SIST EN ISO 128-3:2022

SLOVENSKI STANDARD
01-november-2022
Nadomešča:
SIST EN ISO 128-3:2020
SIST ISO 128-43:2016
Tehnična dokumentacija izdelkov - Splošna načela prikazovanja - 3. del: Pogledi,
prerezi in odrezi (ISO 128-3:2022)
Technical product documentation (TPD) - General principles of representation - Part 3:
Views, sections and cuts (ISO 128-3:2022)
Technische Produktdokumentation (TPD) - Allgemeine Grundlagen der Darstellung - Teil
3: Ansichten, Schnitte und Schnittansichten (ISO 128-3:2022)
Documentation technique de produits (TPD) - Principes généraux de représentation -
Partie 3: Vues, sections et coupes (ISO 128-3:2022)
Ta slovenski standard je istoveten z: EN ISO 128-3:2022
ICS:
01.110 Tehnična dokumentacija za Technical product
izdelke documentation
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 128-3
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2022
EUROPÄISCHE NORM
ICS 01.100.01 Supersedes EN ISO 128-3:2020
English Version
Technical product documentation (TPD) - General
principles of representation - Part 3: Views, sections and
cuts (ISO 128-3:2022)
Documentation technique de produits (TPD) - Technische Produktdokumentation (TPD) - Allgemeine
Principes généraux de représentation - Partie 3: Vues, Grundlagen der Darstellung - Teil 3: Ansichten,
sections et coupes (ISO 128-3:2022) Schnitte und Schnittansichten (ISO 128-3:2022)
This European Standard was approved by CEN on 13 August 2022.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 128-3:2022 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 128-3:2022) has been prepared by Technical Committee ISO/TC 10 "Technical
product documentation" in collaboration with CCMC.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by March 2023, and conflicting national standards shall
be withdrawn at the latest by March 2023.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 128-3:2020.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 128-3:2022 has been approved by CEN as EN ISO 128-3:2022 without any modification.

INTERNATIONAL ISO
STANDARD 128-3
Second edition
2022-08
Technical product documentation
(TPD) — General principles of
representation —
Part 3:
Views, sections and cuts
Documentation technique de produits (TPD) — Principes généraux de
représentation —
Partie 3: Vues, sections et coupes
Reference number
ISO 128-3:2022(E)
ISO 128-3:2022(E)
© 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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 128-3:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 S c op e . 1
2 Nor m at i ve r ef er enc e s . 1
3 Terms and definitions . 1
4 Basic conventions for views .2
4.1 G eneral information on views. 2
4.2 C hoice of views . 3
4 . 3 P a r t i a l v iew s . 3
4.4 S implified view of symmetrical parts . 4
4.5 F irst-angle projection method . 4
4.6 F irst-angle projection method views . 4
4.7 F irst-angle projection graphical symbol . 5
4.8 Third-angle projection method . 5
4.9 T hird-angle projection method views . 5
4.10 T hird-angle projection graphical symbol . 6
4.11 O ther projection methods . 6
4 .12 E n l a r g e d f e at u r e s . 6
5 Re ference indication for views and enlarged features . 7
5.1 G eneral . 7
5.2 D etails of the reference indication . 7
5.3 E xamples of indication . 8
6 G eneral information on cuts and sections . 9
6.1 General . 9
6.2 I ndication of cuts and sections . 9
6 . 2 .1 Cut t i n g pl a ne . 9
6.2.2 I dentification of the cutting plane . 9
6.2.3 I dentification of the cuts and sections . 9
6.2.4 R eference indication for cuts and sections . 10
6.3 S ections revolved in the relevant view . 11
6.4 C uts/sections of symmetrical parts .12
6 . 5 L o c a l c ut s/s e c t ion s .12
7 B asic conventions for representing areas on cuts and sections .13
7.1 G eneral information on cuts and sections . 13
7. 2 Hat c h i n g. 13
7.3 S hading or toning . 14
7.4 E xtra-wide continuous outlines . 15
7. 5 T h i n s e c t ion s . 15
7.6 T hin adjacent sections . 15
7.7 S pecific materials . 16
Annex A (normative) Graphical symbols .17
Annex B (informative) Former practices .20
Annex C (normative) Views on mechanical engineering technical drawings .22
Annex D (normative) Sections on mechanical engineering technical drawings .34
Annex E (normative) Projection methods in building technical drawings .39
Annex F (normative) Representation of views, sections and cuts on construction drawings .41
Bibliography .48
iii
ISO 128-3:2022(E)
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, in
collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/SS
F01, Technical drawings, in accordance with the Agreement on technical cooperation between ISO and
CEN (Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 128-3:2020), of which it constitutes a
minor revision, and ISO 128-43:2015. The changes are as follows:
— Clause 2: reference to ISO 10209 has been updated;
— Figures A.3, A.4, A.5, B.4, D.10, E.1 and E.2 have been redrawn to be consistent with the text;
— minor editorial changes.
