C

Measurement

resistance, Ω

Resistance in

TPW, Ω

Uncertainty,

°C

INM 07.08.2015 0,0100 100,1290 100,1289 0,006

CSM 02.12.2015 0,0000 100,1178 100,1218 0,02

GEOSTM 30.06.2016 -0,0006 100,1240 100,1282 0,005

IMBiH 31.10.2016 0,0100 100,1304 100,1304 0,001


UME 30.03.2017 0,0100 100,1318 100,1318 0,01

KazInMetr 22.12.2017 0,3450 100,2700 100,1362 0,024

INM 28.02.2018 0,0100 100,1295 100,1295 0,006

Figure 3. Control measurements at the water triple point

The results obtained for both thermometers are given in Tables 4 and 5 and graphically in figure 3.

The uncertainties showed are those supplied by the laboratories in the reception formats. No significant

drifts were observed during the comparison. The temperature drift of the thermometers over the interval

of the comparisons, as observed by INM, does not exceed 4 mK.

7 Calibration method and instrumentation used

The calibration method to be used was by comparison, in isothermal media, against previously

calibrated reference standards. The Annex 3 of this report includes the comparison protocol, which

describes the process and measurement points.

The procedure used by each laboratory was the one used in routine calibrations. The Annex 2 shows

a summary of the instrumentation used by the participants.

8 Analysis of results

In order to compare the results, the data sent by each laboratory were extrapolated to the reference

temperatures given in the protocol. For this were use sensitivity coefficients (defined as the resistance

change of each PRT with temperature). They were calculated using the fitting curves obtained in the last

calibration in INM. A least-square fit to the differences between the measured values and the ITS-90

reference functions were made. The deviation equation used in the complete range was:

211 tt WbWatW (1)

The evaluation of the results was made in terms of the reduced resistance Wt in each calibration point

in order to eliminate possible PRTs instabilities. The last measured value by each laboratory in the triple

point of water or ice point was use for Wt calculation (tables 10 and 11).


9 Uncertainty calculation of the reference values

For each calibration point it was considered as the reference values the mean between the first and

the last calibration at INM because the thermometers shown enough stability throughout the

comparison. For calculating the uncertainty of the reference value, the following mathematical model

was considered:

tWtWtWtW

tW extstabINMINM

ref

2

21 (2)

Where:

tW 1INM and tW 2INM : the values of W at the calibration point t measured at the first and the

last calibration at INM respectively.

tWstab : Correction due to lack of stability at the calibration point t of the PRT.

tWext : Extrapolation value in the calibration point for getting the reference temperature t.

Taken into account that the uncertainties corresponding to the first and final INM calibrations are

highly correlated, applying the law of propagation of uncertainties to (2):

extstabINMref WuWuWuWu 2222 (3)

Where:

u(Wref): standard uncertainty of the W reference value at the calibration point t.

u(WINM): INM calibration standard uncertainty at the calibration point t.

u(δWstab): standard uncertainty due to the lack of stability of the PRT throughout the comparison.

It was calculate considering the difference between the first and the last calibration of the PRT at the

point t as the maximum value for this cause and using a rectangular probability distribution.

3

21 tWtWWu INMINM

stab

(4)

u(ΔWext): standard uncertainty due to the extrapolation of the measured values to the nominal

value of the calibration point. It was consider a value of 0,004 °C corresponding to the standard

deviation of the fitting residues.

The uncertainties in Wt were calculated by using the corresponding uncertainty in Rt and the

calculated thermometers sensitivity coefficients as they appear in tables 12 to 23.

The values of u(δWstab) and u(ΔWext) are small and have little influence on the uncertainty of the

reference value u(Wref).

10 Standardized Deviation Coefficients calculation

In order to assess the results of the participant laboratories, the standardized deviation coefficients

were calculated at each calibration point and for each laboratory. They were defined as:

t

refxlab

refxlab

n dW/dttUtU

tWtWtE

22 (5)


Where:

tW xlab - The value calculated for laboratory at temperature t;

tWref - The reference value calculated for the pilot laboratory at temperature t;

tU xlab - Calibration expanded uncertainty of the laboratory x at the temperature t;

tUref - Expanded uncertainty of the pilot laboratory at temperature t.

11 Results

The results are presented in tabular and graphical form for both PRTs at each calibration point. In the

tables 6 to 11, each column is:

Column 1 - Identification of the participants.

Column 2 - t, reference measured temperatures reported by the participants.

Column 3 - R(t), measured resistance values reported by the participants.

Column 4 - R(tcp), PRT resistance values extrapolated to the nominal value of the calibration point t.

Column 5 - U(t), calibration expanded uncertainty (k = 2) for R(t), in ºC, reported by the participants.

Column 6 - U(tcp), calibration expanded uncertainty (k = 2) for R(tcp), in ºC, calculated by combining

the expanded uncertainty reported by the laboratories and uncertainty of extrapolation.

Column 7 - En, standardized deviation coefficient.

Column 8 - Immersion depth of the thermometer in the calibration point.

In the tables 12 to 23, in the column 5, W(tcp): calculated W at the nominal value of the calibration

point tcp. The R (0,01 ºC) used is the one calculated for each participant at the end of the calibration

(tables 10 and 11). The extrapolated results obtained at each calibration, with their corresponding

uncertainties, are plotted in figures 4 to 21 where three solid lines represents the reference values and

the upper and lower limits of their expanded uncertainty. A coverage factor k = 2 has been considered.

