National Institute of Standards and Technology May 16, 2008 – Federal Register Recent Federal Regulation Documents

The International System of Units (SI) (the metric system of measurement) has been recognized for use in the United States since 1866 (15 U.S.C. 204) and is the preferred system of measurement for trade and commerce. The SI was established and is maintained by the General Conference of Weights and Measures and is interpreted or modified for use in the United States by the National Institute of Standards and Technology (NIST) by authority of the Secretary of Commerce (15 U.S.C. 205). This notice describes the recent modifications to the SI and announces the publication of the latest interpretation of the SI for the United States in the 2008 Edition of NIST Special Publication 330 ``The International System of Units.'' The 2008 Edition of NIST Special Publication 811 ``Guide for the Use of the International System of Units'' was also published. Together these publications provide the legal interpretation of and guidelines for the use of the SI in the United States.