A list of all parts in the ISO 128 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.
iv
ISO 128-3:2022(E)
Introduction
This document contains generally applicable rules for the presentation of views, sections and cuts in all
kinds of technical product documentation. The first-angle projection method (formerly referred to as
method E) and the third-angle projection method (formerly referred to as method A) are described in
more detail in ISO 5456-2.
All figures in this document, excluding Figure 1, Figure 6 and Figure 7, have been drawn in first-angle
projection method unless other methods are stated. It should be understood that third-angle projection
or other methods could have been used equally well without prejudice to the principles established.
The application of views, sections and cuts within drawings of special technical fields varies
considerably. Therefore, rules of application specific to technical fields are given in Annexes C, D, E and
F.
v
INTERNATIONAL STANDARD ISO 128-3:2022(E)
Technical product documentation (TPD) — General
principles of representation —
Part 3:
Views, sections and cuts
1 S cope
This document specifies the general principles for presenting views, sections and cuts applicable to
various kinds of technical drawings (e.g. mechanical, electrical, architectural, civil engineering),
following the orthographic projection methods specified in ISO 5456-2. Views and sections for
shipbuilding technical drawings are discussed in ISO 128-15. Views and sections for 3D models are
discussed in ISO 16792.
Attention has also been given in this document to the requirements of reproduction, including
microcopying in accordance with ISO 6428.
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.
1)
ISO 128-2:—, Technical product documentation (TPD) — General principles of presentation — Part 2:
Basic conventions for lines
ISO 129-1, Technical product documentation (TPD) — Presentation of dimensions and tolerances — Part 1:
General principles
ISO 3098-1, Technical product documentation — Lettering — Part 1: General requirements
ISO 5456-2, Technical drawings — Projection methods — Part 2: Orthographic representations
ISO 6428, Technical drawings — Requirements for microcopying
ISO 10209:2022, Technical product documentation — Vocabulary — Terms relating to technical drawings,
product definition and related documentation
ISO 15519-1, Specification for diagrams for process industry — Part 1: General rules
ISO 81714-1, Design of graphical symbols for use in the technical documentation of products — Part 1:
Basic rules
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 10209:2022 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
1) Under preparation. Stage at the time of publication: ISO/FDIS 128-2:2022.
ISO 128-3:2022(E)
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
cut
sectional view
section (3.2) showing, in addition, outlines beyond the cutting plane
Note 1 to entry: While “cut” is generally used in the construction field, “section” is generally used in the
mechanical engineering field, regardless of the definitions in 3.1 or 3.2.
[SOURCE: ISO 10209:2022, 3.2.10, modified — Note 1 to entry added.]
3.2
section
representation showing only the outlines of an object lying in one or more cutting planes
Note 1 to entry: While “cut” is generally used in the construction field, “section” is generally used in the
mechanical engineering field, regardless of the definitions in 3.1 or 3.2.
[SOURCE: ISO 10209:2022, 3.2.58, modified — Note 1 to entry revised.]
