Use unit abbreviations when the unit is preceded by a numeric quantity, with the exception of days.
EXAMPLES:
Unit Abbreviated
30%
6 hr
8 in.
2 yr
8 mo
Unit Spelled Out
the percentage of chromium
heat treated for as many hours as required
the number of inches will be determined
the requirements will change in a few years
after several months of delay
NOTE: See ABBREVIATIONS FOR UNITS OF MEASURE AND OTHER COMMONLY USED WORDS for a detailed list of unit abbreviations used in ASME codes and standards.
Unit abbreviations are expressed in the singular regardless of the quantity.
EXAMPLES:
|
Unit Abbreviated |
Unit Spelled Out |
|
1 ft, 3 ft |
One foot, Three feet |
|
1 lb, 7 kg |
One pound, Seven kilograms |
Separate the unit from the quantity by a normal word space (1 unit space, 27 m or 487 ksi, but 30%). See Horizontal Spacing under Math and Technical Terminology.
Use unit abbreviations in nomenclature (see Nomenclature).
In figures and tables, do not use a preposition before the unit abbreviation (in captions, column heads, etc.). For example, “…for High Alloy Steel, ksi,” not “…for High Alloy Steel in ksi.”
Abbreviate “equation” and “Figure” when they precede a reference number (not including figure captions). Spell out these terms when they begin a sentence.
EXAMPLES:
Figure UCS-66 illustrates a hex flange.
See Fig. UCS-66 for an illustration of a hex flange.
Refer to eq. (1).
Equation (1) is presented in UNF-12.
Spell out “through.” Do not abbreviate as “thru.”