Draft report – Results of the APMP pressure supplementary ...Draft B APMP.M.P-S3, 4 April 2012, version 1 Page 1 of 36 Final report on APMP.M.P-S3 Results of the supplementary comparison

Draft B APMP.M.P-S3, 4 April 2012, version 1 Page 1 of 36

Final report on

APMP.M.P-S3

Results of the supplementary comparison in gas media in the

range 1.77 MPa to 6.8 MPa.

Prepared by

N. Owen1 and M. Bergoglio

2

Date: April 2012

1 National Measurement Institute, Australia (NMIA), Port Melbourne laboratory, Unit 1 -153

Bertie St Port Melbourne, Australia, 3207

2 Istituto Nazionale di Ricerca Metrologica (INRIM), Strada delle Cacce 91, 10135 Torino,

Italy

Abstract

This report provides the results of the supplementary bilateral comparison

APMP.M.P-S3 between NMI Australia, (NMIA) and INRIM, Italy executed from

November 2010 to November 2011. NMIA acted as the pilot laboratory and provided

a Ruska G series piston gauge as the transfer standard, with a nominal area 16.8 mm²

requiring a nominal load of 12 kg to balance a pressure of 7.0 MPa. The purpose of

this supplementary bilateral comparison was to provide data for linking NMIA to

CCM.P-K1.c in the pressure range greater than 4 MPa to extend the range covered by

Key Comparison APMP.M.P-K1c. The original protocol called for the pressure range

from 80 kPa to 6.80 MPa. Both participants agreed to limit this comparison range to

1.77 MPa to 6.50 MPa.


TABLE OF CONTENTS

1. INTRODUCTION 3

2. MEASUREMENT SCHEDULE 3

3. TRANSFER STANDARD 3

3.1 Description of the transfer standard and calibration procedure 3

3.2 Stability of the transfer standard during comparison 3

4. PARTICIPANTS STANDARDS 4

4.1 About the participant standards 4

4.2 Results obtained by participants 4

4.3 Estimation of uncertainty 5

5. ANALYSIS OF RESULTS 5

5.1 Relative deviation to reference value 6

5.2 Linking to CCM 6

6. DISCUSSION 7

7. CONCLUSION 8

8. ACKLOWLEDGEMENTS 8

9. REFERENCES 8

APPENDIX A: Figure 1 Stability of the transfer standard 9

Figure 2 INRIM and NMIA bilateral comparison bi 9

Figure 3a to 3e Linking of NMIA to CCM.P-K1c 10

APPENDIX B: Table 2 Participant reference standards 13

Table 3 Effective area of the TS as determined by each participant 14

Table 4 Relative difference of bilateral comparison 14

Table 5 Linking of APMP.M.P-S3 to CCM.P-K1c 15

APPENDIX C: Protocol for 7 MPa Pneumatic Pressure Comparison, APMP.M.P-S3 16

APPENDIX D: Data from the participating laboratories 33


1. Introduction

INRIM Italy (previously IMGC-CNR) piloted CCM.P-K1.c to establish a comparison

in gas media and gauge mode in the pressure range 80 kPa to 7 MPa completed in

May 1999 and reported results [1]. This original comparison utilised two piston

gauges of different ranges as the transfer standard. NMIA (previously NML)

participated in APMP.M.P-K1c over the range 0.4 MPa to 4.0 MPa completed in

September 2001 with results reported [2]. The main purpose of this current

comparison APMP.M.P-S3, was to confirm NMIA’s measurement capability in the

pressure range from 4 MPa to 7 MPa and establish linking to CCM.P-K1.c.

2. Measurement Schedule

This comparison was conducted according to the schedule noted in Table 1.

Table 1 Schedule of Activity

Activity Period

Preliminary examination by NMIA Nov 2010/Jan 2011

Measurement by INRIM May 2011

Measurement by NMIA Oct/Nov 2011

3. Transfer Standard

3.1 Description of the transfer standard and calibration procedure

The Transfer Standard (TS) was a Ruska model 2468-730 G series tungsten carbide

piston gauge with nominal area 16.8 mm². This piston gauge was manufactured with

a clearance to suit operation at a full scale pressure of 7.0 MPa (nominal 12 kg load).

The piston gauge was mounted in a Ruska 2465 base and supplied with one Ruska

500 g bell and two standard sets of Ruska ring masses. The ring masses were not

weighed as part of this comparison and mass values were supplied by the pilot

laboratory.

Laboratory environmental conditions and TS temperature were measured by each

participant using their own equipment.

The difference between the reference level of the TS and the laboratories reference

standards were minimised. Each laboratory measured the level differences and made

appropriate corrections (refer Table 2).

3.2 Stability of the Transfer Standard during Comparison

In September 2007 the TS was calibrated traceable to NMIA primary reference

standards over the range 0.81 MPa to 7.0 MPa. In 2010 and 2011 the calibration was

repeated using calibration points that better matched the protocol of this comparison.

Common points from these 3 successive calibrations have been analysed and are

presented in Figure 1 and have been used to assess the TS stability.


The results in 2007 and 2010 did not coincide precisely with the comparison test

points of CCM.P-K1.c hence the effective areas have been adjusted by up to 0.2 MPa

using equation (1) where Am is the measured effective area at pressure Pm and Ac is the

adjusted effective area at the comparison pressure Pc, adjusted using the distortion

coefficient λ declared by the pilot laboratory for the TS of 1.45 x 10-6

. The effective

area adjustment was less than 5 10-6

mm² (or a relative adjustment of 0.3 10-6

) in

each case.

mcmc PPAA 1 (1)

An estimation of stability of the TS for the duration of the comparison can be

obtained by considering the maximum difference in area at each test pressure for

successive calibrations. Between 2007 and 2010 the maximum difference occurred at

3 MPa and amounts to a relative change of 4.4 10-6

. Between 2010 and 2011 (the

duration of the comparison) the maximum difference occurred at 6.5 MPa and

amounts to a relative change of 4.2 10-6

. When compared to previous assessments

of this type of piston gauge [1,2] this is a very consistent stability. For the purpose of

this report the TS was considered to have an estimated relative stability over the

comparison period of 4 10-6

.

4 Participants Standards

4.1 About the participant’s standards

Table 2 provides the details of the primary standards used by each participant. The

NMIA primary standard is a nominal 25 mm diameter dimensionally characterised

piston cylinder unit for which both effective area and distortion coefficient were

calculated by finite element analysis (FEA) modelling. This primary standard is an

oil operated piston gauge mounted in a Harwood 500 kg load frame with a full scale

range of 10 MPa. To interface with the gas operated TS an oil – gas interface with an

integrated oil level pointer was used. Oil level can be monitored and controlled to

within ±0.1 mm or 1 Pa.

The INRIM pressure standard is a Ruska V series piston gauge traceable via a set of

gas operated piston gauges to an INRIM mercury column primary reference standard

and dimensional measurements of piston and cylinder.

The results in this comparison are considered mutually independent and uncorrelated

with those obtained by other laboratories participating in the CCM.P-K1.c

comparison.

