ISO 81346-10:2022

Industrial systems, installations and equipment and industrial products - Structuring principles and reference designation - Part 10: Power supply systems

ISO 81346-10:2022 This document provides rules for structuring of systems in the domain of power supply systems, being supplementary to the general principles for the structuring of systems including structuring of information about systems specified in IEC 81346-1.
Based on these principles, rules and guidance are given for the formulation of unambiguous reference designations for objects in any system.
The reference designation identifies objects for the purpose of creation and retrieval of information about an object and, where realized, about its corresponding component.
A reference designation labelled at a component is the key to finding information about that object among different kinds of documents.
The principles are general and are applicable to all technical areas (e.g. mechanical engineering, electrical engineering, construction engineering, process engineering). They can be used for systems based on different technologies or for systems combining several technologies.
This document also defines classes for systems and spaces in the field of power supply systems.

General Information

• Status: Published
• Publication Date: 31-Jul-2022
• ICS: 01.110 - Technical product documentation
• Technical Committee: TC 3 - Documentation, graphical symbols and representations of technical information
• Drafting Committee: JWG 24 - TC 3/JWG 24
• Current Stage: PPUB - Publication issued
• Start Date: 12-Aug-2022
• Completion Date: 17-Oct-2022

Relations

• Replaces: ISO TS 81346-10:2015 - Industrial systems, installations and equipment and industrial products - Structuring principles and reference designation - Part 10: Power plants
• Effective Date: 05-Sep-2023

Overview

ISO 81346-10:2022 specifies structuring principles and a reference designation system for power supply systems (RDS-PS). Supplementary to the general rules in IEC/ISO 81346-1, this part focuses on power generation, transmission, distribution and related assets. It provides rules and guidance for forming unambiguous reference designations that identify objects (systems, components, spaces, locations) for the purpose of creating, retrieving and linking information across documents and life‑cycle activities.

Key topics and requirements

• Scope and concepts: Defines core concepts used in RDS-PS - object, aspect, system, function, product/component, location and type - tailored to power supply domains (generation plants, substations, storage, renewables).
• Structuring principles: Guidance for building structures using single or multiple aspects (function‑oriented, product‑oriented, location‑oriented, type‑oriented or combined aspects) to represent systems consistently.
• Reference designation construction: Rules for forming single‑level and multi‑level designations, use of letter codes, and management of different structures within the same aspect.
• Reference designation set & presentation: Requirements for maintaining a designation set, labeling components, designating locations and presenting designations in documentation.
• Properties and application: How designations map to object properties and how to apply the system across planning, erection, operation and maintenance.
• Annexes: Normative letter code classifications for systems and constructions (Annex B/C), informative examples (Annex D) and mapping from ISO/TS 81346-10:2015 (Annex E).

Practical applications and users

ISO 81346-10:2022 is practical for organizations that need consistent identification and information retrieval across the lifecycle of power assets, including:

• Power plant designers and electrical engineers
• Utilities and grid operators (generation, transmission, distribution)
• EPC contractors and system integrators
• Asset managers, maintenance teams and operators
• Document controllers, technical authors and BIM/asset information managers
• Software vendors for asset management, CMMS and digital twin platforms

Benefits include clearer documentation, improved cross‑discipline integration, faster information retrieval, consistent labeling for maintenance and regulatory records, and better support for digitalization and lifecycle data management.

Related standards

• IEC/ISO 81346-1 (general structuring and reference designation principles)
• ISO 81346-12 (construction works / RDS‑CW) - harmonization for built environments
• ISO 81346 series (other domain‑specific parts)
• Replaces ISO/TS 81346-10:2015 (mapping provided in Annex E)

