Date: 2025-10-21

ISO/DIS 12006-2.2:2025(en)

ISO TC 59/SC 13/WG 2

Secretariat: SN

Building construction — Organization of information about construction works — Part 2: Framework for classification and breakdown structures

Construction immobilière — Organisation de l'information des travaux de construction — Partie 2: Plan type pour la classification

© ISO 2025

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Contents

Foreword vii

Introduction ix

1 Scope 1

2 Normative references 1

3 Terms and definitions 1

3.1 Information structures 1

3.2 Objects 2

3.3 Asset 3

3.4 Process 5

3.5 Resource 6

3.6 Object aspects 7

4 Principles for structuring information for the built environment 7

4.1 Concept model 7

4.2 Information structures 8

4.3 Breakdown structures 8

4.4 Partial breakdown structures 9

4.5 Classification structures 9

Table 1 — Summary of recommended classification tables@003@004@005@003@005 10

4.4 Options for subsidiary tables 11

Figure 5 — Possible subsidiary tables 11

5 Implementation 12

5.1 Information structure development 12

5.2 Short code or name 12

5.3 Descriptive phrase 12

5.4 Maintenance 13

5.5 Conversion 13

5.6 Uses of information structures 13

5.7 Combining information structures 14

5.8 Use within applications and databases 14

5.9 Other classification tables 14

Annex A (informative) Classification table examples 15

A.1 General 15

A.2 Information 15

A.3 Components 15

A.4 Actors 16

A.5 Aids 17

A.6 Management 18

A.7 Tasks 18

A.8 Complexes 19

A.9 Entities 20

A.10 Spaces 21

A.11 Elements 23

A.12 Package 24

A.13 Properties 25

A.14 Zones 26

A.15 Uncertainties 27

A.16 Information Purposes 27

Annex B (informative) Example breakdown and classification structures 29

B.1 Industry Foundation Classes (IFC) 29

Figure B.1 — ISO 16739-1 IFC 30

B.2 Reference designation system for construction works (RDS-CW) 30

Figure B.2 —ISO/IEC 81346-12 31

B.3 Omniclass 31

Figure B.3 — Omniclass 31

B.4 Uniclass 31

Figure B.4 — Uniclass 33

B.5 CoClass 33

Figure B.5 — CoClass 33

B.6 CCI 33

Figure B.6 — CCI 34

B.7 NL/SfB 34

Figure B.7 — NL/SfB 35

Annex C (informative) Correspondence between table names used in this document and in the previous edition. 36

Table C.1 — Summary of table names in this and previous editions 36

Table name 36

Previous table name 36

Refer to 36

Information 36

Construction information 36

Annex A.2 36

Components 36

Construction products 36

Annex A.3 36

Actors 36

Construction agents 36

Annex A.4 36

Aids 36

Construction aids 36

Annex A.5 36

Management 36

Management 36

Annex A.6 36

Tasks` 36

Construction process 36

Annex A.7 36

Complexes 36

Construction complexes 36

Annex A.8 36

Entities 36

Construction entities 36

Annex A.9 36

Spaces 36

Built spaces 36

Annex A.10 36

Elements 36

Construction elements 36

Annex A.11 36

Package 36

Work results 36

Annex A.12 36

Properties 37

Construction properties 37

Annex A.13 37

Zones 37

(new) 37

Annex A.14 37

Uncertainties 37

(new) 37

Annex A.15 37

Information Purposes 37

(new) 37

Annex A.16 37

Bibliography 38

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of ISO document should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

ISO draws attention to the possibility that the implementation of this document may involve the use of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s) which may be required to implement this document. However, implementers are cautioned that this may not represent the latest information, which may be obtained from the patent database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.

Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISO's adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 59, Buildings and civil engineering works, Subcommittee SC 13, Organization and digitization of information about buildings and civil engineering works, including building information modelling (BIM), in collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC 442, Building Information Modelling (BIM), in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).

This third edition cancels and replaces the second edition (ISO 12006‑2:2015), which has been technically revised.

The main changes are as follows:

— Consideration of the whole life cycle of the built environment, removing the prefix ‘construction’ from concepts.

— Distinguishing breakdown structures (previously compositional hierarchy) from classification structures (previously classification hierarchy).

— Refining the previous Figure 1 (now Figure 2) and Table 1 to focus on non-abstract concepts.

— Addition of zones, uncertainty and information purpose whilst maintaining the list of recommended classification tables and the annex listing examples.

— Refining the definitions according to the intensional principle described in ISO 704 clause 6.2.

A list of all parts in the ISO 12006 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A complete listing of these bodies can be found at www.iso.org/members.html.

Introduction

0.1   Background

This document was first produced when there was little international standardization of classification structures for the built environment. Now, the IEC/ISO 81346 series and several national classification structures have been developed, for example, in North America, Scandinavia, and the UK, that implement the 2001 and 2015 editions. Lessons learned in these implementations have been applied in this third edition.

This document has also been revised to take into account developments in information technology (notably building information modelling) and construction procurement. It has been extended and definitions have been refined to better serve all sectors, including building, civil engineering, infrastructure and process engineering. It continues to serve traditional information technologies and procurement methods.

0.2   The need for standardization

Building information modelling and modern forms of procurement require that object groupings are used. Information management and building information modelling, in particular, is about exchange of information of all types throughout the asset life cycle, including delivery and operational phases, between participants and applications. This is also the case for cooperative forms of procurement. For this exchange to be successful, a complete and consistent approach to object classification is required. This document is intended to facilitate this exchange.

