ISO/TS 81346-10:2015

TECHNICAL ISO/TS
SPECIFICATION 81346-10
First edition
2015-02-15
Industrial systems, installations and
equipment and industrial products —
Structuring principles and reference
designation —
Part 10:
Power plants
Systèmes industriels, installations et appareils et produits
industriels — Principes de structuration et désignation de
référence —
Partie 10: Centrales électriques
Reference number
©
ISO 2015
© ISO 2015
All rights reserved. Unless otherwise specified, 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
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2015 – All rights reserved

Contents Page
Foreword .iv
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Designation systematic . 5
4.1 General . 5
4.2 Process of forming designations . 5
4.3 General rules for designation structure . 6
4.4 Rules for forming designations . 7
5 Designation tasks. 8
5.1 General . 8
5.2 Conjoint designation . 8
5.3 Designation of technical objects — Reference designation . 9
5.3.1 General. 9
5.3.2 Function aspect . 9
5.3.3 Product aspect .10
5.3.4 Transition from function aspect to product aspect .10
5.3.5 Location aspect .11
5.4 Specific designations .11
5.4.1 Signal designation .11
5.4.2 Terminal designation .11
5.4.3 Document designation .12
6 Structure and contents of designation blocks .12
6.1 General .12
6.2 Designation block “Conjoint designation” .12
6.3 Function aspect.12
6.3.1 Designation block “Function”.12
6.3.2 Designation block “Function allocation” .13
6.4 Product aspect — Designation block “Product” .14
6.5 Transition from function aspect to product aspect .15
6.6 Location aspect .19
6.6.1 Designation block “Point of installation” .19
6.6.2 Designation block “Location” .21
6.7 Specific designations .22
6.7.1 Signal designation .22
6.7.2 Terminal designation .25
6.7.3 Document designation .26
7 Application of designation .26
7.1 Combination of designation blocks .26
7.2 Designation notation .27
7.2.1 General.27
7.2.2 Notation in technical documents .27
7.2.3 Notation in the plant . .28
Annex A (normative) Representation of designations.29
Annex B (normative) Special stipulations .31
Annex C (informative) Stipulations between parties to the project .35
Annex D (informative) Application examples .36
Bibliography .44
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International
Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies
casting a vote.
In other circumstances, particularly when there is an urgent market requirement for such documents, a
technical committee may decide to publish other types of normative document:
— an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical
experts in an ISO working group and is accepted for publication if it is approved by more than 50 %
of the members of the parent committee casting a vote;
— an ISO Technical Specification (ISO/TS) represents an agreement between the members of a
technical committee and is accepted for publication if it is approved by 2/3 of the members of the
committee casting a vote.
An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for
a further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or
ISO/TS is confirmed, it is reviewed again after a further three years, at which time it must either be
transformed into an International Standard or be withdrawn.
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.
ISO/TS 81346-10 was prepared by Technical Committee ISO/TC 10, Technical product documentation,
Subcommittee SC 10, Process plant documentation and tpd-symbols.
Documents in the 80000 to 89999 range of reference numbers are developed by collaboration between
ISO and IEC.
ISO 81346 consists of the following parts, under the general title Industrial systems, installations and
equipment and industrial products — Structuring principles and reference designation:
— Part 3: Application rules for a reference designation system [Technical Specification]
— Part 10: Power plants [Technical Specification]
IEC 81346 consists of the following parts, under the general title Industrial systems, installations and
equipment and industrial products — Structuring principles and reference designation:
— Part 1: Basic rules
— Part 2: Classification of objects and codes for classes
Further parts on sector-specific rules are under consideration.
iv © ISO 2015 – All rights reserved

NOTE ISO/TC 10/SC 10 and IEC/TC 3 have agreed to integrate their publications on structuring principles and
reference designation in the ISO/IEC 81346 series to ensure a consistent set of publications based on IEC 81346–1
and −2. Against this background, ISO/TS 16952-10 has been converted to ISO/TS 81346-10 following its systematic
review. At this time, apart from necessary updates, no further changes have been made. Among the issues to be
considered at the next review/revision is how to make the referenced VGB publications, although recognized as
having wide acceptance and authoritative status as well as being publicly available, better accessible to ISO/IEC
users, e.g. by integrating them in the ISO/IEC 81346 series.
