Graphical symbols for diagrams by kxb86934


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                                            Graphical symbols
                                              for diagrams
By Jorgen Aagaard and Siv Velander, Chairman and     power field, for example –                                              Non-return valve,
Secretary of ISO/TC 10, Technical product documen-                                                                           check valve acc.
tation, SC 10, Process plant documentation and       have found the situation                                                to ISO 538
tpd-symbols                                          satisfactory because they
                                                                                                                             Non-return valve,
                                                     normally do not need to use                                             check valve acc.
Over the last decades,                               any other symbols than                                                  to ISO 4067-1

the numbers of complaints                            those developed specially for                                           Non-return valve,
                                                                                                                             check valve acc.
and questions regarding                              their own fields.                                                       to DIN 2481,
symbols for use on                                                                                                           DIN 2429-2

diagrams has increased,                              The more the different                                                  Non-return valve,
especially from the end                              technical fields overlap with                                           check valve acc.
                                                                                                                             to BS 1192
users, i.e. personnel                                each other and the more
employed at industrial                               plant installations are split                                           Non-return valve
                                                                                                                             acc. to E 04-202
plants, from engineers                               between different suppliers –                                           (France)

designing plants, and from                           a trend today – the more                                                Check valve acc.
persons responsible for                              the need for a harmoniza-                                               to E 04-202
creating CAD (Computer                               tion is recognized.
                                                                                                                             Check valve acc.
Aided Drawing) libraries                                                                                                     to ANSI ASA
with symbols. These
                                                     Within IEC (International Electrotechni-         Figure 1 – Various existing symbols
complaints concern the                               cal Commission), all work with symbols           for a non-return, check valve.
many different symbols for                           for use on diagrams is concentrated
the same thing, and the                              within one and the same technical com-
                                                                                                                             Shut-off valve
                                                     mittee, TC 3, Documentation and
same symbols used for                                                                                                        shown in closed
                                                                                                                             position acc. to
                                                     graphical symbols. The experts there get
different things that can be                         requests or proposals for symbols for new
                                                                                                                             DIN 2429.

found in existing symbol                             products from various product commit-            Figure 2 – A normal shut-off valve
                                                                                                      shown in closed position.
standards.                                           tees, but all the proposals are discussed for
                                                     coordination and published by TC 3.             Figure 1 gives some examples of a symbol
On the other hand, persons                              ISO deals with more than 200 technical       for a non-return valve, a check valve that
                                                     fields, and the situation was totally differ-   can be found in international and some
working within a certain                             ent. Symbols for use on diagrams were           national standards. The symbol in b) in
technical field – the vacuum                                                                         particular is dangerous since the same
                                                     developed by various technical commit-          symbol – see Figure 2 – also can represent
technique field or the fluid                         tees, most of whose participants were           a normal shut-off valve in closed position.

12        ISO BULLETIN MARCH 2003
                                                  nature and Parts 7 to 12 and 15 symbols for
                                                  objects where the functions are mainly
                                                  implemented by mechanical means.
                                                    No major differences between the symbols
                                                  in ISO 14617 and IEC 60617 exist, thanks to
                        Hydraulic motor           the work done by the joint working group.