Keywords: ISO 81346-10:2022, RDS-PS, reference designation, power supply systems, structuring principles, IEC 81346-1, asset management, power generation, transmission, distribution.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 81346-10
First edition
2022-08
Industrial systems, installations and
equipment and industrial products —
Structuring principles and reference
designations —
Part 10:
Power supply systems
Systèmes industriels, installations et appareils, et produits
industriels — Principes de structuration et désignations de
référence —
Partie 10: Centrales électriques
Reference number
© ISO 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .v
Introduction . vi
1 S c op e . 1
2 N or m at i ve r ef er enc e s . 1
3 Terms and definitions . 1
4 C onc ep t s . 3
4.1 General . 3
4 . 2 Obje c t . 3
4 . 3 A sp e c t . 3
4.4 Systems . 3
4.4.1 General . 3
4.4.2 Power supply systems . 3
4.4.3 Technical systems . 4
4.4.4 C omponent systems . . 4
4 . 5 S t r uc t u r i n g . 4
4 . 6 F u nc t ion . 4
4.7 Products and components . 4
4 . 8 L o c at ion . 4
4.8.1 General . 4
4.8.2 Construction complexes . 4
4 . 8 . 3 C on s t r uc t ion ent it ie s . 5
4 . 8 .4 C on s t r uc t ion s p ac e s . 5
4.9 T ypes . 5
4.10 O bject occurrences and product individuals . 5
4.11 R elations between concepts . 5
4.12 Ma n a gement a s p e c t . 5
5 S t r uc t u r i n g pr i nc iple s. 5
5.1 G eneral . 5
5 . 2 F or m i n g s t r uc t u r e s . 5
5 . 3 F u nc t ion- or ient e d s t r uc t u r e . 6
5 .4 P r o duc t- or ient e d s t r uc t u r e. 6
5 . 5 L o c at ion- or ient e d s t r uc t u r e . 6
5.6 T ype-oriented structure . 6
5.7 S tructures based on “other aspects” . 7
5.8 S tructures based on more than one aspect . 7
6 Construction of reference designations . 7
6.1 General . 7
6.2 F ormat of reference designations . 7
6 . 2 .1 Si n g le le vel . 7
6. 2. 2 M ul t i-le vel . 7
6.2.3 U se of letter codes . 7
6.3 D ifferent structures within the same aspect . 10
7 Re ference designation set .10
8 Designation of locations .11
9 P resentation of reference designations .11
10 L ab el l i n g .11
11 Designation of properties .11
12 Application of the reference designation system .12
13 A pplication of annexes in IEC 81346-1 .14
iii
Annex A (informative) Application of annexes in IEC 81346-1 .15
Annex B (normative) Classification letter codes for systems .16
Annex C (normative) Classification letter codes for constructions .22
Annex D (informative) Examples of application .35
Annex E (informative) Mapping of letter codes between ISO/TS 81346-10:2015 and this
document .39
Bibliography . 44
iv
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 documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
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 10, Technical product documentation,
Subcommittee SC 10, Process plant documentation, in cooperation with the Technical Committee
IEC/TC 3, Information structures and elements, identification and marking principles, documentation and
graphical symbols.
This document cancels and replaces ISO/TS 81346-10:2015, which has been technically revised.
The main changes are as follows:
— converted to an International Standard;
— structure adapted to that of IEC 81346-1;
— only requirements constituting a modification or addition to those of IEC 81346-1 have been
included;
— reference is made to ISO 81346-12, with which this document is intended to be used, if needed;
— the abbreviation RDS-PS is introduced for reference designation system for power supply systems,
providing an identifier to reference designation systems according to this document.
Documents in the 80000 to 89999 range of reference numbers are developed by collaboration between
ISO and IEC.
A list of all parts in the ISO 81346 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.
v
Introduction
This document considers and supports planning, erection, utilization and operation of power supply
systems. The application of a reference designation system for power supply systems (RDS-PS) can
lead to restructuring and reorientation of these activities and thereby offers chances and potential of
increasing efficiency and economization.
This document has shifted from the focus of the previous technical specification (ISO/TS 81346-10:2015),
where fixed syntax and focus on coding mechanism were dominant, towards full flexibility in dividing
systems into system elements in a non-fixed manner (i.e. no fixed syntax), using one or more aspects
at the same time to designate objects of interest. Locations can also be designated accordingly
in order to reference the location of objects. Annex E provides a mapping of letter codes between
ISO/TS 81346-10:2015 and this document.
Furthermore, this document is aligned with ISO 81346-12 for construction works (referred to as RDS-
CW), in order to support harmonization of methods and principles for forming reference designations
across the industry-specific applications of the ISO 81346 series.
The following advantages of designation systems in accordance with this document and the