Introduction
Based on ISO/TS 81346-3, this part of ISO 81346 serves to designate plants, sections of plants and
items of equipment in any type of installation for industrial production of electrical and thermal energy
according to task, type and location. This sector-specific Reference Designation System (RDS) is intended
for application by all engineering disciplines for the entire life cycle of a plant, from planning, licensing,
construction, operation and maintenance, re-powering, extension and recreation, to dismantling and
demolition. Based on the structuring principles and reference designation rules of IEC 81346 and other
documents, ISO 81346 breaks down these rules into interdisciplinary guidelines for practical application.
The relationships of input documents with this part of ISO 81346 are shown in Figure 1.
Figure 1 — Structuring and designation standards
This part of ISO 81346 establishes the prerequisites for
— uniform designation of all power plant processes (see Figure 2 for a summary of the energy
conversion cycle),
— uniform designation of all power plant types,
— language-independent codes to ensure international applicability,
— adequate capacity and possible detail for designation of all systems, equipment and structures,
— adequate extension possibilities for new technologies,
— consistent designation for planning, licensing, construction, operation, maintenance and
decommissioning,
— common applicability in mechanical, electrical, instrumentation and control (I&C) and civil
engineering, with the simultaneous possibility to designate according to function, product and
location aspects,
vi © ISO 2015 – All rights reserved

— fulfilment of quality management requirements,
— fulfilment of the technical documents management system requirements,
— fulfilment of the requirements for occupational safety and ergonomics.
Figure 2 — Principle of energy conversion including supply and disposal processes
TECHNICAL SPECIFICATION ISO/TS 81346-10:2015(E)
Industrial systems, installations and equipment and
industrial products — Structuring principles and reference
designation —
Part 10:
Power plants
1 Scope
This part of ISO 81346 contains sector-specific stipulations for structuring principles and reference
designation rules on technical products and technical product documentation of power plants.
It applies in combination with IEC 81346-2, ISO/TS 81346-3, VGB-B 101 and VGB-B 102 for the
classification of systems and objects, and for function-, product- and location-specific designation of
technical products and their documentation for power plants.
It specifies the designation blocks for the clear identification and localization of the technical products,
which are used for their labelling in the plant, for their designation in technical documents and for the
designation of the technical documents as well.
This part of ISO 81346 encompasses the process of energy conversion. The specifications in this document
apply for the power plant process, for the primary energy supply and final products distribution, as well
as for auxiliary media and auxiliary energy supply, waste materials and waste energy disposal.
This part of ISO 81346 is not applicable to recovery of the primary energy and the media for supplying
the process, nor to the processing of residues from process disposal (e.g. gypsum, slag products, waste
water, etc.).
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
IEC 60445, Basic and safety principles for man-machine interface, marking and identification — Identification
of equipment terminals and of terminations of certain designated conductors, including general rules of an
alphanumeric system
IEC 61082-1, Preparation of documents used in electrotechnology — Part 1: Rules
IEC 61175, Industrial systems, installations and equipment and industrial products — Designations of
signals
IEC 61355-1, Classification and designation of documents for plants, systems and equipment — Part 1: Rules
and application tables
IEC 61666, Industrial systems, installations and equipment and industrial products — Identification of
terminals within a system
IEC 81346-1, Industrial systems, installations and equipment and industrial products — Structuring
principles and reference designations — Part 1: Basic rules
IEC 81346-2, Industrial systems, installations and equipment and industrial products — Structuring
principles and reference designations — Part 2: Classification of objects and codes for classes
ISO/TS 81346-3:2012, Industrial systems, installations and equipment and industrial products —
Structuring principles and reference designations — Part 3: Application rules for a reference designation
system
EN 50005, Low Voltage Switchgear and Controlgear for Industrial Use — Terminal Marking and Distinctive
Number — General Rules
VGB-B 101, Reference designation system for power plants (RDS-PP) — Letter codes for power plant systems
1)
(system key)
VGB-B 102, Reference designation system for power plants (RDS-PP) — Letter codes for basic functions and
1)
product classes
3 Terms and definitions
For the purpose of this document, the terms and definitions given in ISO/TS 81346-3 and the following
apply.
