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The BIPM welcomed visitors for the 38th Journées européennes du Patrimoine


The BIPM opened its doors to the public for the second time on Saturday 18 and Sunday 19 September 2021 for the 38th Journées européennes du Patrimoine (European Heritage Days). The open days attracted 215 participants, who were given a guided tour of the Pavillon de Breteuil, the BIPM collection of historical instruments and the garden.

The European Heritage Days were launched in France in 1985. The Programme has been a joint initiative of the Council of Europe and the European Union since 1999.

Le BIPM ouvrait ses portes au public pour la deuxième fois, samedi 18 et dimanche 19 septembre 2021, à l'occasion des 38es Journées européennes du Patrimoine. Ces journées portes ouvertes ont attiré 215 participants pour une visite guidée du Pavillon de Breteuil, de la collection d'instruments anciens du BIPM et du jardin.

Les Journées européennes du patrimoine ont été lancées en France en 1985. Ce programme est une initiative conjointe du Conseil de l'Europe et de l'Union européenne depuis 1999.



Faster publication of chemistry and biology CMCs with the KCDB 2.0 platform

The time taken from submission to publication of internationally recognized measurement capabilities in the fields of Chemistry and Biology has been reduced with the application of the web-based KCDB 2.0 platform, as reported by the CCQM Key Comparison and CMC Quality Working Group (KCWG). On average, over 300 calibration and measurement capabilities (CMCs) in Chemistry and Biology are reviewed each year at the intra-regional and inter-regional level, with the KCDB 2.0 platform allowing time savings in this process to be achieved.

The inter-regional review process for CMCs for chemical and biological measurements is coordinated by the CCQM KCWG. During 2020 and 2021, the annual face-to face meetings of this group were replaced by on-line meetings and the use of the KCDB 2.0 web platform for the review of chemistry and biology CMCs was introduced.

The adoption by the CCQM of the KCDB 2.0 platform in 2021 was underpinned by preparatory work commencing the previous year. This preparatory work included the organization of BIPM Capacity Building and Knowledge Transfer Programme (CBKT) training sessions for potential CMC writers, reviewers and regional metrology organization (RMO) technical committee (TC) Chairs, as well as mock review exercises. In parallel, an instruction document was prepared for CCQM JCRB review using the platform and the CMC review guidelines developed by the CCQM KCWG were reviewed with the support of the KCDB Office.

During 2021, the first batch of CMCs for Chemistry and Biology have been processed and published with the KCDB 2.0. The new procedure allowed the time taken between submission for inter-regional review (JCRB) to publication of the CMC to be reduced to 60 days. A key improvement in the process, recognized by the CCQM KCWG, is the ability of the KCDB 2.0 system to allow individual processing of the CMCs avoiding delays to the completion of review of other CMCs in the same batch.

The BIPM CBKT programme continues to support national metrology institute (NMI) and designated institute (DI) staff that are new to the KCDB 2.0 process, through a series of online training sessions.


KCDB 2.0 - Online technical exchanges for Chemistry and Biology

Online Technical Exchange

CMC Writers
  • 14 October
  • 2021

Online Technical Exchange

TC Chairs
  • 26 January
  • 2022

For registration, please contact your RMO Secretariat.

Rethinking and modernizing international rulemaking to design better policies for the 21st century

Dr Martin Milton, Director of the BIPM, together with heads of other international organizations (IOs), participated as a panelist in the OECD high-level virtual tour de table: "Rethinking and modernizing international rulemaking to design better policies for the 21st century". The virtual meeting was held on 13 September 2021 as part of the 8th Annual Meeting of International Organisations within the context of the IO Partnership.

Following the high-level event, breakout sessions on technical expert level were held on 14 September 2021 and the BIPM was a moderator of the Breakout session 1: Enhancing the inclusiveness of international rulemaking to discuss follow-up work of the IO Compendium in regard to stakeholder engagement and co-ordination across IOs.

The Compendium of International Organisations' Practices : Working Towards More Effective International Instruments, available at, the first common tool developed collaboratively by some 50 IOs to improve the quality was launched during the 8th Annual IO Meeting. The IO Compendium lists the BIPM practices such as World Metrology Day, CBKT Programme, CIPM MRA Review, JCGM, etc. in five core focus areas. The BIPM is represented in WG2 (implementation of international instruments), WG4 (evaluation of international instruments) and WG5 (IO coordination – as a focal point).

The OECD established the Partnership of international organisations for effective international rulemaking (IO Partnership) as a voluntary platform of IOs, academics and OECD Regulatory Policy Committee delegates, to exchange good practices and promote greater quality, effectiveness, and impact in international rulemaking.

For more information on the 8th Annual Meeting of International Organisations please see:

Report of Session I of the 110th meeting of the CIPM (2021)

Metrology for Clean Air: Launch of on-line Knowledge Transfer Programme on the application of FT-IR for Gas Standard Characterization

The course is intended for NMI scientists working in gas metrology and wishing to further their theoretical and practical knowledge of the use of the FT-IR technique to obtain accurate and traceable quantification of infrared gas active species. The on-line knowledge transfer programme starting in 2021 is a replacement for the on-site training secondments for NMIs scientists, which have been in operation until 2020. The course covers the use and calibration of FT-IR instruments with gas standards to achieve SI traceable measurement results with well-defined uncertainties, as well as methods that rely on the traceability of measurement results to very high-resolution line strength data, and the use of algorithms to generate synthetic spectra, which can be used to calibrate instruments of 1 cm-1 resolution.

Scientists from NMIs and DIs from Member States and Associates will be able to follow the on-line course in one of two ways:

  • 6 month intensive on-line course – with regular BIPM video conference session follow-ups (limited number of participations per annual session and normally run from September to February)
  • Access to on-line material and B-FOS software only, with one on-line workshop for all participants registered for the year

The course is currently being followed by scientists form NIMT(Thailand) and NMISA (South Africa), and applications are open for the course that is limited to on-line material only, as well as the intensive on-line course starting in September 2022.

Further information can be found at:

Report of the 28th meeting of the CCRI (2021)

Published on 20 August 2021.

CIPM 2021 Decisions

Annual Report on Time Activities (2020)

Supplement 2020: Activities of the BIPM Departments

Published on 13 July 2021

BIPM Annual Review 2020/2021

Published on 13 July 2021

Report of the 26th meeting of the CCQM (2021)

Published on 27th July 2021

Outcomes of the 43rd JCRB meeting (2021)

Report of the 29th meeting of the CCT (2020)

Published on 13th July 2021

20th International Metrology Congress - CIM 2021

Registration for the 20th International Metrology Congress, which will be held in Lyon (France) from 7 to 9 September, is open. You will find the complete scientific and technical programme - including more than 200 presentations and six round tables - as well as many other practical details about the congress at

Note that, due to the world-wide pandemic situation, the registration to an ‘Online’ version of the congress is possible in addition to the usual ‘On-site’ registration. ‘Online’ version includes talks and posters in pre-recorded videos as well as livestream of the round tables and the plenary session. Access to the web platform of the congress will also be granted up to 3 months after the congress.



Quick access to the registration form

Quick access to the scientific and technical programme



Financial report 2020

CCQM Strategy 2021-2030

The BIPM-CTBTO Practical Arrangement

Following the CIPM Decision CIPM/108-38 of October 2019 the Practical Arrangement between the BIPM and the Preparatory Commission of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) on collaboration on the metrological traceability of measurements of infrasound, seismic activity and radioactivity was signed by Dr Lassina Zerbo, Executive Secretary of the CTBTO, on 4 May 2021 and by Dr Martin Milton, Director of the BIPM, on 10 June 2021.

The BIPM assists the CTBTO in its role to provide its States Signatories with data and products of the highest quality standard including reaching compatibility and adherence to the International System of Units (Système International d'Unités, the SI), metrological traceability and measurement uncertainty. The CTBTO assists the BIPM in its role of coordinating the development and validation of Calibration and Measurement Capabilities (CMCs) for measurements in the field of low-frequency sound and vibration as well as radionuclide particulates and gases.

Pursuant to this Practical Arrangement representatives of the BIPM will be invited to attend meetings of the CTBTO related to metrological traceability and measurement uncertainty, including the coordination of Pilot Studies and the development and validation of CMCs. Likewise representatives of the CTBTO will be invited to attend the meetings of the Consultative Committee for Acoustics, Ultrasound and Vibration (CCAUV) and the Consultative Committee for Ionizing Radiation (CCRI).

Report of the 109th meeting of the CIPM (2020)

Call for tender BIPM-2021-WS-01: Replacement of windows

World Accreditation Day (9 June 2021) Accreditation: Supporting the implementation of the SDGs

JCGM/WG2 VIM4 Webinar: video now available

The video of the JCGM/WG2 VIM4 Webinar is now available on the BIPM YouTube page. The webinar gave an overview of the Committee Draft of the new edition of the International Vocabulary of Metrology (VIM4).

More than 400 attendees watched the webinar, which was held on 6 May 2021. The panel gave presentations on the Joint Committee for Guides in Metrology (JCGM) and its Working Group 2 (WG2 - VIM Committee); the VIM4 Committee Draft; the significant changes between the VIM3 and the VIM4; and the new entries on nominal properties.

The presentations given at the webinar are available on the VIM4 webinar webpage

Happy World Metrology Day 2021 from the JCTLM!

The Joint Committee for Traceability in Laboratory Medicine (JCTLM) is celebrating World Metrology Day on 20 May 2021 through a series of videos on measurements in laboratory medicine. The theme this year is “Measurement for Health”.

Watch the videos on measurements in Laboratory Medicine for broader perspectives on the importance of metrological traceability in laboratory medicine for individual patients and for risk assessments in populations.

Watch the videos on measurements in laboratory medicine



Workshop: Metrology for Radionuclide Therapy

Safe and effective cancer therapy using ionizing radiation is only possible due to accurate measurement of the radiation dose delivered to the tumour and surrounding tissues. These measurements are particularly complex for radionuclide therapy and involve measuring the activity of the radionuclide administered to the patient, determining the distribution of the radiopharmaceutical in the body and estimating the radiation dose delivered. This field, which combines biology, dosimetry and radionuclide metrology, is at an early stage.

To mark World Metrology Day, the Consultative Committee for Ionizing Radiation (CCRI) and the Bureau International des Poids et Mesures (BIPM) are organizing a workshop on metrology for radionuclide therapy. The aim is to identify the current needs and gaps in metrology. Speakers are from the NIST, the University of Würzburg, the Medical University of Marburg, the NPL and the IAEA.

The workshop will be on 20 May 2021, 11:00-13:00 UTC. Please register in advance using this link:

The new BIPM website

Welcome to the BIPM's new website!

The design of the website has been updated and we hope you'll find it more convenient to browse - particularly on small screens.

To access restricted-access content (for example, working documents for meetings you have attended) please connect to the website by clicking on the button "SIGN IN" in the header. The first time you do this, please click on "Password forgotten" then enter your email address and follow the instructions to reset your password as provided by email.

In case of questions concerning this login, please contact webmaster (a)

A few important pointers:

  1. for the CIPM MRA and the CIPM MRA database (KCDB): look under Coordination / CIPM MRA
  2. for our CBKT programme: look under About us / Our mission and objectives
  3. to find a Committee or Working Group: look under Coordination / CIPM Consultative Committees or Liaison / Joint Committees
  4. for international metrology resources: look under Publications/Events / Metrology resources

Can't find what you're looking for? Try our expanded search engine!
The search engine now includes results from the website (including available working documents), Metrologia, the KCDB, and the JCTLM. If you find too many results initially, you can refine them by selecting one of the four sources, then the type of content listed in the left-hand menu.

Please remember to update your bookmarks to the site. Happy browsing!