IEC/ISO 81346 series in general will become increasingly important in the future. The following should
be noted:
— The reference designation system can be applied in several technical fields in the same way and is
not designed for one field only. Therefore, process, mechanical, electrical and structural design, for
example, can be treated in the same way, which is a basis for company-wide synergy effects.
— The reference designation system allows for integrating any kind of systems and components
without changing the once-defined designations.
— The reference designation is not bound to a fixed structural pattern. Thus, the designation system
is vertically and horizontally expansible, which can make the interpretability in some cases quite
complex. Therefore, an exact documentation and description of the designation system is important
when it is applied.
— The application of different aspects allows for the designation of system elements by function,
realizing products or location independently of each other.
— The different aspects used for structuring and the possibility of creating relations between objects
represented in these structures offer search and filter criteria and information correlations in a
much greater variety than before.
The users of this document will be able to manage objects and related properties in a more efficient and
consistent way. When implemented, information across various data processing systems can be handled
in an unambiguous way. Other information structures besides those described in this document are:
— organization structures;
— utilization structures;
— cost structures;
— performance structures;
— real estate structures.
This document is applicable for all types of assets used for energy conversion and provision to
transmission, distribution or local energy networks, for example:
— large central conventional or renewable power generation systems
— thermal power plants;
vi
— hydropower plants;
— nuclear power plants;
— onshore and offshore wind farms;
— photovoltaic and solar power plants;
— geothermal plants;
— distributed and/or renewable energy resources
— wind turbine generators;
— diesel and gas generators;
— photovoltaic, solar thermal and combined heat and power (CHP) units;
— generation from combustible renewables;
— storage or a combination of storage technologies
— thermal storage;
— electrochemical storage;
— electrical storage;
— mechanical storage;
— power to X technologies
— power to gas;
— power to liquid;
— power to heat;
— transmission and distribution systems, including technical equipment provided by such systems.
New technologies with the purpose of reducing CO emissions, such as coal gasification, air separation
and amine scrubbing, are also covered by this document. It applies, furthermore, to digital process
control systems, operational management systems (e.g. asset management systems and virtual power
plants used for demand response or aggregation) and the designation of related application software.
Due to the natural diversification of international energy infrastructures, this document will enable
and support the establishment of regional or branch-specific application profiles in order to provide the
required level of interoperability of designations among different stakeholder groups.
vii
INTERNATIONAL STANDARD ISO 81346-10:2022(E)
Industrial systems, installations and equipment and
industrial products — Structuring principles and reference
designations —
Part 10:
Power supply systems
1 S cope
This document provides rules for structuring of systems in the domain of power supply systems,
being supplementary to the general principles for the structuring of systems including structuring of
information about systems specified in IEC 81346-1.
Based on these principles, rules and guidance are given for the formulation of unambiguous reference
designations for objects in any system.
The reference designation identifies objects for the purpose of creation and retrieval of information
about an object and, where realized, about its corresponding component.
A reference designation labelled at a component is the key to finding information about that object
among different kinds of documents.
The principles are general and are applicable to all technical areas (e.g. mechanical engineering,
electrical engineering, construction engineering, process engineering). They can be used for systems
based on different technologies or for systems combining several technologies.
This document also defines classes for systems and spaces in the field of power supply systems.
2 Normat ive references
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 81346-1:2022, Industrial systems, installations and equipment and industrial products — Structuring
principles and reference designations — Part 1: Basic rules
IEC 81346-2:2019, Industrial systems, installations and equipment and industrial products — Structuring
principles and reference designations — Part 2: Classification of objects and codes for classes
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 81346-1 and IEC 81346-2 and
the following 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