                                                  Representation of objects                        Figure 4 – Symbols for functions.
                                                                                                   FRC = Flow rate recording and controlling.
                                                  by symbols
                        Heat exchanger                                                            Symbols for functions
                                                      The symbols in ISO 14617 represent
                                                                                                     Typical symbols for functions can be
                        Pipeline                  !    a product in the form of hardware ;
                                                                                                  found in ISO 14617-6, which replaces ISO
 Figure 3 – Symbols for some                           for example, a valve, a motor, and a
                                                                                                  3511-1, 2, and 4 (ISO 3511-3 contained
 hardware products.                                    torque converter or
                                                                                                  mainly symbols for hardware objects).
Figure 3 – Symbols for hardware                   !    a function ; for example, to control, to   The basic symbol consists of a circle in
products. The symbols in Figure 3                      measure, and to monitor.                   which a special letter code is inscribed,
represent hardware products, a pump,                                                              while the symbol for a function, intended
a hydraulic motor, a heat exchanger,
                                                                ISO 14617                         to be implemented by a computer, is a
and a pipeline. From the symbols, any
engineer can deduce how the equip-                        an overall perspective                  hexagon instead. Figure 4 shows an
ment operates.                                                                                    example. The connections between the
                                                      ISO 14617, Graphical symbols for            circles represent a function, to transfer the
mainly interested in the products, not in             diagrams, and IEC 60617,                    result of one function to the next.
documentation. About 20 different ISO                 Graphical symbols for diagrams,
committees have created symbols – with                together form a universal library of
insufficient coordination.                            symbols for all types of diagrams.
                                                      Part 1, General information and              Automatic         Delayed
Decision to develop                                   indexes                                        return           action      Manually operated shut-
                                                                                                                                  off valve with delayed,
a new standard                                        Part 2, Symbols having general appli-                                         automatic return to
                                                      cation                                                                          closed position
In December 1988 in Geneva, ISO and the
                                                      Part 3, Connections and related               Figure 5 – Two symbols for func-
IEC decided to prepare a standard, com-               devices                                       tions and an example of how they
mon to all technical fields, with harmo-              Part 4, Actuators and related devices         may be used.
nized symbols for use on diagrams. An ISO-            Part 5, Measurement and control
IEC joint working group with the task of              components                                    Some other symbols for functions are
listing all discrepancies between existing                                                        shown in Figure 5. That figure also
                                                      Part 6, Measurement and control
standards and proposing relevant measures             functions                                   shows how these symbols may be used to
was set up. In all, more than 40 experts              Part 7, Basic mechanical components         give supplementary information on the
have contributed to the new standard.                 Part 8, Valves and dampers
                                                                                                  function of a shut-off valve.
   ISO has now developed ISO 14617,                   Part 9, Pumps, compressors and fans
Graphical symbols for diagrams, com-                                                              Preparation and costs
                                                      Part 10, Fluid power converters
prising a number of parts. Part 1 contains                                                        ISO 14617, Graphical symbols for dia-
                                                      Part 11, Devices for heat transfer and
no symbols but general information and                heat engines                                grams, is the result of about 12 years of
indexes. All the other parts are organized            Part 12, Devices for separating, purifi-    hard work. Total expenses incurred have
according to a classification system                  cation and mixing                           been estimated as between USD 5 and 7 mil-
designed with regard to the function of the           Part 13, Devices for material process-      lion. Several Swedish companies have paid
objects, independent of which technical               ing                                         the costs for the standards committee work,
field (except the electrotechnical field) the         Part 14, Devices for transport and          the secretariat of which is administered by
object is used in. This is the only possibility       handling of material                        the SIS, Swedish Standards Institute.
to satisfy the objective of getting unique,           Part 15, Symbols for use on installa-          Many conflicts between various interest
consistent, and non-conflicting symbols.              tion diagrams and network maps              groups had to be solved. The work started
Parts 2 to 6 contain symbols of very general                                                      by mapping the symbols in existing ISO
                                                                                                                  ISO BULLETIN MARCH 2003             13
                                               !   clause 4, with application rules for the      The advantage in having a universal
                                                   symbols in clause 3;                       standard is perfectly obvious with the doc-
and IEC standards. Also the most impor-
                                               !   and clause 5, with application exam-       umentation of complete plants. The per-
tant national standards were studied.
                                                   ples, i.e. how to construct composite      sonnel no longer need to find the right
From the comprehensive library of exist-
                                                   symbols.                                   symbol by searching through a number of
ing symbols, those symbols and those
                                                                                              partially contradictory standards.