3.1
ancillary system
system which is not directly required for the power plant process
Note 1 to entry: This includes heating, ventilation, air-conditioning systems, space-heating systems, stationary
compressed air supplies, fire protection systems, cranes, elevators, workshops, staff amenities, etc.
3.2
aspect
specific way of viewing an object
Note 1 to entry: Such ways may be:
— what the system or object is doing (function viewpoint);
— how the system or object is constructed (product viewpoint);
— where the system or object is located (location viewpoint).
[SOURCE: IEC 81346-1:2009, definition 3.3]
3.3
auxiliary system
system which is required for the support of a power plant process
Note 1 to entry: This includes auxiliary steam system, compressed air, carrier air, control air, central chemicals
supply, sampling systems, etc.
3.4
control
purposeful action on or in a process to meet specified objectives
[SOURCE: IEC 60050-351:2013, definition 351-42-19]
Note 1 to entry: This includes measure, count, monitor, indicate, alert, record, log, manipulate, evaluate, optimize,
intervene, manipulate by hand, safeguard, structure, configure, parameter, automate.
3.5
designation block
structured compilation of related information units, consisting of a prefix, letters and numbers, and
optionally a breakdown mark
1)  Source: www.vgb.org.
2 © ISO 2015 – All rights reserved

3.6
document kind class
group of document kinds having similar characteristics concerning the content of information
independent of the form of presentation
[SOURCE: IEC 61355-1:2008, definition 3.7]
3.7
documentation
collection of documents assigned to a specific object
Note 1 to entry: This may include technical, commercial and/or other documents.
[SOURCE: IEC 61082-1:2006, definition 3.1.4]
3.8
functional area
combination of groups and/or elements in a unit that can be used independently
3.9
functional group
combination of elements in a unit that can be used independently
3.10
functional unit
item under consideration defined according to function or effect
Note 1 to entry: A functional unit produces the interactive effect between input variables and output variables.
Note 2 to entry: A functional unit may be implemented by one or several physical units or program modules.
Note 3 to entry: If compound terms are used to designate functional units, the following should be used as the last
word (in ascending order of rank):
— element,
— system.
Note 4 to entry: This entry was numbered 351–32–02 in IEC 60050–351:2006.
[SOURCE: IEC 60050-351:2013, definition 351-56-02]
3.11
multi-level reference designation
reference designation consisting of concatenated single-level reference designations
[SOURCE: IEC 81346-1:2009, definition 3.13]
3.12
object
entity treated in the process of development, implementation, usage and disposal
Note 1 to entry: The entity may refer to a physical or non-physical “thing”, i.e. anything that might exist, exists or
did exist.
Note 2 to entry: The object has information associated to it.
[SOURCE: IEC 81346-1:2009, definition 3.1]
3.13
operating equipment
all products, which serve to implement technical tasks as a whole or in individual parts
3.14
physical unit
item under consideration, defined according to construction or configuration
Note 1 to entry: One or several functional units may be implemented in a single physical unit. The corresponding
functional unit(s) is/are in some cases not explicitly designated.
Note 2 to entry: The various parts of a physical unit need not be functionally interrelated. For example, a physical
unit may be in the form of an integrated circuit with four independent AND modules.
Note 3 to entry: If compound terms are used to designate physical units, the following should be used as the last
word (in ascending order of rank):
— component,
— assembly,
— device,
— plant.