Beginning of the calibration

Calibration point, tcp = 0,010 °C Rref = 100,0784 Ω

PRT sensitivity coefficient = 0,3992 Ω / °C Uref = 0,007 °C

Table 6. PRT s/n 15-57

Laboratory t R(t) R(tcp) U(t) U(tcp) En Immersion

°C Ω Ω °C °C mm

INM 0,010 100,0785 100,0785 0,006 0,006 0,04 260

CSM 0,000 100,0696 100,0736 0,02 0,02 -0,56 200

AzMI -0,135 100,0054 100,0633 0,040 0,040 -0,93 200

GEOSTM 0,000 100,0718 100,0759 0,005 0,005 -0,70 215

IMBiH 0,010 100,0775 100,0775 0,001 0,002 -0,29 280

UME -0,009 100,0708 100,0785 0,010 0,010 0,04 200

KazInMetr 0,084 100,1160 100,0865 0,024 0,024 0,82 180

INM 0,010 100,0782 100,0782 0,006 0,006 -0,04 260


Figure 4. PRT s/n 15-57






INM 0,0100 100,1289 100,1289 0,006 0,006 -0,04 260

CSM 0,0000 100,1179 100,1219 0,02 0,02 -0,84 200

GEOSTM 0,0003 100,1240 100,1278 0,005 0,005 -0,36 215

IMBiH 0,0100 100,1299 100,1299 0,001 0,002 0,29 280

UME -0,0094 100,1242 100,1319 0,010 0,010 0,58 200

KazInMetr 0,0840 100,1650 100,1354 0,024 0,024 0,65 180

INM 0,0100 100,1292 100,1292 0,006 0,006 0,04 260



Mid-point of the calibration






INM 0,010 100,0782 100,0782 0,006 0,006 -0,01 260

CSM -0,003 100,0685 100,0737 0,02 0,02 -0,54 200

AzMI -0,135 100,0058 100,0637 0,040 0,040 -0,90 200

GEOSTM 0,000 100,0718 100,0759 0,005 0,005 -0,68 215

IMBiH 0,010 100,0776 100,0776 0,001 0,002 -0,22 280

UME -0,006 100,0713 100,0777 0,010 0,010 -0,11 200

KazInMetr 0,085 100,1159 100,0860 0,024 0,024 0,78 180

INM 0,010 100,0783 100,0783 0,006 0,006 0,01 260







INM 0,0100 100,1291 100,1291 0,006 0,006 -0,03 260

CSM -0,0030 100,1169 100,1221 0,02 0,02 -0,84 200

GEOSTM 0,0003 100,1240 100,1278 0,005 0,005 -0,40 215

IMBiH 0,0100 100,1299 100,1299 0,001 0,002 0,24 280

UME -0,0060 100,1247 100,1311 0,010 0,010 0,38 200

KazInMetr 0,0850 100,1650 100,1350 0,024 0,024 0,59 180

INM 0,0100 100,1293 100,1293 0,006 0,006 0,03 260



End of the calibration






INM 0,010 100,0780 100,0780 0,006 0,006 -0,05 260

CSM 0,000 100,0696 100,0736 0,02 0,02 -0,54 200

AzMI -0,135 100,0068 100,0647 0,040 0,040 -0,83 200

GEOSTM 0,000 100,0720 100,0759 0,005 0,005 -0,66 215

IMBiH 0,010 100,0780 100,0780 0,001 0,002 -0,07 280

UME 0,010 100,0784 100,0784 0,010 0,010 0,04 200

KazInMetr 0,085 100,1161 100,0864 0,024 0,024 0,83 180

INM 0,010 100,0784 100,0784 0,006 0,006 0,05 260








INM 0,0100 100,1290 100,1290 0,006 0,006 -0,07 260

CSM 0,0000 100,1178 100,1218 0,02 0,02 -0,88 200

GEOSTM -0,0006 100,1240 100,1282 0,005 0,005 -0,30 215

IMBiH 0,0100 100,1304 100,1304 0,001 0,002 0,39 280

UME 0,0100 100,1318 100,1318 0,010 0,010 0,51 200

KazInMetr 0,0845 100,1650 100,1352 0,024 0,024 0,61 180

INM 0,0100 100,1295 100,1295 0,006 0,006 0,07 260


Calibration point, tcp = -40,0 °C Wref = 0,840154 Ω/ Ω



Laboratory t R(t) R(tcp) W(tcp) U(t) U(tcp) En Immersion

°C Ω Ω Ω/ Ω °C °C mm

INM -40,020 84,0442 84,0812 0,840157 0,030 0,030 0,02 250

CSM -39,910 84,1075 84,0782 0,840164 0,03 0,03 0,06 200

AzMI -40,035 84,0588 84,0638 0,840095 0,012 0,012 -0,44 200

IMBiH -40,009 84,0705 84,0734 0,840079 0,008 0,008 -0,58 230

UME -40,093 84,0406 84,0779 0,840120 0,010 0,010 -0,25 300

KazInMetr -39,760 84,1992 84,1067 0,840341 0,038 0,038 0,94 180

INM -39,998 84,0817 84,0809 0,840150 0,030 0,030 -0,02 250








INM -40,0200 84,1281 84,1349 0,840265 0,030 0,030 0,00 250

CSM -39,9100 84,1553 84,1188 0,840165 0,03 0,03 -0,58 200

IMBiH -40,0086 84,1225 84,1253 0,840158 0,008 0,008 -0,83 230

UME -40,0926 84,0916 84,1289 0,840181 0,010 0,010 -0,64 300

KazInMetr -39,760 84,2560 84,1596 0,840459 0,038 0,038 0,97 180

INM -39,998 84,1362 84,1354 0,840266 0,030 0,030 0,00 250








INM -20,072 92,1109 92,0989 0,920271 0,030 0,031 -0,16 250

CSM -19,908 92,1320 92,0963 0,920285 0,02 0,02 -0,09 200

AzMI -19,735 92,0371 92,0996 0,920401 0,009 0,009 0,74 200

IMBiH -20,053 92,0773 92,0991 0,920273 0,008 0,008 -0,19 230

UME -20,249 92,0016 92,1013 0,920291 0,010 0,010 -0,06 300

KazInMetr -19,960 92,2285 92,1265 0,920470 0,037 0,037 0,86 180

INM -20,012 92,1001 92,1049 0,920327 0,030 0,031 0,16 250







INM -20,0720 92,1235 92,1541 0,920353 0,030 0,030 0,04 250

CSM -19,9080 92,1798 92,1434 0,920313 0,02 0,02 -0,22 200

IMBiH -20,0525 92,1294 92,1513 0,920313 0,008 0,008 -0,26 230

UME -20,2492 92,0539 92,1536 0,920323 0,010 0,010 -0,18 300

