The KCDB - the BIPM key comparison database – supports the CIPM MRA. The KCDB contains information on the internationally recognized Calibration and Measurement Capabilities (CMCs) for services available from the participating institutes, and the key and supplementary comparisons supporting these CMCs.

All data listed in the KCDB have been reviewed and approved within the CIPM Mutual Recognition Arrangement
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In the CMCs uncertainty statements, the notation Q[*a*, *b*] stands for the root-sum-square of the terms between brackets: Q[*a*, *b*] = [*a*^{ 2} + *b*^{ 2}]^{1/2}

*Unless otherwise stated the expanded uncertainties given below correspond to **k* = 2 (at a 95 % level of confidence)

China, NIM (National Institute of Metrology)

Time scale difference ,
Time scale difference
:
**-0.5 s to 0.5 s**

Remote clock vs UTC

Absolute expanded uncertainty
:
**1.6E1 ns**

GPS common view

Measurement time : 1 d

Prediction time : 20 d

Excluded DUT's effect

Approved on 31 October 2017

Institute service identifier : NIM/TF-4

Frequency ,
Frequency
:
**100 MHz**

Remote frequency standard

Relative expanded uncertainty
:
**1.1E-13 Hz/Hz**

GPS common view

Measurement time : 1 d

Amplitude : > 0.5 V (50 Ω)

Excluded DUT's effect

Approved on 31 October 2017

Institute service identifier : NIM/TF-16

Frequency ,
Frequency
:
**10 MHz**

Remote frequency standard

Relative expanded uncertainty
:
**1.1E-13 Hz/Hz**

GPS common view

Measurement time : 1 d

Amplitude : > 0.5 V (50 Ω)

Excluded DUT's effect

Approved on 31 October 2017

Institute service identifier : NIM/TF-15

Frequency ,
Frequency
:
**5 MHz**

Remote frequency standard

Relative expanded uncertainty
:
**1.1E-13 Hz/Hz**

GPS common view

Measurement time : 1 d

Amplitude : > 0.5 V (50 Ω)

Excluded DUT's effect

Approved on 31 October 2017

Institute service identifier : NIM/TF-14

Time scale difference ,
Time scale difference
:
**-0.5 s to 0.5 s**

Remote clock vs UTC(NIM)

Absolute expanded uncertainty
:
**1.1E1 ns**

GPS common view

Measurement time : 1 d

Excluded DUT's effect

Approved on 31 October 2017

Institute service identifier : NIM/TF-3

Viet Nam, VMI-STAMEQ (Viet Nam Metrology Institute, Directorate for Standards and Quality)

Frequency ,
Frequency
:
**1 MHz**

Local frequency standard

Relative expanded uncertainty
:
**2.0E-13 Hz/Hz**

Direct frequency measurement

Gate time : 1000 s

Number of measurements : 100

Amplitude : > 0.5 V (50 Ω)

DUT effects excluded

Approved on 19 July 2010

Institute service identifier : VN2.1.1

Mass ,
Mass (E2)
:
**1 mg to 100 mg**

Mass standard

Absolute expanded uncertainty
:
**2.0E-3 mg to 5.3E-3 mg**

Uncertainty table

{"row_1":{"col_1":"","col_2":"E2","col_3":"F1","col_4":"F2","col_5":"M1"},"row_2":{"col_1":"20 kg","col_2":"10.0","col_3":"33.3","col_4":"100","col_5":"333"},"row_3":{"col_1":"10 kg","col_2":"5.3","col_3":"16.7","col_4":"53.3","col_5":"167"},"row_4":{"col_1":"5 kg","col_2":"2.67","col_3":"8.33","col_4":"26.70","col_5":"83.3"},"row_5":{"col_1":"2 kg","col_2":"1.00","col_3":"3.33","col_4":"10.00","col_5":"33.3"},"row_6":{"col_1":"1 kg","col_2":"0.53","col_3":"1.67","col_4":"5.33","col_5":"16.7"},"row_7":{"col_1":"500 g","col_2":"0.267","col_3":"0.830","col_4":"2.670","col_5":"8.33"},"row_8":{"col_1":"200 g","col_2":"0.100","col_3":"0.330","col_4":"1.000","col_5":"3.33"},"row_9":{"col_1":"100 g","col_2":"0.053","col_3":"0.167","col_4":"0.530","col_5":"1.67"},"row_10":{"col_1":"50 g","col_2":"0.033","col_3":"0.100","col_4":"0.330","col_5":"1.000"},"row_11":{"col_1":"20 g","col_2":"0.033","col_3":"0.083","col_4":"0.267","col_5":"0.830"},"row_12":{"col_1":"10 g","col_2":"0.020","col_3":"0.067","col_4":"0.200","col_5":"0.667"},"row_13":{"col_1":"5 g","col_2":"0.0167","col_3":"0.0533","col_4":"0.167","col_5":"0.533"},"row_14":{"col_1":"2 g","col_2":"0.013","col_3":"0.0400","col_4":"0.133","col_5":"0.400"},"row_15":{"col_1":"1 g","col_2":"0.010","col_3":"0.0333","col_4":"0.100","col_5":"0.333"},"row_16":{"col_1":"500 mg","col_2":"0.0083","col_3":"0.0267","col_4":"0.083","col_5":"0.267"},"row_17":{"col_1":"200 mg","col_2":"0.0067","col_3":"0.0200","col_4":"0.067","col_5":"0.200"},"row_18":{"col_1":"100 mg","col_2":"0.0053","col_3":"0.0167","col_4":"0.053","col_5":"0.167"},"row_19":{"col_1":"50 mg","col_2":"0.0040","col_3":"0.0133","col_4":"0.040","col_5":"0.133"},"row_20":{"col_1":"20 mg","col_2":"0.0033","col_3":"0.0100","col_4":"0.033","col_5":"0.100"},"row_21":{"col_1":"10 mg","col_2":"0.0027","col_3":"0.0083","col_4":"0.027","col_5":"0.083"},"row_22":{"col_1":"5 mg","col_2":"0.0020","col_3":"0.0067","col_4":"0.020","col_5":"0.067"},"row_23":{"col_1":"2 mg","col_2":"0.0020","col_3":"0.0067","col_4":"0.020","col_5":"0.067"},"row_24":{"col_1":"1 mg","col_2":"0.0020","col_3":"0.0067","col_4":"0.020","col_5":"0.067"}}