Information types include geometrical, functional, technical, cost and maintenance data amongst others. The asset life cycle runs from inception to eventual deconstruction. Participants include clients and owners, designers, authorities, constructors, end users and operators. Applications include modelling, specification, product information, and cost information systems.

Overarching principles for classification and breakdown structures are also needed for different international and national reporting, so that quantities and values are defined according to the same principles and are comparable. These values and quantities can be related to sustainability and financing.

While national classifications that implement this document can still differ in their detail (e.g. due to differences in construction, culture and legislation), mapping between them can be aided if they are using the same overarching classification and breakdown structure frameworks. This, in turn, can help with international project work with participants from many countries and with development of applications intended to be used internationally.

0.3   Breakdown structures and classification structures

Information structuring is critical to the delivery of the information purposes. Information purposes can be expressed in terms of desired outcomes as use cases, or in terms of specific outputs as documentation. The purpose of information structures including breakdown structures and classification structures is to organize concepts hierarchically thereby supporting cataloguing and grouping information and sharing unambiguous meaning (semantic interoperability) throughout the information and asset life cycles.

The purpose of a breakdown structure is to organize the decomposition of the domain to support naming of instances, way-finding and search paths and the management of capacity and performance within a given context by making distinctions between types of objects.

The purpose of a classification structure is to organize similar types of objects to support searching, sorting, matching and retrieval.

0.4   Types of information structures

According to ISO 22274, the main principles for structuring can be identified as enumerative, faceted, or a combination of enumerative and faceted.

Enumerative classification structures attempt to list all possible groupings within their defined area of applicability. They are in many cases represented using hierarchies. A complete enumerative classification structure is often very complex in nature, and its basic principles of development can be difficult to identify.

Faceted classification structures allow the assignment of multiple classifications to an object. An object can be characterized by any combination of the groupings from the facets. By using a combination of enumerative and faceted classification, the higher levels of the classification structure can follow an enumerative approach to narrow down the areas of applicability of the individual groupings to a manageable size. At the lower level, faceted approaches are applied to clearly specify the nature of the concepts contained in the leaf groupings of the classification structure.

This document defines a reference breakdown structure for the built environment supported by definitions and a set of requirements for partial breakdown structures and classification tables. It does not propose the implementation of a schema or data model.

0.5   Relationship to other standards

This document addresses breakdown and classification structures whereas ISO 12006-3 identifies a data structure for a data dictionary capable of relating concepts using terms relevant to multiple contexts. ISO 22274 establishes basic principles and requirements for ensuring that classification structures are suitable for worldwide application. ISO 704 provides criteria for the definition of concepts.

Annex B illustrates a number of implementations of this document including the ISO/IEC 81346 series with diagrams developed from Figure 2 and keys to name the included tables. ISO 16739-1 is illustrated as a data schema.

Building construction — Organization of information about construction works — Part 2: Framework for classification and breakdown structures

This document defines a framework for the development of built environment information structures. The framework is a breakdown structure supporting the spatial, physical, process aspects along with relevant resources and support. This framework provides a set of recommended titles for classification structures for a range of information object groupings according to particular views, supported by definitions.

This document applies to the complete life cycle of assets. It applies to both building and civil engineering work, including associated engineering services, landscaping and its natural environment. It is intended for use by organizations which develop and publish such classification structures and tables. This document aims to facilitate the harmonization of local classification structures and tables during their development.

The management of the built environment above the level of complexes, entities and projects/programmes is outside the scope of this document.

This document gives possible examples for the content of the tables. It also provides examples of current classification structures.

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.

ISO 22274, Systems to manage terminology, knowledge and content — Concept-related aspects for developing and internationalizing classification systems

For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp

— IEC Electropedia: available at https://www.electropedia.org/

3.1.1

information structure

classification system

systematic collection of classes organized according to a known set of rules, and into which objects may be grouped

Note 1 to entry: A hierarchy does not need to be a tree but, with multiple links, can be a directed network (polyhierarchy), for example, if an occurrence is a member of several groupings.

Note 2 to entry: ISO 22274 defines classification system to include both breakdown and classification structures.

[SOURCE: ISO 22274:2013, 3.6, modified - Note 1 to entry has been removed. The examples have been removed. The preferred term “information structure” has been added.]

3.1.2

breakdown structure

meronomy

hierarchy related to part-whole decomposition or other non-specialisation relations

Note 1 to entry: A breakdown structure comprises a hierarchy of named dissimilar groupings organized by whole-part or other extrinsic associations such as ‘contains’, ‘bounds’, ‘enables’, ‘serves’ or ‘specifies’ used for controlling aspects of the process, physical and spatial objects of the built environment.

Note 2 to entry: Clause 4 provides a reference breakdown structure and discusses partial breakdown structures.

Note 3 to entry: ISO 7817-1 and ISO21500 provide similar definitions to ISO 11179-3.

3.1.3

classification structure

taxonomy

hierarchy related to specialization relations

Note 1 to entry: A classification structure comprises a hierarchy of named similar groupings organized by type-of relationships based on intrinsic properties, creating an exhaustive set of mutually exclusive categories to aggregate objects at a pre-prescribed level of specialization for a specific purpose

Note 2 to entry: Clause 5 provides requirements for the development and application of classification structures.