KazInMetr -19,9600 92,1851 92,1691 0,920446 0,037 0,037 0,52 180

INM -20,0120 92,1483 92,1531 0,920339 0,030 0,030 -0,04 250



Calibration point, tcp = 30,0 °C Wref = 1,118579 Ω/ Ω





INM 29,985 111,9408 111,9444 1,118571 0,012 0,012 -0,12 250

CSM 29,961 111,9245 111,9429 1,118606 0,02 0,02 0,28 200

AzMI 30,065 111,8511 111,9271 1,118548 0,009 0,009 -0,50 200

GEOSTM 30,003 111,9430 111,9463 1,118614 0,012 0,012 0,49 200

IMBiH 29,976 111,9337 111,9427 1,118554 0,007 0,007 -0,43 230

UME 30,072 111,9725 111,9449 1,118572 0,010 0,010 -0,11 300

KazInMetr 30,030 112,0997 111,9625 1,118659 0,046 0,046 0,42 180

INM 30,015 111,9523 111,9465 1,118588 0,012 0,012 0,12 250








INM 29,9850 111,9874 111,9953 1,118510 0,012 0,012 0,05 250

CSM 29,9610 111,9718 111,9884 1,118521 0,02 0,02 0,15 200

GEOSTM 29,9888 111,9868 111,9929 1,118495 0,012 0,012 -0,16 200

IMBiH 29,9759 111,9862 111,9954 1,118495 0,007 0,007 -0,20 230

UME 30,0721 112,0294 111,9996 1,118521 0,010 0,010 0,23 300

KazInMetr 30,0300 112,0511 112,0142 1,118629 0,046 0,046 0,64 180

INM 30,0150 111,9998 111,9952 1,118503 0,012 0,012 -0,05 250







INM 156,993 160,9993 161,0006 1,608751 0,030 0,031 -0,15 250

CSM 157,033 161,0072 161,0028 1,608844 0,04 0,041 0,34 200

AzMI 156,756 160,8727 160,9785 1,608745 0,011 0,014 -0,24 200

GEOSTM 157,280 161,1121 161,0124 1,608902 0,017 0,018 0,88 200

IMBiH 157,010 161,0041 160,9989 1,608734 0,008 0,011 -0,32 230

UME 157,040 161,0188 161,0021 1,608760 0,015 0,017 -0,12 250

INM 157,023 161,0196 161,0064 1,608802 0,030 0,031 0,15 250








INM 156,9930 161,0436 161,0494 1,608419 0,030 0,030 0,09 250

CSM 157,0330 161,0530 161,0404 1,608445 0,04 0,04 0,21 200

GeoSTM 156,8993 161,0134 161,0470 1,608407 0,017 0,017 0,02 200

IMBiH 157,0099 161,0583 161,0529 1,608431 0,008 0,009 0,22 230

UME 157,0399 161,0743 161,0603 1,608483 0,015 0,016 0,59 250

INM 157,0230 161,0522 161,0473 1,608390 0,030 0,030 -0,09 250








INM 232,152 189,1250 189,0757 1,889284 0,030 0,031 -0,14 250

CSM 232,042 189,0813 189,0740 1,889349 0,04 0,041 0,22 200

AzMI 232,077 188,9445 189,0591 1,889369 0,011 0,013 0,48 300

GEOSTM 232,583 189,2966 189,0883 1,889448 0,023 0,024 0,94 200

IMBiH 231,859 189,0239 189,0792 1,889318 0,009 0,012 0,08 230

UME 232,633 189,3118 189,0781 1,889299 0,015 0,017 -0,06 250

KazInMetr 231,985 189,0392 189,1167 1,889535 0,055 0,055 0,96 140

INM 232,031 189,0865 189,0813 1,889331 0,030 0,031 0,14 250







INM 232,1520 189,1871 189,1222 1,888785 0,030 0,031 0,12 250

CSM 232,0420 189,1274 189,1095 1,888795 0,04 0,04 0,15 200

GEOSTM 232,2428 189,2113 189,1244 1,888822 0,023 0,024 0,38 200

IMBiH 231,8592 189,0788 189,1340 1,888876 0,009 0,011 0,88 230

UME 232,6330 189,3698 189,1372 1,888882 0,015 0,016 0,87 250

KazInMetr 231,9850 189,0951 189,1542 1,888987 0,055 0,055 0,93 140

INM 232,0310 189,1389 189,1192 1,888746 0,030 0,031 -0,12 250








INM 419,995 256,5865 256,5850 2,563850 0,500 0,500 0,01 190

CSM 420,024 256,5545 256,5554 2,563668 0,500 0,500 -0,07 200

AzMI 419,846 256,3949 256,6060 2,564401 0,500 0,500 0,23 150

IMBiH 420,722 256,8687 256,6160 2,564160 0,600 0,600 0,12 250

UME 420,158 256,6445 256,5898 2,563888 0,020 0,021 0,03 250

KazInMetr 419,760 256,6465 256,5881 2,563667 0,065 0,066 -0,09 140

INM 420,014 256,5893 256,5826 2,563816 0,500 0,500 -0,01 190








INM 419,9950 256,6167 256,6220 2,562914 0,500 0,500 0,01 190

CSM 420,0240 256,6007 256,5936 2,562815 0,500 0,500 -0,03 200

IMBiH 420,7218 256,9253 256,6728 2,563385 0,600 0,600 0,18 250

UME 420,1580 256,7041 256,6479 2,563101 0,020 0,022 0,12 250

KazInMetr 419,7600 256,5121 256,5670 2,562204 0,065 0,066 -0,39 140

INM 420,0140 256,6198 256,6180 2,562861 0,500 0,500 -0,01 190


12 Conclusions

The thermometers have shown an acceptable behavior throughout the comparison as figures 4 and 5

show then, the results can be considered valid for comparing the measurement capabilities of the

participant laboratories. The small changes in TPW resistance of the PRTs, measured by INM (6.4),

support the conclusions that the PRTs were sufficiently stable.

The determined values |En| are ≤ 1 for all laboratories in the comparison. That means the

measurement results of all laboratories confirm the declared by them the expanded uncertainties.