The expanded uncertainties given in this table are expressed in mg

Comparison in air

Temperature : 20 °C

Humidity : (40 to 50) % RH

Approved on 09 September 2010

Institute service identifier : VMI-STAMEQ/1

Mass ,
Mass (E2)
:
**0.1 kg to 1 kg**

Mass standard

Absolute expanded uncertainty
:
**5.3E-2 mg to 0.53 mg**

Uncertainty table

{"row_1":{"col_1":"","col_2":"E2","col_3":"F1","col_4":"F2","col_5":"M1"},"row_2":{"col_1":"20 kg","col_2":"10.0","col_3":"33.3","col_4":"100","col_5":"333"},"row_3":{"col_1":"10 kg","col_2":"5.3","col_3":"16.7","col_4":"53.3","col_5":"167"},"row_4":{"col_1":"5 kg","col_2":"2.67","col_3":"8.33","col_4":"26.70","col_5":"83.3"},"row_5":{"col_1":"2 kg","col_2":"1.00","col_3":"3.33","col_4":"10.00","col_5":"33.3"},"row_6":{"col_1":"1 kg","col_2":"0.53","col_3":"1.67","col_4":"5.33","col_5":"16.7"},"row_7":{"col_1":"500 g","col_2":"0.267","col_3":"0.830","col_4":"2.670","col_5":"8.33"},"row_8":{"col_1":"200 g","col_2":"0.100","col_3":"0.330","col_4":"1.000","col_5":"3.33"},"row_9":{"col_1":"100 g","col_2":"0.053","col_3":"0.167","col_4":"0.530","col_5":"1.67"},"row_10":{"col_1":"50 g","col_2":"0.033","col_3":"0.100","col_4":"0.330","col_5":"1.000"},"row_11":{"col_1":"20 g","col_2":"0.033","col_3":"0.083","col_4":"0.267","col_5":"0.830"},"row_12":{"col_1":"10 g","col_2":"0.020","col_3":"0.067","col_4":"0.200","col_5":"0.667"},"row_13":{"col_1":"5 g","col_2":"0.0167","col_3":"0.0533","col_4":"0.167","col_5":"0.533"},"row_14":{"col_1":"2 g","col_2":"0.013","col_3":"0.0400","col_4":"0.133","col_5":"0.400"},"row_15":{"col_1":"1 g","col_2":"0.010","col_3":"0.0333","col_4":"0.100","col_5":"0.333"},"row_16":{"col_1":"500 mg","col_2":"0.0083","col_3":"0.0267","col_4":"0.083","col_5":"0.267"},"row_17":{"col_1":"200 mg","col_2":"0.0067","col_3":"0.0200","col_4":"0.067","col_5":"0.200"},"row_18":{"col_1":"100 mg","col_2":"0.0053","col_3":"0.0167","col_4":"0.053","col_5":"0.167"},"row_19":{"col_1":"50 mg","col_2":"0.0040","col_3":"0.0133","col_4":"0.040","col_5":"0.133"},"row_20":{"col_1":"20 mg","col_2":"0.0033","col_3":"0.0100","col_4":"0.033","col_5":"0.100"},"row_21":{"col_1":"10 mg","col_2":"0.0027","col_3":"0.0083","col_4":"0.027","col_5":"0.083"},"row_22":{"col_1":"5 mg","col_2":"0.0020","col_3":"0.0067","col_4":"0.020","col_5":"0.067"},"row_23":{"col_1":"2 mg","col_2":"0.0020","col_3":"0.0067","col_4":"0.020","col_5":"0.067"},"row_24":{"col_1":"1 mg","col_2":"0.0020","col_3":"0.0067","col_4":"0.020","col_5":"0.067"}}