3.2.1

object

any part of the perceivable or conceivable world

[SOURCE: ISO 1087:2019, 3.1.1, modified – The word "anything" has been replaced with "any part of". Words "perceivable or conceivable" have been replaced with "perceivable or conceivable world" The deprecated term “construction object” has been added.]

Note 1 to entry: An object is something abstract or physical toward which thought, feeling, or action is directed.

3.2.2

built environment

managed environment

collection of artificial or induced physical objects located in a particular area or region

[SOURCE: ISO 6707-3:2022(en), 3.1.3, modified – The word "man-made" has been replaced with "artificial”. The words “in a particular area or region” have been added]

EXAMPLE: Towns, drainage.

Note 1 to entry: The built environment can be viewed spatially as a collection of spaces, physically as a collection of components or process as a collection of activities.

3.2.3

natural environment

collection of naturally occurring physical objects located in a particular area or region

EXAMPLE: Hills, rainfall.

3.3.1

asset

item, thing or entity that has potential or actual value to an organization

[SOURCE: ISO 55000:2024,^[10] 3.1.1, modified — The notes to entry have been removed.]

3.3.2

complex

site

set of entities (3.3.5) serving a common function or user activity

EXAMPLE: Airport, motorway, hospital, business park. For example, an airport typically is composed of the entities such as runway, control tower, terminal building, aircraft hangar. A business park typically is composed of a number of buildings, access roads, and landscaping (each an object in its own right). A motorway typically is composed of service stations, the motorway pavement, bridges, embankments, landscaping, etc.

Note 1 to entry: A complex serves at least one function or user activity within a geo-spatial boundary.

Note 2 to entry: See A.8.

3.3.3

zone

set of spaces (3.3.4) sharing at least one characteristic

EXAMPLE: Access zone, fire safety zone, climate zone, smoking area, quiet zone.

Note 1 to entry: The set can consist of one or more spaces, and these spaces need not be next to each other.

Note 2 to entry: Characteristics can relate to regulations, purposes, control or functions.

Note 3 to entry: Spaces and Zones can have a ‘many to many’ relationship.

Note 4 to entry: Zones can be hierarchical, if the shared characteristic is possible to break down.

Note 5 to entry: See A.15.

3.3.4

space

activity space

location

area

spatial extent defined physically or notionally

EXAMPLE: Traffic lane, bedroom, room defined by floor, ceiling, and walls, footpath, power-line corridor defined by natural forest.

Note 1 to entry: A space is an identified spatial extent in 2 or 3 dimensions having a common purpose or other property.

Note 2 to entry: A space can be defined by user activity, bounds or work extent.

Note 3 to entry: ‘Location’ is often used within infrastructure to denote an area of interest

Note 3 to entry: See 4.7 and A.10.

3.3.5

entity

facility

building

structure

independent unit of the built environment (3.3.2), consisting of elements (3.3.6), with a characteristic form and spatial structure, intended to serve at least one function or user activity

EXAMPLE: Bridge, hotel, car park.

Note 1 to entry: An entity serves at least one function or user activity. It is recognizable as a physically independent object even though a number of entities can be seen as parts of a particular complex. Ancillary works such as access roads, landscaping, service connections, can be regarded as part of an entity or if the ancillary works are of sufficient scale, they can be regarded as entities in their own right.

Note 2 to entry: See A.9. Previously ‘construction entity’.

3.3.6

element

functional system

system

set of components (3.3.7) with a characteristic function, form or position

EXAMPLE: Load-bearing system, roof system, wall system, HVAC (heating, ventilation or air-conditioning) system, drainage system, electrical system, communication system, transportation system, planting system, landscape system, window system, suspension system, hinge system, fan system.

Note 1 to entry: The ISO/IEC 81346 series defines "element" as "object with characteristics which predominantly represents an overall inherent function".

Note 2 to entry: Components can be part of one or more elements and do not need to be contiguous. Elements therefore serve an entity rather than be part of the entity.

Note 3 to entry: Elements can be hierarchical, with higher level functions being disaggregated into lower-level (technical) systems. A single technical system (such as a wall system) can satisfy several elements; or many technical systems can satisfy a single element (such as a security system).

Note 4 to entry: The concept of element is used in a broad sense, not linked to any specific domain or discipline.

Note 5 to entry: See A.11.

3.3.7

component

technical system

assembly

product

material

object (3.2.1) manufactured or processed as a distinct unit to serve a specific function or functions

EXAMPLE: A lighting pole, a door, a beam, wall assembly, lighting system. door unit, material, soil type.

Note 1 to entry: A component is generally incorporated in a permanent manner in an entity. Otherwise, this would be an aid (3.5.1). Components can initially be resources.

Note 2 to entry: The admitted terms vary primarily in their scale.

Note 3 to entry: The ISO/IEC 81346 (all parts) defines "technical system" as "object with characteristics which predominantly represents a coherent technical solution with an inherent function".

Note 4 to entry: See 4.7 and A.3

[SOURCE: ISO 6707-1:2020,^[12] 3.4.1.3, modified – The word “item” has been replaced with “object”. An example has been added. The notes to entry have been added.]

3.4.1

process

set of interrelated or interacting activities (3.4.4) that use components and resources (3.5.1) to deliver an intended result

[SOURCE: ISO 9000:2015^[11],3.4.1, modified — The notes to entry have been removed. Inputs replaced with components and resources. ]

3.4.2

management

coordinated activities to direct and control

EXAMPLE: New-build, renovation, capital works project, programme of works.