The equivalence between the participant laboratories in the calibration of platinum resistance

thermometers by comparison in the range from (-40) ºC up to 420 ºC has been demonstrated.


ANNEX 1. Participant laboratories uncertainty budgets

CSM Uncertainty budget

Calibration point: (-40) °С, PRT s/n 15-57

Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)

Contribution of UUC (PRT)

PRT reading (Ω) 0,000197 Normal 2,5 0,0004925

Drift of PRT at 0 °C 0,00003 Rectangular 2,5 0,000075

Self - heating of PRT (Ω) 0,00024 Rectangular 2,5 0,0006

Calibration of indicator (Ω) (accuracy) 0,00027 Rectangular 2,5 0,000675

Reference standard

Temperature reading of SPRT(°C) 0,000 Normal 1 0,000

SPRT calibration (°C) 0,003 Normal 1 0,003

Indicator calibration of (°C) 0,0014 Normal 1 0,0014

Temperature source

Axial uniformity of temperature source (°C) 0,000 Rectangular 1 0,000

Radial uniformity of temperature source (°C) 0,0121 Rectangular 1 0,0121

Instability of temperature source (°C) 0,0038 Rectangular 1 0,0038

Combined standard uncertainty 0,013

Expanded uncertainty (k = 2) 0,03


Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard




Temperature source







Calibration point: 0 °C, PRT s/n 15-57

Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard




Temperature source







Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard




Temperature source








Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard




Temperature source







Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard




Temperature source








Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard




Temperature source







Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)



Drift of PRT at 0 °C 0 Rectangular 2,5 0



Reference standard




Temperature source








Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard




Temperature source







Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard




Temperature source








Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard




Temperature source







Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard




Temperature source








Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard




Temperature source







Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard




Temperature source







INM Uncertainty budget

Calibration point: (-40) °C

Quantity Units Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi), mK

Reference standard

SPRT reading °C 0,0091 Normal 1,0 9,07

SPRT calibration °C 0,0040 Normal 1,0 4,00

SPRT drift °C 0,0012 Rectangular 1,0 1,15

Resistance bridge calibration Ω 0,000015 Normal 2,5 0,04

Drift of the resistance bridge Ω 0,000058 Rectangular 2,5 0,14

Temperature source

Uniformity of temperature source °C 0,004 Rectangular 1,0 4,04

Instability of temperature source °C 0,003 Rectangular 1,0 3,46


PRT reading Ω 0,0007 Normal 2,5 1,77

Drift of PRT at TPW Ω 0,0005 Rectangular 2,5 1,11

Self - heating of PRT Ω 0,0010 Normal 2,5 2,47



Combined standard uncertainty, °C 0,015

Expanded uncertainty (k = 2), °C 0,03



uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi), mK

Reference standard






Temperature source












Calibration point: 0,01 °C


uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi), mK

Reference standard

Repeatability mK 0,0000036 Normal 1,0 0,004

Resistance bridge calibration mK 0,0376 Normal 1,0 0,038

Drift of the resistance bridge mK 0,1447 Rectangular 1,0 0,145

Resolution of the resistance bridge mK 0,0007 Rectangular 1,0 0,001

Standard Resistor calibration mK 0,0031 Normal 1,0 0,003

Drift of the Standard Resistor mK 0,0145 Rectangular 1,0 0,014

Stability of the bath of Standard

Resistor mK 0,0003 Rectangular 1,0 0,000

Isotopic composition of PTW mK 0,0312 Rectangular 1,0 0,031

Hydrostatic Pressure Effect mK 0,0021 Rectangular 1,0 0,002







Resolution of the resistance bridge Ω 0,00016 Rectangular 2,5 0,394



Calibration point: 30 °C


uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi), mK

Reference standard






Temperature source














uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi), mK

Reference standard





Drift of the resistance bridge Ω 5,773E-05 Rectangular 2,7 0,16

Temperature source













uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi), mK

Reference standard






Temperature source














uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi), mK

Reference standard






Temperature source

Radial uniformity °C 0,014 Rectangular 1,0 14,43

Axial uniformity °C 0,231 Rectangular 1,0 230,9











AzMI Uncertainty budget


Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)


Bridge calibration (°C) 0,0012 Normal 1 1,33E-06

Temperature reading of SPRT (°C) 0,0004 Normal 1 0,00000016

PRT reading (Ω) 0,0002 Normal 2,6 2,0E-07

Calibration of indicator (Ω) 0,00057 Rectangular 2,6 2,21E-06

Self - heating of PRT (Ω) 8,66E-05 Rectangular 2,6 5,19E-08

Drift of PRT at 0 °C 0,00058 Rectangular 2,5 2,18E-06

Uniformity of temperature source (°C) 0,004 Rectangular 1 1,63E-05





Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)



Temperature reading of SPRT(°C) 0,0003 Normal 1 1,09E-07


Calibration of indicator (Ω) 0,00056 Normal 2,6 2,21E-06








Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)








Uniformity of temperature source (°C) 0,016 Rectangular 1 0,00027






Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)







Drift of PRT at 0°C 0,000577 Rectangular 2,5 2,184E-06






Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)

SPRT calibration 0,0015 Normal 1 0,00000225

Bridge calibration 0,00115 Normal 1 1,33E-06



Calibration of indicator (Ω or °C) 0,000566 Rectangular 2,6 2,214E-06








Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)














Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)








Uniformity of temperature source (°C) 0,248 Rectangular 1 0,0616




IMBiH Uncertainty budget

Calibration point: (-40) °C, PRT s/n 15-57

Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)

