ISO/IEC 80000
The International Size System, abbreviated ISQ (of English International System of Quantities ) is a sizing system that is used with the International System of Units (SI). This size system has been published in the multipart international standard series ISO or IEC 80000.
International sizing system ( ISQ )
In order to apply a system of units as the SI, a corresponding size of the system is required. In particular, a set of equations is needed to define the relationships between the variables, since these equations define as the relationships between the units. For the definition of units in a limited selection of SI units is selected as the base units so that all the units other than those derived units, i.e., can be expressed as a product of powers of the base units. Similarly, the corresponding variables are described as base quantities and derived quantities in the ISQ.
The equations that return the values derived on the basis of variables can also be used to express the derived units using the base units. In general, it is therefore advisable to first determine the sizes and the equations that relate the variables to each other, and then select the appropriate units.
Most of the units have already been developed before the concept of the size of the system has been defined. The sizing system to use with the SI is given by the variables and equations used in scientific publications and manuals. Such sources, however, contain only a small selection of the many possible variables and equations. A large number of variables and equations have been compiled in the international standards ISO 31 and IEC 60027. The content of these standards was subsequently harmonized by the ISO and the IEC and published from 2006 as international standard ISO / IEC 80000 Quantities and Units.
In the EN ISO 80000 is the size system that is used with the SI, "International size system " called. The abbreviation " ISQ " ( from the English International System of Quantities ) shall apply in all languages.
ISO 80000 and IEC 80000
The ISO or IEC 80000 Quantities and units in two equal- language versions in English ( Quantities and units ) and French ( Grandeurs et Units) units appeared. This international standard has been adopted in various national standards and this translated into the appropriate languages . Thus, the various parts of ISO 80000 and the European Committee for Standardization ( CEN), without any change for the corresponding parts of the European standard EN ISO 80000 were taken. The German versions were published as DIN EN ISO 80000 and DIN EN 80000. Versions in German language have also been published as ÖNORM EN ISO 80000 or OVE / ÖNORM EN 80000 in Austria or are in draft form.
The ISO or IEC 80000 consists of 14 individually available parts, each of the ISO ( 11 parts ) and the IEC (3 parts) were published. The body responsible for drafting the Standards Technical Committee (English Technical Committee, abbreviated TC) is at the ISO TC 12 ( Quantities, units, symbols, conversion factors ) and the IEC TC 25 ( Quantities and units, and Their letter symbols ). The first valid expenditure of the individual parts are published in the period from 2006 to 2009. They replaced the so repealed standards ISO 31 and ISO 1000 The following table gives an overview of the individual parts.:
Part 1 General applies for general use within the different areas of science and technology. It contains general information and definitions regarding sizes (especially the ISQ ) and units (especially the SI) as well as extensive writing rules. It thus serves as an introduction to the other parts of ISO or IEC 80,000.
Part 2 of Mathematical symbol for science and technology mainly applies to science and technology; However, it can also be used in other areas where mathematics is used. It contains general information about mathematical signs, their meaning, speech and application.
The remaining parts contain names, symbols and definitions for quantities and units to each of a scientific topic.
The number of variables used in the scientific field is unlimited, so it is not possible to create a full list of sizes and derived units. It is therefore inevitable that some users who work in special field of knowledge, want to use sizes that are not listed in the ISO or IEC 80000 or other international standard. However, this is not an obstacle that could exclude the definitions of units for their own sizes, provided that these quantities can be related to similar examples given in relationship.