ISO 80000 or IEC 80000 is an

international standard international standard is a technical standard developed by one or more international standards organizations. International standards are available for consideration and use worldwide. The most prominent such organization is the International Or ...

introducing the

International System of Quantities The International System of Quantities (ISQ) consists of the quantities used in physics and in modern science in general, starting with basic quantities such as length and mass, and the relationships between those quantities. This system underlie ...

(ISQ). It was developed and promulgated jointly by the

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 Ar ...

(ISO) and the

International Electrotechnical Commission The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organization that prepares and publishes international standards for all electrical, electronic and r ...

(IEC). It serves as a style guide for the use of

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 examp ...

and 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 ...

, formulas involving them, and their corresponding units, in scientific and educational documents for worldwide use. The ISO/IEC 80000 family of standards was completed with the publication of Part 1 in November 2009.

Overview

, ISO/IEC 80000 comprises 13 parts, two of which (parts 6 and 13) were developed by IEC and the remaining 11 were developed by ISO, with a further three parts (15, 16 and 17) under development. Part 14 was withdrawn.

Subject areas

The 80000 standard currently has 13 parts.

Part 1: General

ISO 80000-1:2009 replaces ISO 31-0:1992 and ISO 1000:1992. It gives general information and definitions concerning quantities, systems of quantities, units, quantity and unit symbols, and coherent unit systems, especially the International System of Quantities (ISQ) and the International System of Units (SI). The text of the informative sections of this document is publicly available.

Part 2: Mathematics

ISO 80000-2:2019 revises ISO 80000-2:2009, which superseded

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 ...

. It specifies mathematical symbols, explains their meanings, and gives verbal equivalents and applications. The text of the informative sections of this document is publicly available.

Part 3: Space and time

ISO 80000-3:2019 revises ISO 80000-3:2006, which supersedes

ISO 31-1 ISO 31-1 is the part of international standard ISO 31 that defines names and symbols for quantities and units related to ''space and time''. It was superseded in 2006 by ISO 80000-3. Definitions Its definitions include: Annex A Annex A ...

and

ISO 31-2 ISO 31-2 is the part of international standard ISO 31 ISO 31 ( Quantities and units, International Organization for Standardization, 1992) is a superseded international standard concerning physical quantities, units of measurement, their inte ...

. It gives names, symbols, definitions and units for quantities of space and time. The text of this document is publicly available.

Part 4: Mechanics

ISO 80000-4:2019 revises ISO 80000-4:2006, which superseded ISO 31-3. It gives names, symbols, definitions and units for quantities of mechanics. The text of this document is publicly available.

Part 5: Thermodynamics

ISO 80000-5:2019 revises ISO 80000-5:2007, which superseded

ISO 31-4 ISO 31-4 is the part of international standard ISO 31 that defines names and symbols for quantities and units Unit may refer to: Arts and entertainment * UNIT, a fictional military organization in the science fiction television series ''Doctor ...

. It gives names, symbols, definitions and units for quantities of thermodynamics. The text of this document is publicly available.

Part 6: Electromagnetism

IEC 80000-6:2022 revises IEC 80000-6:2008, which superseded

ISO 31-5 ISO 31-5 is the part of international standard ISO 31 that defines names and symbols for quantities and units related to ''electricity and magnetism''. It is superseded by ISO 80000-6 ISO 80000 or IEC 80000 is an international standard intro ...

as well as IEC 60027-1. It gives names, symbols, and definitions for

quantities Quantity or amount is a property that can exist as a multitude or magnitude, which illustrate discontinuity and continuity. Quantities can be compared in terms of "more", "less", or "equal", or by assigning a numerical value multiple of a unit ...

and

units 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 (album), ...

electromagnetism In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions of a ...

. The text of the informative sections of this document is publicly available.

Part 7: Light and radiation

ISO 80000-7:2019 revises ISO 80000-7:2008, which superseded

ISO 31-6 ISO 31-6 is the part of international standard ISO 31 that defines names and symbols for quantities and units related to ''light and related electromagnetic radiations''. It is superseded by ISO 80000-7 ISO 80000 or IEC 80000 is an internati ...

