The standard introduces the International System of Quantities (ISQ). It is a style guide for the use of physical quantities and units of measurement, formulas involving them, and their corresponding units, in scientific and educational documents for worldwide use. In most countries, the notations used in mathematics and science textbooks at schools and universities follow closely the guidelines in this standard.
The ISO/IEC 80000 family of standards was completed with the publication of Part 1 in November 2009.
In 2019, ISO/IEC 80000 comprises 13 parts, two of which (parts 6 and 13) were developed by IEC. The other 11 were developed by ISO. Part 14 was withdrawn.
|ISO 80000-1||2009||General||ISO 31-0, IEC 60027-1 and IEC 60027-3||under review|
|ISO 80000-2||2019||Mathematics||ISO 31-11, IEC 60027-1||published|
|ISO 80000-3||2019||Space and time||ISO 31-1 and ISO 31-2||published|
|ISO 80000-4||2019||Mechanics||ISO 31-3||published|
|ISO 80000-5||2019||Thermodynamics||ISO 31-4||published|
|IEC 80000-6||2008||Electromagnetism||ISO 31-5||under review|
|ISO 80000-7||2019||Light and radiation||ISO 31-6||published|
|ISO 80000-8||2007||Acoustics||ISO 31-7||under review|
|ISO 80000-9||2019||Physical chemistry and molecular physics||ISO 31-8||published|
|ISO 80000-10||2019||Atomic and nuclear physics||ISO 31-9 and ISO 31-10||published|
|ISO 80000-11||2008||Characteristic numbers||ISO 31-12||under review|
|ISO 80000-12||2019||Condensed matter physics||ISO 31-13||published|
|IEC 80000-13||2008||Information science and technology||subclauses 3.8 and 3.9 of IEC 60027-2:2005||published|
|IEC 80000-14||2008||Telebiometrics related to human physiology||IEC 60027-7||withdrawn|
The 80000 standard currently has 13 parts.
ISO 80000-2:2019 revises ISO 80000-4:2009, which superseded ISO 31-11. The text of the informative sections of this document are publicly available. It specifies mathematical symbols, explains their meanings, and gives verbal equivalents and applications.
ISO 80000-3:2019 revises ISO 80000-3:2006, which supersedes ISO 31-1 and ISO 31-2. The text of this document is publicly available and gives names, symbols, definitions and units for quantities of space and time.
ISO 80000-4:2019 revises ISO 80000-4:2006, which superseded ISO 31-3. The text of this document is publicly available and gives names, symbols, definitions and units for quantities of mechanics.
ISO 80000-5:2019 revises ISO 80000-5:2007, which superseded ISO 31-4. The text of this document is publicly available and gives names, symbols, definitions and units for quantities of thermodynamics.
ISO 80000-7:2019 revises ISO 80000-7:2008, which superseded ISO 31-6. The text of this document is publicly available and gives names, symbols, definitions and units for quantities used for light and optical radiation in the wavelength range of approximately 1 nm to 1 mm.
ISO 80000-8:2007 specifies names, symbols for quantities and units of acoustics and provides definitions for these quantities and units. It supersedes ISO 31-7 and is under review. It has a foreword; introduction; scope; normative references; and names, symbols and definitions. The standard includes definitions of sound pressure, sound power and sound exposure, and their corresponding levels: sound pressure level, sound power level and sound exposure level. For example:
IEC 80000-13:2008 defines quantities and units used in information science, and specifies names and symbols for these quantities and units. The current edition was published in 2008, and replaces subclauses 3.8 and 3.9 of IEC 60027-2:2005 and IEC 60027-3. It has a scope; normative references; names, definitions and symbols; and prefixes for binary multiples. Quantities defined in this standard are:
The Standard also includes definitions for units relating to information technology, such as the erlang (E), bit (bit), octet (o), byte (B), baud (Bd), shannon (Sh), hartley (Hart) and the natural unit of information (nat).
Clause 4 of the Standard defines standard binary prefixes used to denote powers of 1024 as 10241 (kibi-), 10242 (mebi-), 10243 (gibi-), 10244 (tebi-), 10245 (pebi-), 10246 (exbi-), 10247 (zebi-) and 10248 (yobi-).
Part 1 of ISO 80000 introduces the International System of Quantities and describes its relationship with the International System of Units (SI). Specifically, its introduction states "The system of quantities, including the relations among the quantities used as the basis of the units of the SI, is named the International System of Quantities, denoted 'ISQ', in all languages.", and further clarifies that "ISQ is simply a convenient notation to assign to the essentially infinite and continually evolving and expanding system of quantities and equations on which all of modern science and technology rests".
The standard includes all SI units but is not limited to only SI units. Units that form part of the standard but not the SI include the units of information storage (bit and byte), units of entropy (shannon, natural unit of information and hartley), the erlang (a unit of traffic intensity) and units of level (neper and decibel). The standard includes all SI prefixes as well as the binary prefixes kibi-, mebi-, gibi-, etc., originally introduced by the International Electrotechnical Commission to standardise binary multiples of byte such as mebibyte (MiB), for 10242 bytes, to distinguish them from their decimal counterparts such as megabyte (MB), for precisely one million (10002) bytes. In the standard, the application of the binary prefixes is not limited to units of information storage. For example, a frequency ten octaves above one hertz, i.e., 210 Hz (1024 Hz), is one kibihertz (1 KiHz).
These binary prefixes were standardized first in a 1999 addendum to IEC 60027-2. The harmonized IEC 80000-13:2008 standard cancels and replaces subclauses 3.8 and 3.9 of IEC 60027-2:2005, which had defined the prefixes for binary multiples. The only significant change in IEC 80000-13 is the addition of explicit definitions for some quantities.