The expanded uncertainties given in this table are expressed in mg

Comparison in air

Temperature : 20 °C

Humidity : (40 to 50) % RH

Approved on 09 September 2010

Institute service identifier : VMI-STAMEQ/5

Fluid flow ,
Static volume of liquid
:
**5 L to 500 L**

Volumetric test measure (vessel overflow type 5 L to 50 L and graduated neck type 50 L to 500 L)

Relative expanded uncertainty
:
**2.0E-2 % to 1.2E-2 %**

Gravimetric determination

Liquid : distilled water

Temperature of liquid : 20 °C ± 1 °C

Temperature variation : less than 1 °C in hour

Approved on 18 April 2012

Items for defining ITS-90 ,
Temperature
:
**419.527 °C**

SPRT

Absolute expanded uncertainty
:
**2 mK**

Zinc freezing point cell

3-zone furnace, seal cellModified on 09 February 2015

Approved on 22 January 2013

Institute service identifier : VMI-STAMEQ/T-5-132

Linear dimensions ,
Line standards
:
**0.01 mm to 1000 mm**

Precision line scale: line spacing L, glass

Absolute expanded uncertainty
:
**0.6 µm to 1.7 µm**

Q[0.6 µm, 1.5E-6*L]* L representing length

Line scale interferometer

Temperature : (20 ± 0.5) °C

Approved on 28 February 2011

Institute service identifier : VMI-STAMEQ/V01-32

Items for defining ITS-90 ,
Temperature
:
**29.7646 °C**

SPRT

Absolute expanded uncertainty
:
**0.6 mK**

Gallium melting point cell

Cryostat, seal cellModified on 09 February 2015

Approved on 22 January 2013

Institute service identifier : VMI-STAMEQ/T-3-132

Mass ,
Mass (E2)
:
**10 g to 100 g**

Mass standard

Absolute expanded uncertainty
:
**2.0E-2 mg to 5.3E-2 mg**

Uncertainty table

{"row_1":{"col_1":"","col_2":"E2","col_3":"F1","col_4":"F2","col_5":"M1"},"row_2":{"col_1":"20 kg","col_2":"10.0","col_3":"33.3","col_4":"100","col_5":"333"},"row_3":{"col_1":"10 kg","col_2":"5.3","col_3":"16.7","col_4":"53.3","col_5":"167"},"row_4":{"col_1":"5 kg","col_2":"2.67","col_3":"8.33","col_4":"26.70","col_5":"83.3"},"row_5":{"col_1":"2 kg","col_2":"1.00","col_3":"3.33","col_4":"10.00","col_5":"33.3"},"row_6":{"col_1":"1 kg","col_2":"0.53","col_3":"1.67","col_4":"5.33","col_5":"16.7"},"row_7":{"col_1":"500 g","col_2":"0.267","col_3":"0.830","col_4":"2.670","col_5":"8.33"},"row_8":{"col_1":"200 g","col_2":"0.100","col_3":"0.330","col_4":"1.000","col_5":"3.33"},"row_9":{"col_1":"100 g","col_2":"0.053","col_3":"0.167","col_4":"0.530","col_5":"1.67"},"row_10":{"col_1":"50 g","col_2":"0.033","col_3":"0.100","col_4":"0.330","col_5":"1.000"},"row_11":{"col_1":"20 g","col_2":"0.033","col_3":"0.083","col_4":"0.267","col_5":"0.830"},"row_12":{"col_1":"10 g","col_2":"0.020","col_3":"0.067","col_4":"0.200","col_5":"0.667"},"row_13":{"col_1":"5 g","col_2":"0.0167","col_3":"0.0533","col_4":"0.167","col_5":"0.533"},"row_14":{"col_1":"2 g","col_2":"0.013","col_3":"0.0400","col_4":"0.133","col_5":"0.400"},"row_15":{"col_1":"1 g","col_2":"0.010","col_3":"0.0333","col_4":"0.100","col_5":"0.333"},"row_16":{"col_1":"500 mg","col_2":"0.0083","col_3":"0.0267","col_4":"0.083","col_5":"0.267"},"row_17":{"col_1":"200 mg","col_2":"0.0067","col_3":"0.0200","col_4":"0.067","col_5":"0.200"},"row_18":{"col_1":"100 mg","col_2":"0.0053","col_3":"0.0167","col_4":"0.053","col_5":"0.167"},"row_19":{"col_1":"50 mg","col_2":"0.0040","col_3":"0.0133","col_4":"0.040","col_5":"0.133"},"row_20":{"col_1":"20 mg","col_2":"0.0033","col_3":"0.0100","col_4":"0.033","col_5":"0.100"},"row_21":{"col_1":"10 mg","col_2":"0.0027","col_3":"0.0083","col_4":"0.027","col_5":"0.083"},"row_22":{"col_1":"5 mg","col_2":"0.0020","col_3":"0.0067","col_4":"0.020","col_5":"0.067"},"row_23":{"col_1":"2 mg","col_2":"0.0020","col_3":"0.0067","col_4":"0.020","col_5":"0.067"},"row_24":{"col_1":"1 mg","col_2":"0.0020","col_3":"0.0067","col_4":"0.020","col_5":"0.067"}}