Note 4 to entry: The entry was numbered 351–32–03 in IEC 60050–351:2006.
[SOURCE: IEC 60050-351:2013, definition 351-56-03]
3.15
plant
complete set of technical equipment and facilities for solving a defined technical task
Note 1 to entry: A plant includes apparatus, machines, instruments, devices, means of transportation, control
equipment and other operating equipment.
Note 2 to entry: This entry was numbered 351–21–45 in IEC 60050–351:2006.
[SOURCE: IEC 60050-351:2013, definition 351-42-35]
3.16
plant section
part of a process plant that can, at least occasionally, be operated independently
[SOURCE: ISO 10628:1997, definition 3.7]
3.17
power plant process
process for the generation of electrical energy and/or heat energy products, including the conversion,
supply, and disposal processes
3.18
power plant unit
technical plant including all equipment needed for fulfilment of a power plant process
3.19
system
set of interrelated objects considered in a defined context as a whole and separated from their
environment
Note 1 to entry: A system is generally defined with the view of achieving a given objective, e.g. by performing a
definite function.
Note 2 to entry: Elements of a system may be natural or man-made material objects, as well as modes of thinking
and the results thereof (e.g. form of organization, mathematical methods, programming languages).
Note 3 to entry: The system is considered to be separated from the environment and from the other external
systems by an imaginary surface, which cuts the links between them and the system.
4 © ISO 2015 – All rights reserved

Note 4 to entry: The term “system” should be qualified when it is not clear from the context to what it refers, e.g.
control system, colourimetric system, system of units, transmission system.
Note 5 to entry: When a system is part of another system, it may be considered as an object as defined in this
standard.
[SOURCE: IEC 81346-1:2009, definition 3.2]
3.20
technical equipment
physical or functional unit used to fulfil a technical task
3.21
terminal
point of access to an object intended for connection to an external network
Note 1 to entry: The connection may refer to
a) a physical interface between conductors and/or contacts, or piping and/or duct systems to provide a signal,
energy or material flow path,
b) an association of functional nature established between logical elements, software modules, etc. for
conveying information.
Note 2 to entry: The external networks may be of different nature and accordingly they may be classified.
IEC 81714–3 provides such classifications.
[SOURCE: IEC 61666:2010, definition 3.9]
3.22
works
system of industrial complexes and the associated infrastructure in one location
[SOURCE: ISO 10628:1997, definition 3.4]
4 Designation systematic
4.1 General
The designation systematic has to be understood as a well-organized, methodical process of forming
permanent designations with ergonomic notation according to simple, easily learned rules that are
based on predefined standards.
4.2 Process of forming designations
Starting from site plans, process flow diagrams, overview diagrams, etc., the entire power plant shall be
broken down into plant sections, units and, if necessary, sub-units.
These shall then be further broken down, based on functional aspects, into systems, subsystems and
technical equipment. Consistent compliance with the rule of constituency (an object can contain more
than one sub-objects but is a constituent of one higher object only) shall be ensured. The objects identified
in this way shall be classified based on specified letter codes in accordance with VGB-B 101 for systems
and subsystems and VGB-B 102 for technical objects, and then provided with reference designations. All
information about the object is governed under this designation.
Structuring of location-specific systems (structures, sites, etc.) shall be performed in the same way.
In further processing, the products required for fulfilment of the tasks shall be specified and designated.
The combination of the function and product aspects generates a unique designation.
The results shall be documented.
4.3 General rules for designation structure
The general designation structure corresponds to ISO/TS 81346-3:2012, 6.1. It shall consist of a
maximum of three main parts, see Figure 3.
Figure 3 — Parts of the identifier
The permitted combinations and their sequence are given in Figure 4.
Figure 4 — Permitted combinations of identifier parts
Each of the three identifier parts consists of one or more designation blocks (see Figure 5 and Clause 6).
Each designation block always contains
— a prefix in accordance with Table 1 and
— letters and numbers in accordance with Figure 6.