4.2 Results obtained by participants

The comparison protocol called for test pressures at 79.4, 137.8, 196.0, 1767.0,

2935.7, 4104.4, 5273.1, 6441.8, 6792.4 in kPa. The participants agreed that the lower

3 pressures would not be collected as these would require a different reference

standard and were less than 3% of the full scale range of the TS. Also due to the set

of weights and test time limitations the test pressures at nominally 6.4 and 6.8 MPa

were replaced with a single test pressure at 6.5 MPa. These revised pressures were


applied in increasing then decreasing order. Three cycles were conducted giving 30

experimental determinations of the effective area of the TS with 6 values at each of 5

nominal pressures. The average effective area A’p in mm² at 20 °C (as defined in

Appendix C equation 2) at each nominal test pressure is given in Table 3.

The protocol requires the selected test pressures be within ± 1 kPa when tested at each

laboratory. Due to the large difference in gravity value between Australia and Italy

the test pressure deviated by between 1 kPa and 4 kPa across the test pressure range

while loading the transfer standard with the same masses at each laboratory. Both

laboratories agreed this was the preferred approach.

4.3 Estimation of Uncertainty

In this report all uncertainty calculations are performed and reported as relative

standard uncertainties with k = 1.

Each laboratory supplied the relative standard uncertainty of the test pressure (up), the

relative standard uncertainty associated with test temperature (uT) and the relative

standard deviation of the effective area, s(A’p) at each test pressure. An estimate of

the type A relative standard uncertainty (uA) associated with the average effective area

can be found from (2).

n

Asu

p

A

'

(2)

Where: n is the number of results collected at each test pressure.

'

pAs is the relative standard deviation of area at each test pressure

The combined relative standard uncertainty for effective area at each test pressure is

given by equation (3) as described in the attached protocol in Appendix C.

222

PTAc uuuu (3)

The combined relative standard uncertainty uc at each nominal test pressure for each

laboratory is given in Table 3.

5 Analysis of Results

The analysis is conducted in two parts. The first part considers the bilateral

comparison between INRIM and NMIA. The second part considers the linking of

NMIA via the CCM key comparison CCM.P-K1c reported October 2000.

All charts in this report have the same vertical scale of ± 30 × 10-6

relative units to

permit convenient comparison.


In this analysis the degrees of equivalence described in the bilateral comparison is

referred to using the term bi and the degrees of equivalence described in the linking

analysis is referred to using the term di.

5.1 Relative difference to APMP.M.P-S3 reference value

The average effective area A’p and combined relative standard uncertainty uc(A

’p)

determined by each participant are provide in Table 3. Using procedure A of [3] the

following value were calculated for the INRIM and NMIA data and are presented in

Table 4 and shown in Fig 2;

1. weighted mean comparison reference value Aref

2. relative standard uncertainty in this value u(Aref)

3. degrees of equivalence bi

4. relative standard uncertainty u(bi)

Where for 2 participants:

NMIApcINRIMpc

NMIApcNMIApINRIMpcINRIMp

refAuAu

AuAAuAA

'2'2

'2''2'

11 (4)

NMIApcINRIMpcref AuAuAu '2'22

111 (5)

refINRIMpi AAb ' (6)

refcINRIMpci AuAubu 2'22 (7)

The degrees of freedom in this case is 1. In accordance with [3] using equation (8)

regard the consistency check as failing if

05.0Pr 22

obs (8)

For this work no results failed this test.

The results in Fig 2 are shown as offset from the nominal pressure for convenience

only.

5.2 Linking to CCM

This bilateral comparison APMP.M.P-S3 was conducted using a different artefact to

that used during the original key comparison CCM.P-K1c. To link the results of

NMIA obtained in the bilateral comparison APMP.MP-S3, to the KCRV of

CCMP-K1c, the method described in [4] was used with INRIM (formerly IMGC-

CNR) as the linking laboratory. It was necessary to transform the data collected for

APMP.M.P-S3 via a set of estimated r values to express this data in the terms of the

original CCM.P-K1c data. These were determined as the ratio of the effective area


determined by the linking laboratory for CCM.P-K1c and APMP.M.P-S3 at each test

pressure as given by equation (9) at each test pressure.

INRIMp

IMGCp

A

Ar

'

'

(9)

These r values are then multiplied by each NMIA and INRIM effective area

determined during the APMP.M.P-S3 comparison to give a transformed effective area

A’pT suitable to compare with CCM.P-K1c. An estimate of the degrees of

equivalence and associated standard uncertainty was determined using equations (10)

to (18) of [4] with an assumed correlation coefficient ρl of 0.8. The calculations were

performed on both NMIA and INRIM data to compare the INRIM results with the

reported values in [1] for IMGC. It is noted that using the method described in [4],

the values determined for relative standard uncertainty of degrees of equivalence is

smaller in this current evaluation than the original key comparison or u2

c(A’pINRIM) <

u2

c(A’pIMGC). This is related to the application of the more recent evaluation method of

[4].

The results for transformed effective area A’pT, degree of equivalence di, and relative

standard uncertainty of degree of equivalence u(di) are tabulated in Table 5 for each

laboratory.

The charts of Fig 3a to Fig 3e provide the original CCM.P-K1c data with the results

of APMP.M.P-S3 added.

6 Discussion

(a) Due to operational constraints a maximum test pressure at 6.5 MPa was

substituted for test pressures at 6.4 MPa and 6.8 MPa. The area data collected

at 6.5 MPa was adjusted using equation (1) to area values at 6.44 MPa to

allow direct comparison with CCM.P-K1c. This adjustment did not exceed

1.5 x 10-6

mm².

(b) To compensate for using a different artefact in this bilateral comparison,

APMP.M.P-S3 from that used in the original comparison CCM.P-K1c, a

scaling factor r has been applied to the APMP data. The validity of this

scaling factor was checked by comparing the INRIM data from APMP.M.P-S3

with the IMGC data from CCM.P-K1c. From Figure 3a to 3e it can be seen

that the INRIM and IMGC relative difference (di) values are nominally

identical as expected.

(c) The pressure standards at INRIM have been periodically checked to assure

reliable conformance with the CCM.P-K1c.

(d) Using the method described in [3] for the bilateral comparison, the values of

u(bi), given in Table 4 represent the relative standard uncertainty associated

with the bilateral comparison. As expected the uncertainty of the bilateral


comparison is smaller than u(di) of Table 5 calculated for linking NMIA with

the KCRV of CCM.P-K1c.

7 Conclusion

As a participant in the original CCM.P-K1c, IMGC (now called INRIM) provided a

linking laboratory for NMIA to examine measurement capability in the gas operating

pressure range up to nominally 7 MPa.

As shown in Table 4 the relative difference to each comparison value for INRIM and

NMIA are smaller than the relative standard uncertainty estimated for each difference.

These comparison results are considered satisfactory.

Despite using a different transfer standard in this comparison it was possible to select

pressure test points that matched the pressure point of CCM.P-K1c to within 4 kPa,

thereby testing was conducted under as near as possible the same conditions in

APMP.M.P-S3 as in CCM.P-K1c.

By making reference to [1] and [4] it was possible to link the NMIA results to the

original CCM.P-K1c KCRV. As shown in Table 5 the relative difference to the

CCM.P-K1c KCRV for each comparison value for NMIA is smaller than the relative

standard uncertainty estimated for each difference. These comparison results are

considered satisfactory.

8 Acknowledgments

The authors would like to thank Gianfranco Molinar for his encouragement and

support to undertake this comparison and for his participation in the data collection

(quite possibly his last bench work before fully retiring) and data analysis for this

report.