The expanded uncertainties given in this table are expressed in mg

Comparison in air

Temperature : 20 °C

Humidity : (40 to 50) % RH

Approved on 09 September 2010

Institute service identifier : VMI-STAMEQ/4

Mass ,
Mass (E2)
:
**1 g to 10 g**

Mass standard

Absolute expanded uncertainty
:
**1.0E-2 mg to 2.0E-2 mg**

Uncertainty table

The expanded uncertainties given in this table are expressed in mg

Comparison in air

Temperature : 20 °C

Humidity : (40 to 50) % RH

Approved on 09 September 2010

Institute service identifier : VMI-STAMEQ/3

Radiations of the mise en pratique ,
Laser radiations
:
**474 THz**

Frequency stabilized laser

Absolute expanded uncertainty
:
**2.4E1 kHz**

Optical beat frequency

Temperature : (20 ± 3) °C

Approved on 28 February 2011

Institute service identifier : VMI-STAMEQ/V01-50

Linear dimensions ,
End standards
:
**0.5 mm to 100 mm**

Gauge blocks: central length L, tungsten carbide

Absolute expanded uncertainty
:
**6.2E1 nm to 1.4E2 nm**

Q[62 nm, 1.2E-6*L*] *L* in mm, value varies from 62 nm to 135 nm

The uncertainty is expressed in nm

The uncertainty is expressed in nm

Mechanical comparison

Temperature : (20 ± 0.5) °C

Approved on 28 February 2011

Institute service identifier : VMI-STAMEQ/V01-06

Linear dimensions ,
Line standards
:
**0.01 mm to 1000 mm**

Precision line scale: line spacing L, steel

Absolute expanded uncertainty
:
**0.6 µm to 1.9 µm**

Q[0.6 µm, 1.8E-6*L]* L representing length

Line scale interferometer

Temperature : (20 ± 0.5) °C

Approved on 28 February 2011

Institute service identifier : VMI-STAMEQ/V01-32

Mass ,
Mass (E2)
:
**1 kg to 20 kg**

Mass standard

Absolute expanded uncertainty
:
**0.53 mg to 1.0E1 mg**

Uncertainty table

The expanded uncertainties given in this table are expressed in mg

Comparison in air

Temperature : 20 °C

Humidity : (40 to 50) % RH

Approved on 09 September 2010

Institute service identifier : VMI-STAMEQ/6

Fluid flow ,
Gas flowrate volume
:
**0.05 m**^{3}/h to 5 m^{3}/h

Gas-flow meter

Relative expanded uncertainty
:
**0.15 % to 0.3 %**

Turbine, rotameter, gasmeter

Fluid : dry air

Temperature : ambient, 15 °C to 30 °C

Pressure : 100 kPa to 800 kPa

Pressure at inlet DUT

Approved on 18 April 2012

Pressure ,
Gauge pressure: oil medium
:
**0.5 MPa to 100 MPa**

Pressure gauge

Absolute expanded uncertainty

6.0E-05*p*

*p* pressure in Mpa

The uncertainty is expressed in MPa

Direct comparison with pressure standard

Temperature : (20 ± 2) °C

Approved on 18 October 2011

Institute service identifier : VMI-P-2-3.2.2

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Acoustics, Ultrasound, Vibration

This metrology area covers the fields of acoustics, ultrasound and vibration.

Electricity and Magnetism

This metrology area covers the fields of DC and AC measurements, impedance, electric and magnetic fields, radiofrequencies and measurements on materials.

Length

This metrology area covers the fields of laser frequencies and dimensional metrology.

Mass and related quantities

This metrology area covers the fields of mass standards, force, pressure, density, hardness, torque, gravity and viscosity.

Chemistry and Biology

This metrology area covers all fields relevant to chemistry and biology.

Ionizing Radiation

This metrology area covers the fields of dosimetry, radioactivity and neutron measurements.