FED STD- Preferred Metric Units for General Use by the Federal Government

5. DETAILED REQUIREMENTS

This section gives detailed requirements for the selection of units, consistent with ANSI/IEEE Std 268. The subsections list conversion factors to the appropriately sized metric unit, either an SI unit with appropriate prefix or a non-SI unit that is accepted for use with SI. ANSI/IEEE Std 268, which has been recommended by the Metrication Operating Committee of the Interagency Council on Metric Policy for use by all agencies and departments of the Federal Government, lists conversion factors to SI units only. The SI units are the coherent set of base, supplementary, and derived units without prefixes, except for the base unit kilogram.

Government agencies may develop supplemental lists of accepted units applicable to their special fields. Such supplemental lists shall be consistent with this Federal Standard and with ANSI/IEEE Std 268. Other Derived Quantities. It is not practical to list all quantities, but others not listed can be readily derived using the conversion factors given. For example, to convert from inches per second to centimeters per second, multiply by 2.54; to convert from Btu per pound to joules per kilogram, multiply by (1055.056)/(0.453 592 37) or 2326. Note on Mixed Units and Fractions. Mixed units, which are commonly used with inch-pound units, are not used in metric practice. Thus, while a distance may be given in inch-pound units as 27 ft, 5 in, metric practice shows a length as 3.45 m rather than 3 m, 45 cm. Binary fractions (such as 1/2 or 3/8) are not used with metric units. For example, a person's weight is given as 70.5 kg, not 70-1/2 kg.