9 References

[1] Results of the CCM pressure key comparison (Phase B) in gas media and

gauge mode from 80 kPa to 7 MPa. Molinar, Legras, Jajer, Ooiwa, Schmidt.

(CCM.P-K1c), IMGC-CNR Technical Report 42, October 2000.

[2] Results of the APMP pressure key comparison in gas media and gauge mode

from 0.4 MPa to 4.0 MPa. Bandyopadhyay, Woo, Fitzgerald, Man, Ooiwa,

Jescheck, Jian, Fatt, Chan, Moore, Tawil. Final report of APMP Key

Comparison (APMP.M.P-K1c).

[3] The evaluation of key comparison data. M. G. Cox. Metrologia, 2002, 39,

589-595.

[4] Proposal for linking the results of CIPM and RMO key comparisons. Elster,

Link, Woger. Metrolgia, 2003, 40, 189-194.

[5] ISO/IEC Guide 98-3. Uncertainty of measurement – Part 3: Guide to the

expression of uncertainty in measurement (GUM:1995).


APPENDIX A

Figure 1 Stability of the transfer standard

-30

-20

-10

0

10

20

30

0 1000 2000 3000 4000 5000 6000 7000

Test Pressure in kPa

Rela

tive C

han

ge in

Eff

ecti

ve A

rea X

10-6

2007

2010

2011

Figure 2 Relative deviation to reference value

APMP.M.P-S3 bilateral comparison between INRIM and NMIA

-30

-20

-10

0

10

20

30

0 1000 2000 3000 4000 5000 6000 7000

Pressure in kPa

bi x 1

0-6

INRIM

NMIA

Note: Results offset on the pressure scale to aid viewing.


Figure 3a Linking of NMIA to CCM.P-K1c KCRV 1767 kPa

APMP.M.P-S3 Nominal Pressure 1767 kPa

Degree of Equivalence: di with uncertainty bars for a coverage factor k = 1

-30

-20

-10

0

10

20

30

Laboratory

di x 1

0-6

IMGC

BNM-LNE

PTB

NIST

NRLM

INRIM

NMIA

CCM.P-K1.c APMP.M.P-S3

Figure 3b Linking of NMIA to CCM.P-K1c KCRV 2936 kPa



-30

-20

-10

0

10

20

30

Laboratory

di x

10

-6

IMGC

BNM-LNE

PTB

NIST

NRLM

INRIM

NMIA



Figure 3c Linking of NMIA to CCM.P-K1c KCRV 4104 kPa



-30

-20

-10

0

10

20

30

Laboratory

di x

10

-6

IMGC

BNM-LNE

PTB

NIST

NRLM

INRIM

NMIA


Figure 3d Linking of NMIA to CCM.P-K1c KCRV 5273 kPa



-30

-20

-10

0

10

20

30

Laboratory

di x

10

-6

IMGC

BNM-LNE

PTB

NIST

NRLM

INRIM

NMIA



Figure 3e Linking of NMIA to CCM.P-K1c KCRV 6442 kPa



-30

-20

-10

0

10

20

30

Laboratory

di x

10

-6

IMGC

BNM-LNE

PTB

NIST

NRLM

INRIM

NMIA



APPENDIX B

Table 2 Participants Refernce Standards

Details NMI Australia INRIM

Manufacturer Harwood/DHI/NMI via oil/gas interface

Ruska_

Measurement range in MPa 1.2 MPa to 10 MPa Used from 1.8 MPa to 6.5 MPa

Material of piston Tungsten carbide Tungsten carbide

Material of cylinder Tungsten carbide Tungsten carbide

Operation mode, free-deformation or controlled-clearance Free-deformation Free-deformation

Zero-pressure effective area (A0) at reference temperature in mm2 490.2589 8,385652

Relative uncertainty of A0 in 10-6

7.5 9.6

Pressure distortion coefficient ( ) in MPa-1

1.12x10-6

2x10-6

Uncertainty of in MPa-1

0.09 x10-6

0.2 x10-6

Relative uncertainty of mass pieces in 10-6

3 2.2

Linear thermal expansion coefficient of piston and cylinder ( p+ c) in °C-1

9.1x10-6

9.1x10-6

Reference temperature (t0) in °C 20 20

Local gravity (g) in m/s2 9.799499 9.805328

Relative uncertainty of g in 10-6

0.5 1

Height difference between laboratory standard (LS) and TS (h, positive if LS is higher than TS) in mm

-0.3 +1.3

Uncertainty of h in mm 0.3 (includes oil/gas interface)

1


Table 3 Effective area of the TS as determined by each participant

Laboratory INRIM NMIA

Nominal Pressure Average effective area

(A’p)

Combined Relative Standard

Uncertainty

(uc(A’p))

Average effective area

(A’p)

Combined Relative Standard

Uncertainty

(uc(A’p))

MPa mm² 10-6

mm² 10-6

1.8

2.9

4.1

5.3

6.5

16.788858

16.788893

16.788939

16.788986

16.789023

10.1

10.2

10.0

10.0

10.0

16.789020

16.788967

16.788982

16.789035

16.789129

10.2

9.4

9.4

9.5

9.5

Table 4 Relative difference to APMP.M.P-S3 reference value Aref

Comparison Reference Value INRIM NMIA

Nominal Pressure Effective area

(Aref)

Relative standard

uncertainty in

effective area

(u(Aref))

Degrees of

equivalence

(bi)

Relative standard

uncertainty

(u(bi))

Degrees of

equivalence

(bi)

Relative standard

uncertainty

(u(bi))

MPa mm² 10-6

10-6

10-6

10-6

10-6

1.8

2.9

4.1

5.3

6.5

16.78894

16.78893

16.78896

16.78901

16.78908

7.2

6.9

6.8

6.9

6.9

- 4.8

- 2.4

- 1.4

- 1.5

- 3.3

7.1

7.5

7.3

7.3

7.3

+ 4.9

+ 2.0

+ 1.2

+ 1.4

+ 3.0

7.3

6.4

6.4

6.5

6.5


Table 5 Linking APMP.M.P-S3 to CCM.P-K1c KCRV

CCM.P-K1.c (Table 5) INRIM to KCRV NMIA to KCRV

Nominal

Pressure

Ref Value

(A’pT)

Relative

standard

uncertainty

(u(A’pT))

Transformed

effective area

(A’pT)

Degree of

equivalence

(di)

Relative

standard

uncertainty

(u(di))

Transformed

effective area

(A’pT)

Degree of

equivalence

(di)

Relative

standard

uncertainty

(u(di))

MPa mm² 10-6

mm² 10-6

10-6

10-6

10-6

1.8

2.9

4.1

5.3

6.5

8.38859

8.38863

8.38868

8.38872

8.38877

7.2

7.2

7.2

7.2

7.2

8.388538

8.388619

8.388668

8.388683

8.388747

- 5.7

- 1.6

- 1.3

- 5.0

- 3.1

11.2

11.3

11.1

11.1

11.1

8.388619

8.388656

8.388690

8.388708

8.388800

+ 3.9

+ 2.9

+ 1.2

- 2.2

+ 3.2

11.3

10.1

10.1

10.1

10.1


Appendix C:

ASIA-PACIFIC METROLOGY PROGRAMME

7 MPa PNEUMATIC PRESSURE INTERLABORATORY COMPARISON

Comparison Identifier: APMP.M.P-S3

Technical Protocol

Edition 1.0

25 February, 2011

Pilot Institute:

Pressure Group

Melbourne Physical Metrology

National Measurement Institute Australia, NMIA

Contents:

Page

1. General information 2

2. Participating institutes 2

3. Time schedule 3

4. Transfer standard 3

5. Transportation 5

6. Measurements 5

7. Reporting of results 8

8. Preparation of the report 11

References 11

A1. Report for transportation (Arrival) 13

A2. Report for transportation (Departure) 13

A3. State record of the transfer standard 13

A4. Details of the participating institute’s standard 13

A5. Details of the measurement conditions 15

A6. Results in individual cycles 16

A7. Summary of all cycles 17

A8. Calculated result of A’0 and ’ 18

B1. Technical data of the transfer standard 19


1. General information

The National Measurement Institute, Australia (NMIA), has been agreed by

the Asia-Pacific Metrology Programme (APMP) Technical Committee for Mass and

Related Quantities (TCM) to coordinate a bilateral comparison between NMIA and

INRiM Italy for medium pressure. The comparison is identified as APMP.M.P-K1x

by the Bureau International des Poids et Mesures (BIPM) and APMP.

The objective of the project is to compare the performance of pneumatic

pressure standards in participating institutes, in the pressure range 80 kPa to 7 MPa in

gauge mode. The results of this comparison will be essential supporting evidence for

medium pressure CMCs1,2,3

. Both participating institutes have the opportunity to get

results in the comparison at a level of uncertainty appropriate for them4. The results of

this comparison will also be linked to the corresponding CCM key comparison,

CCM.P-K1c5. As this protocol is based on CCM.P-K1c additional information can be

obtained from that protocol.

Pilot institute:

The National Measurement Institute, Australia (NMIA)

Program Coordinator:

Mr Neville Owen

Officer in Charge, Melbourne Physical Metrology

National Measurement Institute, Australia

Unit 1- 153 Bertie Street Port Melbourne, 3207 Victoria, Australia

Tel:+61-03-9644 4907, Fax:+61-03-9644 4888,

E-mail: [email protected]

Document:

This document has been prepared by Mr Neville Owen, NMIA and approved

by the participant (INRiM).

2. Participating institutes

The number of participating institute is 2 including the pilot institute. The

institutes along with their contact persons are listed as follows:


List of participating institutes

Participating Institutes Contact Persons

Country: Italy

Acronym: INRiM

Institute:

Istituto Nazionale di Ricerca Metrologica

Address:

Strada delle Cacce 91

10135 Torino (Italy)

Name: Dr.ssa Mercede Bergoglio

Tel: 39-011-3919 920

Fax: 39-011-3919 926


Country: Australia

Acronym: NMIA

Institute:

National Measurement Institute Australia

Address:

Unit 1 – 153 Bertie Street Port Melbourne, Vic

3207 Australia

Name: Mr. Neville Owen

Tel: 03 9644 4907

Fax: 03 9644 4900


3. Time schedule

Time schedule for this comparison has been developed as follows:

Period of measurement Country Institute Carnet

Dec. to Feb. 2010 Australia NMIA ○

May 2011 Italy INRiM ○

June 2011 Australia NMIA ○

Initial testing of the transfer standard commenced in Dec 2010. The bilateral-

comparison program is scheduled to commence in Feb 2011, and to finish in June

2011. The artifact will travel under ATA CARNET.

4. Transfer standard

In this 7 MPa bilateral comparison, a piston-cylinder assembly of nominally

16.8 mm2 effective area with serial number G137 is circulated as the transfer standard

(TS) and includes a pneumatic pressure balance equipped with a mass loading bell

and a mass set manufactured by Ruska Instrument Corporation, a division of General

Electric Company. Temperature and piston position are monitored using a PC and

Excel spreadsheet via an Agilent logger and sensors supplied with the TS.

The TS stability will be established by the pilot laboratory using calibration

history and by repeat measurements upon return of the TS to Australia. The

characteristics of the pressure balance and the effect on the measured pressure by

environmental condition will be evaluated at NMIA during the initial investigation.

mailto:[email protected]


The details of the initial TS evaluation by the pilot institute and all relevant technical

data of TS are given in Appendix B1.

Some general information concerning the pressure balance is given in the

operation and maintenance manuals6, which can be downloaded from the

manufacturer’s website and will be enclosed in a transfer package.

Reference level

The reference level of the TS is to be taken as the base of the piston. The

value to be used in this comparison is given in Appendix B1. The piston is secured in

the cylinder by a retaining circlip near the base of the piston. For the purpose of this

comparison it will be assumed this circlip occupies the same volume as the gap in

which it is secured thereby contributing no additional volume to the piston.

Connecting port:

The connection type of the pressure balance is ¼” Swagelok. Each

participant has to prepare the necessary pipe and fittings for the connection.

Package of transfer standard: The serial number of instrument platform, piston-cylinder assembly, mass

loading bell used for the TS is as follows:

Type Model Serial number

Piston-cylinder assembly 2468-730 G137

Instrument platform 2465-754 50667

Mass set 2465-799 50664

50666

A single box is used for carrying the TS and logger. A second box is used for

the weights and accessories.

5. Transportation

To prevent the transfer package from any damage, all effort should be made by

each participant to handled equipment with care, i.e., only by qualified metrology

personnel. To expedite this comparison a representative from the pilot institute will

assist with unpacking and set up of the TS at INRiM

ATA carnet:

For the transportation of this comparison, ATA CARNET will be used. ATA

CARNET is valid for a year. Upon each movement of the package the person

organizing the transit must ensure that the carnet is presented to customs on leaving

the country, and upon its arrival in the country of destination. When the package is

sent unaccompanied, the carnet must be included with the other forwarding

documents so that the handling agent can obtain customs clearance.

6. Measurements

Measurements should be done after an appropriate acclimatization time (at

least 1 day after receipt), and the results be written on the forms annexed. The TS


should be handled and the piston-cylinder assembly mounted in accordance with the

instructions given in the Ruska Piston Pressure Gauge Users Manual.

Working fluid:

The TS pressure balance should be operated with high purity nitrogen as a

pressure transmitting medium.

Measurements for determining the environmental condition:

The measurements needed for determining the environmental condition, for

example, atmospheric pressure, ambient temperature and relative humidity, will be

assumed to be available at each institute. The institutes should operate their pressure

standards at their normal operating temperature.

Metrological characterization of the transfer standard

The results of a metrological characterization of TS by the pilot institute are

presented in Appendix B1. They should help participants to verify that the TS

operates normally. In the case of any anomaly or significant deviation from the results

of the pilot institute it should be contacted.

The magnetization of the piston and cylinder will be checked at the pilot

institute during the comparison. If the magnetization at their surfaces is higher than 2

x 10-4

Tesla, the parts will be demagnetized. Participating institutes may check

magnetization using a non magnetizing test procedure but should inform the pilot

institute before taking any action.

Installation of the transfer standard:

Gloves should be worn when handling the piston, the carrying bell and the

masses of TS.