descriptors that were most useful were           ISO 14617, Graphical symbols for dia-           We feel certain that implementation of
selected. To carry out that task, the rules    grams, and IEC 60617, Graphical sym-           this standard is not going to take as long
given in ISO 81714-1, General principles       bols for diagrams, together form a uni-        as can be the case with a number of stan-
for the creation of graphical symbols          versal library of symbols for all types of     dards, though, of course, representatives
were taken into account.                       diagrams.                                      from different application fields will have
   One of the rules implies that a graphical
                                                                                              some difficulties in accepting the new
symbol for an object consisting of several     Future activities                              harmonized standard.
elements should be composed by symbols
                                               Two parts, ISO 14617-13: Devices for              A symbol database is now under devel-
for the integral elements – as far as possi-
                                               material processing, ISO 14617-14:             opment. The possibility of using the same
ble. For that reason, many of the existing
                                               Devices for transport and handling of          database technique that is already in use
symbols used in some restricted fields had
                                               material, are under preparation and are        at IEC will be investigated. Meanwhile, a
to be refused. Many other symbols had to
                                               due to be published in 2003.                   CD-ROM will be produced so that the
be refused because several symbols for the
                                                 The practical use of the standard will       standard can be applied in an easy way as
same object already existed ; many identi-
                                               show what symbols are lacking. How this        soon as possible. This means that the pos-
cal symbols with different meanings also
                                               work is to be organized is laid out in the     sibility for users to build up databases
were in existence. In some cases, none of
                                               2001 ISO/IEC Directives. Any technical         adopted for their own CAD systems will be
the existing symbols fitted into the system,
                                               committee that finds the need for a new or     achieved. In this way, the implementation
so that a new symbol had to be created. Of
                                               revised symbol has to prepare a proposal       of the standard will go faster.
course, the IEC 60617, Graphical symbols
                                               and send this to TC10/SC10 for further
for diagrams, standard was also consulted
                                               processing. We hope that most of the gaps      Symbols needed by other
when relevant.
                                               in the standard will be eliminated over the    technical committees
   For complex objects, the rule above
                                               next five years.
cannot be applied. Instead, block symbols                                                     Now that ISO 14617 is published, the inten-
                                                 At the moment, ISO Central Secretariat
have been developed according to rules                                                        tion is that other committees working
                                               and ISO/TC 10/SC 10 are trying to find
given in ISO 81714-1.                                                                         within specific fields should have the possi-
                                               out the best method for the release of an
   All symbols in the standard have been                                                      bility to prepare “ collective standards ”, i.e.
                                               electronic database containing all the
given a registration number. This number                                                      extracts from ISO 14617. When a technical
                                               symbols and examples in ISO 14617.
will also be maintained in revised editions                                                   committee finds that a new symbol has to
                                                 TC 10 is also working on a standard for
of the standard. Equally, the examples                                                        be developed or an existing symbol has to
                                               the preparation of diagrams, i.e. how the
showing how the symbols can be com-                                                           be modified, the committee will prepare a
                                               symbols should be applied in diagrams.
bined have also got registration numbers,                                                     draft on a special form to be sent to TC
                                               This standard is thought to consist of a
starting with the letter X. Modified sym-                                                     10/SC 10. A “ maintenance team ” studies
                                               general part with the rules common to all
bols and examples in the future will get                                                      the draft and decides if it can be accepted as
                                               types of diagrams and several parts con-
new registration numbers.                                                                     it is or modified or if the drafted symbol has
                                               taining supplementary rules for special
   Each section in the parts of ISO 14617,                                                    to be dealt with according to the ordinary
                                               types or application fields.
Graphical symbols for diagrams, that                                                          procedure. The new or modified symbol
contains symbols has been subdivided                                                          will get a new registration number from the
                                               Implementation of ISO 14167
consistently into five clauses :                                                              TC 10/SC 10 database.
                                               We know that many companies have been              Since symbols are a language-independ-
!    clause 1, with symbols giving basic
                                               waiting a long time for this standard to be    ent method for communication, and com-
     information ;
                                               published. Up till now, they have had          panies to an ever-larger extent work glob-
!    clause 2, with applications rules for     great problems in knowing which stan-          aly using CAD systems, different branches
     the symbols in clause 1 ;                 dards should be applied. For those that        and companies have to cooperate. ISO
!    clause 3, with symbols giving addi-       wanted to establish their own symbol           14617 may be regarded as a breakthrough
     tional information ;                      databases, the problem has been hard.          in a field formerly far too complicated.