building
construction entity (3.3) that has the provision of shelter for its occupants or contents as one of its main
purposes, usually partially or totally enclosed and designed to stand permanently in one place
[SOURCE: ISO 6707-1:2020, 3.1.1.3, modified —works replaced by entity and Note 1 to entry deleted.]
3.2
construction complex
aggregate of one or more construction entities (3.3) intended to serve at least one function or user
activity
[SOURCE: ISO 12006-2:2015, 3.4.1, modified — Note 1 to entry deleted]
3.3
construction entity
independent unit of the built environment with a characteristic form and spatial structure, intended to
serve at least one function or user activity
[SOURCE: ISO 12006-2:2015, 3.4.2, modified — Note 1 to entry deleted]
3.4
component system
system of one or more components providing a fundamental self-contained function
3.5
control
purposeful action on or in a process to meet specified objectives
Note 1 to entry: Actions include measuring, counting, monitoring, indicating, alerting, recording, logging,
manipulating, evaluating, optimizing, intervening and configuring.
[SOURCE: IEC 60050-351:2013, 351-42-19, modified — Note 1 to entry replaced, Note 2 to entry and
Figure 29 deleted.]
3.6
equipment
aggregation of functional elements or assembly of components and modules that belong together in one
physical unit of a plant (3.10) or in a functional unit of a system
[SOURCE: ISO 16484-2:2004, 3.73, modified — Notes 1 and 2 to entry deleted.]
3.7
host installation aspect
location aspect relating objects to locations inside or on a product or product assembly
Note 1 to entry: Product or product assembly is not to be confused with reference designations based on the
product aspect.
3.8
inherent function
function of an object, independent of any application of the object
3.9
power supply system
system representing a process for conversion, transmission and/or distribution of energy
3.10
plant
assembly of different systems on a specific site
[SOURCE: IEC 61355-1:2008, 3.10]
3.11
site of installation aspect
location aspect relating objects to locations inside a space (3.12)
3.12
space
limited three-dimensional extent defined physically or notionally
[SOURCE: ISO 12006-2:2015, 3.1.8]
3.13
technical system
object with characteristics which predominantly represents a coherent technical solution with an
inherent function (3.8)
[SOURCE: ISO 81346-12:2018, 3.21]
3.14
works
system of industrial complexes and the associated infrastructure in one location
4 C oncepts
4.1 General
The requirements of IEC 81346-1:2022, Clause 4, apply.
4.2 Object
The requirements of IEC 81346-1:2022, 4.1, apply.
4.3 Aspect
The requirements of IEC 81346-1:2022, 4.2, apply.
4.4 Systems
4.4.1 General
The requirements of IEC 81346-1:2022, 4.3, apply with the following additions:
In the context of this document, all objects are seen as systems and/or system elements.
The system concept allows a designer to handle wholes (as distinct from parts). By identifying related
systems, the relationships among these can be determined and monitored, for example to ensure that
all systems operate correctly.
Systems and system elements bring together a set of objects for a task that none of the objects can
accomplish on their own.
4.4.2 Power supply systems
Power supply systems are those systems used to convert, transmit, distribute or store energy and to
manage such systems.
Power supply systems shall be classified in accordance with the scheme defined in Annex B, Table B.1.
A power supply system may incorporate another power supply system recursively as one of its elements.
4.4.3 Technical systems
Technical systems are those systems that are not by themselves considered to be power supply systems
but represent technical solutions useful for the realization of a power supply system.
Technical systems shall be classified in accordance with the scheme defined in Annex B, Table B.2.
A technical system may incorporate another technical system recursively as one of its elements.
4.4.4 Component systems
Component systems are systems that are well defined with respect to both their inherent function and
implementation. Component systems are used as part of technical systems and may also be referred to
power supply systems.
Component systems shall be classified in accordance with IEC 81346-2:2019, Table 3.
A component system may incorporate another component system recursively as one of its elements.
4.5 Structuring
The requirements of IEC 81346-1:2022, 4.4, apply.
4.6 Function
The requirements of IEC 81346-1:2022, 4.5, apply.
4.7 Pr oducts and components
The requirements of IEC 81346-1:2022, 4.6, apply.
4.8 Location
4.8.1 General
The requirements of IEC 81346-1:2022, 4.7, apply.
Two different location aspects shall be applied:
— Host installation aspect: this location aspect shall be applied to relate the location of an object to
locations inside or on a product or product assembly.
EXAMPLES Locations within or on a cubicle, a console or a panel.
— Site of installation aspect: this location aspect shall be applied to relate the location of an object to a