1) The TS is set on the place where it is going to be calibrated. TS is recommended

to be located close to the institute’s reference standard to keep the pressure line

between the two instruments as short as possible. It is also recommended to adjust

the height position of TS to minimize the height difference between the reference

level of TS defined in Appendix B1 and the reference level of the participant’s

institute standard. (See “Height difference and head correction” )

2) It is recommended to install a shut off valve between the pressure balance and the

participant’s pressure calibration system to check the TS for leaks.

3) Before mounting the assembly the piston and cylinder should be cleaned

according to the usual practice in the institute. The piston-cylinder assembly

should be installed in the mounting post carefully in accordance with the

instructions given in the Ruska Piston Pressure Gauge Users Manual. The

verticality of the piston and cylinder should be adjusted in the participant’s

manner. After the adjustment, ensure that the platform is firmly mounted on a

surface. Also check the verticality during the course of the measurement.

Applying pressure and leak check:

After the installation, TS will be pressurized using the participant’s standard

up to 7 MPa. Any leak in the calibration system should be checked and fixed.

To check the performance of the TS, the piston fall rate shall be measured at

7 MPa. Wait a minimum of 10 minutes after generating the pressure in the TS

measurement system prior to starting the piston fall rate measurements in order to


stabilize the TS temperature. It is recommended to set a shut off valve between the

pressure balance and the participant’s pressure calibration system. The valve should

be closed when the piston fall rate is measured because even a minimal leak in the

pressure generating system can significantly disturb the results. The target fall rates

are given in Appendix B1.

Height difference and head correction:

The pressure generated by a pressure standard at the reference level of the TS,

p', is represented by the following equation:

p' = ps + (ρf − ρa)·g·h (1)

where, ps is the pressure generated by the institute’s pressure standard at its reference

level; (ρf − ρa)·g·h, is the head correction, with ρf the density of the working fluid, ρa

the air density, g the local acceleration due to gravity, and h the height difference

between the reference levels of the two intercompared standards (institute standard

and TS). h is positive if the level of the institute’s standard is higher.

To minimize uncertainties in pressure measurement, the height difference

between the reference levels should be kept as low as possible. Also, it is

recommended to measure the height difference accurately.

The piston can be rotated by a motor in the platform instrument or manually.

The rotation direction is clockwise. The recommended rotation speed is not critical

but should not exceed 60 rpm when the mass carrier bell is loaded. Do not use the

rotation speed control function more than necessary since the motor is a major source

of heat.

The piston free rotation time is given in Appendix B1.

Reference temperature:

The reference temperature of the comparison is 20 °C. If measurements are

performed at a temperature deviating from 20 °C, the effective area of TS should be

referred to 20 °C using the piston-cylinder thermal expansion coefficient given in

Appendix B1.

Measurement method:

The measurements shall include three cycles each at the nominal pressures:

79.4, 137.8, 196.0, 1767.0, 2935.7, 4104.4, 5273.1, 6441.8, 6792.4 in kPa generated

in increasing then decreasing order. The generated pressures (p' in equation (1))

should not deviate from these nominal values by more than 0.1 kPa up to 1 MPa then

by more than 1 kPa up to 7 MPa. At least 15 minutes should be allowed between two

consequent measurements at 7 MPa.

The time between a pressure level change and the acquisition of the data

corresponding to the equilibrium of the participating institute’s standard and TS

should be not shorter than 5 minutes. It may be necessary to dismantle the TS for

cleaning during testing if the spin time appears to reduce or if stalling occurs at low

rotation speeds. If this is required the TS should be dry wiped only using a lint free

tissue and a spin test conducted to establish normal operation in accordance with

Appendix B1. The TS must be left to stabilize at least an hour after this dry cleaning.


If additional cleaning is required involving solvent or water the TS must be left over

night before resuming testing.

The results of the measurement cycle should be recorded on the measurement

results sheet as shown in Appendix A6. It is desirable to complete either a half or full

cycle in one day.

7. Reporting of results

The pilot institute will collate the results including:

(i) Details of the participating institute’s standard (Appendix A4)

(ii) Details of the measurement conditions (Appendix A5)

(iii) Results in individual cycles [1/3, 2/3, 3/3] (Appendix A6)

(iv) Summary of all cycles (Appendix A7)

(v) Calculated result of A’0 and ’ (Appendix A8)

(vi) Uncertainty budget (using the participant’s usual format).

The participating institute may add other information they think useful.

(i) Participating institute’s standard:

The pilot institute will collate the information related to the institute standard

against which the TS was calibrated, including the origin of its traceability to the SI,

as listed in the table reported in Appendix A4. If more than one standard is used, it

must be clearly indicated the standard used in respect of the established nominal

pressure points.

The type of the piston-cylinder assembly used as institute standard, the

characteristics of its effective area and the estimation of the uncertainty, as well as any

other useful information, will be added to the table.

(ii) Measurement conditions:

The parameters used for the measurements will be reported using Appendix

A5. Those are local gravity, height difference of the reference levels between the

participating institute’s standard and the TS. The instruments for measuring

environmental condition, as well as any other useful information, will be added to the

table.

(iii and iv) Measurement and calculation results:

Calculate the applied pressure with the associated standard uncertainty [k=1]

at the reference level of the TS. Any influence quantity for the institute system must

be taken into account and included in the appropriate uncertainty estimation. The

correction by the height difference of the reference levels between the participating

institute’s standard and the TS should be considered. Record these data in the cell on

the sheet for the measurement results in Appendix A6 as follows.

Example: Meas.

No.

Nom.

Pres.

[MPa]

Local

Time

Ambi

Temp.

[°C]

Atmo

R.H.

[%]

Atmo

Pres.

[kPa]

Temp.

t

[°C]

Temp.

t’

[°C]

Pressure

p’

[MPa]

E. A.

A’p

[mm2]

1 50 9:00 20.0 50.0 100.0 20.0 20.0


- Ambient temperature, relative humidity and atmospheric pressure are measured

using the participant’s own devices.

- Temperature of piston-cylinder assembly is displayed on PC in Excel.

- p’ is the pressure measured with the institute standard at the local gravity g and the

local air density a and calculated at the reference level of the TS using equation (1).

The participating institutes will report their results, which are measured and

calculated values at the 9 nominal pressures specified, each with an uncertainty in the

measurement (coverage factor k = 1). The date(s) on which practical work was

undertaken is reported in the sheet for the measurement results. The uncertainties shall

be estimated and combined following the Guide to the Expression of Uncertainty in

Measurement (GUM).

To help the pilot institute to get the data of each institute in a consistent form,

each institute should use Appendix A6 to send their data (and Ms-Excel file provided

additionally). Appendix A6 is essentially a data sheet reporting the data obtained at

each comparison point, for each cycle of the planned comparison. In current case the

pilot institute expects 3 data sheets from each participant.

Effective area calculation:

The effective area of TS determined from a particular measurement (A’p)

referred to 20 °C can be calculated with the equation

'

0

''

c

'

p

'

'

a'

'

p1

1

ttααp

ρ

ρgm

Ai

i

i

, (2)

where

m’i are true masses of the piston, the mass loading bell and the mass pieces

placed on the mass loading bell of TS;

’i are densities of the parts with masses m’i;

a is air density;

g is local gravity acceleration;

p' is pressure generated by the institute’s standard at the TS reference level;

’p and ’c are thermal expansion coefficients of the piston and cylinder

materials, respectively;

t' is temperature of TS;

t’0 is reference temperature, t’0 = 20 °C.

