American National Standard for Use of the International System of Units (SI): The Modern Metric System
|Publication Date:||26 February 2002|
This document, which supersedes IEEE/ASTM SI 10-1997, is the primary American National Standard for use of the International System of Units (SI). The first version of this standard was published by IEEE and ASTM in 1976. The sponsoring societies welcome comments and suggestions from interested individuals and organizations.
In 1988 the Metric Conversion Act was amended to designate "the metric system of measurement as the preferred system of weights and measures for United States trade and commerce." With the increasing importance of the global marketplace, it has become imperative for U.S. industry to extend its use of SI and for U.S. citizens to gain a working knowledge of this modern metric system. This standard is intended to give authoritative information on SI and appropriate guidance concerning its application.
SI is defined in the document Le Système International d'Unités, published in French, with an English translation, by the International Bureau of Weights and Measures (BIPM). The BIPM was set up by the Convention du Mètre, signed in 1875 (see Annex D). Le Système International d'Unités, known informally as the "BIPM SI brochure," is revised from time to time in accordance with the decisions of the General Conference on Weights and Measures (CGPM) and other international organizations. A U.S. version is published by NIST [B26].
IEEE/ASTM SI 10-2002 is consistent with the SI brochure in all matters that concern the SI itself, except that it presents the degree Celsius as simply another name for the kelvin that is used to express Celsius temperature, while the BIPM SI Brochure lists the degree Celsius as an SI derived unit. Of more practical importance is the difference in approach to non-SI units. IEEE/ASTM SI 10 and its predecessors have traditionally been more restrictive in their recommendations concerning the use of non-SI units. The SI Brochure, for example, lists the ångström as a unit that is "currently accepted for use with the International System," and lists the cgs units and many others as units whose use "is not encouraged." IEEE/ASTM SI 10, intended for the United States and developed under the consensus standardization process, makes the significantly stronger recommendation that these units are "not to be used."
This standard was developed by the IEEE/ASTM Committee for Maintaining IEEE/ASTM SI 10, a joint committee established by the sponsoring organizations. The proposed standard generated by this joint committee was then formally adopted by IEEE and ASTM before transmission to the American National Standards Institute for approval as an American National Standard. At the time of the approval of this revision the joint committee had the following membership. Non-voting members at the time of publication are marked with an asterisk (*):
Oliver K. Lewis, Chair
Bruce B. Barrow, Secretary
John T. Scott, Editor
Robert H. Bushnell
Anthony P. French
Joseph G. Langenstein
Ralph M. Showers
Barry N. Taylor*
Theodore M. Wildi