Standards Development

Scope

This part of the ISO/IEC 81346 International Standard, published jointly by IEC and ISO, provides rules and guidelines for the classification, designation, and representation of relations between objects. This document defines classes of relations, their definitions, and their codes. The defined classes and codes are intended to support the consistent identification, interpretation, and reuse of relational information by enabling the association of relevant metadata with relations.

Based on these principles, rules and guidelines are given for the formulation of unambiguous reference designations for relations associated with any object. 

The reference designation identifies a relation for the purpose of assigning, modifying, retrieving, and exchanging information associated with that relation. A relation is treated as an identifiable information object that can be referenced and associated with metadata. The reference designation of a relation is derived from the reference designations of the participating objects.

The principles are general and are applicable to all technical areas (for example mechanical engineering, electrical engineering, construction engineering, chemical engineering, and software engineering). They can be used for systems based on different technologies or for systems combining several technologies.

Purpose

The ISO/IEC 81346 standard series (Reference Designation System – RDS) provides principles and rules for the structuring and designation of objects in systems. Through the use of aspects such as function, product, location, type, process and properties, the standard series enables the creation of coherent reference models that support the design, realization, operation and maintenance of systems throughout their lifecycle.

The increasing adoption of model-based engineering, systems engineering, digital twins, asset information models and interoperable digital platforms has created a growing need not only to identify objects, but also to identify and manage the relationships between objects. While the existing ISO/IEC 81346 standard series provides methods for the designation and classification of objects and their properties, it does not provide a standardized framework for the classification and designation of relations.

In practice, relations are essential elements of engineering information. Examples include the realization of functions by products, the location of products within spaces, the association of objects with properties, the assignment of objects to types, and the structural, functional, informational and dependency relationships that exist between objects throughout a system lifecycle. Such relations are increasingly represented as digital information objects in engineering tools, databases, digital twins and system models.

The absence of a common framework for identifying and classifying relations results in inconsistent implementations between industries, software vendors and organizations. Similar relationships are often represented using different concepts, naming conventions and data structures, making information exchange, traceability and integration more difficult.

This proposed Part 5 of the IEC 81346 series establishes a common framework for the classification and designation of relations. The framework extends the principles of IEC 81346 from the identification of objects to the identification of the relationships between objects. Relations are treated as identifiable information objects that may be referenced, classified and associated with metadata while maintaining explicit links to the objects they connect.

The proposed standard introduces:

• a classification scheme for relation classes with associated definitions and codes;

• rules for the designation of relations between objects;

• principles for distinguishing foundational semantic relations from domain-specific engineering relations;

• guidance for the application of relation classes between objects belonging to different aspects defined by the IEC 81346 series;

• a basis for associating metadata, lifecycle information and traceability information with relations.

The proposed work supports and complements existing parts of the IEC 81346 series. IEC 81346-1 establishes the general principles for structuring and designation, IEC 81346-2 and related parts establish classification schemes for objects, and IEC 81346-8 establishes a framework for the classification and designation of properties. Part 5 fills an important gap by providing a corresponding framework for relations.

The proposed standard is particularly relevant for organizations implementing systems engineering according to ISO/IEC/IEEE 15288, architecture frameworks based on ISO/IEC/IEEE 42010, model based systems engineering (MBSE), digital twin technologies, asset information management, Building Information Modelling (BIM), industrial automation, process industries, infrastructure systems and other domains requiring consistent representation of relationships between objects.

The standard will support digital transformation by enabling relations to be exchanged, interpreted and managed consistently across tools, disciplines and lifecycle stages. By establishing a common language for relations, the standard will improve interoperability, traceability, data quality and reuse of engineering information in the same manner that the existing IEC 81346 series has done for objects and properties.

The proposed document builds upon the established classification principles already applied within the IEC 81346 series and follows the same fundamental objective: to provide a simple, generic and domain-independent framework capable of supporting a broad range of engineering disciplines while remaining suitable for digital implementation and information exchange.