International Bureau of Weights and Measures

The International Bureau of Weights and Measures (French: Bureau International des Poids et Mesures, BIPM) is an intergovernmental organisation, through which its 64 member-states act on measurement standards in areas including chemistry, ionising radiation, physical metrology, as well as the International System of Units (SI) and Coordinated Universal Time (UTC). It is based in Saint-Cloud, near Paris, France. The organisation has been referred to as IBWM (from its name in English) in older literature.

International Bureau of Weights and Measures

Metre Convention signatories
Abbreviation	BIPM (from French name)
Formation	20 May 1875; 149 years ago (1875-05-20)
Type	Intergovernmental
Location	Saint-Cloud, France
Coordinates	48°49′45.55″N 2°13′12.64″E / 48.8293194°N 2.2201778°E / 48.8293194; 2.2201778
Region served	Worldwide
Membership	64 member states 37 associate states (see the list)
Official language	French and English
Director	Martin Milton
Website	www.bipm.org

Structure

The BIPM is overseen by the International Committee for Weights and Measures (French: Comité international des poids et mesures, CIPM), a committee of eighteen members that meet normally in two sessions per year, which is in turn overseen by the General Conference on Weights and Measures (French: Conférence générale des poids et mesures, CGPM) that meets in Paris usually once every four years, consisting of delegates of the governments of the Member States and observers from the Associates of the CGPM. These organs are also commonly referred to by their French initialisms.

History

The BIPM was created on 20 May 1875, following the signing of the Metre Convention, a treaty among 17 Member States. As of December 2024, there are now 64 members.

It is based at the Pavillon de Breteuil in Saint-Cloud, France, a 4.35 ha (10.7-acre) site (originally 2.52 ha or 6.2 acres) granted to the Bureau by the French Government in 1876. Since 1969 the site has been considered international territory, and the BIPM has all the rights and privileges accorded to an intergovernmental organisation. This status was further clarified by the French decree No 70-820 of 9 September 1970.

Several significant changes to the BIPM have been made throughout its history during the meetings overseen by the CGPM. An example of this would be how in the 12th general council meeting (held in 1964), the BIPM's budget was increased from $300,000 to $600,000 per year. A historic moment for the BIPM occurred during the 26th CGPM in 2018. At this council, it was decided that world standard for the units of kilograms, seconds, amperes, Kelvins, moles, candelas, and meters would be redefined to reflect constants in nature. This is the first time this has happened since the creation of the BIPM. These changes were made official on World Metrology Day in 2019.

Beginning in 1970, the BIPM began publishing the SI Brochure, a document detailing an up-to-date version of the International System of Units. As of December 2024, the most recent version of the SI Brochure was the 9th edition published in 2019.

Function

The BIPM has the mandate to provide the basis for a single, coherent system of measurements throughout the world, traceable to the International System of Units (SI). This task takes many forms, from direct dissemination of units to coordination through international comparisons of national measurement standards (as in electricity and ionising radiation).^{[citation needed]}

Following consultation, a draft version of the BIPM Work Programme is presented at each meeting of the General Conference for consideration with the BIPM budget. The final programme of work is determined by the CIPM in accordance with the budget agreed to by the CGPM.^{[citation needed]}

Currently, the BIPM's main work includes:

• Making brochures that define the International System of Units.

• Scientific and technical activities carried out in its four departments: chemistry, ionising radiation, physical metrology, and time
• Liaison and coordination work, including providing the secretariat for the CIPM Consultative Committees and some of their Working Groups and for the CIPM MRA, and providing institutional liaison with the other bodies supporting the international quality infrastructure and other international bodies
• Capacity building and knowledge transfer programs to increase the effectiveness within the worldwide metrology community of those Member State and Associates with emerging metrology systems
• A resource centre providing a database and publications for international metrology

The BIPM is one of the twelve member organisations of the International Network on Quality Infrastructure (INetQI), which promotes and implements QI activities in metrology, accreditation, standardisation and conformity assessment.

The BIPM has an important role in maintaining accurate worldwide time of day. It combines, analyses, and averages the official atomic time standards of member nations around the world to create a single, official Coordinated Universal Time (UTC).