Reference SPRT: Repeatability (°C) 0,00089 Normal 1 7,8E-07

Reference SPRT: Certificate (°C) 0,0015 Normal 1 0,00000225

Reference SPRT: Annual drift (°C) 0,00078 Rectangular 1 6,04E-07

Homogeneity of the liquid bath (radial,

axial, stability) (°C) 0,0032 Rectangular 1 0,00001

Thermometer under test: Repeatability

(°C) 0,00088 Normal 1 7,78E-07

Hysteresis effects (°C) 0,00116 Rectangular 1 1,34E-06

Resistance Bridge (calibration

certificate/accuracy) (°C) 0,00028 Normal 1 0,00000008

Resolution of the resistance bridge (°C) 7,2E-08 Rectangular 1 5,208E-15

Standard Resistor (calibration

certificate) (°C) 0 Normal 1 0

Drift of Standard Resistor (°C) 0 Rectangular 1 0

Stability of the maintenance bath of

resistors (°C) 0 Rectangular 1 0

Interpolation Equation (°C) 0 Normal 1 0

Self-heating effect (°C) 0,00014 Rectangular 1 1,96E-08





Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)





axial, stability) (°C) 0,0032 Rectangular 1

0,00001


(°C) 0,00088 Normal 1

7,80E-07



certificate/accuracy) (°C) 0,00028 Normal 1

0,00000008



certificate) (°C) 0 Normal 1

0



resistors (°C) 0 Rectangular 1

0






Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)

Reference SPRT: Repeatability (°C) 6,59E-05 Normal 1 4,34E-09





0,00001


(°C) 7,28E-05 Normal 1

5,29E-09




0,00000008




0




0







Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)






0,00001


(°C) 7,84E-05 Normal 1

6,14E-09




0,00000008




0




0






Quantity Standard

uncertainty

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)

Repeatability (°C) 8,01E-06 1 6,42E-11

Isotopic composition (°C) 0,00002 1 4E-10

Impurities (°C) 0,00002 1 4E-10

Self-Heating Effect (°C) 0,00014 1 2,02E-08

Hydrostatic Pressure Effect (°C) 5,16E-05 1 2,67E-09

Heat-flux (°C) 8,31E-05 1 6,90E-09

Resistance Bridge (calibration certificate/accuracy) (°C) 0,00028 1 0,00000008

Resolution of the resistance bridge (°C) 7,22E-08 1 5,21E-15

Standard Resistor (calibration certificate) (°C) 0 1 0

Drift of Standard Resistor (°C) 0 1 6,75E-10

Stability of the maintenance bath of resistors (°C) 0 1 0

Interpolation Equation (°C) 0 1 0





Quantity Standard

uncertainty

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)

Repeatability (°C) 1,35E-05 1 1,82E-10

Isotopic composition (°C) 0,00002 1 4E-10

Impurities (°C) 0,00002 1 4E-10

Self-Heating Effect (°C) 0,00015 1 2,24E-08

Hydrostatic Pressure Effect (°C) 5,16E-05 1 2,67E-09

Heat-flux (°C) 8,31E-05 1 6,9E-09

Resistance Bridge (calibration certificate/accuracy) (°C) 0,00028 1 8E-08

Resolution of the resistance bridge (°C) 7,22E-08 1 5,21E-15

Standard Resistor (calibration certificate) (°C) 0 1 0

Drift of Standard Resistor (°C) 0 1 6,75E-10

Stability of the maintenance bath of resistors (°C) 0 1 0

Interpolation Equation (°C) 0 1 0




Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)





axial, stability) (°C) 0,00276 Rectangular 1 7,60E-06

Thermometer under test: Repeatibility (°C) 9,12E-05 Normal 1 8,32E-09





Standard Resistor (calibration certificate)

(°C) 0 Normal 1 0










Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)






Thermometer under test: Repeatibility (°C) 9,77E-05 Normal 1 9,576E-09






(°C) 0 Normal 1 0









Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)






Thermometer under test: Repeatibility (°C) 0,00037 Normal 1 1,34E-07






(°C) 0 Normal 1 0










Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)












(°C) 0 Normal 1 0









Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)












(°C) 0 Normal 1 0










Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)












(°C) 0 Normal 1 0









Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)












(°C) 0 Normal 1 0










Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u2 (yi)












(°C) 0 Normal 1 0








UME Uncertainty budget

Calibration point: for (-40) °C and (-20) °C, PRT s/n 15-57

Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)


Drift of PRT at 0°C or TPW (Ω) 0,00035 Rectangular 2,5 0,00087


Calibration of indicator (Ω or °C) 0,00019 Rectangular 2,5 0,00048

Drift of indicator (Ω or °C) 0,00005 Rectangular 2,5 0,00012

Reference standard


SPRT drift (°C) 0,00058 Rectangular 1 0,00058

Indicator calibration of (Ω or °C) 0,00115 Rectangular 1 0,00115

Indicator drift (Ω or °C) 0,00058 Rectangular 1 0,00058

Temperature source




Others

Function 0,00167 Rectangular 2,5 0,00419




Calibration point: for 0 °C and 30 °C, PRT s/n 15-57

Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard





Temperature source




Others





Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard





Temperature source




Others






Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard





Temperature source




Others




Calibration point: for (-40) °C and (-20) °C, PRT s/n 15-67

Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard





Temperature source




Others






Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard





Temperature source




Others





Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard





Temperature source




Others






Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)






Reference standard





Temperature source




Others




GeoSTM Uncertainty budget


Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)



Drift of PRT at 0°C (Ω) 0 - - 0,00000


Calibration of indicator (°C) 0,00125 Normal 1 0,00125

Drift of indicator (°C) 0,00064 Rectangular 1 0,00064

Reference standard

SPRT reading (Ω) 0,00028 Normal 0,4 0,00069



Indicator calibration (°C) 0,00125 Normal 1 0,00125

Indicator drift (°C) 0,00064 Rectangular 1 0,00064

Temperature source

Temperature source (°C) 0,00058 Rectangular 1 0,00058





Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)



Drift of PRT at 0°C (Ω) 0 - - 0,00000




Reference standard

SPRT reading (°C) 0,00077 Normal 1 0,00077





Temperature source

Temperature source (°C) 0,00058 Rectangular 1 0,00058




Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)



Drift of PRT at 0°C (Ω) 0 Rectangular 0,00000




Reference standard






Temperature source








Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)



Drift of PRT at 0°C (Ω) 0 - - 0,00000




Reference standard






Temperature source







Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)



Drift of PRT at 0°C (Ω) 0 Rectangular 1 0,00000




Reference standard






Temperature source








Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)



Drift of PRT at 0°C (Ω) 0 - - 0,00000




Reference standard






Temperature source







Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)



Drift of PRT at 0°C (Ω) 0 - - 0,00000




Reference standard






Temperature source








Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)