3.3
technical drawing
drawing showing a technical installation, process or product with a view to clarifying its structure and
enabling its construction
Note 1 to entry: For the purpose of this document, the term “technical drawing” is interpreted in the broadest
possible sense, encompassing the total package of documentation specifying the product (work piece,
subassembly, assembly).
[SOURCE: ISO 5127:2017, 3.4.7.54, modified — Note 1 to entry replaced.]
4 Basic c onventions for views
4.1 Gener al information on views
The most informative view of an object shall be used as the principle view, taking into consideration, for
example, its functioning position, position of manufacturing or mounting.
Each view, with the exception of the front or principal figure (view, plan, principal figure), shall be
given clear identification with a capital letter, repeated near the reference arrow needed to indicate the
direction of viewing for the relevant view. Whatever the direction of viewing, the capital letter shall
always be positioned in normal relation to the direction of reading and be indicated either above or on
the right side of the reference arrow.
The reference arrow is defined in Annex A (for the former practice of arc arrow, see Annex B), as is the
lettering height of the identification.
The designated views may be located irrespective of the principal figure. The capital letters identifying
the referenced views shall be placed immediately above the relevant views (see Figure 1).
ISO 128-3:2022(E)
Figure 1 — Identification of referenced views
For applying views and sections to mechanical engineering technical drawings, Annex C and Annex D
shall apply. For applying projection methods in building technical drawings, Annex E shall apply. For
applying views, sections and cuts to construction technical drawings, Annex F shall apply.
4.2 Choic e of views
When views (including cuts and sections) are needed, these shall be selected according to the following
principles:
— limit the number of views (and cuts and sections) to the minimum necessary but sufficient to fully
delineate the object without ambiguity;
— avoid the need for hidden outlines and edges;
— avoid unnecessary repetition of a detail.
Views and sections for 3D models are given in ISO 16792.
4.3 Partial views
Features needing specific illustration, but not meriting a full view, can be illustrated using a partial view
limited by a continuous narrow line with zigzags of type 01.1 according to ISO 128-2:— (see Figure 2).
ISO 128-3:2022(E)
Figure 2 — Partial view
4.4 Simplified view of symmetrical parts
To save time and space, symmetrical objects can be drawn as a fraction of the whole [see Figure 3 a), b)
and c)].
The line of symmetry is identified at each of its ends by two narrow short parallel lines drawn at right
angles to it [see Figure 3 a), b) and c)]. The graphical symbol for symmetry shall be drawn in accordance
with A.3.
a) Example 1 b) Example 2 c) Example 3
Figure 3 — Examples of simplified views of symmetrical parts
4.5 First-ang le projection method
The first-angle projection method, if used, shall be in accordance with ISO 5456-2.
4.6 First-ang le projection method views
With reference to the front view, (a), the other views are arranged as follows (see Figure 4):
— the view from above, (b), is placed underneath;
— the view from below, (e), is placed above;
— the view from the left, (c), is placed on the right;
ISO 128-3:2022(E)
— the view from the right, (d), is placed on the left;
— the view from the rear, (f), may be placed on the left or right, as convenient.
Figure 4 — First-angle projection method
4.7 First-ang le projection graphical symbol
The graphical symbol for the first angle projection method is shown in Figure 5. The proportions and
dimensions of this graphical symbol are specified in ISO 5456-2.
Figure 5 — First angle projection graphical symbol
4.8 Thir d-angle projection method
The third-angle projection method, if used, shall be in accordance with ISO 5456-2.
4.9 Thir d-angle projection method views
With reference to the front view, (a), the other views are arranged as follows (see Figure 6):
— the view from above, (b), is placed above;
— the view from below, (e), is placed underneath;
— the view from the left, (c), is placed on the left;
— the view from the right, (d), is placed on the right;
— the view from the rear, (f), may be placed on the left or right, as convenient.
ISO 128-3:2022(E)
Figure 6 — Third-angle projection method
4.10 Thir d-angle projection graphical symbol
The graphical symbol for the third-angle projection method is shown in Figure 7. The proportions and
dimensions of this graphical symbol are specified in ISO 5456-2.