If you encounter any problems, please send your feedback to webmaster (a)


Launch of the BIPM's new e-learning platform

The BIPM has launched an e-learning platform for staff from NMIs/DIs of Member States and Associates. The platform offers tailored courses related to scientific metrology activities, including the mechanisms of the CIPM MRA. The NMI/DI community will have access to the platform around the clock and on any device.

The first course, introducing the CIPM MRA, is now available.


Access the platform by clicking here:

Announcement of the 14th NEWRAD (2021)

Launch of Greenhouse Gas Scale Task Group: expanding accessibility to standards for CO2 atmospheric monitoring and emissions authentication

A Task Group for Greenhouse Gas Scale Comparisons has been established within the CCQM Working Group on Gas Analysis (CCQM-GAWG) with the goal of increasing global accessibility to standards for underpinning long-term monitoring and emissions authentication of CO2 in the atmosphere with internal consistency of 0.01 μmol/mol over the amount fraction range from 400 μmol/mol to 800 μmol/mol.

Setting up and evaluating a robust economic system based on the mitigation of carbon dioxide is expected to require multiple measurement sites around the world, including around urban areas. This is expected to increase world-wide demand for appropriate CO2 in air gas standards. The CO2 scale system enables the production and value assignment of standards that have very small uncertainties in relationship to each other. This high degree of consistency is important for atmospheric monitoring applications where small temporal and spatial changes are important. The reported consistency between tertiary standards is of the order of 0.01 μmol/mol. The best-known example of the scales approach is provided by the WMO, with the SI traceability of their primary standards demonstrated in the recent CCQM-K120 comparison. This relationship between standards in the scale approach is maintained in a database, and the value of any standard can be traced back to the primary standard set defining the scale.

The CCQM-GAWG, chaired by P. Brewer (NPL, UK), includes the WMO Central Calibration Laboratory, maintained at NOAA ESRL GML (USA), and National Metrology Institutes that are active in working towards establishing facilities for CO2 scale standard provision, with a requirement that differences in scales must be close to the internal consistencies which are currently achieved by the WMO scale approach. To minimize any potential scale bias, it is planned to maintain scale equivalence equations by using CIPM MRA on-going key comparisons.

The CCQM-GAWG Task Group on GHG Scale Comparisons (CCQM-GAWG-TG-GHG) is chaired by J. Carney (NIST, USA) and supported by reference and comparison facilities maintained within the BIPM laboratories. This includes the CO2-PVT manometric reference facility developed at the BIPM with visiting scientists from NIST (USA) and RISE (Sweden) and validated in the CCQM-P188 comparison. The facility will be the basis for future on-going comparisons of CO2 in air standards (BIPM.QM-K2) ensuring SI traceability of assigned values and comparisons of CO2 in air scales (BIPM.QM-K5) to ensure their consistency at the 0.01 μmol/mol level.

BIPM Manometric reference facility for the comparison of carbon dioxide in air standards. The facility was developed at the BIPM together with visiting scientists from the NIST (USA) and the RISE (Sweden), and operates through the principal of cryogenic separation of CO2 from air samples, with measurement of pressure, temperature and volume of both samples. Initially validated in the CCQM-P188 and CCQM-K120 comparisons, the facility will provide reference values for the future on-going BIPM.QM-K2 comparison of CO2 in air standards, allowing on-demand comparisons of NMI/DI standards anywhere in the range of 380 μmol/mol to 800 μmol/mol, as well as comparison of CO2 in air scale standards (BIPM.QM-K5).

Launch of laboratory based on-line knowledge transfer programme on Metrology for Food Safety: Calibrators

The BIPM has launched its on-line knowledge transfer courses and studies on Metrology for Food Safety focusing on primary reference materials and calibration solution characterization. The first course covers ‘Quantification of Non-structurally Related Impurity Content in Organic Pure Materials’, previously provided as an on-site course for National Metrology Institutes and Designated Institutes developing mycotoxin standards for food testing applications.

The goal of the course is to transfer knowledge and practical experience on the implementation of Elemental analysis, Thermal Gravimetric Analysis, Karl Fisher Titration, Sorption Balance, and VOC analysis methods for the accurate quantification of non-related structure impurities in pure organics and applicable to mycotoxin materials, and further information can be found at:

Quantification of non-structurally related impurity content in organic pure materials

The Metrology for Food Safety Capacity Building and Knowledge transfer programme, which started in 2016, is designed to allow NMIs to work together to strengthen mycotoxin metrology infrastructure; provide knowledge transfer to scientists developing capabilities in this area, including periods as visiting scientists at the BIPM; and enable NMIs to provide mycotoxin calibrant and matrix reference materials and proficiency test materials to support mycotoxin testing laboratories within their countries.

The project has support from a number of NMIs who are providing scientific expertise and raw materials to the project. The technical activities at the BIPM focus on Mycotoxin Calibrants and providing appropriate training and knowledge transfer.

The first series of on-site knowledge transfer activities were completed in 2020, and BIPM activities for the period 2021-2024 are focused on demonstrating equivalence of Mycotoxin Standards provided by NMIs/DIs through the coordination of CCQM comparisons on mycotoxin calibration solutions for aflatoxin B1, deoxynivalenol, patulin and ochratoxin A. Guidelines for the purity evaluation and calibrant assessment of mycotoxin primary reference materials and calibration solutions are also being made available.

The knowledge transfer programmes have been transferred to on-line versions using the BIPM’s e-learning platform in 2021. The first course to be on-line will be for ‘Measurement of non-related structure impurities in organic pure materials’, with the first module available in May 2021.

New Member State: Republic of Estonia

The Republic of Estonia, which had been an Associate since 2005, became a Member State on 19 January 2021.


New Member State: Republic of Belarus

The Republic of Belarus, which had been an Associate since 2003, became a Member State on 13 January 2020.


New Member State: Ecuador

Ecuador, which has been an Associate since 2000, became a Member State on 6 August 2019.


Videos from the BIPM Workshop: The International System of Units (SI) in FAIR digital data

Videos from the BIPM Workshop "The International System of Units (SI) in FAIR digital data" are now available on the BIPM YouTube page...

The virtual workshop was held on 22-26 February and brought together leading experts and groups in digitalization related to metrology and data science in order to exchange ideas about the first steps to proceed in this direction aiming at agreeing on basic standards for a "Digital SI" framework.

Further details are available on the dedicated BIPM Workshop webpage.



Beginning of a new phase of the dissemination of the kilogram

New Chair of the JCTLM

Dr Greg Miller has been appointed Chair of the Joint Committee for Traceability in Laboratory Medicine (JCTLM), taking over from Prof. Ian Young who recently completed his two-year term as Chair.

Dr Miller is a Professor in the Pathology Department at Virginia Commonwealth University where he serves as Co-director of Clinical Chemistry and Director of Pathology Information Systems.  His professional interests and research have focused on standardization and harmonization of laboratory results, quality control and external quality assessment/ proficiency testing. His current professional activities include: Associate Editor of the journal Clinical Chemistry, Chair of the Working Group for Commutability in Metrological Traceability of the International Federation of Clinical Chemistry and Laboratory Medicine, Chair of the Laboratory Working Group of the National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (US), a member of the Harmonization Oversight Group of the International Consortium for Harmonization of Clinical Laboratory Tests, a member of the US delegation to ISO Technical Committee 212 for Clinical Laboratory Testing and In Vitro Diagnostic Test Systems, and other work groups for clinical laboratory standards.

Dr Miller is a past-president of the American Association for Clinical Chemistry and of the Clinical and Laboratory Standards Institute. He received the Outstanding Lifetime Achievement Award in Clinical Chemistry and Laboratory Medicine from the American Association for Clinical Chemistry, the Robert Schaffer Award for Outstanding Achievements in the Development of Standards for Use in Laboratory Medicine from the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC), and the Russell J. Eilers Memorial Award from the Clinical and Laboratory Standards Institute.

Most recently Dr Miller has been working with the JCTLM, IFCC, BIPM and International Consortium for Harmonization of Clinical Laboratory Results (ICHCLR) to organize a joint workshop on ‘Overcoming challenges to global standardization of clinical laboratory testing:  reference materials and regulations’, which will be held as a virtual meeting hosted by the BIPM in December 2021.

New signatory of the CIPM MRA: NMC (Cambodia)

On behalf of the National Metrology Center (NMC, Cambodia), Mr H.E. By Pitou signed the CIPM MRA on 1st February 2021.

Report of the 31st meeting of the CCEM (2019)

Report of the 109th meeting of the CIPM

CIPM meeting 12-14 October 2020

Revised CIPM MRA documents

The documents supporting the CIPM Mutual Recognition Arrangement (CIPM MRA) - the framework through which National Metrology Institutes demonstrate the international equivalence of their measurement standards and the calibration and measurement certificates they issue - have been revised and published on 11 January 2021.

The Arrangement was originally signed in 1999 by 38 Member States and two international organizations and has since matured into a well-recognized pillar of the international quality infrastructure which now covers 258 institutes: signatories from 62 Member States, 40 Associates of the CGPM and four international organizations as well as 152 further institutes designated by the signatory bodies.

To cover the needs of international stakeholders in the nine core Metrology areas, the Arrangement has been supplemented by various clarifications and interpretations which previously amounted to 27 documents. To ensure sustainability after a decade and a half of successful operation, the 25th Meeting of the CGPM (2014) invited a review of the implementation of the Arrangement and to streamline its operation within the existing framework.

The international review of the Arrangement was undertaken in 2016 with a series of recommendations agreed in 2018. This initiated a process to consolidate and update the supporting documents. The revised suite, which was reviewed by both the Consultative Committees and the Regional Metrology Organizations prior to approval by the JCRB, now collates the information in three policy and three guidance documents:

The previous set of documents will be stored at the BIPM and available through the JCRB Members' working area or the JCRB Executive Secretary.


CIPM MRA documents

World Metrology Day 2021: Resource website now live

On behalf of the World Metrology Day Team, we are pleased to announce that the 2021 World Metrology Day Resource Website is now live. The theme this year is Measurement for Health.

This theme was chosen to create awareness of the important role measurement plays in health, and thus in the wellbeing of every one of us.

Indeed more widely metrology, the science of measurement, plays a central role in scientific discovery and innovation, industrial manufacturing and international trade, in improving the quality of life and in protecting the global environment.

World Metrology Day is an annual celebration of the signature of the Metre Convention on 20 May 1875 by representatives of seventeen nations. The Convention set the framework for global collaboration in the science of measurement and in its industrial, commercial and societal applications. The original aim of the Metre Convention – the world-wide uniformity of measurement – remains as important today as it was in 1875.


Accurate Results for Patient Care Workshop 2019 - A JCTLM Members' and Stakeholders' Meeting

The biennial JCTLM Members' and Stakeholders' meeting will be held at the BIPM on 2 and 3 December 2019. A cordial invitation is extended to anyone who has an interest in traceability in laboratory medicine and method standardization. These include laboratory medicine specialists, EQA providers, IVD manufacturers and national metrology institutes.

The meeting takes the form of a workshop that looks at a wide range of global initiatives to reduce between-method variability as a means to support improved clinical outcomes and patient safety. Interaction between the speakers and the audience will be a feature.

The first day of the programme focuses on Challenges and opportunities with lectures on Challenging the status quo and reports on New concepts to improve quality in laboratory medicine; International standards and regulation of IVDs; Meeting the challenge of method harmonization in haematology or biological standardization for infectious diseases.

The theme of the second day of the programme is Getting the right answer with consideration of commutability, harmonization of methods for difficult analytes and looking at international projects for harmonization/standardization.

Participants in the conference will be able to present posters of their work in the area of traceability and method standardization/harmonization. An abstract of the poster should be included with the on-line registration. This is an opportunity for young investigators to discuss their projects with peers and experts in a supportive global community.