The values of p’, a and t’ as well as the masses of the participating institute

are to be calculated or measured by the institute. All other parameters can be

found in Appendix B1.

In Appendix A7, each institute should report whether equation (2) or an

alternative equation was used for A’p determination. The formula to calculate p’

should be given.

(v) Calculated result of A’0 and ’:

In Appendix A8, the zero-pressure effective area of TS (A’0) and its pressure

distortion coefficient ( ’) which satisfy equation

A’p = A’0(1+ ’p) (3)


and are based on the results of all 60 measurements, the combined standard

uncertainties of A’0 and ’ as well as a description of how they were calculated should

be included.

Any additional information which in opinion of the participating institute is

important for the interpretation of the comparison results is welcome.

(vi) Uncertainty budget:

A list of the principal components of the uncertainty and any necessary

advice on how uncertainties are estimated should be reported. This is based on the

principles laid out in the Guide to the Expression of Uncertainty in Measurement

(GUM)4. In addition to the principal components of the uncertainty, common to all of

the participants, individual institutes may add any others they consider appropriate.

Uncertainties are evaluated at a level of one standard uncertainty (coverage factor k =

1).

Submission:

Reports (i) – (vi) described above are expected to be prepared as a WORD

file with the tables from Appendixes A6 and A7 being additionally provided in an

EXCEL file. The reports should be sent to the pilot institute by e-mail to the address

Mr Neville Owen

Officer in Charge, Melbourne Physical Metrology

National Measurement Institute, Australia

Unit 1- 153 Bertie Street Port Melbourne, 3207 Victoria, Australia

Tel:+61-03-9644 4907, Fax:+61-03-9644 4888,


8. Preparation of the report

The pilot institute is responsible for the preparation of a report on the

comparison. The analysis of data, based on results of participants, will be done by the

pilot institute. In principle, the pilot institute will treat all data and reports according

to the guidelines described in the reference 1.

References:

1.Guidelines for CIPM key comparisons, (Appendix F to the "Mutual recognition of

national measurements standards and of measurement certificates issued by national

metrology institutes" (MRA)), 1999. revised 2003

(http://www.bipm.fr/pdf/guidelines.pdf)

2.Formalities required for the CCM key comparisons (2nd

revised draft), 2001.

3.Entering the details and results of RMO key and supplementary comparisons into the

BIPM key comparison database, 2000.

4.ISO/IEC 2008 Guide 98-3 Guide to the Expression of Uncertainty in Measurement

(GUM: 1995) (Geneva: International Organization for Standardization).

5.G. Molinar et al, IMGC-CNR Technical Report 42 October 2000. Draft B–Results of

the CCM Pressure key comparison (Phase B) in gas media and gauge mode from 80

kPa to 7 MPa.

6.General Electric Company, Ruska Instrument Division, Gas Lubricated Piston

Pressure Gauge Model 2465-754 Users Manual (Release 2465-1D01, revisions G,

December 3, 1992).


Appendix A1. Report for transportation (Arrival)

Advise the pilot institute by email of the date and condition upon arrival.

Appendix A2. Report for transportation (Departure)

Advise the pilot institute by email of the date of departure.

Appendix A3. State record of the transfer standard

Advise the pilot institute by email of any fault or failure of the TS during testing.

Appendix A4. Details of the participating institute’s standard

Institute:

Details of the pressure balances used for the comparison:

Manufacturer Model Description

Base

Piston-cylinder Operation mode#1

:

Pressure range [MPa]:

Weights Total mass [kg]:

Typical relative uncertainty of mass

pieces (k=1) [ppm]:

Thermometer

#1 for example: Simple or controlled-clearance, etc

Details of the piston-cylinder:

Material Linear thermal expansion

coefficient ( ) [°C-1

]

Piston

Cylinder


Details of the Effective area of the piston-cylinder:

Value Unc. [k=1] Traceability#2

Cali.Date (if applicable)

Zero-pressure effective area

[mm2] at ref. temp., A0,tr

#3

(Ref. temp.: tr)

(tr : [°C])

Pressure distortion

coefficient #3

[MPa-1

]

Pressure distortion

coefficient #3

[MPa-2

] (if applicable)

#2 for example: from PTB, Certificate number 1234, or mercury manometer, etc.

#3 Ap = A0 (1 + p + p2)

Piston rotation:

Method: ( ) By hand or ( ) By Motor [Please check one]

Rotational Speed: [rpm]

Details of the traceability to SI units (for primary standard):

Traceability of the participating institute’s standard to SI units should be explained.

Details of how A0 and ( ) and their uncertainties were determined should be

reported.

Comments:


Appendix A5. Details of the measurement conditions

Institute:

Local gravity:

g [m/s2] u(g) [m/s

2] (k=1)

Height difference of the reference levels between the participating institute’s

standard and the transfer standard: (Positive: if the level of the institute’s standard is higher).

h [mm] u(h) [mm] (k=1)

Instruments for measuring environmental condition:

Uncertainty[k=1] Comments

Atmo. Temp

Atmo. RH

Atmo.

Pressure

Method for achieving pressure equilibrium:

It should be reported how TS was connected to the institute standard and how their

pressure equilibrium was achieved and controlled.

Comments:


Appendix A6. Results in individual cycles

Institute:

Date:

Cycle Number: ( )/ 3

Meas.

No.

Nom.

Pres.

[MPa] Local

Time

Ambi

Temp.

[°C]

Atmo

R.H.

[%]

Atmo

Pres.

[kPa]

Temp.

t

[°C]

Temp.

t’

[°C]

Pressure

p’

[MPa]

E. A.

A’p

[mm2]

1 79.4

2 137.8

3 196.0

4 1767.0.

5 2935.7

6 4104.4

7 5273.1

8 6441.8

9 6792.4

10 6792.4

11 6441.8

12 5273.1

13 4104.4

14 2935.7

15 1767.0

16 196.0

17 137.8

18 79.4

t is temperature of the participating institute’s standard;

t’ is temperature of the TS; p’ is the pressure measured with the institute standard at the local gravity g and the local air density a

and calculated at the reference level of the TS.

A’p is effective area of TS at the reference temperature 20 °C.

The formula to calculate p’ must be reported.


Appendix A7. Summary of all cycles

Institute:

Period: dd mm 20yy - dd mm 20yy

: Nom.

Pres.

[MPa]

Typical min.

adjusted mass

[mg] 1)

Average of A’p,

< A’p > [mm2] 2) Rel. standard

deviation of

< A’p > [10-6] 3)

Rel. standard

uncertainty of

p’ [10-6] 4)

Standard

uncertainty of

t’ [°C] 5)

Rel. standard

uncertainty of

< A’p > [10-6] 6)

79.4

137.8

196.0

1767.0.

2935.7

4104.4

5273.1

6441.8

6792.4

1) the smallest mass adjusted on the piston of the TS to reach the equilibrium between

it and the participating institute’s standard, if the classical fall rate method to control

the equilibrium is used. If another method is applied, the typical uncertainty of the

pressure difference between the reference standard and TS (in MPa) due to this

method should be given. In this case the heading of this column shall be appropriately

changed;

2) average of the values measured at the same nominal pressure;

3) standard deviation of the mean value;

4) type B uncertainty including the uncertainty of the pressure at the reference level of

TS, which includes uncertainty of pressure generated by the institute’s standard, of the

height difference between the institute standard and TS, of the density of the pressure

transmitting medium, etc.;

5) type B uncertainty of the temperature measurement on TS;

6) combined uncertainty of the mean values in 2);

In addition, a list of the main uncertainty sources and their contributions to

<A’p> for pressures 80 kPa and 7 MPa must be presented in a separate sheet.

