ISO 31
ISO 31 is a deprecated international standard for the use of physical quantities and units of measurement, and formulas involving them, in scientific and educational documents. It is superseded by ISO/IEC 80000.
Parts
The standard comes in 14 parts:- ISO 31-0: General principles
- ISO 31-1: Space and time
- ISO 31-2: Periodic and related phenomena
- ISO 31-3: Mechanics
- ISO 31-4: Heat
- ISO 31-5: Electricity and magnetism
- ISO 31-6: Light and related electromagnetic radiations
- ISO 31-7: Acoustics
- ISO 31-8: Physical chemistry and molecular physics
- ISO 31-9: Atomic and nuclear physics
- ISO 31-10: Nuclear reactions and ionizing radiations
- ISO 31-11: Mathematical signs and symbols for use in the physical sciences and technology
- ISO 31-12: Characteristic numbers
- ISO 31-13: Solid state physics
Coined words
introduced several new words into the English language that are direct spelling-calques from the French. The intention was that these words be used in scientific papers for the sake of convenience and clarity.| New phrase | Existing phrase | Technical meaning |
| massic | specific | a quantity divided by its associated mass |
| volumic | | a quantity divided by its associated volume |
| areic | surface | a quantity divided by its associated area |
| lineic | linear | a quantity divided by its associated length |
Related national standards
- Canada: CAN/CSA-Z234-1-89 Canadian Metric Practice Guide
- United States: There are several national SI guidance documents, such as , , , IEEE/ASTM SI 10, SAE J916. These cover many aspects of the ISO 31-0 standard, but lack the comprehensive list of quantities and units defined in the remaining parts of ISO 31.