Editing Metrology (section)

==== International Bureau of Weights and Measures ====
[[File:Metric seal.svg|thumb|upright|alt=BIPM seal: three women, one holding a measuring stick|BIPM seal]]
The [[International Bureau of Weights and Measures]] ({{langx|fr|Bureau international des poids et mesures}}, or BIPM) is an organisation based in Sèvres, France which has custody of the [[international prototype of the kilogram]], provides metrology services for the CGPM and CIPM, houses the secretariat for the organisations and hosts their meetings.<ref>{{cite web|title=Mission, Role and Objectives|url=https://www.bipm.org/utils/en/pdf/BIPM-MissionRoleObjectives.pdf|publisher=BIPM|access-date=26 March 2018|archive-date=6 October 2016|archive-url=https://web.archive.org/web/20161006231136/http://www.bipm.org/utils/en/pdf/BIPM-MissionRoleObjectives.pdf|url-status=dead}}</ref><ref name=IPK>{{cite web|title=International Prototype of the Kilogram|url=https://www.bipm.org/en/bipm/mass/ipk/|publisher=BIPM|access-date=26 March 2018|archive-date=12 March 2020|archive-url=https://web.archive.org/web/20200312065104/https://www.bipm.org/en/bipm/mass/ipk/|url-status=dead}}</ref> Over the years, prototypes of the metre and of the kilogram have been returned to BIPM headquarters for recalibration.<ref name=IPK/> The BIPM director is an [[ex officio member]] of the CIPM and a member of all consultative committees.<ref>{{cite web|title=Criteria for membership of a Consultative Committee|url=https://www.bipm.org/en/committees/cc/cc-criteria.html|publisher=BIPM|access-date=26 March 2018|archive-date=26 March 2018|archive-url=https://web.archive.org/web/20180326202532/https://www.bipm.org/en/committees/cc/cc-criteria.html|url-status=dead}}</ref>