Registration to the meeting are open until 31 October 2019.

For any questions please contact the JCTLM Secretariat.

Charles-Édouard Guillaume

Symposium to celebrate the centenary of the award of the Nobel Prize in Physics to Charles-Édouard Guillaume

On 17 October 2020, the BIPM celebrated the life and work of Charles-Édouard Guillaume with a symposium, both online and at the BIPM, considering his legacy.

The year 2020 marks the centenary of the award of the Nobel Prize in Physics to Charles-Édouard Guillaume (1861-1938). He was born into a watchmaking family in Fleurier (Switzerland), and dedicated more than half a century to metrology through his work at the BIPM. His major study of the properties of nickel-iron alloys spanned more than twenty-five years and not only revolutionized geodesy measurements but also chronometry and precision horology; numerous applications still exist for these alloys. In 1915, he became Director of the BIPM, a position he held until his retirement in 1936.

Guillaume was awarded the Nobel Prize in Physics in 1920 "in recognition of the service he has rendered to precision measurements in Physics by his discovery of anomalies in nickel steel alloys".

Details and registration

New JCRB Executive Secretary

On 10 January 2019, Dr Sten Bergstrand, on a two-year secondment from RISE (Sweden), took over as Executive Secretary of the Joint Committee of the Regional Metrology Organizations and the BIPM (JCRB Executive Secretary). Sten takes over from Nikita Zviagin who has returned to VNIIM (St Petersburg, Russian Federation), having completed a two-year secondment at the BIPM.

Sten, the ninth seconded Executive Secretary of the JCRB, has a broad background from geophysical geodesy and length metrology. Until taking up his role at the BIPM he was leading RISE's group in dimension and positioning metrology, with particular interest in GNSS applications and local tie measurements of co-located techniques at space geodetic stations. He has published papers on GNSS monument stability and deformations of geodetic telescopes and was the Swedish representative to EURAMET technical committee for length.

The primary role of the JCRB is to coordinate the activities among the RMOs in establishing confidence for the recognition of calibration and measurement certificates, according to the terms of the CIPM Mutual Recognition Arrangement (CIPM MRA). The JCRB, which is chaired by the Director of the BIPM, is supported by Executive Secretaries seconded from the NMIs from across the globe. This approach strengthens the links between the BIPM and the RMOs, helps transfer knowledge to the RMOs and brings recent "front line" experience to the BIPM. Previous JCRB Executive Secretaries were: Dr Angela Samuel (NMIA, Australia), Dr Ismael Castelazo (CENAM, Mexico), Dr Pedro Espina (NIST, USA), Mr Luis Mussio (LATU, Uruguay), Mr Ömer Altan, (UME, Turkey), Mr Chingis Kuanbayev (KazinMetr, Kazakhstan) and Dr Douglas Olson (NIST, USA).

International Year of the Periodic Table 2019 recognizes Mendeleev's achievements

2019 is the 150th anniversary of the Periodic Table of Chemical Elements and has been proclaimed the "International Year of the Periodic Table (IYPT 2019)" by the United Nations General Assembly and UNESCO.

The periodic classification of the elements was proposed in 1869 by Dmitri Ivanovich Mendeleev, a Russian chemist and former member of the CIPM. He found that by arranging the known elements in order of increasing atomic weight (relative atomic mass), their chemical and other properties regularly repeated. He was therefore able to make a more compact arrangement that was also predictive. By 1871, he produced a more satisfactory version of the table where he left gaps, hoping that they would one day be filled by elements not yet known and predicting with uncanny accuracy the properties of three of those elements, which were very soon discovered: gallium, scandium and germanium. He also predicted a fourth missing element with an atomic weight (relative atomic mass) of about 100. This turned out to be technetium, the lightest element that has no stable isotopes. Mendeleev relied in part on atomic weights accurately measured by Jean-Servais Stas, a Belgian analytical chemist who had also been an important member of the CIPM from its inception in 1875 until his death in 1891, aged 78.

Mendeleev was awarded the Royal Society's award for achievements in chemistry, the Davy Medal, in 1882 (shared with Lothar Meyer, a German chemist). Stas received the same award in 1885.

From 1895 to 1901 Mendeleev was a CIPM member, a role for which he was well qualified following his appointment in 1892 as director of the Main Chamber of Weights and Measures of the Russian Empire (now known as the D.I. Mendeleev Institute for Metrology). During that period he also served as a member of the CIPM Commission on Instruments and Works. He was unanimously granted the status of Honorary member of the CIPM upon his retirement in 1901.

His proposal to complete the redefinition of the unit of volume - the litre by specifying the reference air pressure at which 'one kilogram of pure water at its maximum density (about 4 °C) occupies one litre' was unanimously adopted at the CIPM meeting in 1897 and became incorporated in Resolution 1, 'Declaration concerning the definition of the litre' of the 3rd meeting of the CGPM (1901). (Although his suggestion to specify the air pressure illustrates Mendeleev's life-long attention to detail, the idea of defining the litre to be slightly different from 1000 cm3 did not stand the test of time and was abrogated in 1964, making the litre simply equal to 1000 cm3.)

Mendeleev's 'Examination of Relationship between the Fundamental Measurements of Russia, France and Great Britain based on the data at the beginning of 1897' was published as an Annex to the Minutes of the 20th meeting of the CIPM (1897).

Review paper in Metrologia: "The revision of the SI - the result of three decades of progress in metrology"

An open-access paper published in Metrologia reviews the changes to the SI that will come into force on 20 May 2019. In particular, the definition of the kilogram will change for the first time since 1889. The definitions of the ampere, the kelvin and the mole will be changd at the same time.

Following three decades of intensive work by the world-wide metrology community, the 26th General Conference on Weights and Measures (CGPM) agreed this major revision of the SI at its meeting in November 2018. The paper includes as an Annex the complete text of Resolution 1 of the 26th CGPM (2018) – On the revision of the International System of Units (the SI).

This Resolution presents the definitions of the base units in a new format that highlights the link between each unit and a defined value of an associated constant. The physical concepts underlying the definitions of the kilogram, the ampere, the kelvin and the mole have been changed. The new definition of the kilogram is of particular importance because it eliminates the last definition referring to an artefact (the international prototype of the kilogram, IPK). In this way, the new definitions use the rules of nature to create the rules of measurement and tie measurements at the atomic and quantum scales to those at the macroscopic level.

The podcast of the historic decision to revise the SI can be viewed on the BIPM's YouTube channel.

BIPM YouTube channel



  • Stock M., Davis R., de Mirandés E., Milton M.J.T., The revision of the SI – the result of three decades of progress in metrology, Metrologia, 2019, 56, 022001

First Regional Quality Infrastructure (QI) Workshop in the Pacific region

Access to Quality Infrastructure is a major challenge for the island countries of the Pacific. In collaboration with its development partners, the Pacific Islands Forum Secretariat (PIFS) convened the first Regional Quality Infrastructure (QI) Workshop in the Pacific in Nadi (Fiji) on 2-6 September 2019. Andy Henson, Director of the International Liaison and Communication Department at the BIPM was pleased to both present and contribute to the workshop.

The initiative brought together over 80 participants, including government officials and private sector representatives from Forum Island Countries (FIC); international, regional and national organizations playing a leading role in QI; and donor partners.

The workshop prepared and endorsed a Regional Quality Statement summarizing the regional consensus. The workshop will also enable the PIFS to prepare a concept for the second phase of the QI initiative, including a high-level workplan, outlining the implementation of priorities identified by FICs.

This concept note will serve to inform resource mobilization, including but not limited to identification and formulation of a project proposal to be submitted to the Enhanced Integrated Framework (EIF) in the coming months. The EIF is the multilateral partnership dedicated exclusively to assisting least developed countries (LDCs) in their use of trade as an engine for growth, sustainable development and poverty reduction.

The statement, workplan and concept note will also be submitted to the next Pacific Islands Forum Trade Meeting for endorsement.

The new instrument for comparing primary standards of pure β-emitting radionuclides

New instrument for comparing primary standards of pure β-emitting radionuclides

The accurate measurement of radioactivity is essential for applications of ionizing radiation such as medical imaging, cancer therapy and environmental protection. To ensure that such measurements are harmonized world-wide, the BIPM operates a set of very stable and precise instruments to compare national standards of radioactivity. Up till now it has been possible to compare standards of radionuclides that emit gamma rays; setting up an equivalent instrument for radionuclides that only emit beta rays has proved to be a technical challenge. Scientists from the BIPM have worked closely with colleagues from national metrology institutes in Germany, France, Poland, China and the UK to develop a new instrument; the device combines signals from three detectors surrounding a sample of the radioactive standard to determine an accurately reproducible parameter that is proportional to the activity (Bq) of the sample. The method was inspired by one of the techniques used to realize primary standards of radioactivity ('Triple-to-double coincidence counting'). Details have been published in Metrologia.

The new instrument, known as the ESIR, will enable metrology institutes to compare primary standards of pure beta-emitting radionuclides, reducing the need for complex and time-consuming multi-centre comparison exercises.

Contact Romain Coulon for more information.



ICSH: a new Executive Committee member of the JCTLM

The JCTLM has welcomed the International Council for Standardization in Haematology (ICSH) as a new Executive Committee Member, effective December 2019. The ICSH joins the BIPM, International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) and International Laboratory Accreditation Cooperation (ILAC) on the Executive Committee.

The ICSH coordinates Working Groups of experts to examine laboratory methods and instruments for haematological analyses, to deliberate on issues of standardization and to stimulate and coordinate scientific work as necessary towards the development of international standardization materials and guidelines.

This important collaboration brings expertise in clinical laboratory haematology to the JCTLM and provides the opportunity to align the standardization and harmonization of haematology laboratory methods with the reference measurement system of the JCTLM, further enhancing the aim of 'accurate results for patient care'.

2019 BIPM-APMP Workshop "Important transitions in the CIPM MRA infrastructure"

Over 100 participants from APMP Member NMIs/DIs took part in the joint BIPM-APMP CBKT Workshop entitled "Important transitions in the CIPM MRA infrastructure". The workshop was held on 29-30 November 2019 during the 35th APMP General Assembly in Sydney (Australia). The Workshop was sponsored by the APMP within funds granted as TCI Project TCQS_01_TCQS 2019.

Important transitions

Recommendations from the Working Group on the Implementation and Operation of the CIPM MRA are being implemented. The international standards ISO/IEC 17025 and ISO 17034 have been revised, and NMIs/DIs are improving their systems to complete their transition to these new standards within the three-year period. As an outcome of the CIPM MRA review, the BIPM is renewing the infrastructure of the BIPM key comparison database to transition to the KCDB 2.0, which will include both documentation and web-based tools and systems.

The 2019 BIPM-APMP Workshop was intended to inform participants about these important changes as well as to provide a forum to share experiences.

The Workshop consisted of three sessions:

  • "the CIPM MRA infrastructure from the history to the vast transitions in 2019" with three invited lecturers (Day 1, over 100 participants),
  • "KCDB 2.0 - the new platform for the CIPM MRA" featuring a live demonstration of KCDB 2.0 (Day 2, over 40 participants),
  • "Monitoring the transition of the quality management system to ISO/IEC 17025:2017 and ISO 17034:2016" with fourteen talks from NMIs/DIs presenting their experience in making the transitions (Day 2, around 20 participants).

The workshop provided an effective forum to share knowledge about the KCDB 2.0 and changes to the international standards ISO/IEC 17025 and ISO 17034. An interactive atmosphere was encouraged at the workshop, with many questions from the participants.

Files of the presentations given on Day 1 of the workshop are publicly available on the APMP TCQS website, in the open access area for the TCQS Workshop.

