ISO 31 explained

ISO 31 (Quantities and units, International Organization for Standardization, 1992) is a superseded international standard concerning physical quantities, units of measurement, their interrelationships and their presentation.^[1] It was revised and replaced by ISO/IEC 80000.

Parts

The standard comes in 14 parts:

• ISO 31-0

General principles (replaced by ISO/IEC 80000-1:2009)

• ISO 31-1

Space and time (replaced by ISO/IEC 80000-3:2007)

• ISO 31-2

Periodic and related phenomena (replaced by ISO/IEC 80000-3:2007)

• ISO 31-3

Mechanics (replaced by ISO/IEC 80000-4:2006)

• ISO 31-4

Heat (replaced by ISO/IEC 80000-5)

• ISO 31-5

Electricity and magnetism (replaced by ISO/IEC 80000-6)

• ISO 31-6

Light and related electromagnetic radiations (replaced by ISO/IEC 80000-7)

• ISO 31-7

Acoustics (replaced by ISO/IEC 80000-8:2007)

• ISO 31-8

Physical chemistry and molecular physics (replaced by ISO/IEC 80000-9)

• ISO 31-9

Atomic and nuclear physics (replaced by ISO/IEC 80000-10)

• ISO 31-10

Nuclear reactions and ionizing radiations (replaced by ISO/IEC 80000-10)

• ISO 31-11

Mathematical signs and symbols for use in the physical sciences and technology (replaced by ISO 80000-2:2009)

• ISO 31-12

Characteristic numbers (replaced by ISO/IEC 80000-11)

• ISO 31-13

Solid state physics (replaced by ISO/IEC 80000-12)

A second international standard on quantities and units was IEC 60027.^[2] The ISO 31 and IEC 60027 Standards were revised by the two standardization organizations in collaboration (http://www.bipm.org/en/si/si_brochure/chapter1/1-2.html, https://web.archive.org/web/20090301164428/http://www.iec.ch/zone/si/si_present.htm) to integrate both standards into a joint standard ISO/IEC 80000 - Quantities and Units in which the quantities and equations used with SI are to be referred as the International System of Quantities (ISQ). ISO/IEC 80000 supersedes both ISO 31 and part of IEC 60027.

Coined words

ISO 31-0 introduced several new words into the English language that are direct spelling-calques from the French.^[3] Some of these words have been used in scientific literature.^{[4] [5] [6] [7]}

New phrase	Existing phrase	Technical meaning
massic	specific	a quantity divided by its associated mass
volumic	[volumic] density	a quantity divided by its associated volume
areic	surface density	a quantity divided by its associated area
lineic	linear density	a quantity divided by its associated length

Related national standards

• Canada: CAN/CSA-Z234-1-89 Canadian Metric Practice Guide (covers some aspects of ISO 31-0, but is not a comprehensive list of physical quantities comparable to ISO 31)
• United States: There are several national SI guidance documents, such as NIST SP 811, NIST SP 330, NIST SP 814, 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.

See also

• SI – the international system of units
• BIPM – publishes freely available information on SI units http://www.bipm.org/en/si/si_brochure/, which overlaps with some of the material covered in ISO 31-0
• IUPAP – much of the material in ISO 31 comes originally from Document IUPAP-25 of the Commission for Symbols, Units and Nomenclature (SUN Commission) https://web.archive.org/web/20050906064148/http://www.physics.umanitoba.ca/IUPAP/C2.html of the International Union of Pure and Applied Physics
• IUPAC – some of the material in ISO 31 originates from the Interdivisional Committee on Terminology, Nomenclature and Symbols https://web.archive.org/web/20050828172951/http://www.iupac.org/standing/ictns.html of the International Union of Pure and Applied Chemistry
• Quantities, Units and Symbols in Physical Chemistry – this IUPAC "Green Book" covers many ISO 31 definitions
• IEC 60027 Letter symbols to be used in electrical technology
• ISO 1000 SI Units and Recommendations for the use of their multiples and of certain other units (bundled with ISO 31 as the ISO Standards Handbook – Quantities and units)

References

• Book: International Organization for Standardization. ISO Standards Handbook: Quantities and units. ISO. International Organization for Standardization. Geneva. 1993. 92-67-10185-4. 3rd. (contains both ISO 31 and ISO 1000)
• Cohen. E. R.. Giacomo, P.. Symbols, Units, Nomenclature and Fundamental Constants in Physics (1987 Revision), Document IUPAP-25 (IUPAP - SUNAMCO 87 - 1). Physica A. 146. 1987. 1 . 1 - 68. 10.1016/0378-4371(87)90215-9. 1987PhyA..146D...9C .

External links

• ISO TC12 standards – Quantities, units, symbols, conversion factors

Notes and References

1. Web site: ISO 31-0:1992 Quantities and units — Part 0: General principles . International Organization for Standardization . 8 May 2021.
2. Tolga, G. O. K. (2016). The importance of symbols and units in natural science. The Eurasia Proceedings of Educational and Social Sciences, 4, 165-167.
3. https://physics.nist.gov/cuu/pdf/sp811.pdf NIST SP811
4. Mills, I. (1993). Quantities, units and symbols in physical chemistry/prepared for publication by Ian Mills...[et al.]. Oxford; Boston: Blackwell Science; Boca Raton, Fla.: CRC Press [distributor].
5. Taylor, B. (1995). Guide for the use of the International System of Units (SI): the metric system. DIANE Publishing.
6. Dietrich . P. M. . Streeck . C. . Glamsch . S. . Ehlert . C. . Lippitz . A. . Nutsch . A. . B. . Beckhoff . Unger . W. E. S. . 2015 . Quantification of silane molecules on oxidized silicon: are there options for a traceable and absolute determination? . Analytical Chemistry . 87 . 19 . 10117–10124 . 10.1021/acs.analchem.5b02846. 26334589 . free .
7. Sertlek . H. Ö. . Slabbekoorn . H. . Ten Cate . C. . Ainslie . M. A. . 2019 . Source specific sound mapping: Spatial, temporal and spectral distribution of sound in the Dutch North Sea . Environmental Pollution . 247 . 1143–1157 . 10.1016/j.envpol.2019.01.119. 30823343 .