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Standards for Good Measure: ISO Publishes Updated SI Guide for the International System of Units


New York, Apr 16, 2008

ISO SI Guide As part of a continuing effort to maintain global standards for units and derived units, the International Organization for Standardization (ISO) recently published an updated SI Guide. This thirty-two page guide serves as a condensed user manual for the SI, the International System of Units (Système International d’Unités).

A comprehensive metric and decimal system, the SI provides information on seven base units of measure, including length, mass, time, electric current, thermodynamic temperature, amount of substance and luminous intensity.

The latest version of the SI Guide also contains two new components: the SI derived unit "katal," used primarily in clinical chemistry, and the inclusion of prefixes for binary multiples used in information technology.

Based on the International Standard ISO 31, Quantities and units, the information referenced in the guide was developed by ISO Technical Committee (TC) 12, Quantities, units, symbols, conversion factors. The National Institute of Standards and Technology (NIST), a government member of the American National Standards Institute (ANSI), serves as the ANSI-accredited Administrator of the U.S. Technical Advisory Group (TAG) to TC 12.

In addition to its work in the ISO arena, NIST is responsible for developing and maintaining metrology standards in the United States. Standardization of physical measurements, as well as uniformity in U.S. weights and measures laws, regulations and standards, are overseen by NIST in order to achieve equity between buyers and sellers in the marketplace.

To learn more about NIST’s measurement services program area, click here.


For more information about the SI Guide, view the ISO press release.

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