Drift of PRT at 0°C (Ω) 0 - - 0,00000




Reference standard






Temperature source






KazInMetr Uncertainty budget



uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi), mK

Reference standard





certificate/accuracy) °C 0,0010 Rectangular 1,0 1,00

Drift of the resistance bridge °C 0,00014 Rectangular 1,0 0,14

Temperature source




PRT reading °C 0,0079 Normal 1,0 7,90

Drift of PRT at TPW °C 0,0024 Rectangular 1,0 2,40

Self - heating of PRT °C 0,0041 Normal 1,0 4,05




Combined standard uncertainty, mK 19,00





uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi), mK

Reference standard







Temperature source














uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi), mK

Reference standard







Temperature source















uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi), mK

Reference standard







Temperature source














uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi), mK

Reference standard







Temperature source















uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi), mK

Reference standard







Temperature source












ANNEX 2. Equipment used

INM Equipment used

Item Description Manufacturer Model Serial number Traceability

1 SPRT Hart Scientific 5681 1618 INM

2 SPRT Hart Scientific 5698-25 985061 INM

3 Resistance Bridge Hart Scientific 1590 A89449 INM

4 Standard Resistance Russia P331 169178 INM

5 Water Triple Point Cell Hart Scientific 5901 C-G C-G2061 INM

6 Alcohol Bath Hart Scientific 7381 A89194 INM

7 Alcohol Bath Hart Scientific 7312 A57109 INM

8 Oil bath Hart Scientific 6331 A57074 INM

9 Block calibrator Hart Scientific 9173 A8A429 INM

CSM Equipment used


1 SPRT Hart Scientific 5699 0559 UME

2 Thermometer readout Hart Scientific 1575А A95283 UME

3 Thermometer readout Hart Scientific 1575А A95281 UME

4 Low temperature bath Hart Scientific Fluke 7381 А96220

5 Water bath Hart Scientific Fluke 7321 А95155

6 Oil bath Hart Scientific Fluke 6331 А95278

7 Block calibrator Hart Scientific Fluke 9173 А95473

GeoSTM Equipment used



1 Resistance Bridge Russia P - 3003 00835 GEOSTM

2 Standard Resistance Russia P - 3030 0940 GEOSTM

3 Oil bath Germany U-10 18689

4 Water Bath Germany U-10 18663

5 SPRT Russia ПТС-25 141 BelGYM

KazInMetr Equipment used


1 SPRT Russia ЭТС-100

2 Resistance Bridge Russia ТЕРКОН

3 Alcohol Bath Fluke 7380

4 Salt Bath Fluke 6050H

AzMI Equipment used


1 SPRT ISOTECH 670 SH 034 BelGYM

2 SPRT ISOTECH 670SL 007 UME

3 Resistance Bridge Agilent 3458 A MY45044931 UME

4 Bath ISOTECH 796М 31892-1

5 Bath ISOTECH 796 Н 31892-2

6 Bath ISOTECH 798M 29838-1

7 Dry block AMETEK 650B 548487-00739

8 Bath LAUDA RP1290 LBT0251

IMBiH Equipment used


1 SPRT ISOTECH 670 SQ /25.5 D-670 SQ/153 LMK, Slovenia

2 Super-Thermometer FLUKE 1594A B5B287 FLUKE

3 Oil bath ISOTECH 915H 30474/13

4 Alcohol/water bath ISOTECH 915LW 30474/12

5 Dry block ISOTECH Medusa 511 30474/14

UME Equipment used


1 Oil Bath Fluke 6024H A5A246 TUBITAK UME

2 Salt Bath Fluke 6050H A5A253 TUBITAK UME

3 Water Bath Isotech 796m 341641/1 TUBITAK UME

4 Alcohol Bath Heto CB217 93030376 TUBITAK UME

5 Resistance Bridge Hart Scientific 1590 A5B314 TUBITAK UME

6 Standard Resistance Isotech 5685A 269123 TUBITAK UME

7 SPRT Hart Scientific 5683 4029 TUBITAK UME

8 SPRT Hart Scientific 5680 1140 TUBITAK UME

9 Resistance Bath Fluke 7008 B02332 TUBITAK UME

10 Resistance Bridge WIKA ASL CTR9000 017578/01 TUBITAK UME

11 Water Triple Point TUBITAK UME Long-Thick UME-05 TUBITAK UME

12 Standart Resistance Isotech 5685A 269122 TUBITAK UME


ANNEX 3. Comparison protocol

COOMET project 642/MD/14

Supplementary comparison

KCDB BIPM COOMET.T-S2

Calibration of industrial platinum resistance thermometers in

thermostats

TECHNICAL PROTOCOL

Pilot laboratory:

National Metrology Institute (INM)

Coordinator:

Constantin Bordianu

National Metrology Institute

Temperature and humidity laboratory

Republic of Moldova, 28, E. Coca str., Chisinau, MD 2064

Phone: + (373) 22 903 103

Fax: + (373) 22 903 111

E-mail: [email protected]

[email protected]

2015




1 Introduction

In accordance with existing practice, prior to calibration, the thermometer is brought to a known

temperature in a suitable environment, and the output parameter (e.g. the electrical resistance) is

determined. There are two method of measurement, the method of fixed points and the method of direct

comparison. In the method of the fixed points, the temperature is realized by the corresponding point,

while the method of direct comparison, the reference and calibrated thermometers are installed close to

each other in a temperature controlled environment, and temperature calibration is determined using a

reference resistance thermometer, which should ensure the traceability of the measured unit. Electrical

measuring devices used in the measurements (resistance measuring bridge, standard resistors) should

also provide traceability and have certificates of calibration. The standard resistor which is used for

measurements in order to obtain accurate measurement is kept at constant temperature in a separate

thermostat. A calibrated thermometer is also needed for the measurement of the ambient temperature.

These comparisons are supplementary COOMET comparisons. The purpose of the comparison is to

check the equivalency between the participant laboratories (see Table 1) in the calibration of platinum

resistance thermometers by direct comparison method in the range from (-40) ºC up to 420 ºC. The

results of the comparison may be used by participants for the confirmation of calibration and

measurement capabilities and publications of CMCs in this range.