Directors

Pavillon de Breteuil in Saint-Cloud, France

Since its establishment, the directors of the BIPM have been:

Name	Country	Mandate	Notes
Gilbert Govi	Italy	1875–1877
J. Pernet	Switzerland	1877–1879	Acting director
Ole Jacob Broch	Norway	1879–1889
J.-René Benoît	France	1889–1915
Charles Édouard Guillaume	Switzerland	1915–1936
	France	1936–1951
Charles Volet	Switzerland	1951–1961
Jean Terrien	France	1962–1977
Pierre Giacomo	France	1978–1988
Terry J. Quinn	United Kingdom	1988–2003	Honorary director
Andrew J. Wallard	United Kingdom	2004–2010	Honorary director
Michael Kühne	Germany	2011–2012
Martin J. T. Milton	United Kingdom	2013–present

See also

• History of the metre
• Institute for Reference Materials and Measurements
• International Organization for Standardization
• Metrologia
• National Institute of Standards and Technology
• Seconds pendulum
• World Metrology Day
• Versailles project on advanced materials and standards

Notes

1. English translations by government agencies have used the initialism IBWM in documentation.

References

1. Staff writer (2024). "Bureau international des poids et mesures (BIPM)". UIA Global Civil Society Database. uia.org. Brussels, Belgium: Union of International Associations. Yearbook of International Organizations Online. Retrieved 1 February 2025.
2. "Welcome". BIPM. Retrieved 4 March 2024.
3. "5 FAH-3 H-310 Organization acronyms". Foreign Affairs Manual. Retrieved 23 January 2024.
4. "International Committee for Weights and Measures (CIPM)". BIPM. Retrieved 9 April 2021.
5. Pellet, Alain (2009). Droit international public. LGDJ. p. 574. ISBN 978-2-275-02390-8.
6. Schermers, Henry G.; (2018). International Institutional Law. Brill. pp. 302–303. ISBN 978-90-04-38165-0.
7. "Member States". BIPM. Retrieved 6 December 2024.
8. Page, Chester H; Vigoureux, Paul, eds. (20 May 1975). The International Bureau of Weights and Measures 1875–1975: NBS Special Publication 420. Washington, D.C.: National Bureau of Standards. pp. 26–27.
9. "History of the Pavillon de Breteuil". BIPM. Retrieved 14 May 2020.
10. Astin, A. V. (28 February 1964). "Weights and Measures". Science. 143 (3609): 974–976. Bibcode:1964Sci...143..974A. doi:10.1126/science.143.3609.974. ISSN 0036-8075. PMID 17743934.
11. Reed, EMAP: Emily Li, Graham Strzelecki, Maddie Rouse, and Andrew (1 February 2022). "26th General Conference on Weights and Measures (CGPM)". ArcGIS StoryMaps. Retrieved 31 October 2024.{{cite web}}: CS1 maint: multiple names: authors list (link)
12. Wallard, Andrew J. (March 2006). "The International System of Units (SI brochure (EN)): 8th edition, 2006" (PDF).
13. "The International System of Units (SI)". Peter C. Burbery website. 20 December 2022. Retrieved 7 November 2024.
14. "BIPM: Our work programme". BIPM. Archived from the original on 30 May 2020. Retrieved 14 May 2020.
15. Cai, Juan (Ada). "The Case of the International Bureau of Weights and Measures (BIPM)" (PDF). oecd.org. OECD. Archived (PDF) from the original on 9 October 2022. Retrieved 9 April 2021.
16. "International Network on Quality Infrastructure". INetQI. Retrieved 9 April 2021.
17. "Time Coordinated Universal Time (UTC)". BIPM. Archived from the original on 29 May 2020. Retrieved 14 May 2020.
18. "Directors of the BIPM since 1875". Bureau International des Poids et Mesures. 2018. Archived from the original on 27 March 2015. Retrieved 14 May 2020.
19. "NPL Fellow, Dr Martin Milton, is new Director at foundation of world's measurement system". QMT News. Quality Manufacturing Today. August 2012. Archived from the original on 29 May 2020. Retrieved 14 May 2020.

External links

• Media related to International Bureau of Weights and Measures at Wikimedia Commons
• Official website