Figure 5 — Designation block
The designation blocks are distinguished by prefixes and thus uniquely identified. The prefixes are
always the first data characters in the designation blocks.
6 © ISO 2015 – All rights reserved

Table 1 — Prefixes for designation tasks
Prefix
Prefix origin, basic principles
Designation Designation tasks/aspect
specified in
1 2
# Number Conjoint designation ISO/TS 81346-3
= Equals Function-oriented designation IEC 81346–1
= = Equals-Equals Functional allocation ISO/TS 81346-3
+ Plus Point of installation IEC 81346–1
+ + Plus-Plus Location ISO/TS 81346-3
− Minus Product-oriented designation IEC 81346–1
: Colon Terminal designation IEC 61666
; Semicolon Signal designation IEC 61175
& Ampersand Document designation IEC 61355–1
The letter codes and numbers in the designation blocks are subdivided into breakdown levels, sections
and data characters as the smallest information unit.
The letters classify an object and are specified as letter codes in the corresponding tables (see VGB-B 101
and VGB-B 102).
The numbers are used to distinguish between objects with the same letter code, if they are constituents
of the same object.
The basic structure is shown in Figure 6. Details of the individual designation blocks are specified in
Clause 6.
Key
A Letter
N Number
Figure 6 — Basic structure of the designation part of a designation block
4.4 Rules for forming designations
— Rule 1: Each object can be viewed in one or more ways called aspects (see 5.3.1). The considered aspect
is indicated by a prefix (see Table 1). The prefix shall be written always when a misinterpretation of
the aspect is possible.
— Rule 2: Sections at the beginning and/or at the end of a designation block may be omitted.
— Rule 3: Only the transition from the function aspect to the product aspect is allowed.
— Rule 4: Designation of operating equipment shall be achieved exclusively by the transition from the
functional aspect to the product aspect. The location-oriented designation carries the allocation
information only.
— Rule 5: When designation blocks are combined, the prefix of the block that is the furthest to the
right (smallest object of consideration) shall determine the aspect of the entire designation.
— Rule 6: The structure within an aspect shall comply with the principle of constituency in accordance
with IEC 81346-1. Each object has only one predecessor, but can have one or more successors.
— Rule 7: Information regarding the installation and location of an object as well as the interaction
of the object in the power plant process shall be represented by attaching the designations “+ point
of installation”, “++ location” and “== functional allocation” respectively as a separate additional
designation.
— Rule 8: The multi-level reference designations shall be presented in designation blocks with a fixed
structure. The designation blocks shall be identified with regard to their aspect by prefixes, which
have their own data character positions.
— Rule 9: Each designation section shall consist of a maximum of three data characters, but not all
of these need to be written, depending on the application. The sections shall be structured with
alternating alphabetic (A) and numeric (N) characters.
— Rule 10: The letter codes from VGB-B 101 and VGB-B 102 shall be used for the classification of
objects. Only Roman capitals from A to Z, with the exception of “I” and “O”, are permitted; country-
specific letters and mnemonic assignments shall be avoided.
— Rule 11: Arabic numerals “1” to “9” and “0” (zero) shall be used for numerical data characters;
numbers shall be written with leading zeros.
— Rule 12: For certain designation blocks between breakdown levels, the breakdown mark “.” (full
stop) with its own data position shall be applied. In this case Rule 2 shall apply for each part of the
designation block on the left and on the right side of the breakdown mark.
5 Designation tasks
5.1 General
The designation system for power plants shall fulfil the following main tasks:
a) unambiguous identification of the technical objects and documents;
b) classification of objects according to their purpose, task or composition;
c) coded representation of technical structures;
d) coded representation of networked relationships.
This enables the designation of the following:
— conjoint allocations (factories, plant complexes, power plant units, etc.);
— technical objects (systems, plants, technical equipment, components, etc.);
— electrical and mechanical connections;
— signals and potentials;
— documents.
The structure and contents of designation for these different tasks are specified in Clause 6.