Trustworthy data underpin reproducible research

An article entitled "Trustworthy data underpin reproducible research" - coauthored by Martin Milton, Director of the BIPM, and Antonio Possolo, Chief Statistician, NIST - has recently been published in Nature Physics.

The paper presents three case studies from the world of precision measurement, and argues that the work of metrology provides a different way to think about discrepant data without calling it a "reproducibility crisis".

The paper has already been featured in a Nature Physics editorial published on 21 Feburary 2020 under the heading "When it's fine to fail – The history of metrology holds valuable lessons for initiatives to reproduce results." In this the Editor of Nature writes:

  • When results in the science of measurement cannot be reproduced, argue Martin Milton and Antonio Possolo, it's a sign of the scientific method at work – and an opportunity to promote public awareness of the research process.

Read the editorial at:


Standards and metrology in support of safe food and feed workshop held for GULFMET countries

Thirty participants from six members of the GULFMET RMO took part in the three day workshop on "Metrology for Safe Food and Feed - Organic Analysis and Standards", which was organized as part of the BIPM 'Metrology for Safe Food and Feed Programme' Capacity Building and Knowledge Transfer programme. The workshop was sponsored by the GCC Standardization Organization (GSO) and was held from 4-6 November 2019 in Riyadh (Saudi Arabia).

The course addressed general concepts on the role and activities of organizations concerned with the delivery of SI-traceable measurement services to support the analysis of food and animal feed. The workshop included training on the delivery of the infrastructure, capabilities, activities and quality systems necessary to underpin to the provision of reference services in this area. The topics covered were:

  • metrology in chemistry and the role of the BIPM, CCQM, RMOs and NMIs
  • production and use of Certified Reference Materials (CRMs) and primary calibrators to support the reliability and comparability of routine food analysis
  • description of the measurement infrastructure supporting reference measurement services the role of reference measurement services in ensuring laboratory compliance with relevant international accreditation standards (ISO 17025, ISO 17034 and ISO 17043)
  • case studies of the production and application of CRMs, proficiency testing schemes and the provision of reference measurements to underpin analytical services for:
    • nutrient and trace metal content
    • pesticides and drug residues
    • mycotoxin contamination
    • food supplements and adulterants

Workshop activities consisted of a series of lectures and targeted case studies that were intended to maximize knowledge transfer to the participants. A comprehensive overview was provided of best practice and significant challenges for the provision at the national and regional level, and integration at the international level, of a harmonized system of higher-order measurement services and reference materials. This harmonized system will support and sustain routine laboratory analytical services that monitor food safety as well as livestock, crop and plant health.

The lecturers that delivered the workshop were Steven Westwood (BIPM), Ralf Josephs (BIPM), Alpers Isleyen from UME-TUBITAK (Turkey), Byungjoo Kim from KRISS (Republic of Korea) and John Warren from LGC (UK). The participants were able to visit the Saudi Standards, Metrology and Quality Organization (SASO) National Measurement and Calibration Center (NMCC) laboratory located in Riyadh and toured the facilities for measurement services in chemical metrology.

World Metrology Day 2020: Resource website now live

On behalf of the World Metrology Day Team, we are pleased to announce that the 2020 World Metrology Day Resource Website is now live


The theme for World Metrology Day 2020 is Measurements for global trade. This theme was chosen to create awareness of the important role measurement plays in facilitating fair global trade, ensuring products meet standards and regulations, and satisfying customer quality expectations. Indeed more widely metrology, the science of measurement, plays a central role in scientific discovery and innovation, industrial manufacturing and international trade, in improving the quality of life and in protecting the global environment.


Last year's World Metrology Day was a huge success; we hope to build on that success in 2020.

On the resource website, you may download the Press Release, the Directors' Message and the poster.

Please help us to spread the word about World Metrology Day and let the World Metrology Day Team know by email about the events you are organizing in your country so that we can include them on the website. If you need inspiration, you can see the sort of events organized by other NMIs in previous years on the website.

New paper providing data for improved radiotherapy dose evaluation

A multi-year project involving multiple institutions and coordinated by the International Atomic Energy Agency (IAEA) has culminated in a paper published in the journal Physics in Medicine & Biology. The paper, co-authored by Dr David Burns at the BIPM, provides definitive values for the critical correction factors kQ that enter in the determination of the radiotherapy dose to cancer patients. The new values are derived from a combination of experiment and state-of-the-art Monte Carlo calculations at numerous NMIs and other institutes and have an uncertainty almost a factor of two better than the values currently recommended. They will be incorporated into the IAEA Code of Practice (TRS-398) used by clinicians when evaluating the dose output from their treatment machines. This Code of Practice is currently being revised by a small working group with BIPM participation.

Contact David Burns for more information.


IAEA/WHO SSDL Network Scientific Committee meeting

The International Atomic Energy Agency (IAEA) and the World Health Organization (WHO) co-ordinate a network of Secondary Standards Dosimetry Laboratories (SSDLs), designated by IAEA Member States. The IAEA's Dosimetry Laboratory operates as the central laboratory in the SSDL Network and provides calibrations, reference irradiations, comparison programmes and dosimetry audit services for Member States. The aim of the SSDL Network is to improve accuracy in radiation measurements for cancer therapy; for many countries, the IAEA/WHO Network is the route for traceability to the SI for national dosimetry standards.

A Scientific Committee of seven international experts, including Dr David Burns as representative of the BIPM, meets biennially to advise the Directors General of the IAEA and the WHO regarding the programme of the IAEA/WHO SSDL Network and the activities of the Dosimetry and Medical Radiation Physics Section. A meeting of the Scientific Committee was held in March 2020 to discuss recommendations for future work, covering issues such as the use of the new accelerator facility, knowledge-transfer opportunities, the streamlining of calibration services, and database management. The recommendations will be published in the SSDL Newsletter later in 2020.

Time difference between UTC(OP) and UTC(PTB), in nanoseconds, as measured by the usual Two-Way link (green crosses) and improved by the use of a SDR receiver (blue dots), during the period covered by Circular T 386. Red triangles represent the values that have been retained for the calculation of UTC.

Two-Way Satellite Time and Frequency Transfer: first use of a Software Defined Radio receiver in UTC calculation

Two-Way Satellite Time and Frequency Transfer, improved by the Software-Defined Radio (SDR) receiver, has been used for Circular T calculation for the first time in March 2020. The comparison between the French and German local realizations of UTC, UTC(OP) and UTC(PTB), was performed using SDR receivers, a method that replaces part of the time-transfer hardware with high-speed digitization and software data processing. This significantly improves the 1-day stability of the time comparison.

Development of this particular SDR receiver has been realized by teams from TL (Telecommunication Laboratories (Chinese Taipei)), LNE-Syrte - Observatoire de Paris (France) and several NMIs within the framework of a Pilot Project launched in 2016 by the CCTF Working Group on TWSTFT. This Working Group had the aim of characterizing the performance of the receiving SDR chain, its long-term stability, the possibility of calibration, and of stable and reliable operation in the long term. The first calibration of such a link has been realized between LNE-Syrte - Observatoire de Paris and the PTB (Germany), paving the way for its inclusion in the Circular T calculation. The BIPM Time Department provided support to the development of this new technique, monitored its results, and assessed its long-term usability for UTC calculation over the last few years.

BIPM CBKT Programme extended to include remote-learning

The BIPM CBKT Programme has added a "remote-learning" capability, which will provide online assistance to NMI/DI staff from Member States and Associates in their involvement in the CIPM MRA mechanisms.

The remote learning support has two elements aimed to optimize use of the KCDB tools:

We hope these CBKT programme activities will equip those who are involved in developing CMCs on the KCDB platform, as well as TC/WG Chairs and TC/WG Members, with appropriate information.

Memorandum of Understanding between the BIPM and IFCC

The BIPM-IFCC Memorandum of Understanding was signed electronically by Dr Wynand Louw, President of the CIPM on 14 September 2020, and by Dr Khosrow Adeli, President of the IFCC on 15 September 2020.

The BIPM and the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) cooperate to ensure that data published by the IFCC, related in particular to chemical properties and measurements, makes appropriate consideration and reference to the SI units, metrological traceability and measurement uncertainty and to support the development and maintenance of a traceable measurement infrastructure for clinical chemistry and laboratory medicine.

The IFCC is a major partner in the Joint Committee for Traceability in Laboratory Medicine (JCTLM). The BIPM and the IFCC are founding members of the Joint Committee for Guides in Metrology (JCGM) since 1997. The IFCC participates in the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM) and the Consultative Committee for Units (CCU).


BIPM-IFCC Memorandum of Understanding


BIPM Time Department provides additional information on the use of PSFS in UTC

Starting from March 2020, the Time Department is providing additional graphical information concerning the use of Primary and Secondary Frequency Standards (PSFS) in UTC. A graphical representation of all evaluations of PSFS reported since Circular T 190 (October 2003) is available at:


The plot will report the measurements carried out using PSFS and which are used for the steering of TAI. This information, updated every month, will help to evaluate the impact of PSFS in UTC, in view of a possible redefinition of the second.


According to the roadmap towards a redefinition of the SI second (CCTF 2016); a regular contribution to TAI by the new frequency standards is considered one of the criteria for a new definition of the second.

EURAMET-BIPM Workshop on the KCDB 2.0

The two and half day EURAMET-BIPM Workshop on the KCDB 2.0, dedicated to EURAMET TC Chairs and TC Members, was held at the BIPM from 17-19 February 2020. The Workshop was intended for EURAMET experts who are involved in the CIPM MRA processes. The aim of the workshop was to equip TC Chairs and TC Members (CMC reviewers) with appropriate information to use the KCDB 2.0 effectively.

The KCDB 2.0 is a far more comprehensive system than the one it replaces. The opportunity for the EURAMET experts to gain experience using the simulator was highly appreciated, and they provided the BIPM with useful feedback that will help us optimize the KCDB 2.0 tools going forward.


Andy Henson, Director of the International Liaison and Communication (ILC) Department



The workshop was a follow-up event to the "Optimizing the CIPM MRA - the KCDB 2.0" global course, which was held at the BIPM in November 2019. The content of the workshop was similar to the global course but specifically tailored to the needs of the EURAMET TC community. It was structured to discuss the importance and quality of the data declared into the KCDB; different approaches of EURAMET TCs in intra-regional CMC review practices; CIPM MRA revision outcomes; effective and efficient review practices of the Consultative Committees; and the KCDB tools that have been developed to support these activities.


KCDB 2.0 offline learning tool

Participants worked in groups of five to six on specific topics related to the KCDB 2.0. Practical sessions on the new KCDB 2.0 tools were the most popular part of the workshop; each practical exercise commenced with a demonstration of the relevant KCDB 2.0 tools. The "CMC review simulator" - a dedicated offline KCDB 2.0 learning tool - helped to reinforce the information acquired. The workshop participants simulated the CMC review process using the offline KCDB tool: they prepared and submitted their CMCs as a Writer, acted as Reviewers, submitted comparisons as a Pilot, and finally managed the process as a TC Chair.

The BIPM thanks all participants for their active involvement in the workshop.

Image courtesy of NICT

New radio techniques allow frequency comparison of distant optical clocks

Optical clocks have reached a proven accuracy of the order of 10−18 in relative frequency, surpassing the present Cs fountains by two orders of magnitude and driving the Consultative Committee for Time and Frequency (CCTF) to initiate work towards a redefinition of the second. However, comparing these clocks with a similar uncertainty is only possible using optical fibres and is presently limited to a few links at distances not exceeding 1000 km. Radio techniques have world-wide coverage and are currently regularly used in UTC with GNSS-based techniques and two-way time transfer using geostationary satellites, but they have limited accuracy.