Note 1 to entry: Typically coordinated activities are directed towards the accomplishment of agreed objectives.

Note 2 to entry: See A.6.

[SOURCE: ISO 9000:2015,^[11] 3.3.3, modified — The words “an organization” have been removed. Example has been added. The notes to entry have been replaced.]

3.4.3

package

work package

work section

identified piece of work

EXAMPLE Steel framing, groundworks, fire engineering.

Note 1to entry: A package can be enabling, creating resources.

Note 2 to entry: See A.12.

3.4.4

task

activity

an action required to achieve a result

Note 1 to entry: A task can use resources (3.5.1) to affect components (3.3.7).

Note 2 to entry: See 4.7 and A.7.

[SOURCE: ISO 6707-2:2017,^[13] 3.2.55, modified – The word “activities” has been replaced with “set of activities”.; The word “goal” has been replaced with “result”. An example and notes to entry have been added.]

3.5.1

resource

object (3.2.1) used in a process (3.4.1) to achieve a result

3.5.2

actor

person, organization or organizational unit involved in a process (3.4.1)

EXAMPLE: Supervisor, engineer, labourer.

Note 1 to entry: Organizational units include, but are not limited to, departments, teams.

Note 2 to entry: An actor can be an agent for another or an autonomous device.

Note 3 to entry: See 4.7 and A.4.

3.5.3

aid

construction equipment

temporary works

resource (3.5.1) which assists an actor (3.5.2)

EXAMPLE: Scaffolding, bracing, hammer, excavator.

Note 1 to entry: An aid is generally temporary. An object intended for permanent incorporation is a component.

Note 2 to entry: See A.5.

3.5.4

information

meaningful data

EXAMPLE: Map, model, drawing, specification, product data sheet.

Note 1 to entry: See A.2.

[SOURCE: ISO 9000:2015,^[11] 3.8.2, modified – The deprecated term “construction information” has been added.]

3.6.1

property

defined characteristic suitable for the description and differentiation of an object (3.2.1)

EXAMPLE: Name, description, classification, volume, density, duration.

Note 1 to entry: A property is expected to reflect current or past characteristics.

Note 2 to entry: See A.13.

[SOURCE: ISO 22274:2013, 3.25, modified - The words "the objects in a class" have been replaced with "an object". The example has been replaced. The notes to entry have been added. The deprecated term “construction property” has been added.]

3.6.2

uncertainty

lack of certainty resulting from inaccuracies in, or lack of, information (3.5.3)

EXAMPLE: Fall from height, energy saving.

Note 1 to entry: Uncertainties can be expressed as opportunities and risks, reflecting choices associated with future spatial, physical and process aspects of the built environment. Risks can be managed and treated, whereas opportunities can be enabled and promoted.

Note 2 to entry: See A.15.

Note 3 to entry: An uncertainty can be associated to one or more than one objects in terms of causation and effect.

3.6.3

information purpose

intention or objective for which information (3.5.3) is created for

Note 1 to entry: Information purposes can be defined to organize the production of information and the management of the interventions in the built environment.

Note 2 to entry: See A.16.

Information structuring for the built environment shall address the spatial and physical asset, the processes and the resources involved so as to support its description and narration as shown in Figure 1. Classification tables that should be used are detailed in Figure 2. Figure 2 and Table 1 should be read together with further detail in relation to each aspect in Clause 4 and the details on implementation in Clause 5. Annex C gives the corresponding table names used in previous editions.

NOTE 1 The narrative view sees resources being used to effect processes which affect entities which are contained in complexes. Conversely, the descriptive view sees the built environment as being experienced and exploited spatially, created physically and is affected (designed, constructed and operated) through processes which are effected through using resource.

Figure 1 — Narrative (left to right) and descriptive (right to left) view

^a Components can initially be considered as resources.

^b Information can ultimately be considered as an asset.

Figure 2 — Information structure with recommended classification tables

NOTE 2 Objects labelled © can have classification tables.

NOTE 3 Figure 2 does not define a data model.

Information structures shall be used to support information management for the built environment. Breakdown structures shall create a hierarchy predominantly based on decomposition, whereas classification structures shall create a purely specialization hierarchy.

NOTE 1 Whilst such structures are hierarchical, breakdown structures do not need to be a strict tree, since the presence of horizontal relationships such as ‘serves’ can create a ‘directed network’ (polyhierarchy) where branches converge on a common terminal leaf, as when an occurrence is a member of several management groupings.

As an illustration, Figure 3 shows on the left a wall assembly is decomposed into studs, insulation and plates components and a ventilation element is decomposed into fans, insulation and ductwork, whereas on the right a ventilation system is specialized down to passive, hybrid and mechanical elements, and insulation components is specialized down into wall batts and duct insulation.

Figure 3 — Illustration of a breakdown structure (left) and a classification structure (right)

As an illustration, Figure 4 shows the combination of a breakdown structure and classification structure where a window frame component can be a part of window component which is part of a wall technical system. The window can be classified by its mode of operation, but its glazing components can be classified by its number of glass layers.

Figure 4 — Illustration of combining breakdown and classification structures

NOTE 2 Figures 3 and 4 illustrates the principle behind each kind of hierarchy (type-of and part-of). The graphic representation is based on ISO 1087:2019, Annex A. They serve to illustrate the principle and do not attempt to standardize any class, sub-class, whole, or part.

