Guide for the Use of the International System of Units (SI)

Guide for the Use of the International System of Units (SI) 
 
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A Federal Register Notice of July 28, 1998, [16] declares that there are now only two classes of 
units in the International System of Units: base units and derived units. The units of these two classes form 
a coherent set of units and are designated by the name ‘‘SI units.” 
C.6 Federal Standard 376B 
 
Federal Standard 376B [17] was developed by the Standards and Metric Practices Subcommittee 
of the Metrication Operating Committee, which operates under the Interagency Council on Metric Policy. 
Specified in the Federal Standardization Handbook and issued by, and available from, the General 
Services Administration, Washington, DC, 20406, it is the basic Federal standard that lists preferred metric 
units for use throughout the Federal Government. It gives guidance on the selection of metric units required 
to comply with PL 94-168 (see Preface) as amended by PL 100-418 (see Preface), and with Executive 
Order 12770 [15] (see Sec. C.5). 
C.7 2006 CODATA recommended values of the fundamental constants 
 
The set of self-consistent recommended values of the fundamental physical constants resulting from 
the 2006 Committee on Data for Science and Technology (CODATA) least-squares adjustment of the 
constants, see Ref. [19], can be found at the NIST website: 
http://physics.nist.gov/cuu/Constants/index.html
. 
C.8 Uncertainty in measurement 
 
Reference [20] cites two publications that describe the evaluation and expression of uncertainty in 
measurement based on the approach recommended by the CIPM in 1981 and which have been adopted 
worldwide.

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Guide for the Use of the International System of Units (SI) 
 
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