Now an international collaboration between the NICT, INRIM, INAF and BIPM has compared the Yb lattice clock at INRIM and the Sr lattice clock at NICT using two new and independent radio techniques. One is Very Long Baseline Interferometry (VLBI), a technique used in astronomy for observing extra-galactic objects, and which has been used for the first time for accurate frequency transfer thanks to the development of mobile antennas and ad hoc hardware and processing facilities. The second technique is Integer ambiguity Precise Point Positioning (IPPP) using GNSS signals, the development of which has been driven by the BIPM over the past few years.

The results obtained with the two techniques agree within the uncertainty of the frequency comparisons, below 3 x 10−16 in relative frequency for each technique. In this case, it is limited by the intermittent operation of the optical clocks and the noise contributed by the "flywheel" clocks used to bridge the gaps. Both VLBI and IPPP are capable of frequency transfer accuracy below 1 x 10−16 when averaging several days and they can be easily combined thanks to IPPP using ubiquitous GNSS receivers that can be operated with the heavier VLBI equipment.

Contact Gérard Petit for more information.

Press release:
Signals from distant stars connect optical atomic clocks across Earth for the first time


Mobile VLBI antenna image courtesy of NICT

New series of virtual seminars on ionizing radiation metrology

The field of ionizing radiation metrology is constantly evolving, ensuring the effectiveness and safety of new cancer treatments being just one example. A series of international scientific seminars has been launched to share information on progress in the field.

The seminars are co-ordinated by the Consultative Committee for Ionizing Radiation (CCRI) and hosted by the BIPM. The first seminar was held in October 2020 to mark the 60th anniversary of the founding of the BIPM Ionizing Radiation Department. Topics included the CCRI long-term strategy, the work-in-progress on metrology for radiopharmaceutical therapy and recent developments in low electrical current measurement for ionization chambers.

The second seminar on 5 November 2020 was chaired by Dr Annette Röttger from the PTB (Germany). The presentation was a summary of a EURAMET workshop discussing future needs in radiation protection dosimetry. The presentation is available on the BIPM YouTube Channel.

The webinar on 15 December 2020 will cover the international reference system for gamma-ray emitting radionuclides (the SIR). Topics for 2021 include a review of metrology for radiosterilization and a discussion of the new ISO standard for X and gamma reference radiation for calibrating dosemeters and doserate meters (ISO4037). Anyone with an interest in the field is welcome to attend. Links to the webinars are distributed to members of the CCRI, Sections and Working Groups and are also available from the Chairs of the Ionizing Radiation Technical Committees of the Regional Metrology Organizations.

Beginning a new phase of the dissemination of the kilogram

The new definition of the kilogram, based on the fixed numerical value of the Planck constant, came into force on 20 May 2019. In principle it gives any NMI the possibility to realize the kilogram by using a Kibble or joule balance or by applying the X-ray crystal density technique. Nevertheless, after reviewing the results from the different realization experiments, the CCM decided in 2017 that initially the dissemination of the kilogram should be internationally coordinated, by basing it on the so-called 'consensus value', until the dispersion between values became compatible with the individual realization uncertainties. The consensus value can be seen as an internationally agreed mean kilogram realization and is determined by the CCM Task Group on the Phases for the Dissemination of the Kilogram (CCM-TGPfD-kg). It is based on results of comparisons of kilogram realizations using the different realization methods.

The first key comparison of realizations of the kilogram, CCM.M-K8.2019 has been completed. The objectives of this comparison were to determine the level of agreement between kilogram realizations from different NMIs and to provide information for the calculation of the first CCM consensus value. The CCM started CCM.M-K8.2019 soon after the new definition of the kilogram came into force.

The BIPM was chosen as the pilot laboratory, as it had been for the CCM pilot study in 2016. Seven institutes, including the BIPM, participated with realizations based on Kibble balances, a joule balance and the X-ray crystal density technique. Each participant determined the mass of one or two 1 kg standards under vacuum with their realization method. At the BIPM all mass standards were compared in a vacuum mass comparator with a reference standard. These weighings, together with the mass values determined by the participants, allowed a comparison of the consistency of the individual realizations. The chi-squared test for consistency using the 95 % cut-off criterion was passed, although the two results with the smallest uncertainty were not in agreement with each other (see figure). The weighted mean of the participants' results for a 1 kg mass standard deviates by −0.019 mg from the value based on the BIPM 'as-maintained' mass unit, which is traceable to the International Prototype of the Kilogram (IPK). The results are available from the BIPM Key Comparison Database.

The CCM Task Group on the Phases of the Dissemination of the kilogram has calculated the consensus value as the arithmetic mean of the results of the calibration campaign using the IPK in 2014 [1], the CCM pilot comparison of kilogram realizations in 2016 [2] and the key comparison reference value of CCM.M-K8.2019 [3]. The consensus value for the mass of the IPK thus determined is 1 kg — 0.002 mg [4]. The standard uncertainty is 0.020 mg. Traceability for the SI unit of mass will be taken from the consensus value of the kilogram commencing 1 February 2021.

Since the consensus value is consistent with the value of 1 kg within its uncertainty, no adjustment of the international mass scale needs to be made. However, NMIs with CMCs below or close to 0.020 mg at the level of 1 kg will need to increase their calibration uncertainty.

The BIPM will continue to provide calibrations of 1 kg Pt-Ir prototypes and stainless steel mass standards for Member States, which will be traceable to the Planck constant through the consensus value.

CCM.M-K8.2019: Differences Δmi between mass values attributed to a 1 kg mass standard using the realization experiments of the participants and the key comparison reference value (KCRV), calculated as the weighted mean. The difference between mass values based on the BIPM working standards, traceable to the Planck constant h through the IPK, and those based on the KCRV is also shown as h(IPK).


  1. M. Stock, P. Barat, R. Davis, A. Picard, M. Milton, Calibration campaign against the International Prototype of the kilogram: Part I: Comparison of the International Prototype with its official copies, Metrologia 52 (2015) 310-316.
  2. M. Stock, P. Barat, et al., Comparison of future realizations of the kilogram, Metrologia 55 (2018) T1-T7.
  3. M. Stock, P. Conceição, et al., Report on the CCM key comparison of kilogram realizations CCM.M-K8.2019, Metrologia 57 (2020) Tech. Suppl. 07030.
  4. CCM Task Group on the Phases for the Dissemination of the kilogram following redefinition, Calculation of the Consensus Value for the Kilogram 2020

First CMC submitted, reviewed, approved and published entirely using the KCDB 2.0

The BIPM KCDB office has published the first CMC that has been submitted, reviewed, approved and published entirely using the recently-launched KCDB 2.0.

A significant milestone was achieved for the BIPM and the KCDB 2.0 on 2 April 2020 with the publication of a CMC for gravimetry from CENAM (Mexico). This represents the first CMC that has been submitted, reviewed and approved entirely using the new KCDB web platform (KCDB 2.0). Whilst the BIPM has published many sets of CMCs in the past weeks (and continues to do so), they were sets that had been reviewed using the old JCRB web facility, and post-processed by the KCDB Office for publication on the new platform. This first publication clearly demonstrates the potential of the new system. The CMC was created and submitted for intra-regional review on 26 February 2020. Having completed the SIM review and being subjected to inter-regional review, it was approved and published just five weeks later on the KCDB on 2 April 2020.

CITAC Best Paper Award 2019 for review of pure peptide/protein methods

Scientists from National Metrology Institutes and the BIPM working within the CCQM Protein Analysis Working Group (CCQM-PAWG) have been awarded a CITAC Best Paper Award 2019 for their review paper published in the Metrologia Focus Issue on Advances in Metrology in Chemistry and Biology.

The review, entitled Establishment of measurement traceability for peptide and protein quantification through rigorous purity assessment, concentrates on the progress made in establishing methodologies and capabilities to analyse the mass fraction content of pure peptide /protein substances or solutions thereof. Accurately and rigorously characterized pure peptide primary calibrators are essential for the development of Reference Measurement Systems (RMS) for clinical chemistry and laboratory medicine as the basis of a calibration hierarchy for diagnostic tests performed in medical laboratories. Analytes and the related conditions or diseases for which RMSs have been or are being developed include: angiotensins for hypertension; HbA1c, insulin and C-peptide for diabetes; and parathyroid hormone for chronic kidney disease.

The mission of the Cooperation on International Traceability in Analytical Chemistry (CITAC) is to improve traceability of the results of chemical measurement everywhere in the world and to ensure that analytical measurements made in different countries and/or at different times are comparable.


World Metrology Day 2020: Measurements for global trade

The theme for World Metrology Day 2020 is Measurements for Global Trade. This theme was chosen to raise awareness of the important role measurement plays in facilitating fair global trade - ensuring products meet standards and regulations, and satisfying customer quality expectations. At the time of writing a total of 35 versions of the World Metrology Day 2020 poster have been produced, primarily by NMIs around the world. In addition, 14 events have been organized, many of them virtual. Additional posters and events will be added as the information arrives.

The Directors of the International Bureau of Legal Metrology (BIML) and the International Bureau of Weights and Measures (BIPM), have prepared a joint statement to promote World Metrology Day. This is available from the World Metrology Day website, which also includes four video messages for 2020 presented by the Presidents of the CIPM and the CIML and a joint message presented by the Director of the BIPM, in collaboration with the Director of the BIML. In addition, Dr Milton presents a special video message for World Metrology Day 2020 in the context of the COVID-19 pandemic, particularly how national metrology laboratories and quality infrastructure systems around the world have addressed the fast-moving challenges that have arisen as a result of the crisis.



From NIAID-RML [CC BY 2.0]

Ensuring the reliability of measurements in response to the COVID-19 pandemic: CCQM Webinar and JCTLM Special Edition Newsletter, July 2020

A special edition of the JCTLM Newsletter focuses on the reliability of measurements in COVID-19 diagnostics:

The Newsletter summarizes articles submitted by JCTLM Members and Stakeholders presenting their work on the reliability of COVID-19 diagnostic measurements - including reference materials, reference measurement methods, interlaboratory comparisons and relevant research, publications and seminars.


The Newsletter also includes a report on a special CCQM webinar, held on 7 July 2020. Presentations during the webinar included:

  • Review of diagnostic modalities involved in the response to the COVID-19 pandemic - Prof. Jacob Moran-Gilad
  • International proficiency testing scheme results with molecular diagnostics for SARS-CoV-2 - Prof. Heinz Zeichhardt
  • SARS-CoV-2 antibody testing and what we can learn from interlaboratory studies - Prof. Michael Neumaier
  • The development and assessment of COVID-19 serological platforms - Dr Michael A. Drebot

Webinar programme: Ensuring the reliability of measurements in response to the COVID-19 pandemic

Image: from NIAID-RML [CC BY 2.0]

OECD Webinar: “International Organisations and their Members Facing the Global Crisis Together”

Dr Martin Milton, Director of the BIPM, together with heads of other international organizations (IOs), participated as a panelist in the OECD High-Level Webinar: "International Organisations and their Members Facing the Global Crisis Together". The virtual meeting was held on 3 September 2020 as part of the 7th Annual IO Meeting within the context of the IO Partnership.

Following the High-Level Webinar, a second Webinar: "The IO Partnership in Action: Towards a Compendium of IO Practices and Beyond - Self-reflection, Peer-Learning and Adapting to a Changing World" took place in which the BIPM reported back from the 'WG5 on Coordination among IOs' breakout session, held on 31 August 2020. The BIPM shares the role of focal point of WG5 to better tailor the specific needs of IOs and address more in-depth coordination issues.

The IO Partnership is currently working on a Compendium of International Organisations' Practices for Effective International Rulemaking. The Compendium will use examples from the BIPM and from many other IOs to highlight how IOs work better together and how they can learn from each other about best practices as they go forward.

