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

 

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Guide for the Use of the International System of Units (SI) 
 
vii 
Contents 
Preface.................................................................................................................................................. iii 
Check List for Reviewing Manuscripts ................................................................................................. v 
1 Introduction ....................................................................................................................................... 1 
 1.1 
Purpose 
of 
Guide..................................................................................................................... 1 
1.2 Outline of Guide .................................................................................................................... 1 
2 NIST policy on the Use of the SI ....................................................................................................... 2 
 2.1 
Essential data .......................................................................................................................... 2 
2.1.1 Tables and graphs .......................................................................................................... 2 
 2.2 
Descriptive 
information 
......................................................................................................... 2 
3 Other Sources of Information on the SI.............................................................................................. 3 
 3.1 
 
Publications ........................................................................................................................... 3 
3.2 Fundamental Constants Data Center ..................................................................................... 3 
3.3 Metric Program ..................................................................................................................... 3 
4 The Two Classes of SI Units and the SI Prefixes .............................................................................. 3 
4.1 SI base units .......................................................................................................................... 4 
4.2 SI derived units ..................................................................................................................... 4 
4.2.1 SI derived units with special names and symbols ......................................................... 4 
4.2.1.1 Degree Celsius ................................................................................................. 5 
4.2.2 Use of SI derived units with special names and symbols............................................... 6 
4.3 Decimal multiples and submultiples of SI units: SI prefixes ................................................. 7 
5 Units Outside the SI............................................................................................................................ 7 
5.1 Units accepted for use with the SI .......................................................................................... 7 
5.1.1 Hour, degree, liter, and the like ...................................................................................... 8 
5.1.2 Neper, bel, shannon, and the like ................................................................................... 8 
5.1.3 Electronvolt, astronomical unit, and unified atomic mass unit ...................................... 9 

5.1.4 
Natural 
and atomic units ................................................................................................ 9 
5.2 Non-SI units accepted for use with the SI............................................................................. 10 
5.3 Units not accepted for use with the SI ................................................................................... 10 

5.3.1 
CGS 
units 
..................................................................................................................... 10 
5.3.2 Other unacceptable units .............................................................................................. 11 
5.4 The terms “SI units” and “acceptable units”.......................................................................... 11 
6 Rules and Style Conventions for Printing and Using Units .............................................................. 12 
6.1 Rules and style conventions for unit symbols ....................................................................... 12 

6.1.1 
Typeface 
....................................................................................................................... 12 

6.1.2 
Capitalization ................................................................................................................ 12 

6.1.3 
Plurals............................................................................................................................ 12 

6.1.4 
Punctuation.................................................................................................................... 12 
6.1.5 Unit symbols obtained by multiplication ...................................................................... 12 
6.1.6 Unit symbols obtained by division................................................................................ 13 
6.1.7 Unacceptability of unit symbols and unit names together ............................................ 13 
6.1.8 Unacceptability of abbreviations for units ................................................................... 13 

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