Temperature values will be referred to the International Temperature Scale of 1990 (ITS-90). All

participants of comparisons must act in accordance with the instructions below. Each laboratory should

use in comparisons the accepted practice of the ITS-90.

The basis of the technical protocol is taken the experience of similar practices in other regional

metrological organizations: SIM.T-S2, APMP-T-S3-03, SIM.T-S5 and SIM.T-S8.

2 Participants of comparison

National Metrology Institute (INM) of Republic of Moldova is a pilot laboratory in this comparison.

The tasks of the pilot laboratory:

- Prepare the comparison protocol;

- Follow the CIPM-MRA procedures to include the comparison in the BIPM-KCDB;

- Characterize and calibrate the two thermometers at the beginning and at the end of the

comparison;

- Collect the information from all participants;

- Perform the analysis of the comparison data and elaborate the final report in 3 months after

the last participant report will be receive.

The tasks of participant laboratories:

- Perform the measurements according to the rules of this protocol;

- Send the thermometers to the next participant in due time;

- Send to the coordinator comparison results in 15 days after finishing the measurements.


Table 1 Participants of comparison

NMI Address Contact

person

e-mail address

phone, fax

1

2

3

4

5

6

7

3 Circulation scheme

It is proposed to use the scheme of collapsed star for comparisons (see Figure 1). The scheme allows

to pilot laboratory to replace the artifact in case of its damage during transfer and to continue the

comparison.

Figure 1 Circulation scheme

The measurement sequence of the PRTs is as follows:

1. In the first phase, the pilot laboratory researches and selects two PRT.

2. The PRTs was calibrate by the INM by comparison prior to sending the artefacts to next

laboratory.

3. Selected thermometers will sent, in accordance with the schedule of comparisons to all the

participants.

4. After measurement, thermometers will sent to the next participant, and the measurement results

will forward to the coordinator.

5. All participants calibrate the PRTs, by direct comparison method in thermostats or dry block

calibrators.


6. The PRTs will return to pilot laboratory, where possible deviations are studied.

Note: Each laboratory is responsible for transmitting thermometers to the next participant.

Table 2 Comparison Schedule (preliminary)

Laboratory dispatched Laboratory received Starting of

measurements

Delivery date of

equipments

INM CSM

CSM INM

INM AZSTAND

AZSTAND INM

INM GEOSTM

GEOSTM INM

INM IMBiH

IMBiH INM

INM UME

UME INM

INM KazInMetr

KazInMetr INM

If a participant had troubles for meeting the deadlines, it must notify the affected laboratories and the

coordinator, remaining the responsibility of the coordinator for reorganizing new deadlines.

If unable to meet the planned schedule, the participant should inform INM before sending

thermometers and agree new, more convenient date so that PRTs can be sending to the next laboratory

without further delay.

4 Transfer standards and transport method

The transfer standards will be two 100 Ω (at 0 °C) standard platinum resistance thermometers (PRT),

with the following specifications.

Type: ЭТС – 100/1

Serial Number: 15 - 57

Serial Number: 15 - 67

Manufacturer: VNIIM, Russia

Temperature range: of -200 °C to 661 °C

Nominal resistance values at 0 °C: 100 Ω

Metal sheath thermometer length: 650 mm

Diameter: 6 mm


Figure 2 Transfer standards

The Platinum Resistance Thermometer was house in a box with foam protection. The net weight is

approximately 0,4 kg.

The INM is the reference laboratory where the PRTs will be calibrate before and after circulation.

After receiving the PRTs, before calibration started, participating laboratories should complete the

preliminary work outlined below.

1. Check the integrity of the packaging;

2. The presence of two platinum resistance thermometer S/N: 15 – 57 and 15 - 67

3. Availability of documentation consisting of:

- The protocol which includes instruction to laboratories, a list of contact persons and the

circulation schedule;

- Result sheets;

- Receipt form and dispatch form.

Upon receipt, the host laboratory must inspect PRTs for visual damage then complete the Artifact

receiving form (Annex 1) and forward it to INM (by e-mail or fax). If there is any damage, INM will

advise of how to proceed. Please handle the artifact with care!!!

Perform the initial check for connection wire configuration, insulation leakage etc. If no defect is

found on the artefact, the participant should measure the resistance value of PRTs at the ice point or

PTW (water triple point) using 1 mA and 1,414 mA sensing current as a preliminary measurement.

5 Measurement procedures

The calibration method to be use is direct comparison, in isothermal medium, against previously

calibrated reference standards. All participating laboratories should prepare at least one SPRT to be use

as the reference standard thermometer and should have stirred liquid baths and/or temperature calibrator

whose working space are depth enough. The evidence of their instability and in-homogeneity should be

available.

Prior to the comparison measurements, the PRTs should be stabilize by annealing:


1. Measure the initial value R1 at 0 °С (or TPW), should be corrected for the self-heating effect

and report the value to coordinator by e-mail using the format shown in (Annex 1).

2. Anneal the PRTs at 470 °С for 2 hours, and re-measure ice point value R2.

3. If R1 ≥ R2 and:

- R1− R2 ≤ 2 mΩ, go to calibration procedure;

- R1− R2 ≥ 2 mΩ, repeat step 2 until the difference is less than 2 mΩ or contact INM for

further instruction on the annealing procedure.

4. If R2 ≥ R1, no further annealing is required and go to calibration procedure.

Each laboratory must follow their own procedures, using the equipment to get their best measurement

capability for the calibration of platinum resistance thermometers by comparison. The reported

measurements of the PRTs will be the electrical resistance of the thermometer, with four terminals at the

temperatures shown below:

0 °C; -40 °C; -20 °C; 0 °C; 30 °C; 157 °C; 232 °C; 420 °C; 0 °C

All participants will make measurements at temperatures as close as possible to these temperatures.

The calibration points will done in the order shown, from the highest temperature to the lowest. The

values of resistance of the traveling thermometers at 0 ºC could be determined by each laboratory at the

water triple point or at the ice point. In the latter case, the ice bath temperature must be measure with

their working standards. The self-heating of the thermometer will be determined at 0 ºC.