Breakdown structures shall be distinguished in that they apply extrinsic relationships to create each level, so that breakdown structures shall contain different kinds of objects.

NOTE 1 Breakdown structures are often relevant to the analysis of outcomes and outputs.

The breakdown structure approach shall handle wholes as distinct from parts and also associations such as ‘is-enabled-by’ and ‘specifies’. By identifying related types of objects, the relationships among these shall be determined and monitored, to ensure that all objects are similarly related.

NOTE 2 An object is a part if when added to a whole, the whole still remains.

NOTE 3 ISO 21511-2018 gives guidance on Work Breakdown Structures.

EXAMPLE 1 If a brick is added to or subtracted from a wall system, the whole is still a wall system, or if a wall system is added to an object, the whole is still that object.

EXAMPLE 2 based on ISO/IEC 81346-12;

— using a functional aspect, the function of a part is fundamental to the function of the whole;

— using a spatial aspect, the spatial extension of a part is included in that of the whole;

— using an assembly aspect, the part-whole relation means that the existence of a physical part precedes the existence of the whole.

Partial breakdown structures shall be based on the reference breakdown structure so as to create links to the equivalent classification structures.

Partial breakdown structures shall use a limited number of levels, typically 3 to 5.

EXAMPLE 1 Complex – Entity – Space.

EXAMPLE 2 Entity – Element – Component.

EXAMPLE 3 Entity – Component – Product or Material.

EXAMPLE 4 Product or Material – Space – Element (see ISO/IEC 81346-1).

EXAMPLE 5 Element – Product or Material – Space (see ISO/IEC 81346-10).

NOTE 1 Partial breakdown structures can be used to manage identification and naming of individual objects such as spaces, components and tasks, with or without the insertion of classification codes.

NOTE 2 Organizations can use partial breakdown structures to manage their own project delivery and asset management processes.

NOTE 3 Designation and naming are not within the scope of this document. See for example the ISO/IEC 81346 series^[4] and ISO 4157-1 & 2^[14]

Classification structures shall be distinguished in that they apply intrinsic properties to create each level, so that classification structures shall contain the same type of objects.

NOTE Classification is often relevant to the management of inputs such as libraries and information resources.

A classification table shall define the type of object in the classification. Then the properties of interest to the classification shall be distinguished, and finally the objects shall be assigned by considering the chosen properties.

For the classification to be exhaustive, every object in the collection shall be assignable to a grouping, and in order to be distinct, the groupings shall be mutually exclusive, meaning that any specific object only belongs to one group. A group shall not be divided into sub-groups based on different criteria because a given object shall not belong to more than one sub-division.

Groupings shall be defined by definitive descriptions indicating the properties representing the attributes of interest.

The properties common to the whole collection shall be determined so that the resulting group is the most general in the classification. The general grouping shall be subdivided into more specialized groupings in several steps. The subdivision shall result in groupings that run from the general to the specialized. The groupings shall be ordered in levels determined by the type-of relation, where specific groupings are types of more general groupings.

Groupings shall be divided into sub-groupings by a principle of specialization, resulting in a classification table. If there is a second principle of specialization for a particular grouping, then this shall be applied separately so that another classification table is generated.

EXAMPLE A group representing “furniture” divided into sub-groups such as “office furniture”, “domestic furniture”, “metal furniture”, “wooden furniture” would be problematic

The reference breakdown structure which is shown in Figure 2 and summarized in Table 1 shall be used to organize information structuring.

NOTE Table 1 shows the minimum set of classification tables by aspects along with the suggested criteria when developing specialization with cross-references to examples in Annex A. Implementations can choose to not offer all of these tables. Examples are given in Annex B.

Table 1 — Summary of recommended classification tables<Tbl_--></Tbl_-->

Within the recommended tables shown in Figure 2 and summarized in Table 1, there are options for more specific classification. Figure 5 summarizes some options for sections within classification tables or for multiple subsidiary tables. If tables are split, then a clear distinctions shall be made at the top level around a determining property.

Figure 5 — Possible subsidiary tables

Space classification subsidiary tables can be determined by user task, built extent or work extents or any combination of these.

EXAMPLE 1 RDS-CW (Annex B.2) offers subsidiary tables for activity space and for built space.

Component classification subsidiary tables can be determined by technical system, product, or material or any combination of these.

EXAMPLE 2 Uniclass (Annex B.4) offers subsidiary tables for systems, for products and for materials. CCI (Annex B.4) offers subsidiary tables for technical systems and for components.

Task classification subsidiary tables can be determined by briefing, design/planning, or execution or any combination of these.

EXAMPLE 3 None of the classification structures in Annex B offer subsidiary tables for tasks.

Actor classification subsidiary tables can be determined by discipline, role or skills or any combination of these.

EXAMPLE 4 Omniclass (Annex B.3) offers subsidiary tables for disciplines and for organizational roles.

Implementation of information structures shall support their application, review and use in practice.

NOTE 1 Information structures can be used independently or in combination, according to the need.

Information structures shall be developed so that:

a) each descendant grouping is characterized by either of:

1) one characteristic relationship;

2) one or more characteristic property value;

b) an object has only one grouping;

EXAMPLE If an object is grouped as an entity, it cannot also be grouped as a complex.

c) each grouping has a short code or name and a descriptive phrase.

d) immediate descendants shall be a manageable number

NOTE 2 The number of immediate descendants is typically not more than 10.