14        ISO BULLETIN MARCH 2003
                  Sharing out graphical symbols work
Each ISO technical committee is responsi-          ISO/TC 145, Graphical symbols,                  The review and coordination role of
ble for the selection or creation of graphi-    holds overall responsibility for standardiza-   ISO/TC 145 applies to all committees that
cal symbols within its own field of interest.   tion of graphical symbols in the field of       undertake the responsibility for creation
Graphical symbols may form the main             public information, safety signs, and for use   and standardization of graphical symbols
subject of an International Standard, or a      on equipment. This responsibility includes:     within their own particular fields.
single symbol or several symbols may                                                               Any committee identifying the need for
appear as part of a standard covering wider                                                     new or revised graphical symbols should as
aspects of the subject to which the sym-                                                        soon as possible submit their proposal to
bol(s) refer.                                                                                   the secretariat of the appropriate ISO/TC
   The ISO Technical Management Board                                                           145 subcommittee for review and – once
has assigned overall responsibility for                                                         approved – allocation of a registration
standardization in the field of graphical                                                       number.
symbols to ISO/TC 145, Graphical sym-                                                              ISO/TC 145, in accordance with its
bols 1), and to ISO/TC 10/SC 10, Technical                                                      scope, Graphical symbols, holds general
product documentation (tpd) symbols 2).                                                         responsibility for the review and coordina-
   Their separate and distinct responsibili-                                                    tion for all graphical symbols. The secre-
ties are outlined below :                                                                       tariats of the subcommittees of ISO/TC 145
                                                                                                maintain a data bank of symbols incorpo-
   ISO/TC 10/SC 10, Graphical sym-
                                                                                                rating both the standardized symbols,
bols for use in technical product doc-
                                                                                                already registered, and those in the course
umentation (tpd), holds overall respon-
                                                                                                of standardization.
sibility for standardization in the field of
                                                                                                   ISO/TC 10/SC 10, Technical product
graphical symbols for technical product         !   progressing work items through              documentation symbols, by agreement
documentation (tpd). This responsibility            ISO/TC 145 to respond to general            with and in collaboration with ISO/TC 145,
includes:                                           needs for graphical symbols across all      and in accordance with its scope, ensures
!   maintenance of ISO 81714-1, Design              areas of application of graphical sym-      the review and coordination of graphical
    of graphical symbols for use in the             bols within the scope of ISO/TC 145 ;       symbols used in technical product docu-
    technical documentation of products         !   progressing work items through              mentation. Such coordination is carried
    – Part 1: Basic rules, in cooperation           ISO/TC 145 to define design principles      out in close cooperation with IEC/TC 3.
    with IEC (International Electrotech-            and quality attributes of graphical
    nical Commission);                              symbol-based communications ;               1) Standardization in the field of graphical sym-
                                                                                                bols as well as of colours and shapes, whenever
!   standardization of graphical symbols        !   coordinating and advising on the work       these elements form part of the message that a sym-
    to be used in technical product docu-           items/projects of other committees          bol is intended to convey, e.g. a safety sign.
    mentation, coordinated with IEC;                within ISO for work items involving         Establishing principles for preparation, coordina-
                                                                                                tion and application of graphical symbols. General
!   establishing and maintaining a data-            graphical symbols ;
                                                                                                responsibility for the review and the coordination of
    base for graphical symbols including        !   coordinating and advising on the            those already existing, those under study, and those
    management of registration numbers.             work on graphical symbols of other          to be established. The standardization of new
   Included in its brief is the standardiza-                                                    graphical symbols, when requested by a technical
                                                    standards organizations with official       committee, or where it does not fall within the
tion of symbols for use in diagrams and             liaison to ISO.                             activity of an existing technical committee.
pictorial drawings.                                                                             Excluded: – standardization of letters, numerals,
                                                  ISO/TC 145 has allocated and distrib-
                                                                                                punctuation marks, mathematical signs and sym-
   The Secretariat of ISO/TC 10/SC 10 is        uted these responsibilities as follows :        bols, and symbols for quantities and units. However,
supported by a maintenance group.                                                               such may be used as a component of a graphical
                                                !   ISO/TC 145/SC 1, Graphical symbols
   Any committee identifying the need for                                                       symbol.
                                                    in the field of public information.
new or revised graphical symbols shall as                                                       2) Standardization of specific rules for :
soon as possible submit their proposal to       !   ISO/TC 145/SC 2, Graphical symbols
                                                                                                a) process plant documentation
the secretariat of ISO/TC 10/SC 10 for              in the field of safety signs.
                                                                                                b) application of simplified representation
review and – once approved – allocation         !   ISO/TC 145/SC 3, Graphical symbols          c) application of structuring principles and refer-
of a registration number.                           for use on equipment.                          ence designation.

                                                                                                                  ISO BULLETIN MARCH 2003               15

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