The electrical resistance measurement will be perform with 1mA current.

Correct immersion depths for the thermometers during calibration have to be assure. It is common

practice to test it by immersing the thermometers at the maximum depth allowed by the isothermal

enclosure used and withdrawing them several centimetres. If no significant differences in the readings

are record, then it can be conclude that a correct immersion depth is achieve. If significant differences

are found, then a source of uncertainty due to thermal fluxes has to be taken into account. The

calibration report should be submitter to the actual environmental conditions during measurement.

6 Reporting of the result

After the measurements are completed, pack the PRTs in the same manner as it was received using

the original package, ensuring that the ATA Carnet is together with but outside the package. Forward

the PRTs and the Carnet by airfreight to the next participant, advise the laboratory in the circulation

schedule of the impending arrival of the PRTs. Complete, and send the Artefact dispatch form (Annex

2) to INM and next participant.

Each participant laboratory will send a report by e-mail to the pilot laboratory within two weeks once

calibration is complete, following the format attached to this report:

1. Measurement results (see Annex 3);

2. Uncertainty budget (see Annex 4);

3. Equipment used for calibration (see Annex 5).


7 Calculation of uncertainties

Each participant laboratory must complete the excel format for calculation of uncertainties. At least,

the causes given below shall be quantified:

- Reading of standards;

- Calibration of standards;

- Drift of standards;

- Stability of isothermal media;

- Uniformity of isothermal media;

- Reading of thermometer under calibration;

- Hysteresis of the thermometer under calibration;

- Thermal fluxes.

The participants are reminded that thermal hysteresis results in different resistance values at the same

temperature point, depending on whether the temperature was increasing or decreasing so it experiments

a maximum around at 0 °С (or TPW). The participants are asked to evaluate the hysteresis of the

thermometers using their own methods. The report should explain briefly how was estimated each of

these.

8 Evaluation of results

Pilot laboratory (INM) will evaluate the result of the comparison within 3 months after the

completion of the circulation and send the first draft reports to the participants for comment.

Evaluation of the equivalence between the participating laboratories will be realized by comparing of

the resistance ratio values Wlab(t) of each laboratory with the value Wref(t) obtained by the pilot

laboratory:

)t(W)t(W)t(W reflablab (1)

where:

- Wlab (t): Value for Rt / R0,01 ºC of laboratory at temperature t.

- Wref (t): Value for Rt / R0,01 ºC of pilot laboratory at temperature t.

Evaluation of the results will be made in terms of the reduced resistance Wt in each calibration point

in order to eliminate possible PRTs instabilities. For each laboratory the last measured value of

resistance at 0 °С will be used for Wt calculation.

Also for each laboratory in each calibration point the value will be calculate:

tUtU

tktktE

2ref

2lab

reflab

n

(2)

where:

tklab - The temperature calculated for the laboratory

tkref - The reference temperature calculated for the pilot laboratory

tUlab - Expanded uncertainty of laboratory at temperature t.

tUref - Expanded uncertainty of the pilot laboratory at temperature t.

The degrees of equivalence between the laboratories will be also determined.


ANNEX 1. Reception artifact

ARTIFACT RECEIVED

COOMET comparison 642/MD/14

Receive laboratory:

Contact Person:

Address:

E-mail:

Phone:

Fax:

The platinum resistance thermometers type, , was received at:

,

Dispatched laboratory:

Responsible for sending:

The condition when it was received was PRT

( ) in good physical and working order

( ) damaged (please explain)

Date received thermometers:

Responsible for receive:

Initial Check Resistance Value at Ice point or TPW: Ω

In order to have information about the progress of the comparison and, if necessary to take

appropriate corrective actions, please send by e-mail this form to the pilot laboratory, once the first

measurement at 0 ºC is done.


ANNEX 2. Dispatched artefact

ARTIFACT DISPATCHED

COOMET comparison 642/MD/14

Dispatched laboratory:

Contact Person:

Address:

E-mail:

Phone:

Fax:

The platinum resistance thermometers type, , was received at:

Received laboratory:

Responsible for receives:

The condition when it was received was PRT

( ) in good physical and working order

( ) damaged (please explain)

Date dispatched thermometers:

Responsible for dispatched:

In order to have information about the progress of the comparison and, if necessary to take

appropriate corrective actions, please send by e-mail this form to the pilot laboratory, and receive

laboratory.


ANNEX 3. Measurement sheets

The platinum resistance thermometers type,

Name of participating laboratory:

Date of receipt:

Condition of the artifact when received:

Environment Conditions during the measurement:

- The ambient temperature: ± °C

- Relative humidity: ± %

Other pre - condition preparation work conducted:

Immersion Depth: mm

Initial Check Resistance Value at Ice point or TPW: Ω

Final Check Resistance Value at Ice point or TPW: Ω

Calibration results:

Calibration

point

Standard

Reading

Tested thermometer

reading

Uncertainty of

measurement

Immersion

depth

°C °C Ω °C mm

0

-40

-20

0

30

157

232

420

0

Calibrated by: _____________

Date of calibration: _____________


ANNEX 4. Uncertainty budget

The uncertainties of measurement in the following table have been calculated by comparison against

a standard platinum resistance thermometer (SPRT) as a reference standard.

Quantity Standard

uncertainty

Probability

distribution

Sensitivity

coefficient

Uncertainty

contribution

u(xi) ci u(yi)


PRT reading (Ω)

Drift of PRT at 0°C or TPW (Ω)

Self - heating of PRT (Ω)

Calibration of indicator (Ω or °C)

Drift of indicator (Ω or °C)

Reference standard

Temperature reading of SPRT(°C)

SPRT calibration (°C)

SPRT drift (°C)

Indicator calibration of (Ω or °C)

Indicator drift (Ω or °C)

Temperature source

Axial uniformity of temperature source (°C)

Radial uniformity of temperature source (°C)

Instability of temperature source (°C)

Others

Combined standard uncertainty

Coverage factor k

Expanded uncertainty

ANNEX 5. Equipment used


1

2

3

…

REPORT Calibration of industrial platinum resistance ... - BIPM

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