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Introduction to the STN Units System

The STN Units System was developed to support the expression of Units information for search and retrieval within STN International, the Scientific and Technical Information Network.

The STN Units System is organized in a set of tables, corresponding to Unit Types. Within each Unit Type, the supported Units are listed. For example, the table for Unit Type = Length contains various supported length units supported by STN, such as meter, angstrom, and fathom. Where appropriate, conversion factors between the STN Units system and the SI units system are included for each supported unit.

The STN Units system may also be used to express Units information within the Z39.50 protocol. Read more about Using STN Units within Z39.50.

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Table of Conversion Factors

1. Conversion factors are taken from "Quantities, Units and Symbols in Physical Chemistry (IUPAC, 1988), "Conversion Tables of Units for Science & Engineering (Ari L. Horvath, Elsevier, 1986), and "CRC Handbook of Chemistry and Physics" or are calculated directly from these publications. In most cases, unit symbols are taken from the recommendations in ISO 2955- 1974 (E). For units that did not appear in this publication, symbols were taken from the IUPAC publication cited above.

2. Both abbreviations and the entire unit name may be used, except for multi-word units. Since spaces are not allowed in the unit symbols, multi-word unit terms do not make a lot of sense, and thus are only represented by abbreviations.

3. The units conversion procedure will remove a terminal "s" from a unit designation if no designation with the appended "s" can be found. Thus plurals of unit designations need to be added to the conversion table only in those cases where the plural form is not created merely by adding an "s" to the singular form.