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International Classification for Standards

International Classification for Standards

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International Classification for Standards (ICS) is an international classification system for technical standards
Standardization is the process of developing and implementing technical standards.The goals of standardization can be to help with independence of single suppliers , compatibility, interoperability, safety, repeatability, or quality....

. It is designed to cover every economic sector and virtually every activity of the humankind where technical standards
Standardization is the process of developing and implementing technical standards.The goals of standardization can be to help with independence of single suppliers , compatibility, interoperability, safety, repeatability, or quality....

 may be used.

Developed and maintained by the International Organization for Standardization
International Organization for Standardization
The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...

, the ICS is intended to be a continuous work in progress and is updated when necessary. The latest edition of the ICS can be downloaded free of charge from the ISO web site.

Anyone may submit a proposal for modifications or additions to the ICS.


The ICS serves as a structure for catalogues and database
A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...

s of technical standards
Standardization is the process of developing and implementing technical standards.The goals of standardization can be to help with independence of single suppliers , compatibility, interoperability, safety, repeatability, or quality....

 and other normative documents, and as a basis for standing-order systems for international, regional and national standards.

Classification principles

The ICS uses an hierarchical classification, which consists of three nested levels called fields (Level 1), groups (Level 2) and sub-groups (Level 3). Each field is subdivided into groups, which are further divided into sub-groups.

All classification levels are designated by a classification code (called notation) and a title. The notation is a set of Arabic numerals.

Top-level items, which have no parent levels, use a two-digit notation, for example:

The notations for groups and sub-groups include the parent-level notations. The example below shows a notation for Sub-Group 20 (Level 3), which belongs to Group 040 (Level 2) in Field 43 (Level 1).
43.040.20 Lighting, signaling and warning devices

Level 1 (Fields)

A field is the first level in the International Classification for Standards. It may represent one or a combination of the following:
  • A sector of the economy such as agriculture
    Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...

    , mining
    Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...

    , construction
    In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of human multitasking...

     or the packaging industry;
  • A technology such as telecommunications or food processing
    Food technology
    Food technology, is a branch of food science which deals with the actual production processes to make foods.-Early history of food technology:...

  • An activity such as environment protection, safety
    Safety is the state of being "safe" , the condition of being protected against physical, social, spiritual, financial, political, emotional, occupational, psychological, educational or other types or consequences of failure, damage, error, accidents, harm or any other event which could be...

     assurance and protection of public health
    Public health
    Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals" . It is concerned with threats to health based on population health...

  • A field of science such as mathematics
    Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

     or astronomy
    Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...


At present the classification includes 40 fields.
01 General. Terminology. Standardization. Documentation

03 Sociology. Services. Formation And Management Of Business Entities. Administration. Transportation

07 Mathematics. Natural Sciences

11 Health Care Technology

13 Environment. Health. Safety

17 Metrology And Measurement. Physical Phenomena

19 Testing

21 Mechanical Systems And Components For General Use

23 Fluid Systems And Components For General Use

25 Manufacturing Engineering

27 Energy And Thermal Engineering

29 Electrical Engineering

31 Electronics

33 Telecommunications. Audio And Video Engineering

35 Information Technology. Office Machines

37 Image Technology

39 Precision Mechanics. Jewelry

43 Road Vehicle Engineering

45 Railway Engineering

47 Shipbuilding And Marine Structures

49 Aircraft And Space Vehicle Engineering

53 Hoisting And Conveying Equipment. Materials Handling

55 Packaging And Distribution Of Goods

59 Textile And Leather Technology

61 Clothing Industry

65 Agriculture

67 Food Technology

71 Chemical And Petrochemical Technology

73 Mining And Minerals

75 Petroleum, Natural Gas, And Related Technologies

77 Metallurgy

79 Wood Technology

81 Glass And Ceramics Industries

83 Rubber, Asbestos, And Plastics Industries

85 Pulp And Paper Technology

87 Paint And Coating Industries

91 Construction. Building Materials

93 Civil Engineering

95 Military Engineering

97 Household And Commercial Equipment. Recreation. Sports

Level 3 (Sub-Groups)

Sub-groups are used in the ICS to subdivide groups into subjects that pertain to a particular aspect of the subject covered by a given group. Regardless of the subject, virtually all groups include a sub-group No. 01 that covers the complete subject of the respective group. In addition, most of the groups contain a sub-group No. 99 for standards on subjects which do not correspond either to the subjects of the general sub-groups or to the subjects of the specific sub-groups of the respective groups.

Level 4 (Units)

Level 4 subdivisions are not part of the official ICS document. The ICS rules however allow users of the classification system to subdivide the official ICS sub-groups into so-called units, making them a Level 4 component of the International Classification for Standards. This is accomplished by adding a two-digit number to the notation of the sub-group being subdivided. However, instead of a period, new notations use a hyphen
The hyphen is a punctuation mark used to join words and to separate syllables of a single word. The use of hyphens is called hyphenation. The hyphen should not be confused with dashes , which are longer and have different uses, or with the minus sign which is also longer...

 as a separator. For example:
35.220.20-10 Magnetic tapes


  • The International Classification for Standards has 99 top-level divisions of which only 40 are presently used. The remaining 59 divisions are reserved for topics that are not yet known.

  • There are three "official" levels in the ICS system, each holding ninety nine (99), nine hundred and ninety nine (999) and ninety nine (99) subsets, respectively.

  • Each field of the ICS is designed to hold a maximum of 999 groups. The number 999 is a Kaprekar number
    Kaprekar number
    In mathematics, a Kaprekar number for a given base is a non-negative integer, the representation of whose square in that base can be split into two parts that add up to the original number again. For instance, 45 is a Kaprekar number, because 45² = 2025 and 20+25 = 45. The Kaprekar numbers are...

    since its square (999² = 998,001) can be split into two parts, 998 and 001, which add up to the original number again (998 + 001 = 999).

  • Although any group in the ICS may contain no more than 99 "official" sub-groups, the holding capacity of the group can be expanded 99 times by using "unofficial" Level 4 subdivisions, an option that is built into the ICS. Adding Level 4 subdivisions to all sub-groups within a group increases the group's holding capacity to 9 801 subjects. Splitting this number into two parts, 98 and 01, and then adding them produces 99, the maximum number of "official" sub-groups in any given group of the ICS.

  • The expanded version of the International Classification for Standards is capable of covering nearly 1 billion subjects (969,328,701 to be exact). This can be achieved without any restructuring of its numerical coding system. Since there are currently about 780 000 national standards in the world, the number of subjects that the ICS can offer for classification purposes exceeds 1 200 times the total number of documents that are available for classification.

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