All the uncertainties should be expressed as the standard ones.


Appendix A8. Calculated result of A’0 and ’

Institute:

Period: dd mm 20yy - dd mm 20yy

:

Calculated result of A’0 and ’:

Value Unc. [k=1]

Zero-pressure effective area [mm2]

at ref. temp., A’0,t’0 #

(t’0 = 20 °C)

Pressure distortion coefficient ’ # [MPa

-

1]

# A’p = A’0(1+ ’p)

Details of how A’0 and ’ and their uncertainties were determined should be reported.

Comments:


Appendix B1. Technical data of the transfer standard

All uncertainties in this appendix are the standard ones.

Piston-cylinder assembly:

The serial number is G137. The nominal effective area of the assembly is:

A’0,nom = 16.8 mm

2.

Piston-cylinder material properties:

The type of piston-cylinder assembly is simple, free deformation. The

measurement range is up to 7 MPa. The cylinder of the assembly is made of tungsten

carbide, and the piston is made of tungsten carbide with the following linear thermal

expansion coefficient ( ).

Material [°C]

Piston Tungsten carbide 4.55 ·10-6

Cylinder Tungsten carbide 4.54 ·10-6

The thermal expansion coefficient of the piston-cylinder unit can be taken as

’p + ’c = (9.1 0.46) 10-6

°C-1 #

.

Piston mass and density:

True mass [g] Equivalent density [kg/m3]

#

Piston 22.174 99 ± 0.000 31 11 200·(1 5·10-2

)

Piston length:

The total piston length (distance from the piston lower face to the upper

piston cup edge) is 64 ± 0.05 [mm].

Reference level and piston working position:

The reference level of the TS is the base of the piston. The recommended

piston working position is physically about 6 mm above its lowermost (low stop)

position.

Note: Please use the participant’s own devices to measure the piston working

position.

Typical cross-float sensitivity and reproducibility:

The relative cross-float sensitivity is between 5 and 10 mg over the test

pressure range. The relative experimental standard deviations of single values of the

effective areas measured at the pressures specified for the comparison are less than 1

10-6

.

Piston fall rates:

Piston fall rate (vf) measured by the pilot institute at around 20 °C is

p [MPa] vf [mm/min]

6.9 1.8


It should be waited minimum 10 minutes after generating the pressure in the

TS measurement system prior to starting the piston fall rate measurements in order to

stabilize the TS temperature. It is recommended to set a shut off valve between the

pressure balance and the participant’s pressure calibration system. When the valve is

available, it should be closed when the piston fall rate is measured because even a

minimal leak in the pressure generating system can significantly disturb the results.

Piston free rotation time:

When piston rotates freely (without motor) with a load of 20 g applied to the

piston (pressure nominally 24.6 kPa) and a temperature of 20 °C, the rotation speed

descends from 90 rpm to stationary within 1.9 minutes.

Stability of the transfer standard:

Several measurements performed between 2007 and 2010 showed maximum

differences in generated pressure of 5·10-6

.

Mass loading bell, mass and density:

The mass loading bell, serial number 50664, is made of non-magnetic

stainless steel and is one of the mass component items.

Temperature probe:

The temperature of the piston-cylinder assembly (t’) is measured with a platinum

resistance thermometer (PRT) supplied with a logger, PC and data acquisition

software and should be used to determine the temperature of the piston-cylinder unit.

Pressure transmitting medium:

The working fluid is high purity nitrogen.

FINAL COMPARISON REPORT MAR 2013 (APMP REVIEW).DOC 33

Appendix D: Data from the participating laboratories.

INRIM

Table 1 - Laboratory standard and measurement conditions

The uncertainties here are expressed as the standard ones.

Manufacturer Ruska_

Measurement range in MPa Used from 1.8 MPa to 6.5 MPa

Material of piston Tungsten carbide

Material of cylinder Tungsten carbide

Operation mode, free-deformation or controlled-clearance Free-deformation

Zero-pressure effective area (A0) at reference temperature in mm2 8,385652


9.6


2x10-12


2.0 x10-13


2.2


9.1x10-6

Reference temperature (t0) in °C 20

Local gravity (g) in m/s2 9.805328


1


+1.3

Uncertainty of h in mm 1

Table 2 - Results in individual cycles

Laboratory name: INRIM

Date (period): 12 May 2011 :

Cycle number: 1

Meas. number

Nominal pressure [MPa]

tamb [°C] R.H. [%]

p atm [kPa]

t [°C] t’ [°C] DUT

p’ [Pa] A’p [mm2]

1 1.8 21.60 49.9 98860 21.03 21.31 1764882.27 16.788872

2 2.9 21.65 51.5 98846 21.19 21.54 2932814.63 16.788913

3 4.1 21.80 51.2 98850 21.30 21.70 4106579.85 16.788918

4 5.3 21.80 51.5 98852 21.34 21.75 5274451.11 16.789013

5 6.4 21.70 51.8 98838 21.37 21.79 6448182.92 16.789040

6 6.5 21.80 52.4 98803 21.41 21.84 6506577.17 16.789039

7 6.5 21.80 52.5 98679 21.37 21.76 6506581.18 16.789044

8 6.4 21.80 53.0 98640 21.42 21.87 6448176.37 16.789051

9 5.3 21.80 53.5 98623 21.46 21.92 5274455.29 16.788980

10 4.1 21.80 51.9 98608 21.55 22.01 4106560.34 16.788956

11 2.9 21.90 52.5 98601 21.54 22.01 2932801.08 16.788928

12 1.8 21.90 52.8 98618 21.52 22.02 1764875.50 16.788838



Date (period): 14 May 2011

Cycle number: 2

Meas. number


tamb [°C] R.H. [%]

p atm [kPa]

t [°C] t’ [°C] DUT


1 1.8 21.00 33.2 99325 20.67 20.97 1764882.99 16.788896


2 2.9 21.00 32.8 99154 20.88 21.22 2932820.76 16.788906

3 4.1 21.00 32.4 99189 20.85 21.19 4106586.51 16.788944

4 5.3 21.00 32 99220 20.83 21.15 5274488.99 16.788962

5 6.4 21.00 32.2 99297 20.77 21.10 6448207.03 16.789063

6 6.5 21.10 32.2 99309 20.73 21.06 6506611.87 16.789048

7 6.5 21.20 32.3 99073 20.93 21.28 6506611.85 16.789017

8 5.3 21.10 32.8 99076 20.94 21.29 5274468.34 16.789012

9 4.1 21.10 33.1 99107 20.93 21.31 4106582.58 16.788948

10 2.9 21.10 32.8 99119 20.92 21.28 2932818.62 16.788914

11 1.8 21.20 32.8 99138 20.89 21.23 1764882.00 16.788872


Laboratory name: INRIM Date (period): 17 May 2011 : Cycle number: 3

Meas. number


tamb [°C] R.H. [%]

p atm

[kPa]

t [°C] t’ [°C]