5.2 Conjoint designation
It may be required to identify different sites. Moreover, different power plant units, non-unit-aligned
or common plants and systems, different extension stages as well as power plant extrinsic works can
exist or be planned on the same site (e.g. at cogeneration power plants). Conjoint designation facilitates
a unified identification of such different plant complexes (for an example see Figure D.1).
8 © ISO 2015 – All rights reserved

Conjoint designation is a reference designation of a plant/system with respect to the site not being
related to one of the defined aspects.
If it is used as part of the identifier, then systems, objects and products which fulfil the same task in
different plants can have the same reference designation. The unambiguous nature of the equipment
designation is achieved by using different conjoint designations. This provides significant ergonomic
and economic advantages.
The use of the conjoint designation is optional.
5.3 Designation of technical objects — Reference designation
5.3.1 General
Reference designation identifies objects for the purpose of correlating information about an object among
different kinds of documents with the products implementing the system. A reference designation shall
unambiguously identify an object of interest within the considered system.
An object within a system can be viewed in different ways, called aspects:
— What does the object do? (function aspect)
— How is the object constructed? (product aspect)
— Where is the object located? (location aspect)
5.3.2 Function aspect
A function-oriented structure is based on the purpose of a system, without necessarily taking into
account the products with which this purpose is fulfilled or their location.
Designation by function aspect is applied in an early planning phase of a project, and remains unchanged
over the entire service life of an overall plant.
In power plant engineering, a distinction is made between functional units with static tasks (see 6.3.1)
and those with dynamic effect (see 6.3.2).
Figure 7 shows a diagram of a system consisting of several functions.
NOTE The notations in this diagram are not based on standardized letter codes.
Subtask =ST2 consists of heat exchanger =EP1 and pump =GP1
Figure 7 — Diagram of functional units by task (subtasks ST) and effect (subprocesses SP)
As a subfunction of subtask =ST2, heat exchanger =EP1 has effects both in subprocess ==SP1 as well as
in ==SP2.
Figure 8 shows the relationships in two structure trees with the constituent relations in each of the
tree-like structures (solid lines) and the allocation (associative relations) between these two structures
(dashed lines).
Figure 8 — Function structures by task (subtasks ST) and effect (subprocesses SP)
5.3.3 Product aspect
A product-oriented structure is based on the way in which a system is implemented, constructed or
delivered, including the use of intermediate or end products, without necessarily taking into account
their functions and/or locations.
Designation by product aspect is used in the manufacture of equipment parts without taking into
account their application or places of use.
In power plant engineering, the designation according to product aspect is specifically restricted (see
6.4).
5.3.4 Transition from function aspect to product aspect
It is possible and often expedient to identify an object in a system using two aspects. Different aspects
may be used for successive objects by making a transition from one aspect to another. Prerequisite for
this is that the object is exclusively associated with the preceding functional unit.
10 © ISO 2015 – All rights reserved

Figure 9 shows the transition from the function aspect to the product aspect and allocation to the
location structure for the example of the multi-level reference designation =LAB12 QM001 QA01 (feed
water piping system, train 12, isolation 1; power breaker 1).
Figure 9 — Transition from function aspect to product aspect and allocation (associative
relation)
5.3.5 Location aspect
A location-oriented structure is based on the topographical layout of a system and/or the surroundings
in which the system is located, without necessarily taking into account products and/or functions.
This additional aspect enables distinction between the following:
— designation of points of installation within design units or modules of electrical and I&C systems, as
well as designation of locations in mechanical engineering equipment (installation aspect);
— designation of object locations (erection aspect).
Designation by location aspect is applied in the designation of objects which perform the task of
providing points of installation for other technical objects.
This type of designation is used for allocation of the equipment parts to their locations (point of
installation, location).
5.4 Specific designations
5.4.1 Signal designation
Signals are the carriers of information and shall be designated unambiguously. The principles are
specified in IEC 61175.
5.4.2 Terminal designation
Electrical and mechanical terminals shall be designated unambiguously. The principles are specified in
IEC 61666.