location defined inside a larger location, irrespective of the existence of physical objects making up
that larger location.
EXAMPLES A site, a construction complex, a construction entity (a building), a part of a building, a storey, a
room, an outside area, a green area, a park area.
4.8.2 Construction complexes
Construction complexes are spaces which are an aggregation of construction entities in the context
of this document. Construction complexes are used to represent spaces, i.e. locations, within the site
installation aspect.
Classes of construction complexes are shown in Annex C, Table C.1.
A construction complex may recursively incorporate another construction complex as one of its
elements.
4.8.3 Construction entities
A construction entity is an independent unit of a built environment forming a construction complex. In
the context of this document, construction entities are used to represent spaces, i.e. locations, within
the site installation aspect.
Classes of construction entities are shown in Annex C, Table C.2.
A construction entity may recursively incorporate another construction entity as one of its elements.
4.8.4 Construction spaces
Construction spaces are spaces, i.e. locations, within the site installation aspect that are well defined
with respect to their intended use. Construction spaces are used as part of construction entities and
may also be referred to as construction complexes.
Construction spaces shall be classified in accordance with IEC 81346-2:2019, Table 4.
A construction space may recursively incorporate another construction space as one of its elements.
4.9 Types
The requirements of IEC 81346-1:2022, 4.8, apply.
4.10 Object oc currences and product individuals
The requirements of IEC 81346-1:2022, 4.9, apply.
4.11 R elations between concepts
The requirements of IEC 81346-1:2022, 4.10, apply.
4.12 Management aspect
For the purpose of this document, the management aspect signifies an aspect of the considered system
that is not covered by the other aspects defined. The management aspect is used to relate objects within
the considered system to the system independent of any other aspects.
The application of the management aspect shall be explained in supporting documentation. See also
IEC 81346-1:2022, 5.7.
NOTE This aspect was formerly known as the “conjoint aspect”.
5 Str uctur ing princip les
5.1 General
The requirements of IEC 81346-1:2022, 5.1, apply.
5.2 Forming structures
The requirements of IEC 81346-1:2022, 5.2, apply.
5.3 Function-oriented structure
The requirements of IEC 81346-1:2022, 5.3, apply.
A function-oriented structure is important for the full life cycle of a system, for example system design,
design of process and control functions, commissioning and locating failures of functionality, service
operations and optimization works during system operation.
A reference designation based on a function-oriented structure may be shown in any kind of document,
for example an overview diagram, a process diagram, a function diagram or a circuit diagram.
5.4 Product-oriented structure
The requirements of IEC 81346-1:2022, 5.4, apply.
A product can realize one or more functions, for example a heat exchanger can heat or cool, an ornament
can be used for covering and for providing a presentation of some artwork. Several control functions
can be implemented in one control system unit.
A product can, alone or together with others, be located at one or more locations, for example a
measuring system with location of measuring unit and displaying unit or a duct system extended to
several different locations.
For the structuring and assessment of objects in planning and implementation as preparation of the
operation phase, the product-oriented aspect is important, for example for assembling and maintenance.
A reference designation based on a product-oriented structure may be shown in any kind of document,
for example product description, construction drawing, assembly drawing, exploded view drawing,
network part drawing or maintenance instruction. Such a reference designation will only designate the
product occurrence within a system and not the real-world product individual being used.
5.5 Location-oriented structure
The requirements of IEC 81346-1:2022, 5.5, apply.
A location-oriented structure is used for locating objects.
A reference designation based on a location-oriented structure may be shown in any kind of document,
for example a site plan, a floor plan, a sectional drawing, an elevation drawing, a ground plan, an
arrangement drawing or an installation drawing.
The following separate location-oriented structures shall be made, if applicable:
— host installation-oriented structure utilizing the host-installation aspect;
— site installation-oriented structure utilizing the site installation aspect.
A host installation-oriented structure may be based on a coordinate system, a defined grid zone, area
or similar. It may also be based on a physical product, e.g. a cabinet.
5.6 Type-oriented stru cture
The requirements of IEC 81346-1:2022, 5.6, apply.
A type-oriented structure may be used to relate object occurrences to a company's object-type library