The OECD established the Partnership of international organisations for effective international rulemaking (IO Partnership) as a voluntary platform of IOs, academics and OECD Regulatory Policy Committee delegates, to exchange good practices and promote greater quality, effectiveness, and impact in international rulemaking.

For more information on the 7th Annual Meeting of International Organisations please see


BIPM CBKT Programme goes virtual

The BIPM CBKT Programme launched its "Remote learning support" initiative in May 2020 with the delivery of its first online short course for RMOs (COOMET) and its first online technical exchange for CMC writers (Q/A sessions).

The KCDB 2.0 - an online short course

This newly developed online course attracted more than 100 participants from COOMET who are directly involved in the operation of the CMC review process and who pilot comparisons. The short course was split into three one-day sessions from 25 to 27 May, with each session lasting around three hours. The modules addressed:

  • User accounts
  • Creation of CMCs
  • CMC review processes
  • Comparisons
  • KCDB search facilities
  • Statistics.

Each module was followed by a series of multiple choice questions to the participants to establish immediately how well the content had been understood. This allowed the KCDB experts to continue by focusing on the aspects participants had found most challenging.


On behalf of COOMET President, COOMET expresses its gratitude to the BIPM for the provided opportunity of participation for a wide range of experts from COOMET NMIs/DIs in the short online course on the KCDB 2.0 issues and to all speakers for their interesting reports. Thank you very much!

Nadezhda Liakhova, Head of the COOMET Secretariat

See also:

COOMET news about this event


Technical exchanges

As part of a brand-new initiative, the BIPM is delivering capacity building and knowledge transfer directly to those NMIs/DIs staff around the world who initiate CMCs.

The first of a series of one-hour technical exchanges on the KCDB 2.0 were focused on CMC writers in General physics and took place on 9 June 2020. In order to cover all time zones and ensure the participation of CMC writers around the world, the sessions were organized at 09:00 and again at 16:00 CET. This flexible approach to timing allowed the participation of 129 CMC writers, representing almost all regions. The technical sessions are based on a 'question and answer' format. All registered participants submitted their questions in advance to allow the KCDB experts to prepare and deliver tailored demonstrations using the KCDB CBKT training platform.

The "Remote learning support" initiative was launched to assist NMI/DI staff from Member States and Associates with their involvement in the CIPM MRA mechanisms. The BIPM is confident that these initiatives will equip those who are initiating CMCs, and those who operate the CMC review processes, thus increasing the effectiveness of the KCDB database as a reliable source for information on metrological traceability.

The BIPM is highly satisfied with the initial outcomes of the remote learning support. The feedback has been very positive, with the RMOs and participants in both activities clearly stating that they have received valuable and practical information that can be implemented directly in their work.

Chingis Kuanbayev, BIPM International Liaison and Communication Department

Dr Patrizia Tavella awarded the Enrico Fermi Prize by the Italian Physical Society

Dr Patrizia Tavella, Director of the BIPM Time Department, has been awarded the Enrico Fermi Prize by the Italian Physical Society. The prize was awarded jointly to Patrizia and Dr Giovanni Mana (INRIM), Deputy Editor of Metrologia. The citation reads: "for their original and important contributions to the measurement of time and to the definition of mass".

The Prize was established in 2001 to mark the centenary of the birth of Enrico Fermi and is awarded by the Italian Physical Society each year to those who have made important contributions to physics. It was presented during the Opening Ceremony of the 106th National Congress of the Italian Physical Society which was held on-line.

Many congratulations to Patrizia and to Giovanni. The award of the prize to scientists working in metrology underlines the importance of this field to the world of science.

Towards more accurate monitoring of surface ozone

Participants at the BIPM virtual workshop on 'Accurate Monitoring of Surface Ozone' from air quality monitoring networks, environment agencies, instrument manufacturers and metrology institutes, agreed to work together to develop an implementation plan to enable more accurate surface ozone measurements world-wide. The workshop was held from 5 to 9 October 2020. Over 100 participants connected online to provide input into the recommendation of the virtual workshop, which was organized by the CCQM Working Group on Gas Analysis (CCQM-GAWG).

The reference method for ground-level ozone measurements is based on UV photometry, with NIST Standard Reference Photometers (SRP) acting as primary standards for numerous national and international ozone-monitoring networks. Measurements of ozone amount fractions in ambient air are ultimately anchored to the value and uncertainty of the ozone absorption cross-section at the wavelength 253.65 nm. A review of all measurements of the absorption was carried out and published in 2019, providing a consensus value 1.23 % lower, and an uncertainty six times smaller, than the historically used value. A globally coordinated effort will now be required to implement the 2019 value in ozone measurement systems around the world in an orderly way.

The workshop gathered representatives of reference laboratories, monitoring networks, regulators and ozone analyzer manufacturers to develop a plan and timetable to allow a globally coordinated and universal implementation of the ozone absorption cross-section value published in 2019.

Presentations given during the workshop are available on the workshop webpage, including the results of discussions held within the four Task Groups and reported during the last day. A more detailed report of the workshop will be published soon.

BIPM virtual workshop on 'Accurate Monitoring of Surface Ozone'


The workshop noted the importance of accurate measurements of ozone and their uniformity, independently of the region of the atmosphere or with measurement platform or technique with which they were made. It recommended that a Task Group be created to manage the change process of the ozone cross section value, and this be established by the CCQM Working Group on Gas Analysis (CCQM-GAWG), with membership to include all stakeholder communities. The recommendations of the workshop will be published before the end of 2020, including a communication on the intention to implement a change in the globally used value of the ozone cross section and its uncertainty. The workshop estimated that the change process may take between three to five years to be completed, noting that documentary standards and air quality regulations would require updating as part of the change process. A detailed plan and roadmap of the change process will be developed by the task group.


CCQM-GAWG Statement

Following stakeholder consultation during the Workshop, the CCQM Gas Analysis Working Group is issuing a statement on its intention to change the Ozone Cross-Section Value used for Surface Ozone Standards and Measurement.

Statement: Intention to change the Ozone Cross-Section Value for Surface Ozone Measurement

Report of the 12th meeting of the CCAUV (2019)

Published on 28 February 2019.

Principles governing photometry, BIPM/CIE, Rapport BIPM-2019/05 (2019)

Published on 16 May 2019.

Report of the 24th meeting of the CCPR (2019)

Published on 2 February 2021.

Report of the 24th meeting of the CCU (2019)

Published on 1st December 2020.

Report of the 17th meeting of the CCM (2019)

Published on 14 October 2019.

Report of the 25th meeting of the CCQM (2019)

Published on 22 July 2019.

Annual Report on Time Activities (2019)

Report of the 27th meeting of the CCRI (2019)

Published on 17 October 2019.

International comparison demonstrates accuracy of the global atmospheric CO2 measurement scale

The results of the CCQM comparisons on CO2 in air standards (CCQM-K120 and CCQM-P188) were presented at the 20th WMO/IAEA Meeting on Carbon Dioxide, Other Greenhouse Gases, and Related Measurement Techniques (GGMT-2019), which was held in Jeju (Republic of Korea) from 2-5 September 2019. This coincided with the presentation of an updated carbon dioxide scale (WMO-CO2-X2019), the primary reference for the WMO-GAW monitoring network on which all global background observations of carbon dioxide are based.

The scale will be used by the WMO Global Atmosphere Watch programme in its global monitoring network for tracking trends in the background carbon dioxide amount fraction in the atmosphere. The accuracy of the scale was demonstrated in the key comparison (CCQM-K120), organized by the CCQM Gas Analysis Working Group with comparative measurements performed at the BIPM. The comparison was a substantial undertaking involving the analysis of the composition of 46 gas reference materials from 13 National Metrology Institutes (NMIs) and The National Oceanic and Atmospheric Administration (NOAA), the institute designated by the WMO.

Progress in reducing uncertainties in SI traceable standards has led to a key comparison reference value for carbon dioxide in air concentrations with state-of-the-art uncertainties of parts in 104. This has enabled benchmarking of international comparability and provided support for an update to the global scale. Standards developed by NMIs with gravimetric preparation were a major contributor in delivering reference values for CO2 in air with the smallest uncertainties achieved to date. The comparison also required methods to accurately calibrate optically-based instruments for CO2 isotope ratio (δ13C and δ18O) measurements to be developed at the BIPM as well as a manometric facility for future ongoing comparisons of CO2 in air standards, the performance of which was demonstrated in the CCQM-P188 study.

The developments to the global scale recognize the substantial collaborative progress made between the metrology and atmospheric monitoring communities since the WMO signed the CIPM Mutual Recognition Arrangement (CIPM MRA) in 2010.

New Presidents of the CCAUV and CCRI

Dr Héctor Laiz, Director of Metrology, Quality and Environment at the Instituto Nacional de Tecnología Industrial (INTI), Argentina, was appointed as the President of the Consultative Committee for Acoustics, Ultrasound and Vibration (CCAUV). Dr Laiz succeeds Dr Takashi Usuda, who had been CCAUV President since 2014.

Dr Martyn Sené, Deputy CEO of the National Physical Laboratory (NPL), UK, was appointed as President of the Consultative Committee for Ionizing Radiation (CCRI). Dr Sené succeeds Dr Wynand Louw, who has stepped down from the role that he had held since 2014.

Both Dr Laiz and Dr Sené have been members of the CIPM since 2016.

Announcement of the 20th International Congress of Metrology (CIM 2021)

The 20th International Congress of Metrology, CIM 2021, will be held from 28-30 September 2021 in Paris (France). The congress will explore scientific and industrial challenges in the field of measurement through a varied programme focusing on the main following topics.

  • Controlled Measurements: uncertainties, traceability, cost optimization, certification, standardization, conformity and risks... for measurement, analysis and testing processes.
  • Optimized Measurements: techniques and best practices for mass, force, flow, pressure, dimension, electricity, time-frequency, temperature, hygrometry, optics and photonics, ionizing radiation, chemical measures, biological measures...
  • Advanced Measurements:
    • new technologies, smart sensors, IIOT
    • data qualification, analysis and security
    • quantum technology, AI, blockchain
    • jobs evolution, recruitment.

The topics have applications in all sectors: mechanics, chemistry, pharmaceuticals, health, agro-food, environment, pollution, energy...

The call for papers is open from 1 October 2020 to 15 January 2021.

More information about the congress programme and the call for papers can be found at

CCRI Workshop (2019) on the 2020-2025 Strategic Plan and the CIPM MRA Review

Published on 9 September 2019.

Dr Patrizia Tavella receives the European Frequency and Time Award 2019

Dr Patrizia Tavella, Director of the BIPM Time Department, has been awarded the European Frequency and Time Award 2019 "for her engagement and key achievements in time and frequency dissemination at both scientific and educational levels." The European Frequency and Time Award recognizes outstanding contributions in all fields covered by the EFTF.

CDC/ Alissa Eckert, MSMI; Dan Higgins, MAMS

National Measurement Institutes demonstrate high accuracy reference measurement system for SARS-CoV-2 testing

Twenty-one National Metrology Institutes and expert laboratories from sixteen countries have demonstrated that highly accurate measurements of the amount of the SARS-CoV-2 viral RNA can be achieved worldwide using reverse transcription-digital PCR (RT-dPCR). The ability to accurately measure the amount of the viral cause of COVID-19 with global equivalence will considerably improve testing confidence and support countries in effectively tackling the pandemic.