5.4.3 Document designation
Documents shall be designated unambiguously. A non-manufacturer-specific, uniform and object-
related designation in accordance with IEC 61355-1 is required for power plant technology.
6 Structure and contents of designation blocks
6.1 General
The designations are structured in the form of designation blocks, which are subdivided into sections
(alphabetical and numerical). The number and type of data characters for the individual designation
tasks are specified and described in the following subclauses.
The alphabetical sections classify systems, plants and technical equipment, components, points of
installation and locations as well as signals, connections and documents according to their purpose or
task. The numerical sections serve for distinction and numbering.
The rules specified in 4.4 apply.
6.2 Designation block “Conjoint designation”
Each of the two breakdown levels has a maximum of 12 data characters. The structure of the designation
block, the contents, the meaning as well as the type and number of data characters shall be defined
separately for every project.
Figure 10 shows the structure and contents of the designation block “Conjoint designation”.
Figure 10 — Structure and contents of designation block “Conjoint designation”
6.3 Function aspect
6.3.1 Designation block “Function”
This designation block is used for function-oriented structuring with regard to the task and purpose
(static tasks) of the technical objects. It is used to designate systems, plants, subsystems and technical
equipment, see Figure 11.
12 © ISO 2015 – All rights reserved

Figure 11 — Structure and contents of designation block “Function”
Figure D.2 shows an example of breakdown level 0. Figure D.3 shows an example of a civil engineering
object.
6.3.2 Designation block “Function allocation”
6.3.2.1 General
This designation block is used for function-oriented structuring with regard to interaction (dynamic
effect) of technical objects. It is used to designate relationships between functions, technical equipment
and components.
6.3.2.2 Designation of functional areas and groups as “Function allocation (group level)”
This designation block is used to designate functional areas and/or functional groups of technical
objects, which are represented under a functional aspect different to that in the designation block
“Function”, see Figure 12.
Universally valid contents cannot be specified (for examples see Figures D.4 and D.5).
Figure 12 — Structure and contents of designation block “Function allocation” for functional
areas
6.3.2.3 Designation of technical equipment as “Function allocation (individual level)”
This designation block is used to designate technical equipment which is viewed in the sense of the
function allocation. See Figure 13 and Table 2.
Figure 13 — Structure and contents of designation block
“Function allocation for technical equipment”
Table 2 — Control tasks for “Function allocation”, section 5, data characters 1 and 2
Code Denomination
AA Alarms, monitoring
CA Closed-loop feedback control
CB Reference loop control
HA Operation and monitoring
MA Direct measurement
MB Measurand calculation
SA Individual control
SB Group control
ZA Equipment protection
ZB Plant protection
Further stipulations, if necessary, should be project-specific.
6.4 Product aspect — Designation block “Product”
This designation block is used for product-oriented designation of electrical and mechanical objects, see
Figure 14.
If an object is to be further broken down into its parts, the “nested product-oriented designation” shall
be applied, where several blocks are concatenated in the sense of the multi-level reference designation.
The prefix shall be placed in front of the first designation block only (example see Figure D.6).
14 © ISO 2015 – All rights reserved

Figure 14 — Structure and contents of designation block “Product”
6.5 Transition from function aspect to product aspect
For unambiguous identification of technical objects in power plant engineering, the possibility is used
to simultaneously follow objects according to both function and product aspects. The structure of such
a designation block is shown in Figure 15, with Examples 1 and 2.
Figure 15 — Structure of the designation block “Equipment”
EXAMPLE 1 =C01 MDK51 GP001 –MA01XD02
wind turbine generator system C01, wind turbine system MD, power transmission
(drive train) K,
transmission lubricant subsystem 51, conveying GP001; electric motor MA01, junction
box XD02
EXAMPLE 2 =C01 MDY10 QA001 –QA07
wind turbine generator system C01, wind turbine system MD, control system Y10,
power unit QA001;
circuit breaker QA07
The first
...