. It gives names, symbols, definitions and units for quantities used for

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 tera ...

and

optical radiation Optical radiation is part of the electromagnetic spectrum. It is subdivided into ultraviolet radiation (UV), the spectrum of light visible for man (VIS) and infrared radiation Infrared (IR), sometimes called infrared light, is electromagnetic ...

in the wavelength range of approximately 1 nm to 1 mm. The text of this document is publicly available.

Part 8: Acoustics

ISO 80000-8:2020 revises ISO 80000-8:2007, which revised ISO 31-7:1992. It gives names, symbols, definitions and units for quantities of

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 acoustician ...

. The text of the informative sections of this document are publicly available. It has a foreword, scope introduction, scope, normative references (of which there are none), as well as terms and definitions. It includes definitions of

sound pressure Sound pressure or acoustic pressure is the local pressure deviation from the ambient (average or equilibrium) atmospheric pressure, caused by a sound wave. In air, sound pressure can be measured using a microphone, and in water with a hydrophone ...

sound power Sound power or acoustic power is the rate at which sound energy is emitted, reflected, transmitted or received, per unit time. It is defined as "through a surface, the product of the sound pressure, and the component of the particle velocity, at ...

and

sound exposure Sound exposure is the integral, over time, of squared sound pressure. The SI unit of sound exposure is the pascal squared second (Pa2·s). Mathematical definition Sound exposure, denoted ''E'', is defined by :E = \int_^ p(t)^2\, \mathrmt, where * ...

, and their corresponding

levels Level or levels may refer to: Engineering *Level (instrument), a device used to measure true horizontal or relative heights *Spirit level, an instrument designed to indicate whether a surface is horizontal or vertical *Canal pound or level *Regr ...

sound pressure level Sound pressure or acoustic pressure is the local pressure deviation from the ambient (average or equilibrium) atmospheric pressure, caused by a sound wave. In air, sound pressure can be measured using a microphone, and in water with a hydrophone ...

sound power level Sound power or acoustic power is the rate at which sound energy is emitted, reflected, transmitted or received, per unit time. It is defined as "through a surface, the product of the sound pressure, and the component of the particle velocity, at ...

and

sound exposure level Sound exposure is the integral, over time, of squared sound pressure. The SI unit of sound exposure is the pascal squared second (Pa2·s). Mathematical definition Sound exposure, denoted ''E'', is defined by :E = \int_^ p(t)^2\, \mathrmt, where *t ...

. It includes definitions of the following quantities: * logarithmic frequency range * static pressure * sound pressure * sound particle displacement * sound particle velocity * sound particle acceleration * volume flow rate, volume velocity * sound energy density * sound energy * sound power * sound intensity * sound exposure * characteristic impedance for longitudinal waves * acoustic impedance * sound pressure level * sound power level * sound exposure level * reverberation time

Part 13: Information science and technology

IEC 80000-13:2008 was reviewed and confirmed in 2022 and published in 2008, and replaces subclauses 3.8 and 3.9 of IEC 60027-2:2005 and IEC 60027-3. It defines quantities and units used in information science, and specifies names and symbols for these quantities and units. It has a scope; normative references; names, definitions and symbols; and prefixes for binary multiples. Quantities defined in this standard are: *

traffic intensity In telecommunication networks, traffic intensity is a measure of the average occupancy of a server or resource during a specified period of time, normally a busy hour. It is measured in traffic units ( erlangs) and defined as the ratio of the time ...

'A'' ''number of simultaneously busy resources in a particular pool of resources'' *

traffic offered intensity Traffic comprises pedestrians, vehicles, ridden or herded animals, trains, and other conveyances that use public ways (roads) for travel and transportation. Traffic laws govern and regulate traffic, while rules of the road include traffic l ...

'A''₀ ''traffic intensity ... of the traffic that would have been generated by the users of a pool of resources if their use had not been limited by the size of the pool'' *

traffic carried intensity Traffic comprises pedestrians, vehicles, ridden or herded animals, trains, and other Public conveyance, conveyances that use public ways (roads) for travel and transportation. Traffic laws govern and regulate traffic, while rules of the roa ...