The comparison study (CCQM-P199.b) organized by the CCQM Working Group on Nucleic Acid Analysis (CCQM-NAWG), and coordinated by the National Measurement Laboratory at LGC (UK), NIM (China), NIBSC (UK) and NIST (US), required quantification of the same viral genetic sequences targeted by many of the diagnostic tests. The RT-dPCR results were found to agree very well with each other and different SI-traceable non-molecular orthogonal methods; most values were within +/-40% of mean. The reproducibility of the method is unprecedented for absolute molecular measurements, where orders of magnitude of spread in reported copy numbers can be found using conventional molecular diagnostic methods. This work, made possible by over a decade of CCQM led collaborative efforts within the bio-metrology community, represents the most comprehensive example of highly reproducible and sensitive measurement of RNA and opens the possibility for SI-traceable quantification of viral genes. The methods and results are already being used by National Metrology Institutes to value assign reference materials that underpin the quality of SARS-CoV-2 diagnostic tests. The comparison was conducted under an accelerated timeline, with the worldwide comparison completed in under six months, and the final report expected in early 2021.

In the longer term, these capabilities have far wider implications as they can provide a global foundation for ensuring the accuracy of associated molecular methods whether applied to COVID-19, as preparation for any future global pandemic or for wider diagnostic uses such as in testing for antibiotic resistance or cancer.

Results from part of the study demonstrating that laboratories performing molecular RT-dPCR methods are able to perform with good agreement with each other and the SI-traceable orthogonal methods (isotope-dilution mass spectrometry and single molecule flow cytometry), the latter providing the basis for the RT-dPCR method's claimed accuracy. The RT-dPCR results were compared with orthogonal methods using different concentrations of the same RNA material. The different concentrations were prepared using gravimetric dilution. Diamonds show individual laboratories' results with solid black line (mean) and dotted green lines +/-40% of mean value.

New Member State: Kingdom of Morocco

The Kingdom of Morocco became a Member State on 24 May 2019

The international dosimetry chain: standards and quality assurance in medical radiation dosimetry

The IAEA organizes a major international symposium on standards, applications and quality assurance in medical radiation dosimetry (IDOS) about once every 10 years. The aim of the symposium is to disseminate advances in radiation dosimetry for medicine and radiation protection, summarizing the trends in the field and identifying areas for improvement.

The 2019 conference was held in Vienna (Austria) on 18-21 June, and was attended by more than 500 clinicians, medical physicists and metrologists from 105 countries. In addition to covering developments in dosimetry for external beam radiotherapy, radiography and radiation protection, the challenge of accurate dosimetry for molecular radiotherapy was discussed.

The BIPM was actively involved in the symposium, contributing to the organizing committee and presenting an overview of traceability in radiation dosimetry.

Proceedings of the 26th meeting of the CGPM (2018) are now available

The BIPM is pleased to announce that the Proceedings of the 26th meeting of the General Conference on Weights and Measures (CGPM), 13 to 16 November 2018, are now available for download.

The CIPM appoints new Presidents of the CCQM and CCTF

The CIPM appointed two new Consultative Committee (CC) Presidents at Session I of its 108th meeting (March 2019).

Dr Sang-Ryoul Park, President of the Korea Research Institute of Standards and Science (KRISS), Republic of Korea, was appointed as President of the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM) for a four-year term. Dr Park succeeds Dr Willie May, who has stepped down from the role that he had held since 2011.

Dr Noël Dimarcq, Deputy Director of the Observatoire de la Côte d'Azur, France, was appointed as the President of the Consultative Committee for Time and Frequency (CCTF) for a four-year term. Dr Dimarcq succeeds Mr Luc Érard, who had been CCTF President since 2007.

Both Dr Park and Dr Dimarcq were elected to the CIPM at the 26th meeting of the CGPM in November 2018. They took their seats at the CIPM for the first time in March 2019.

Election of the CIPM bureau

During the first session of its 108th meeting (20-21 March 2019) the CIPM elected the following to form the bureau of the Committee:

  • President - Dr W. Louw (South Africa)
  • Secretary - Dr T. Usuda (Japan)
  • Vice-Presidents - Prof. J. Ullrich (Germany) and Dr J. Olthoff (United States of America)

The 108th meeting was the first to be held following the 26th meeting of the CGPM (November 2018), at which all 18 CIPM members were elected. Six of those elected participated in the CIPM for the first time:

  • Dr D. del Campo Maldonado (Spain)
  • Dr N. Dimarcq (France)
  • Prof. P. Neyezhmakov (Ukraine)
  • Dr J. Olthoff (United States of America)
  • Dr S.-R. Park (Republic of Korea)
  • Dr A. Steele (Canada).

The International System of Units - making measurements fundamentally better

The 20th May 2019 marks a particularly special celebration of World Metrology Day because it is the day chosen for the implementation of the changes agreed to the definitions of the SI base units. These landmark changes were decided at the 26th meeting of the General Conference on Weights and Measures (CGPM), which took place in Versailles in November 2018.

From 20 May 2019 the International System of Units (SI) embraces one of the most significant changes since its establishment - the definitions of four units (the kilogram, the ampere, the kelvin and the mole) are also linked to physical constants, which ensure their stability and universality. More information on the impact the redefinition has on the realization of the units is available on the BIPM website.

The world-wide promotional activities surrounding the meeting of the CGPM last November were very successful; we hope that the efforts to generate awareness about the implementation of the decisions will be similarly effective. Many examples of initiatives under way around the world are available from the World Metrology Day resource website (

Whilst the motivation for the changes to the definitions has been to provide new opportunities to increase access to accurate measurements there are some small changes that come into effect today that will concern laboratories working at the highest levels in the mass and electricity communities. Information about these changes is available on the BIPM website.

We wish success to all activities around the world on World Metrology Day that are raising awareness of how the SI is "Fundamentally Better".

The state of the art of radionuclide metrology

The biennial international conference on radionuclide metrology (ICRM) was held on 27-31 May 2019 in Salamanca (Spain). The conference covered developments in primary standards and novel technologies for measuring radioactivity (for example, the use of unmanned airborne spectrometers for environmental measurements).

Staff from the BIPM contributed presentations on the international reference system for pure beta emitting radionuclides (the ESIR) and the first measurement of 11C in the transportable instrument for short-lived gamma emitters (SIRTI).

The Chair of CCRI Section II gave a presentation on the long-term strategy for radionuclide metrology. The proceedings will be published in a special issue of Applied Radiation and Isotopes.

Metrology School 2019: New frontiers for metrology: from biology and chemistry to quantum and data science.

The BIPM and the Italian Physical Society ran the highly successful joint Metrology School "New frontiers for metrology: from biology and chemistry to quantum and data science" at the International School of Physics Enrico Fermi in Varenna (Italy), from 4-12 July 2019. The school was jointly organized with INRIM and this was the seventh summer school in metrology held since 1976. A total of 81 applications were received from 25 different countries and 56 students and observers were selected to participate.

Sponsorship by METAS, the Swiss NMI, under the auspices of the BIPM CBKT programme, provided opportunities for a number of participants to attend from NMIs/DIs of Member States or Associates that have emerging metrology systems. These award winners were able to combine their attendance at the Metrology School with a short (two- to six week) placement at METAS to pursue a specific metrology topic of interest. The grant was aimed at young metrologists with strong scientific ability and potential and who are expected to be the 'high flyers' of tomorrow.

The Metrology School had a world-class line-up of 22 lecturers including five from the BIPM and the Nobel laureate Prof. William Phillips. There were numerous opportunities for the students and lecturers to network informally at events outside the lectures, providing opportunities to form useful contacts for the future.

The Varenna Metrology School consisted of modules on physical and chemical metrology as well as fundamental issues common to all parts of metrrology.

More accurate CO2 measurements thanks to isotopic analysis

A recent publication from the BIPM demonstrates how the isotopic composition of CO2 in air standards can be used to correct precise spectroscopic measurements to achieve the accurate assignment of concentration. The method was applied to the international comparison of 46 standards from sixteen NMIs and designated institutes, demonstrating reference values with standard uncertainties of 1 part in 104, providing the most accurate comparison of greenhouse gas standards for background and urban concentrations to date.

The paper [1] has confirmed that spectroscopic (FTIR, but also applicable to laser-based systems) based measurements of CO2 mole fraction can be employed to achieve standard uncertainties reaching 0.05 µmol mol−1, even if sample and calibration gases isotopic ratios differ. The measurement of, and correction for, isotope ratios of CO2, for amount of substance fraction comparisons was recently demonstrated in the CCQM-K120 [2] (2019) and CCQM-P188 [3] (2019) comparisons of CO2 in air standards at nominally (380, 480 and 800) µmol/mol. These compared 46 standards from National Metrology Institutes, the WMO's Central Calibration Laboratory and the Integrated Carbon Observation System‑Central Analytical Laboratories (ICOS-CAL) laboratory, as well as the reference systems at the BIPM. The comparisons, carried out with comparative measurements at the BIPM, including bias corrections from differences in isotope ratios in standards, allowed reference values with standard uncertainties of 0.05 µmol/mol to be determined: a four-fold reduction compared to comparisons performed 10 years previously. The pilot study comparison also demonstrated the performance of the manometric reference facility for CO2 in air standards, which is being developed at the BIPM, as a unique common reference to be used in the on-demand comparison (BIPM.QM-K2) of CO2 in air standards across the range (380-800) µmol/mol.

The comparisons on CO2, form part of series of comparisons on greenhouse gas standards, also including methane and nitrous oxide, coordinated by the BIPM on behalf of the CCQM Working Group on Gas Analysis and described in two recent publications on 'SI traceability and scales for underpinning atmospheric monitoring of greenhouse gases' [4] and 'Advances in reference materials and measurement techniques for greenhouse gas atmospheric observations' [5]. Future comparisons are planned for 2019 (N2O), 2022 (CO2) and 2023 (CH4). A comparison of isotope ratio measurements in CO2 gas (CCQM-P204) is being coordinated by the BIPM in collaboration with the IAEA, with measurements planned in 2020.

  1. Flores E., Viallon J., Moussay P., Idrees F. and Wielgosz R. I. An FTIR method for accurate CO2 mole fraction measurements with correction for differences in isotopic composition of gases, Metrologia, 2019, 56(4), 044005.
  2. Flores E. et al. CCQM-K120 (Carbon dioxide at background and urban level), Metrologia, 2019, 56, Tech. Suppl., 08001.
  3. Flores E., Viallon J., Choteau T., Moussay P., Idrees F., Wielgosz R.I., Meyer C., Rzesanke D. Report of the pilot study CCQM-P188: Carbon dioxide in air (380 to 800) µmol/mol., Metrologia, 2019, 56, Tech. Suppl, 08012.
  4. Brewer P.J., Brown R.J.C., Tarasova O.A., Hall B., Rhoderick G.C., Wielgosz R.I. SI traceability and scales for underpinning atmospheric monitoring of greenhouse gases, Metrologia, 2018, 55(5), S174-S181.
  5. Brewer P. J., Flores E., Viallon J. et al. Advances in reference materials and measurement techniques for greenhouse gas atmospheric observations, Metrologia, 2019, 56(3), 034006.

Mr Mohammed Berrada, Director of the LPEE-LNM (Morocco), has signed the CIPM MRA

On 15 July 2019 the BIPM hosted a visit by a delegation from the Kingdom of Morocco composed of representatives from the Ministère de l'Industrie, de l'Investissement, du Commerce et de l'Economie Numérique and the Laboratoire national de métrologie, Laboratoire public d'essais et d'études (LPEE-LNM). The visit was joined by representatives from the BIPM, LNE, PTB (project coordinator for the Maghreb) and the BIML.

Dr Martin Milton, Director of the BIPM, welcomed the delegation and congratulated the Kingdom of Morocco on its recent accession to the Metre Convention. He gave a presentation on the activities of the BIPM. The LPEE-LNM gave a presentation that focused on their activities and future plans for successful involvement in the work of the BIPM.

The visit culminated with the signing of the CIPM MRA by Mr Mohammed Berrada, LPEE-LNM Director, and was followed by a tour of the BIPM's physical, chemical metrology and ionizing radiation laboratories with presentations by the scientific staff.

