IEC 81346-2-2019 pdf free.Industrial systems, installations and equipment and industrial products – Structuring principles and reference designations – Part 2: Classification of objects and codes for classes.
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 81346-1:2009, Industrial systems, installations and equipment and industrial products — Structuring principles and reference designations — Part 1: Basic rules
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 81346-1 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.orgl
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1 inherent function function of an object, independent of any application of the object
Note 1 to entry: Inherent is regarded as existing in something as a permanent, essential, or characteristic attribute
3.2 classification scheme descriptive information for an arrangement or division of objects into groups based on criteria such as characteristics, which the objects have in common.
4 Classification principles
4.1 General
The purpose of classifying is to distinguish among objects in a collection based on differentiation of characteristics of interest. Classes are organized in type-of relations and are defined by different values of a specific characteristic of interest.
The classification in this document is made with an entry class based on function in a broad sense. This is in accordance with Iso 22274:2013, 5.44 which recommends an enumerative and faceted classification system with an entry class.
When a class code is applied in a reference designation, the purpose is to classify the occurrence of the object, not the individual, as described in IEC 81346-1:2009, 4.8 and Table 1 (general rules). In such a situation, the object is generally specified and assigned its inherent function in the design stage of the project. Classes can also be used by manufacturers to show multiple potential use of a product. In this way, the classification can enhance searchability.
The class name (preferred term) assigned to the classes and the examples of terms provided in this document are based on the inherent function of an object. i.e. independent of any application.
This classification scheme ensures a life cycle stable class code, as the stable object occurrence is classified by the stable inherent function of the object occurrence: A stake is a stake, a door is a door and so on. no matter what individual is used to realize the occurrence.
Objects related to a class may be considered as a discrete collection of objects, and may therefore be further classified into sub-classes based on the differentiation of a specific characteristic. In this document, this has resulted in a classification scheme starting with classes representing general types based on function in a broad sense (ist letter code), continuing into classes representing types that are more specialized in two steps, represented by 2d and 3’d class code.
All examples and terms in the classification scheme of this document are recognized as being used to name a member of their class. As different branches have different usage of terminology, the same example or term might occur in different classes.
4.2 Relation between classification and composition
IEC 81346-1 defines rules on how an object may be structured into its constituent objects resulting in a composition hierarchy. For the purpose of classifying objects, this document defines classes and codes that results in a classification hierarchy, see Figure 1, which is a copy of Figure 2 in 4.2 of ISO 12006-2:201 5.IEC 81346-2 pdf download.