'Y'' ''traffic intensity ... of the traffic served by a particular pool of resources'' *

mean queue length There are several kinds of mean in mathematics, especially in statistics. Each mean serves to summarize a given group of data, often to better understand the overall value (magnitude and sign) of a given data set. For a data set, the '' ari ...

'L'', (''Ω'') time average of queue length * loss probability 'B'' ''probability for losing a call attempt'' *

waiting probability Waiting, Waitin, Waitin', or The Waiting may refer to: Film * ''Waiting'' (1991 film), a film by Jackie McKimmie * ''Waiting...'' (film), a 2005 film starring Ryan Reynolds * ''Waiting'' (2007 film), a film by Zarina Bhimji * ''Waiting'' (20 ...

'W'' ''probability for waiting for a resource'' *

call intensity, calling rate Call or Calls may refer to: Arts, entertainment, and media Games * Call, a type of betting in poker * Call, in the game of contract bridge, a bid, pass, double, or redouble in the bidding stage Music and dance * Call (band), from Lahore, Paki ...

'λ'' ''number of call attempts over a specified time interval divided by the duration of this interval'' * completed call intensity 'μ'' ''call intensity ... for the call attempts that result in the transmission of an answer signal'' * storage capacity, storage size 'M''* equivalent binary storage capacity 'M''_e* transfer rate 'r'', (''ν'')* period of data elements 'T''* binary digit rate, bit rate 'r''_b, ''r''_bit (''ν''_b, ''ν''_bit)* period of binary digits, bit period 'T''_b, ''T''_bit* equivalent binary digit rate, equivalent bit rate 'r''_e, (''ν''_e)* modulation rate, line digit rate 'r''_m, ''u''* quantizing distortion power 'T''_Q* carrier power 'P''_c, ''C''* signal energy per binary digit 'E''_b, ''E''_bit* error probability 'P''* Hamming distance 'd''_n* clock frequency, clock rate 'f''_cl* decision content 'D''_a* information content 'I''(''x'')* entropy 'H''* maximum entropy 'H''₀, (''H''_max)* relative entropy 'H''_r* redundancy 'R''* relative redundancy 'r''* joint information content 'I''(''x'', ''y'')* conditional information content ''y'')* conditional entropy, mean conditional information content, average conditional information content ''Y'')* equivocation 'H''(''X''∣''Y'')* irrelevance 'C''* transinformation content 'T''(''x'', ''y'')* mean transinformation content 'T''* character mean entropy 'H''′* average information rate 'H''** character mean transinformation content 'T''′* average transinformation rate 'T''** channel capacity per character; channel capacity 'C''′* channel time capacity; channel capacity 'C''* The Standard also includes definitions for units relating to information technology, such as the erlang (E),

bit The bit is the most basic unit of information in computing and digital communications. The name is a portmanteau of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represente ...

(bit),

octet Octet may refer to: Music * Octet (music), ensemble consisting of eight instruments or voices, or composition written for such an ensemble ** String octet, a piece of music written for eight string instruments *** Octet (Mendelssohn), 1825 compos ...

(o),

byte The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit ...

(B),

baud In telecommunication and electronics, baud (; symbol: Bd) is a common unit of measurement of symbol rate, which is one of the components that determine the speed of communication over a data channel. It is the unit for symbol rate or modulatio ...

(Bd), shannon (Sh),

hartley Hartley may refer to: Places Australia *Hartley, New South Wales *Hartley, South Australia **Electoral district of Hartley, a state electoral district Canada *Hartley Bay, British Columbia United Kingdom *Hartley, Cumbria *Hartley, Plymou ...

(Hart) and the natural unit of information (nat). Clause 4 of the Standard defines standard

binary prefix A binary prefix is a unit prefix for multiples of units. It is most often used in data processing, data transmission, and digital information, principally in association with the bit and the byte, to indicate multiplication by a power of& ...

es used to denote powers of 1024 as 1024¹ (

kibi- A binary prefix is a unit prefix for multiples of units. It is most often used in data processing, data transmission, and digital information, principally in association with the bit and the byte, to indicate multiplication by a power of& ...