or a company's product catalogue (the compilation of information about their products) or to a project-
type library.
A reference designation based on a type-oriented structure may be shown in any kind of document and
is especially applicable to object libraries and bills of quantities.
5.7 Structur es based on “other aspects”
The requirements of IEC 81346-1:2022, 5.7, apply.
A management-oriented structure is based on the subdivision of the system into constituent objects
with respect to the management aspect without taking into account other possible aspects of these
objects.
On a power supply site, it is recognized that different systems, such as generators, switchgears or
buildings, can exist. The management aspect is used to relate these units with respect to the site,
without considering the other aspects defined. The management information aspect is often used as site
reference in asset management systems, where all aspect-related designation structures are related to.
A reference designation based on a management-oriented structure may be shown in any kind of
document.
5.8 Structur es based on more than one aspect
The requirements of IEC 81346-1:2022, 5.8, apply.
6 C onstruction of reference designations
6.1 General
The requirements of IEC 81346-1:2022, 6.1, apply.
6.2 F ormat of reference designations
6.2.1 Single level
The requirements of IEC 81346-1:2022, 6.2.1, apply.
Except for designation of spaces, a single-level reference designation shall be formed by applying the
method of a prefix followed by a letter code followed by a number.
IEC 81346-1:2022, 6.2.1, Rule 7 does not apply. Instead, the following applies:
The prefix signs used to indicate the type of aspect in a reference designation shall be:
a) “=” (EQUALS SIGN) when relating to the function aspect of the object;
b) “‒” (MINUS SIGN) when relating to the product aspect of the object;
c) “+” (PLUS SIGN) when relating to the host installation aspect of the object;
d) “++” (PLUS SIGN, PLUS SIGN) when relating to the site installation aspect of the object;
e) “%” (PERCENT SIGN) when relating to the type aspect of the object;
f) “#” (NUMBER SIGN) when relating to the management aspect of the object.
6.2.2 Multi-level
The requirements of IEC 81346-1:2022, 6.2.2, apply.
6.2.3 Use of letter codes
The requirements of IEC 81346-1:2022, 6.2.3, apply.
Where a two-letter code for a technical system or construction entity is not applicable or possible to
determine, it is recommended that the relevant one-letter code is applied followed by the character “?”
(QUESTION MARK) to indicate a missing sub-class.
Where a three-letter code for a component system or construction space is not applicable or possible to
determine, it is recommended that the relevant one-letter code or two-letter code is applied, followed
by the characters “??” (two QUESTION MARKs) or “?” (QUESTION MARK), respectively, to indicate a
missing sub-class(es).
Figure 1 illustrates the application of the ONE- TWO- and THREE-letter codes related to power supply
systems (ONE), technical systems (TWO) and component systems (THREE). Figure 2 provides the same
illustration related to construction complexes (ONE), construction entities (TWO) and construction
spaces (THREE).
Figure 1 — Classes of power supply, technical and component systems
Figure 2 — Classes of construction complexes, entities and spaces
Annex B for letter codes for classes of power systems or technical systems shall be used for designation
of objects within a function-orientated structure, or product-orientated structure or designation of
types.
See Annex C for letter codes for classes of construction complexes or construction entities to be used
for designation of objects within a location-orientated structure.
Table 1 shows examples of the use of “?” in a letter code, and Table 2 shows examples of reference
designation in accordance with this document.
Table 1 — Example of application of wildcard in selection of a motor
Class designation Object Examples
Electromagnetic rotational driving object (class MA)
MA? Motor of any kind (unspecified)
with no further division of type
Electromagnetic rotational driving object providing
MAA Electric motor, AC motor, DC motor
continuous rotation (class MAA)
Electromagnetic rotational driving object providing
MAB Stepper motor, servo motor
discrete rotational steps (class MAB)
Table 2 — Examples of objects or systems
Object or system Reference designation
Condensate system (derived from Class C “Power supply system = C2
transporting energy or energy carrier”)
Low pressure preheater system 1 = C2 = HD1
Part of condensate system
or
= C2.HD1
Main pump = C1 = KE2 = KE1 = GP?1
Part of feed water pump system 2
or
Part of feed water pump system
= C1.KE2.KE1.GP?1
Part of feed water system
Voltage metering 11 -D1-HD3-BE?11
Part of electrical backup supply system 3
or
Part of internal electrical supply system 1
-D1.HD3.BE?11
Cabinet 1 +D2+HD4+UCA1
Part of 230 V supply system 4
or
Part of electrical auxiliary system 2
+D2.HD4.UCA1
Slot 02 +UCA5+AB+02
Part of top hat rail AB
or
Part of cabinet 5