The Kingdom of Morocco had become a Member State on 24 May 2019, raising the number of Member States to 60.

BIPM-TÜBİTAK UME project placements completed with success

The joint BIPM–TÜBİTAK UME initiative "TÜBİTAK UME project placements" has proven a great success. The BIPM collaborated with TÜBİTAK UME, the National Metrology Institute (NMI) of Turkey, to support young metrologists from 14 countries to gain in-depth knowledge and experience on a subject of scientific interest.

Over two cycles, organized in 2018 and 2019, the BIPM and TÜBİTAK UME initiative sponsored 20 participants from AFRIMETS, APMP, COOMET and GULFMET. All participants were from NMIs that have recently become a signatory to the CIPM MRA, or were inexperienced in the CIPM MRA processes. The placements, of between 1 and 3 months, hosted in the TÜBİTAK UME laboratories, allowed participants to focus on specific metrological projects, to learn the theory and to test it in practical situations in order to maximize the transfer of knowledge. In addition, participants were able to gain a better understanding of the international aspects of metrology during the seminars organized under the joint initiative and delivered by BIPM and TÜBİTAK UME staff.

Brief reports from the participants are available from the BIPM's CBKT pages.

The number of applications received for both cycles demonstrates the huge interest and demand for this joint initiative. The first cycle received 58 applications from 23 countries and the second 48 applications from 18 countries, competing for the 10 slots that were available in each cycle.

As a consequence of the success of this training initiative and the significant ongoing demand for capacity building and knowledge transfer training, we invite other NMIs to join this initiative. These actions reflect the encouragement to carry out knowledge transfer and mentoring activities that were underlined in the Recommendations from the Working Group on the Implementation and Operation of the CIPM MRA.

The BIPM acknowledges with thanks the major contributions of TÜBİTAK UME to the BIPM's CBKT activities.


Andy Henson and I were delighted to meet the participants at our joint capacity building initiative with TÜBİTAK UME.

The seminars provided a great opportunity to mingle with the new generation of metrologists. Their enthusiasm was infectious, and our discussions were continued in a very friendly atmosphere over lunch, during coffee breaks and free time. They were open and ready to share their experiences and challenges... and really keen to learn and gain experience.

I wish all the participants the best of luck in implementing the outcomes of their projects, and every success in their next steps in the world of measurement uncertainties and metrological traceability.

Huge thanks to TÜBİTAK UME colleagues for making the initiative a success!

Chingis Kuanbayev, BIPM

The CIPM has made Dr Barry Inglis an honorary member

At Session II of its 108th meeting (October 2019), the CIPM decided that it would bestow honorary membership on Dr Barry Inglis in recognition of his accomplishments as the President of the CIPM. These accomplishments had an impact across the organization.

Dr Inglis was a member of the CIPM from 2000 to 2019 and served as President of the CIPM for eight years from 2011 to 2019. In addition, Dr Inglis had been President of the Consultative Committee for Electricity and Magnetism (CCEM) from 2003 to 2015 and Vice-President of the CIPM from 2002 to 2011.

During his time as President of the CIPM, Dr Inglis led the organization through two meetings of the General Conference on Weights and Measures (CGPM). He led the CIPM through the governance review and subsequent launch of the reform of its processes. His work in coordinating the work of the CIPM with its Consultative Committees and the global NMI community led to the successful adoption of revised definitions for the SI units in 2018. The CIPM acknowledged that Dr Inglis always took a strategic and long-term view of the impact of the CIPM on world metrology.

The new KCDB website (KCDB 2.0) is live

The new KCDB website (KCDB 2.0) went live on 29 October 2019 with extended search facilities. It is now possible to search on CMCs and comparisons using a free-keyword search - quick search - or by using a predefined menu - advanced search. You may also filter on CMC approval dates, combine an advanced search with free key words, filter CMC measurand values and uncertainties numerically, sort results and export search results to a spreadsheet.

A user platform with restricted access for creating and reviewing CMCs, and registering comparisons, will open in November 2019.

A new statistical tool is planned for the beginning of 2020.

Memorandum of Understanding between the BIPM and IUPAC

The BIPM and IUPAC have formalized their long-standing cooperation through the signature on 17 October 2019 of a Memorandum of Understanding.

The BIPM-IUPAC Memorandum of Understanding was signed by Dr Wynand Louw, President of the CIPM, and by Christopher M.A. Brett, Vice President of IUPAC, on behalf of the IUPAC President, Qifeng Zhou.

The BIPM has for many years been represented on the IUPAC Interdivisional Committee on Terminology, Nomenclature and Symbols (ICTNS), and IUPAC participates in the CCQM, the CCU and the JCGM.

CIPM MRA experts have received training to optimize their use of the newly-launched KCDB 2.0

The one-week course entitled "Optimizing the CIPM MRA - the KCDB 2.0", organized by the BIPM and sponsored by NIST, was held from 4-8 November 2019 at the BIPM and was attended by 27 CIPM MRA experts. The aim of the course was to equip those who operate the CIPM MRA CMC review processes with appropriate information, and to ensure that they will not learn the new KCDB 2.0 elements by 'trial and error'.

The BIPM, in response to the recommendations from the CIPM ad hoc Working Group on Implementing the Recommendations from the Review of the CIPM MRA, developed and launched a new system - the KCDB 2.0 in October 2019. It integrates the whole CMC review process into a single platform - from development of CMCs to publication in the KCDB. The manual transfer of the CMCs' Excel files for review and publication is no longer required in the new system. The system also encourages the consistency of data from the beginning. In the original KCDB, the first of the two-tier CMC review process was organized remotely and was coordinated manually by the RMO TC Chairs at the regional level, and the inter-RMO review process was organized through the JCRB database. The CMCs themselves were developed using the Excel templates by NMIs/DIs, and communicated manually to the review processes.

Optimizing necessary competences

Operation of the CMC review process is complex and requires careful examination of NMI/DI capabilities submitted for publication in the KCDB. It was considered that the KCDB 2.0 could present a challenge if TC/WG Chairs and TC/WG Members were not familiar with the new menu of tools in the database; the course was designed to optimize their knowledge of these tools. Each practical exercise commenced with a demonstration of the relevant tools available in the KCDB 2.0. The "CMC review simulator" - a dedicated offline KCDB 2.0 learning tool - helped to reinforce the information acquired. The course participants wrote and submitted their CMCs as a Writer, acted as Reviewers, submitted comparisons as a Pilot, and finally managed the process as a TC Chair. The hope is that the participants will share experiences within their TC/WG community and explain the operation of the KCDB 2.0 to the NMIs.

Refreshing the knowledge about the CIPM MRA and sharing best operation practices

The course content additionally provided information to refresh participants' knowledge about the CIPM MRA requirements and its review outcomes. Each stage of the process during the practical exercises was supported with lectures describing the requirements.

The course content also addressed the different approaches taken by the Consultative Committees and RMOs for CMC review and comparisons. Their guidelines and templates ensure a reduced workload and harmonization of different RMO practices within their metrology area. With respect to this, Elsa Batista, a participant from EURAMET TC F CMC Coordinator group, stated in her feedback that:

"This was a very good opportunity to be informed about the organization of each CC and learn from other fields of activities. It was verified that there are guides and templates available on several committees webpages that can be adopted in my one area of work, Flow and Volume. I would suggest that the Chairs of each TC can meet more often in order to exchange good practices for a decreased workload of the MRA."

Support of NIST

The BIPM acknowledges the US Government Grant from the National Institute of Standards and Technology (NIST) which enabled the BIPM to run this course.


This CBKT course on the new KCDB 2.0 and on efficient implementation of the CIPM MRA has been a great success. I highly appreciated that straight from the very beginning of this course, there were extensive and lively discussions of the participants and the lecturers on the subjects presented. The course provided ample opportunities for the participants (many of them TC chairs) to learn how to more effectively implement the CIPM MRA and to exchange best practices between RMOs and different technical disciplines. This CBKT course has made a highly valuable contribution into further efficient implementation of the CIPM MRA. I expect that the extensive training in the use of the just-launched KCDB 2.0 will be of great value in the successful introduction of the KCDB 2.0 in the metrology community. I thank BIPM for doing such a great job in the organization of this CBKT course, and I thank NIST for their financial support to make this CBKT course happen.

Dr Gert Rietveld, CCEM President and CIPM member


The brainstorming activity at the end of the course was the best strategy to consolidate the knowledge acquired in a week, taking as an example the case studies and best practices shared by the participating colleagues. The list of the "hints of use of the KCDB 2.0" constitutes an excellent introduction manual to familiarize new users of the KCDB 2.0 and also to clarify doubts of the constant users.


Liz Catherine Hernández Forero, INM, Colombia
The BIPM frequency comb installed in the laboratory at INTI

BIPM frequency comb successfully installed by INTI

Before retiring in March 2018, Dr Lennart Robertsson dismantled the former BIPM Length section's laser laboratory. A number of pieces of equipment were identified as being worth offering to NMIs for use in their work programmes. In particular, there were two frequency combs, which had been built by the BIPM and which are used in comparing microwave to optical frequency radiations. Information about the frequency combs was circulated among the NMIs and INTI (Argentina) offered to acquire one of the combs.

Karina Bastida from INTI visited the BIPM in November 2018, where she worked for one week alongside BIPM colleagues and Lennart Robertsson, who returned to the BIPM to explain the operation of the different components. Karina, with the support of Laurent Tisserand and the BIPM workshop, prepared six large shipping containers ready for transporting the comb. In addition she prepared a list of documents to obtain customs clearance with the support of the BIPM Director's Office.

It took more than nine month to receive the custom clearance, and on 16 October 2019 the comb left the BIPM. It arrived at INTI a few days later and Karina and her colleagues have successfully installed the equipment. INTI is pleased with the new capability in its length laboratory. Dr Héctor Laiz, CIPM member and Director of Metrology at INTI, provided considerable support towards this transfer to improve INTI's capabilities in this area.

2019 Varenna Metrology School and METAS project

In July 2019 the BIPM, in collaboration with the Italian Physical Society organized the Metrology Summer School "New frontiers for metrology: from biology and chemistry to quantum and data science" in Varenna (Italy).

The Summer School was presented as a series of modules, with a 3-day core module on the "Fundamental Metrology" and a choice of two 3-day optional modules: "Physical metrology" and "Quality of life".

METAS, the Swiss NMI, supported the participation of three young metrologists with strong scientific ability/potential, who are expected to be the 'high flyers' of tomorrow under the auspices of the BIPM Capacity Building and Knowledge Transfer Programme. The three award winners Rafidah Rosli from NMIM (Malaysia), Julián Gigena from INTI (Argentina) and Jorge Pereira from IPQ (Portugal) were able to combine their attendance at the Metrology School with a short placement at METAS. During their internship of two-to-four weeks, they received dedicated training and pursued a specific metrology topic of interest.

Brief reports from the participants are available from the METAS news.

BIPM Kibble balance makes significant progress towards realizing the new kilogram definition in 2019

The year 2019 marked a crucial step towards the completion of the BIPM Kibble balance for realizing the new kilogram definition.

The uncertainty due to misalignment was significantly reduced after the integration of a new interferometer, which is firmly mounted on the magnetic circuit. The electrical grounding of the whole apparatus has been improved, the measurement sequence has been optimized and the apparatus control and data processing software has been refined.

Thanks to METAS (Switzerland), a new measurement of the gravitational acceleration has been carried out with an absolute gravimeter. As a consequence, the relative standard uncertainty has been reduced to about 5 × 10−8. This will allow the BIPM to participate in the first key comparison of realizations of the new definition of the kilogram, CCM.M-K8.2019.