Coding shall support conventional alphanumeric sorting of the tree hierarchy into a sequence using a depth first approach using one of:

a) fixed length codes that sort appropriately;

EXAMPLE 1 AA, BA,CA, …

b) lengthening codes, reflecting the depth in the tree, that sort appropriately;

EXAMPLE 2 A, AA, AB, ABA

c) separately detailed sort order, if the short codes or names are not sortable.

EXAMPLE 3 1, 2, 3 …

Descriptions shall support comprehension and selection by:

a) being unambiguous, avoiding exceptions;

b) being expressed consistently in the plural or singular, describing the set of applicable and selected objects;

c) being self-contained without the need to refer to adjacent or superior descriptions;

d) identifying the determining characteristic(s).

NOTE Singular descriptions, such as ‘door or window’, are more useful when reporting on a single object in isolation, plural descriptions, such as ‘doors and windows’ are more useful when reporting on groups of objects.

Information structures shall:

a) be stable except for extensions and improvements;

b) avoid the re-use of codes;

c) deprecate but not remove superseded entries.

NOTE These steps can simplify the impact of releasing revised versions of information structures.

Guidance on conversion or mapping between information structures shall:

a) use exemplar objects as intermediaries between information structures;

b) record mappings as either uni-directional or bi-directional;

c) explain the equivalence of any relationships or characteristic values.

NOTE Direct conversion between information structures is possible only if the driving properties are closely matched. Otherwise, example objects can often be mapped to multiple classification structures.

Information structures shall be used to support the activities of searching and matching information, sorting and reporting on information and identifying gaps in information.

Classification structures shall be considered for use to aid the managing of libraries and catalogues They shall also be considered for use to aid the managing of information exchanges and information management processes including specifying information requirements, planning information delivery, developing information, checking information and using the information for the intended purposes.

EXAMPLE 1: Classification structures can be organized in support of social development goal, environmental social and governance and triple bottom line reporting.

Breakdown structures and partial breakdown structures shall be considered for use at the portfolio, asset and operational levels to support briefing, design and engineering and construction and operations and way-finding using consistent designations.

EXAMPLE 2: Breakdown structures can be used in tracking the capacity, performance and impacts of assets.

Where possible, classification entries from different tables shall be listed to characterise an object in several ways so as to reduces pressure to over-extend the individual tables and ease search and retrieval tasks.

Short codes from partial breakdown structures, optionally with individual object identifiers, shall be considered for use in combination to generate designations.

NOTE The specific punctuation to be used is defined by standards such as the ISO/IEC 81346 series.

Objects within an application or database shall be classified to a classification structure independent of any modelling platform, using a facetted approach where possible. Where only one classification can be held for each instance then a choice shall be made as to whether to use the relevant grouping or library classification table.

EXAMPLE Replacement management can prefer to use a ‘component’ table, whereas operations management can prefer an ‘element’ table.

NOTE 1 Some legacy facility management systems can only hold a single classification.

NOTE 2 Specialization can be done in different ways, either by replacing an object with another, e.g. an instance of a sub-grouping, or by adding properties to the original object. It can be considered advantageous to keep the original object throughout the full life cycle of the model. For example, a load-bearing wall does not need to be created by instantiation of the group “load-bearing wall” in the model but may instead be specialized by the property “load bearing”.

Any information object belonging to a basic group, such as “wall”, can be given additional properties so that it can receive additional classification, e.g. fire rating class or sound attenuation class.

The properties can be classified within their own classification scheme, e.g. by a faceted classification structure.

The tables proposed in Figure 2 and summarized in Table 1 are the smallest set that spans the built environment domain.

If classification tables other than those described in this document are proposed, they shall be constructed in accordance with ISO 22274, with a supporting documentation which clearly states the sorting criteria.

1. 
   (informative)
   
   Classification table examples
   1. General

The tables titles given in this annex are recommended, but the examples given and their sequence are for information only and are not exhaustive.

• 1. Information

These can be classified by any combination of:

— content;

— form.

The following are examples of groupings by content:

— agreement, minutes, geometry, specification.

The following are examples of groupings by form: text, data, drawing, model.

NOTE Classification of metadata is given in the IEC 82045 series.

• 1. Components

These can be classified by any combination of:

— function;

— form;

— material;

— user;

— medium (air/water/gas/oil etc).

The following are examples of groupings by combination of function and form:

— ground treatment and retention products;

— structural and space division products;

— wall technical system (assembly, construction);

— access, barrier, and circulation products;

— covering, cladding, lining products;

— general purpose civil engineering and construction fabric products;

— services products;

— fixtures and furnishing products.

The following are examples of groupings by material:

— wood products;

— stone products;

— cement-based products;

— metal products;

— plastic products;

— glass products;

— composite products.

The following are examples of groupings by user:

— maintenance walkway;

— pedestrian lighting.

The following are examples of groupings by medium:

— gas boiler;

— water heater.

• 1. Actors

These can be classified by any combination of:

— discipline;

— role.

The following are examples of groupings by discipline:

— architecture;

— structural engineering;

— civil engineering;

— services engineering;

— project management;

— IT management;

— real estate agency;

— financing;

— building regulatory compliance;

— urban planning;

— facilities management;

— commissioning;

— product design.

The following are examples of groupings by role:

— client;

— administrator;

— main contractor;

— sub-contractor;

— supplier;

— fabricator;

— manufacturer;

— designer;

— project manager;

— construction manager;

— quality controller;

— safety coordinator;

— supervisor.