Figure 7 — Third-angle projection graphical symbol
4.11 Other pr ojection methods
Refer to ISO 5456-2 for information on other projection methods, such as mirrored orthographic
projections.
4.12 Enlarged features
When the scale of a technical drawing does not allow all features to be clearly shown or dimensioned,
the unclear features shall be enclosed or encircled by a continuous narrow line (type 01.1), with the
area thus enclosed identified by a capital letter. The features in the area shall also be shown on an
enlarged scale, in a view that is broken with a continuous narrow freehand or free-formed curve line
(type 01.1). This shall be accompanied by the identification letter and an indication of the scale beside
it between parentheses, as shown in Figure 8. The rules for lettering height are discussed in Annex A.
Figure 8 — Enlarged features
ISO 128-3:2022(E)
For unambiguous relation between the circle and the identification letter, a leader line by a continuous
narrow line (type 01.1) and a reference line by a continuous narrow line (type 01.1) should be drawn.
See Figure 9.
Figure 9 — Enlarged features with leader line
5 R eference indication for views and enlarged features
5.1 General
On large-format mechanical technical drawings and technical drawings consisting of more than one
drawing sheet with an extensive amount of views and enlarged features, the readability should be
improved by information (reference indication) after the identification letter of the views.
The purpose is to find the views and the identification letters more easily on the technical drawing or
drawings.
On construction drawings, designations for views and enlarged features can be complemented by
general reference to other drawings containing the views or features.
5.2 Details of the r eference indication
The reference indication after the identification letter on the views shall be in accordance with
ISO 15519-1.
Examples with explanation are shown in Figure 10 and Figure 11.
Figure 10 — Details of the reference indication with a single drawing
ISO 128-3:2022(E)
Figure 11 — Details of the reference indication with multiple drawings
5.3 Ex amples of indication
Examples of indication are given in Table 1.
Table 1 — Examples of indication
Indication on technical drawing Interpretation
View A is represented at technical drawing
coordinates C10 on the same sheet.
The identification letter and reference arrow on the
main view is represented at technical drawing
coordinates A3 on the same sheet.
Enlarged feature Z is represented at technical drawing
coordinates D5 on sheet 2.
The indication of the enlarged feature Z is represented
at technical drawing coordinates B3 on sheet 1.
ISO 128-3:2022(E)
6 Gener al information on cuts and sections
6.1 General
The general rules for the arrangement of views apply equally when drawing cuts and sections.
6.2 Indication of cuts a nd sections
6.2.1 Cutting plane
The position of the cutting plane(s) shall be indicated by means of a cutting line represented with a
dashed dotted wide line (type 10.2) according to ISO 128-2:—, Annex E and Annex G. A straight cutting
plane shall be drawn (see Figure 12).
If the cutting plane changes its direction, the cutting line should only be drawn at the ends of the cutting
plane, where the cutting plane changes direction (see Figure 13).
If necessary for its legibility, the cutting line may be connected with a long-dashed dotted narrow line
of the type 04.1 according to ISO 128-2:—, Annex D or 04.1 according to ISO 128-2:—, Annex F.
The direction of viewing for the relevant cut and section is indicated by the reference arrows as defined
in Annex A.
The designated cut and section can be located irrespective of the view in which the cutting plane is
taken.
Representation of areas on cuts and sections is covered in Clause 7.
6.2.2 Identification of the cutting plane
Each cut and section plane shall be given clear identification with twice the same capital letter, once at
each of the cut and section arrows. This identification should be positioned for reading from the bottom
of the technical drawing.
The 30° or 90° cut and section arrow is defined in A.4, as is the lettering height of the identification.
6.2.3 Identification of the cuts and sections
The identification of the referenced cuts and sections shall be placed immediately above the relevant
representation. (see Figure 12 and 13).
Figure 12 — Example from construction field
ISO 128-3:2022(E)
Figure 13 — Example
...