), 1024² (

mebi- A binary prefix is a unit prefix for multiples of units. It is most often used in data processing, data transmission, and digital information, principally in association with the bit and the byte, to indicate multiplication by a power of& ...

), 1024³ (

gibi- A binary prefix is a unit prefix for multiples of units. It is most often used in data processing, data transmission, and digital information, principally in association with the bit and the byte, to indicate multiplication by a power of& ...

), 1024⁴ (

tebi- A binary prefix is a unit prefix for multiples of units. It is most often used in data processing, data transmission, and digital information, principally in association with the bit and the byte, to indicate multiplication by a power of& ...

), 1024⁵ (

pebi- A binary prefix is a unit prefix for multiples of Units of measurement, units. It is most often used in data processing, data transmission, and digital information, principally in association with the bit and the byte, to indicate multiplicatio ...

), 1024⁶ (

exbi- A binary prefix is a unit prefix for multiples of units. It is most often used in data processing, data transmission, and digital information, principally in association with the bit and the byte, to indicate multiplication by a power of& ...

), 1024⁷ (

zebi- A binary prefix is a unit prefix for multiples of Units of measurement, units. It is most often used in data processing, data transmission, and digital information, principally in association with the bit and the byte, to indicate multiplicatio ...

) and 1024⁸ (

yobi- A binary prefix is a unit prefix for multiples of units. It is most often used in data processing, data transmission, and digital information, principally in association with the bit and the byte, to indicate multiplication by a power of& ...

International System of Quantities

Part 1 of ISO 80000 introduces the International System of Quantities and describes its relationship with the

International System of Units The International System of Units, known by the international abbreviation SI in all languages and sometimes pleonastically as the SI system, is the modern form of the metric system and the world's most widely used system of measurement. E ...

(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." It 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. ISQ is a shorthand notation for the 'system of quantities on which the SI is based'."

Units of the ISO and IEC 80000 series

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 (

and

), units of

entropy Entropy is a scientific concept, as well as a measurable physical property, that is most commonly associated with a state of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodynam ...

( shannon, natural unit of information and

), the erlang (a unit of traffic intensity) and units of

level Level or levels may refer to: Engineering *Level (instrument), a device used to measure true horizontal or relative heights *Spirit level, an instrument designed to indicate whether a surface is horizontal or vertical *Canal pound or level *Regr ...

(

neper The neper (symbol: Np) is a logarithmic unit for ratios of measurements of physical field and power quantities, such as gain and loss of electronic signals. The unit's name is derived from the name of John Napier, the inventor of logarithms. As ...

and

decibel The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a po ...

). The standard includes all

SI prefix The International System of Units, known by the international abbreviation SI in all languages and sometimes pleonastically as the SI system, is the modern form of the metric system and the world's most widely used system of measurement. E ...

es as well as the

es kibi-, mebi-, gibi-, etc., originally introduced by the

to standardise binary multiples of byte such as

mebibyte The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit ...

(MiB), for ² bytes, to distinguish them from their decimal counterparts such as megabyte (MB), for precisely one million (²) bytes. In the standard, the application of the binary prefixes is not limited to units of information storage. For example, a frequency ten

octaves In music, an octave ( la, octavus: eighth) or perfect octave (sometimes called the diapason) is the interval between one musical pitch and another with double its frequency. The octave relationship is a natural phenomenon that has been refer ...

above one hertz, i.e., 2¹⁰ Hz (), is one kibihertz (1 KiHz).
(22 pages) These

es were standardized first in a 1999 addendum to IEC 60027, 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.

References

External links

BIPM SI Brochure

nbsp;– Quantities, units, symbols, conversion factors

nbsp;– The International System of Units

nbsp;– Guide for the Use of the International System of Units {{DEFAULTSORT:ISO IEC 80000 + Measurement #80000