DUT


1 1.8 20.90 38.3 99356 20.54 20.78 1764893.19 16.788827

2 2.9 21.00 37.7 99336 20.71 21.01 2932835.98 16.788846

3 4.1 21.00 37.4 99307 20.76 21.08 4106594.89 16.788925

4 5.3 21.10 37.9 99272 20.79 21.10 5274493.25 16.788955

5 6.5 21.00 38.4 99242 20.82 21.14 6506631.75 16.788981

6 6.5 21.10 37.6 99156 20.84 21.17 6506618.98 16.789012

7 5.3 21.10 37.4 99094 20.87 21.24 5274475.90 16.788994

8 4.1 21.10 37.6 99045 20.91 21.28 4106585.22 16.788942

9 2.9 21.1 38.4 98999 20.99 21.44 2932825.47 16.788851

10 1.8 21.1 55.6 98742 20.55 20.76 1764893.16 16.788845

Table 5 - Summary of all cycles

Nominal pressure

(MPa)

Typical min.

adjusted mass

(mg) 1)

Average of A’p,

(mm2)

2)

Relative standard

deviation of A’p

mean (10

-6)

3)

u(p’)/p’

(10-6

) 4)

u(t

’)

(°C) 5)

Rel. stan-dard

uncertainty of <A

’p>

(10-6

) 6)

1.8 2 16.788858 1.5 10.0 0.015 10.1

2.9 2.5 16.788893 2.1 9.9 0.015 10.2

4.1 5 16.788939 0.9 9.9 0.015 10.0

5.3 4 16.788986 1.5 9.9 0.015 10.0

6.5 5 16.789024 1.5 9.8 0.015 10.0


NMIA

Table 1 - Laboratory standard and measurement conditions

The uncertainties here are expressed as the standard ones.

Manufacturer Harwood/DHI/NMI via oil/gas interface

Measurement range in MPa 1.2 MPa to 10 MPa

Material of piston Tungsten carbide

Material of cylinder Tungsten carbide

Operation mode, free-deformation or controlled-clearance Free-deformation

Zero-pressure effective area (A0) at reference temperature in mm2 490.2589


7.5


1.12x10-6


0.09 x10-6


3


9.1x10-6

Reference temperature (t0) in °C 20

Local gravity (g) in m/s2 9.799499


0.5


-0.3

Uncertainty of h in mm 0.3 (includes oil/gas interface)


Laboratory name: NMIA

Date (period): 25 Oct 2011 :

Cycle number: 1

Meas. number

Nominal pressure

[MPa]

tamb [°C] R.H. [%]

p atm

[kPa]

t [°C] t’ [°C]

DUT


1 1.8 20.39 39.75 101.675 20.24 20.36 1763839.2 16.78888

2 2.9 20.45 39.99 101.670 20.30 20.39 2931104.0 16.78882

3 4.1 20.46 40.49 101.384 20.30 20.40 4104191.8 16.78881

4 5.3 20.52 40.49 101.697 20.35 20.45 5271408.5 16.78883

5 6.4 20.51 41.17 101.700 20.39 20.48 6444456.8 16.78888

6 6.5 20.48 39.66 101.693 20.43 20.49 6502757.4 16.78903

7 6.4 20.49 39.47 101.721 20.47 20.53 6444390.1 16.78904

8 5.3 20.49 39.12 101.737 20.48 20.52 5271360.4 16.78897

9 6.5 20.48 34.78 102.164 20.15 20.35 6502758.8 16.78904

10 4.1 20.51 35.07 102.180 20.23 20.41 4104147.5 16.78898

11 2.9 20.48 35.03 102.195 20.30 20.45 2931074.3 16.78896

12 1.8 20.49 35.4 102.201 20.35 20.47 1763823.6 16.78900



Date (period): 28 Oct 2011

Cycle number: 2

Meas. number

Nominal pressure

[MPa]

tamb [°C] R.H. [%]

p atm [kPa]

t [°C] t’ [°C] DUT


1 1.8 20.6 44.06 100.940 20.30 20.32 1763856.2 16.78874


2 2.9 20.59 43.78 100.914 20.40 20.38 2931098.0 16.78888

3 4.1 20.58 44.8 100.888 20.47 20.43 4104156.9 16.78897

4 5.3 20.57 45.38 100.854 20.53 20.47 5271335.3 16.78908

5 6.4 20.57 46.46 100.729 20.49 20.47 6444364.9 16.78914

6 6.5 20.6 45.87 100.695 20.52 20.49 6502692.3 16.78923

7 6.5 20.62 47.39 100.666 20.53 20.50 6502695.9 16.78922

8 6.4 20.6 47.28 100.624 20.56 20.52 6444328.4 16.78923

9 5.3 20.64 46.63 100.557 20.51 20.51 5271309.3 16.78917

10 4.1 20.64 47.58 100.530 20.52 20.52 4104115.8 16.78914

11 2.9 20.61 49.67 100.494 20.58 20.54 2931055.0 16.78911

12 1.8 20.62 49.91 100.488 20.62 20.56 1763803.6 16.78922


Laboratory name: INRIM Date (period): 31 Oct 2011 : Cycle number: 3

Meas. number

Nominal pressure

[MPa]

tamb [°C] R.H. [%]

p atm [kPa] t [°C] t’ [°C] DUT


1 1.8 20.33 35.19 102.511 20.12 20.14 1763827.2 16.78900

2 2.9 20.35 35.64 102.504 20.15 20.18 2931092.2 16.78890

3 4.1 20.33 35.48 102.467 20.21 20.21 4104175.5 16.78889

4 5.3 20.38 35.7 102.460 20.27 20.24 5271354.0 16.78901

5 6.4 20.43 35.93 102.438 20.32 20.27 6444384.9 16.78907

6 6.5 20.36 36.04 102.413 20.37 20.29 6502718.5 16.78914

7 6.5 20.4 35.76 102.410 20.39 20.29 6502728.8 16.78912

8 6.4 20.39 35.85 101.643 20.18 20.14 6444363.0 16.78917

9 5.3 20.38 35.52 101.685 20.27 20.21 5271319.3 16.78915

10 4.1 20.39 35.35 101.688 20.30 20.24 4104128.2 16.78910

11 2.9 20.44 35.29 101.668 20.36 20.27 2931052.9 16.78913

12 1.8 20.46 35.84 101.665 20.40 20.28 1763798.0 16.78928

Table 5 - Summary of all cycles

Nominal pressure

(MPa)

Typical min.

adjusted mass

(mg) 1)

Average of A’p,

(mm2)

2)

Relative standard

deviation of A’p

mean (10

-6)

3)

u(p’)/p’

(10-6

) 4)

u(t

’)

(°C) 5)

Rel. stan-dard

uncertainty of <A

’p>

(10-6

) 6)

1.8 0.62 16.789020 12.10 8.82 0.18 10.24

2.9 0.86 16.788967 7.57 8.76 0.18 9.43

4.1 1.71 16.788982 7.40 8.76 0.18 9.39

5.3 2.23 16.789035 7.55 8.81 0.18 9.46

6.5 3.43 16.789130 5.08 8.84 0.18 9.49

Documents

Draft report – Results of the APMP pressure supplementary ...Draft B APMP.M.P-S3, 4 April 2012, version 1 Page 1 of 36 Final report on APMP.M.P-S3 Results of the supplementary comparison