• 1. Aids

These can be classified by any combination of:

— function;

— form;

— material;

— permanence.

The following are examples of groupings by combination:

— ground water lowering plant, contractor’s pumps;

— steel reinforcement cutting and bending plant and equipment;

— formwork and scaffolding;

— lifting appliances and conveyors;

— excavators, crawler and wheeled loaders, scrapers, bulldozers and graders;

— drafting equipment;

— model-making equipment;

— computers and ancillaries;

— maintenance tools;

— explosives;

— document copying equipment;

— 3D printers;

— portable production aids;

— ephemerals.

• 1. Management

The following are examples of groupings by management activity:

— administrative management;

— financial management;

— personnel management;

— marketing/sales management;

— project management;

— risk management;

— cost management;

— time management.

• 1. Tasks

These can be classified by any combination of:

— activity;

— life cycle stage;

— material.

The following are examples of groupings by construction task:

— inception;

— procurement planning;

— feasibility study;

— development of business case;

— briefing;

— design competition;

— outline proposals, programme preparation;

— scheme design/costing;

— detail design/costing;

— production information and bills of quantities preparation;

— tender action;

— construction preparation (mobilization);

— construction operations on site;

— completion;

— refurbishment, alteration and recommissioning;

— decommissioning/demolition;

— feedback.

The following are examples of groupings by life cycle stage:

— pre-design;

— design;

— production;

— maintenance.

The following are examples of groupings by material:

— concrete erection;

— steel erection.

• 1. Complexes

These can be classified by any combination of:

— function;

— form;

— user activity.

The following are examples of groupings by combination:

— transport complexes;

— public health complexes;

— industrial complexes;

— administrative complexes;

— health, welfare complexes;

— refreshment complexes;

— entertainment complexes;

— sports complexes;

— educational complexes;

— residential complexes.

• 1. Entities

These can be classified by any combination of:

— function;

— form;

— user activity.

The following are examples of groupings by form:

— buildings;

— prefabricated buildings;

— roads;

— railways;

— landscapes

— tunnels;

— embankments;

— retaining walls;

— tanks;

— bridges;

— masts;

— pipe ways.

The following are examples of groupings by combination of form and function and user activity:

— hospital buildings;

— footbridges;

— railway embankments;

— airport terminal buildings;

— school buildings;

— sports grounds;

— houses;

— residential buildings;

— car traffic roadways;

— tram track ways;

— waste water pipe ways.

• 1. Spaces

Spaces can be classified by any combination of:

— function;

— form;

— user activity.

The following are examples of groupings by function:

— space for human activity:

— space for living;

— space for sanitary;

— space for isolation;

— space for work;

— space for production;

— space for expression;

— space for gathering;

— space for storage:

— space for materials;

— space for equipment;

— space for animals;

— space for plants;

— space for technical systems:

— space for operational technique;

— space for production equipment;

— space for infrastructure:

— space for connecting spaces;

— space for routing;

— space for transportation.

The following are examples of groupings by combination:

— office spaces;

— operating theatres;

— hospital wards;

— consulting rooms;

— sick bays;

— canteens;

— auditoria;

— amphitheatres;

— sports stadium;

— living room;

— bedrooms;

— turnabout;

— roadways;

— corridors.

• 1. Elements

These can be classified by any combination of:

— function;

— form;

— position.

The following are examples of groupings by function:

— floor system;

— wall c system;

— roof system;

— water system;

— cooling system;

— ventilation system;

— power system;

— garbage system;

— transportation system;

— fire protection system;

— storage system;

— planting system;

— furniture system.

The following are examples of groupings by combination of position and form:

— substructure:

— pile;

— foundation masonry;

— natural ground;

— superstructure:

— road embankment;

— road pavement;

— railway tracks;

— slab;

— wall;

— beam;

— column;

— window;

— roof;

— furniture.

• 1. Package

These can be classified by any combination of:

— work activity;

— resources.

The following are examples of groupings by work activity and resources used:

— pre-design packages for complexes, entities and components:

— inception;

— procurement plan;

— feasibility study;

— business case;

— brief;

— design packages for complexes, entities and components:

— design competition result;

— outline proposal, programme;

— scheme design/cost;

— detail design/cost;

— production information and bills of quantities;

— production packages for complexes, entities and components:

— excavation and filling;

— ground anchoring;

— brick and block walling;

— structural precast concrete;

— stone slab cladding;

— mastic asphalt roofing;

— curtain walling;

— raised access flooring;

— ceramic wall and floor tiling;

— drainage below ground;

— low temperature hot water heating;

— fire sprinklers;

— emergency lighting;

— lift installations;

— maintenance packages for complexes, entities and components:

— maintained entity;

— refurbished or altered entity;

— decommissioned or demolished entity.

• 1. Properties

These can be classified by the property type.

— intrinsic properties

— extrinsic properties

The following are examples of intrinsic properties:

— physical properties:

— functional properties:

— structural performance;

— mechanical operation;

— fire performance;

— thermal performance;

— environmental impact;

— acoustic performance;

— process performance, e.g. efficiency;

— spatial and temporal properties:

— shape, size;

— time, e.g. duration, lead time, priority;

— compositional (internal) properties:

— methods of assembly and disassembly;

— weight, density;

— surface structure;

— behaviour;

The following are examples of extrinsic properties:

— experiential properties:

— colour;

— loudness;

— comfort;

— symbolizing properties:

— meaning;

— inscription;

— administrative properties:

— name;

— style;

— class;

— price;

— metadata.