+UCA5.AB.02
Machine room 1 ++Q1++UH2++DBA1
Part of gate entity 2 or
Part of reservoir complex 1 ++Q1.UH2.DBA1
Annex D provides application examples of reference designations for power supply systems.
Rule 15 c) of IEC 81346-1:2022, 6.2.3 does not apply. Instead, the following applies.
Letter codes indicating the class of power supply systems shall be selected from Table B.1.
Letter codes indicating the class of technical systems shall be selected from Table B.2, preferably
applying the two-letter codes.
Letter codes indicating the class of components systems shall be selected from IEC 81346-2:2019,
Table 3, preferably applying the three-letter codes.
Letter codes indicating the class of construction complexes shall be selected from Table C.1.
Letter codes indicating the class of construction entities shall be selected from Table C.2, preferably
applying the two-letter codes.
Letter codes indicating the class of construction spaces shall be selected from IEC 81346-2:2019,
Table 4, preferably applying the three-letter codes.
6.3 Differ ent structures within the same aspect
The requirements of IEC 81346-1:2022, 6.3, apply.
7 R eference designation set
The requirements of IEC 81346-1:2022, Clause 7, apply.
A reference designation set is useful where a supplier with no knowledge of the further functional use
by the client can decide to designate the product(s) by making a product structure based on the product
aspect only, and thereby disregard the functionality of the system delivered. The client's general
engineering can designate the system by the functional aspect independently of the solution made.
Figure 3 shows an example of an electrical diagram where the manufacturer of the switchboard has
designated the components by single level reference designations using the product aspect (e.g. -FCB4)
irrespective of the functionality they form part of, whereas the functionality the components form part
of is designated with multi-level reference designations (e.g. = C2.HD1.FCB1). Figure 3 shows that one
object (e.g. a circuit breaker) has multiple reference designations, here: (=) and (-), put together as a
reference designation set.
NOTE Further information can be found in IEC 61082-1:2014, 5.20.1 and Figure 17 and ISO 15519-1:2010,
7.2.4 and Figure 6.
NOTE The sign “>” (greater than) implies that the reference designation is complete and not to be
concatenated to any other reference designations in the actual presentation, see IEC 81346-1.
Figure 3 — Reference using two aspects (=) and (-) for designation
8 De signation of locations
The requirements of IEC 81346-1:2022, Clause 8, apply.
9 Pr esentation of reference designations
The requirements of IEC 81346-1:2022, Clause 9, apply.
10 Labelling
The requirements of IEC 81346-1:2022, Clause 10, apply.
11 De signation of properties
The requirements of IEC 81346-1:2022, Clause 11, apply.
Table 3 illustrates how properties of objects relevant within the domain of power supply systems can
be designated.
Table 3 — Examples of how to add properties
Property data and Reference designation with
Object Property
reference property information
Turbine no. 1 Power rating 750 kW %RB1 (750 kW)
Preheater no. 1 Heating capacity 73 MW %HE1 (73 MW)
3 3
Pump no. 2 Capacity (pressure, volume flow) 400 bar, 1 m /s = GPA02 (400 bar, 1 m /s)
12 A pplication of the reference designation system
The requirements of IEC 81346-1:2022, Clause 12, apply.
The reference designation system allows the same object to be designated based on viewing the
objects using different or multiple aspects. It is even possible to apply different application parts of the
IEC/ISO 81346 series for defining those reference designations or to apply different application parts
for different parts of the system considered.
In the context of this document, the application of ISO 81346-12 (RDS-CW) should be used for all
systems belonging to the construction works domain. This includes buildings, general housing, garages
and workshops, roads and access tunnels. It also includes dam constructions, but not key systems for
the power generation process within the dam (e.g. floodgates) as these shall be considered part of the
supply or storage system, as they are a sub-function of the reservoir system.
Where reference designations according to RDS-CW are used, these should be formed by applying a
top-node identifier in accordance with IEC 81346-1:2022, 6.3, see Figure 4.
Figure 4 shows an example where a dam is used to make the reservoir used in the process of producing
electrical energy by hydro power. At the same time, from another point of view, the dam is a wall with
design parameters allocated to it. However, the sluice which controls the flow of water is both a part of
the production process and built into the dam physically.
Based on the classification scheme of RDS, a dam is classified as a wall in RDS-CW and a reservoir is
classified as an open tank in RDS-PS. RDS thus offers the product aspect to structure the construction
works of the dam itself (as a product), including walls, decks, gangways and lighting, but also the sluice
gates built into
...