ISO 31 ( Quantities and

unit Unit may refer to: Arts and entertainment * UNIT, a fictional military organization in the science fiction television series ''Doctor Who'' * Unit of action, a discrete piece of action (or beat) in a theatrical presentation Music * ''Unit'' (a ...

International Organization for Standardization The International Organization for Standardization (ISO ) is an international standard development organization composed of representatives from the national standards organizations of member countries. Membership requirements are given in A ...

, 1992) is a superseded international standard concerning

physical quantities A physical quantity is a physical property of a material or system that can be quantified by measurement. A physical quantity can be expressed as a ''value'', which is the algebraic multiplication of a ' Numerical value ' and a ' Unit '. For exam ...

, units of

measurement Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events. In other words, measurement is a process of determining how large or small a physical quantity is as compared ...

, their interrrelationships and their presentation. It was revised and replaced by ISO/IEC 80000.

Parts

The standard comes in 14 parts: *

ISO 31-0 ISO 31-0 is the introductory part of international standard ISO 31 on quantities and units. It provides guidelines for using physical quantities, quantity and unit symbols, and coherent unit systems, especially the SI. It is intended for use in ...

: General principles (replaced by ISO/IEC 80000-1:2009) * ISO 31-1:

Space Space is the boundless three-dimensional extent in which objects and events have relative position and direction. In classical physics, physical space is often conceived in three linear dimensions, although modern physicists usually consi ...

and

time Time is the continued sequence of existence and event (philosophy), events that occurs in an apparently irreversible process, irreversible succession from the past, through the present, into the future. It is a component quantity of various me ...

(replaced by ISO/IEC 80000-3:2007) * ISO 31-2: Periodic and related

phenomena A phenomenon ( : phenomena) is an observable event. The term came into its modern philosophical usage through Immanuel Kant, who contrasted it with the noumenon, which ''cannot'' be directly observed. Kant was heavily influenced by Gottfried ...

(replaced by ISO/IEC 80000-3:2007) * ISO 31-3: Mechanics (replaced by ISO/IEC 80000-4:2006) *

ISO 31-4 ISO 31-4 is the part of international standard ISO 31 that defines names and symbols for quantities and units related to ''heat''. It is superseded by ISO 80000-5. Its definitions include: Annex A of ISO 31-4 lists units of heat based on the ...

Heat In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is ...

(replaced by ISO/IEC 80000-5) *

ISO 31-5 ISO 31-5 is the part of international standard international standard is a technical standard developed by one or more international standards organization, standards organizations. International standards are available for consideration and us ...

Electricity Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as describe ...

and

magnetism Magnetism is the class of physical attributes that are mediated by a magnetic field, which refers to the capacity to induce attractive and repulsive phenomena in other entities. Electric currents and the magnetic moments of elementary particles ...

(replaced by ISO/IEC 80000-6) * ISO 31-6:

Light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 t ...

and related

electromagnetic radiation In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visib ...

s (replaced by ISO/IEC 80000-7) *

ISO 31-7 ISO 31-7 is the part of international standard ISO 31 that defines names and symbols for quantities and units related to ''acoustics Acoustics is a branch of physics that deals with the study of mechanical waves in gases, liquids, and solids ...

Acoustics Acoustics is a branch of physics that deals with the study of mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acousticia ...

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

ISO 31-8 ISO 31-8 is the part of international standard ISO 31 that defines names and symbols for quantities and units related to ''physical chemistry and molecular physics''. Quantities and units Notes In the tables of quantities and their units, the I ...

: Physical

chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a natural science that covers the elements that make up matter to the compounds made of atoms, molecules and ions: their composition, structure, proper ...

and molecular physics (replaced by ISO/IEC 80000-9) * ISO 31-9: Atomic and

nuclear physics Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter. Nuclear physics should not be confused with atomic physics, which studies t ...

(replaced by ISO/IEC 80000-10) *

ISO 31-10 ISO 31-10 is the part of international standard ISO 31 that defines names and symbols for quantities and units related to ''nuclear reaction In nuclear physics and nuclear chemistry, a nuclear reaction is a process in which two nuclei, or a ...

Nuclear reaction In nuclear physics and nuclear chemistry, a nuclear reaction is a process in which two nuclei, or a nucleus and an external subatomic particle, collide to produce one or more new nuclides. Thus, a nuclear reaction must cause a transformatio ...

s and

ionizing radiation Ionizing radiation (or ionising radiation), including nuclear radiation, consists of subatomic particles or electromagnetic waves that have sufficient energy to ionize atoms or molecules by detaching electrons from them. Some particles can travel ...

s (replaced by ISO/IEC 80000-10) *

ISO 31-11 ISO 31-11:1992 was the part of international standard ISO 31 that defines ''mathematical signs and symbols for use in physical sciences and technology''. It was superseded in 2009 by ISO 80000-2:2009 and subsequently revised in 2019 as ISO-800 ...

: Mathematical signs and

symbol A symbol is a mark, sign, or word that indicates, signifies, or is understood as representing an idea, object, or relationship. Symbols allow people to go beyond what is known or seen by creating linkages between otherwise very different conc ...

s for use in the physical sciences and

technology Technology is the application of knowledge to reach practical goals in a specifiable and reproducible way. The word ''technology'' may also mean the product of such an endeavor. The use of technology is widely prevalent in medicine, scien ...

(replaced by ISO 80000-2:2009) * ISO 31-12: Characteristic numbers (replaced by ISO/IEC 80000-11) *

ISO 31-13 ISO 31-13 gives name, symbol and definition for 62 quantities and units of solid state physics Solid-state physics is the study of rigid matter, or solids, through methods such as quantum mechanics, crystallography, electromagnetism, and metal ...

Solid state physics Solid-state physics is the study of rigid matter, or solids, through methods such as quantum mechanics, crystallography, electromagnetism, and metallurgy. It is the largest branch of condensed matter physics. Solid-state physics studies how the ...

(replaced by ISO/IEC 80000-12) A second international standard on quantities and units was

IEC 60027 IEC 60027 (formerly IEC 27) is a technical international standard for letter symbols published by the International Electrotechnical Commission (IEC), comprising the following parts: * IEC 60027-1: General * IEC 60027-2: Telecommunications and ele ...

. The ISO 31 and IEC 60027 Standards were revised by the two standardization organizations in collaboration

to integrate both standards into a joint standard ISO/IEC 80000, ''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

introduced several new words into the

English language English is a West Germanic language of the Indo-European language family, with its earliest forms spoken by the inhabitants of early medieval England. It is named after the Angles, one of the ancient Germanic peoples that migrated to the ...

that are direct spelling- calques from the

French French (french: français(e), link=no) may refer to: * Something of, from, or related to France ** French language, which originated in France, and its various dialects and accents ** French people, a nation and ethnic group identified with Franc ...

. Some of these words have been used in scientific literature.Taylor, B. (1995). Guide for the use of the International System of Units (SI): the metric system. DIANE Publishing.

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 a
NIST SP 811NIST SP 330NIST 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.

Notes

References

* (contains both ISO 31 and ISO 1000) *

External links

ISO TC12 standards
– Quantities, units, symbols, conversion factors {{DEFAULTSORT:Iso 31 #00031 #00031 + Measurement