• 1. Zones

These can be classified by:

— user;

— service provision.

The following are examples of groupings by user:

— public realm;

— escorted realm;

— private realm.

The following are examples of groupings by service provision:

— cooling zone;

— compartmentation zone.

• 1. Uncertainties

These can be classified by:

— causal objects;

— uncertain object (hazard or option);

— affected objects and outcomes.

The following are examples of groupings by causal objects:

— asbestos;

— working at height.

The following are examples of groupings by uncertain objects or outcomes:

— fall;

— material selection.

The following are examples of groupings by affected objects:

— air quality;

— thermal performance.

• 1. Information Purposes

These can be classified by:

— functional intention, use-cases;

— management controls;

— operational actions.

The following are examples of groupings by functional intention, use-cases (outputs, outcomes):

— models;

— social, political and economic assessments.

The following are examples of groupings by management controls

— data compliance and business rules;

— shape and positioning completeness.

The following are examples of groupings by operational actions:

— identification;

— grouping.

NOTE ISO 12911:2023^[9] Annex A gives a classification of information purposes by function, management and operations.

1. 
   (informative)
   
   Example breakdown and classification structures
   1. Industry Foundation Classes (IFC)

IFC is a data schema defined in ISO16739-1 (see reference [8]). IFC uses classification to enrich the sematic meaning of objects beyond the basic object names and sub-types within IFC. Classification can be added as additional objects which relate to any of the items named in Figure B.1. IfcClassification provides the information about the classification structure and table and IfcClassificationReference provides information about the entry.

Key

Figure B.1 — ISO 16739-1 IFC

• 1. Reference designation system for construction works (RDS-CW)

RDS-CW is defined in reference [4]. See Figure B.2.

Key

A activity space

B built space

C construction complex

D construction aid

E construction entity

G construction agent

L construction element

P construction product

R construction process

S storey

Z zone

^a Components can initially be considered as resources.

^b Information can ultimately be considered as an asset.

Figure B.2 —ISO/IEC 81346-12

• 1. Omniclass

Omniclass is described in Reference [18]. See also Figure B.3.

Key

Figure B.3 — Omniclass

• 1. Uniclass

Uniclass is described in Reference [19]. See also Figure B.4.

Key

Figure B.4 — Uniclass

• 1. CoClass

CoClass is defined in Reference [11]. See also Figure B.5.

Key

BX construction complex

BV construction entity

UT space

FS functional system

KS constructive system

KO components

PR work results

AK activities

FA maintenance activities

^a Components can initially be considered as resources.

^b Information can ultimately be considered as an asset.

Figure B.5 — CoClass

• 1. CCI

CCI is defined in Reference [15]. See also Figure B.6.

Key

CC construction complex

CE construction entity

CS space

CF functional system

CT technical system

CO components

^a Components can initially be considered as resources.

^b Information can ultimately be considered as an asset.

Figure B.6 — CCI

• 1. NL/SfB

NL/SfB is described in Reference [20]. See also Figure B.7.

Key

0 spatial facilities (building) 0-9

1 functional building elements (building part) 0-9

2 construction methods (manufacturing system) 0-9

3 construction resources (building materials) A-Za-z

4 activities, features and properties A-Z

^a Components can initially be considered as resources.

^b Information can ultimately be considered as an asset.

Figure B.7 — NL/SfB

1. 
   (informative)
   
   Correspondence between table names used in this document and in the previous edition.

This annex provides in table C.1 the table names specified in this standard aligned with the table names used in previous editions along with the Annex A clauses used in both.

Table C.1 — Summary of table names in this and previous editions

Bibliography

[1] ISO 12006‑3, Building construction — Organization of information about construction works — Part 3: Framework for object-oriented information

[2] ISO 22263, Organization of information about construction works — Framework for management of project information

[3] ISO/IEC/IEEE 15288, Systems and software engineering — System life cycle processes

[4] ISO/IEC 81346, Industrial systems, installations and equipment and industrial products – Structuring principles and reference designations

[5] IEC 82045 (all parts), — Document management

[6] ISO 704, Terminology work — Principles and methods

[7] ISO 1087:2019, Terminology work and terminology science — Vocabulary

[8] ISO 16739‑1, Industry Foundation Classes (IFC) for data sharing in the construction and facility management industries — Part 1: Data schema

[9] ISO 12911:2023, Organization and digitization of information about buildings and civil engineering works, including building information modelling (BIM) — Framework for specification of BIM implementation

[10] ISO 55000:2024, Asset management — Vocabulary, overview and principles

[11] ISO 9000:2015, Quality management systems — Fundamentals and vocabulary

[12] ISO 6707‑1:2020, Buildings and civil engineering works — Vocabulary — Part 1: General terms

[13] ISO 6707‑2:2017, Buildings and civil engineering works — Vocabulary — Part 2: Contract and communication terms

[14] ISO 4157‑1, Construction drawings — Designation systems — Part 1: Buildings and parts of buildings

[15] CCI https://cci-collaboration.org

[16] CoClass https://byggtjanst.se/tjanster/coclass/

[17] Omniclass https://www.csiresources.org/standards/omniclass

[18] Uniclass https://www.thenbs.com/our-tools/uniclass

[19] NL/SfB https://www.bimloket.nl/p/542/NLSfB