EN ISO 24096-2:2024

SLOVENSKI STANDARD
01-november-2024
Tehnična dokumentacija proizvodov (TDP) - Razvrščanje zahtev - 2. del:
Razvrščanje po težavnosti in občutljivosti (ISO 24096-2:2024)
Technical product documentation (TPD) - Classification of requirements - Part 2:
Classification based on severity and susceptibility (ISO 24096-2:2024)
Technische Produktdokumentation(TPD) - Klassifizierung von Anforderungen - Teil 2:
Klassifizierung nach Schweregrad und Empfindlichkeit (ISO 24096-2:2024)
Documentation technique de produits (TPD) - Classification des exigences - Partie 2:
Classification en fonction de la gravité et de la susceptibilité (ISO 24096-2:2024)
Ta slovenski standard je istoveten z: EN ISO 24096-2:2024
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 24096-2
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2024
EUROPÄISCHE NORM
ICS 01.100.01
English Version
Technical product documentation (TPD) - Classification of
requirements - Part 2: Classification based on severity and
susceptibility (ISO 24096-2:2024)
Documentation technique de produits (TPD) - Technische Produktdokumentation(TPD) -
Classification des exigences - Partie 2: Classification en Klassifizierung von Anforderungen - Teil 2:
fonction de la gravité et de la susceptibilité (ISO 24096- Klassifizierung nach Schweregrad und Empfindlichkeit
2:2024) (ISO 24096-2:2024)
This European Standard was approved by CEN on 24 August 2024.

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
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 24096-2:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 24096-2:2024) 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 2025, and conflicting national standards shall
be withdrawn at the latest by March 2025.
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.
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 24096-2:2024 has been approved by CEN as EN ISO 24096-2:2024 without any
modification.
International
Standard
ISO 24096-2
First edition
Technical product documentation
2024-09
(TPD) — Classification of
requirements —
Part 2:
Classification based on severity and
susceptibility
Documentation technique de produits (TPD) — Classification des
exigences —
Partie 2: Classification en fonction de la gravité et de la
susceptibilité
Reference number
ISO 24096-2:2024(en) © ISO 2024

ISO 24096-2:2024(en)
© ISO 2024
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 24096-2:2024(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2  Normative references . 1
3  Terms and definitions . 1
4 Basic rules . 2
5  Classification with severity and susceptibility . 2
5.1 The three steps .2
5.1.1 General .2
5.1.2 Evaluation of severity .3
5.1.3 Evaluation of susceptibility .3
5.1.4 Weighing severity and susceptibility together .3
5.2 Severity and severity lists .4
5.2.1 General .4
5.2.2 Severity description .4
5.2.3 Severity list.5
5.3 Function as the route to severity .5
5.3.1 Function description .5
5.3.2 Effects of deviating functions .5
5.3.3 Final severity .6
5.4 Susceptibility and the requirement pyramid .6
5.5 Weighing together .7
Annex A (informative)  Classification examples with severity and susceptibility . 8
Annex B (informative)  Guidance on susceptibility .21
Bibliography .23

iii
ISO 24096-2:2024(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO’s adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 10, Technical product documentation,
Subcommittee SC 6, Mechanical engineering 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).
A list of all parts in the ISO 24096 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 24096-2:2024(en)
Introduction
This document addresses the classification of requirements. It provides a framework for building a
system to enable the classification of requirements and an indication of the classification in the functional
specification, FUN-SPEC, to support communication of the consequences of nonconformity to functional
requirements. FUN-SPEC (see ISO/TS 21619) is a part of the technical product documentation (TPD). Other
approaches than classification of requirements can be state of the art in achieving the objective of securing
the end product.
This document has been developed mainly to be implemented within industry, e.g. the automotive and
aerospace industries. However, it can also be used in other engineering fields.
Classification of requirements is a tool by which subsequent parties and stakeholders can be informed of
the severity of consequences of nonconformity of requirements. This facilitates the guiding of production
and quality assurance resources (e.g. purchasing, production planning, control, revision). The classification
system relies on established procedures, regulatory framework and contractual agreements for
implementation and follow up as present in all modern industry.
There are several examples of industrial stakeholders that deploy their own or partially self-developed
system and methodology for classification of requirements. There has previously not been any ISO document
that pragmatically describes “what is” and “how to create” a classification system. This series bridges the
identified gap and meets the need to describe how to introduce and work with a classification system in an
industrial and design context.
Knowledge of the consequences of nonconformity with requirements, and actions taken to resolve the source
of the deviation from the given requirements, will have a positive effect on product quality, user safety and
economy of the product. Production and inspection resources can then be used where they are most needed.
Annex A gives classification examples with severity and susceptibility.
Annex B gives guidance on susceptibility.

v
International Standard ISO 24096-2:2024(en)
Technical product documentation (TPD) — Classification of
requirements —
Part 2:
Classification based on severity and susceptibility
1 Scope
This document specifies a method for the classification of requirements based on severity and susceptibility.
The classification method requires a system in line with the framework described in ISO 24096-1 to form a
complete system.
This document:
— gives guidance on the needed elements for a consistent evaluation of the severity over time, and supports
a company business model and its brand image;
— gives background to why additional parameters alongside severity are useful as a base for classification;
— adds susceptibility as a viable parameter along with severity;
— gives guidance on the methodology for classification requirements using severity and susceptibility.
2  Normative 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.
ISO 8015:2011, Geometrical product specifications (GPS) — Fundamentals — Concepts, principles and rules
ISO 10209, Technical product documentation — Vocabulary — Terms relating to technical drawings, product
definition and related documentation
ISO 24096-1, Technical product documentation (TPD) — Classification of requirements – Part 1: Framework
3  Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8015:2011, ISO 10209, ISO 24096-1
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
susceptibility
degree to which a function is affected by nonconformity of a requirement
Note 1 to entry: While a high susceptibility gives a large effect, a low susceptibility gives a lower effect for the same
deviation, see Figures B.1 and B.2.

ISO 24096-2:2024(en)
3.2
severity list
normative assessments of severity within each company or organization
4 Basic rules
Severity of a potential consequence at nonconformity shall be used as a parameter when classifying
requirements. However, equating classification with severity can lead to an overload of classification
indications in the TPD. A classification must therefore encompass more than the severity. In this document,
susceptibility to deviation is used in addition to severity to balance classification, see Clause 5 and Annex A.
All requirements in the product documentation shall be fulfilled in accordance with ISO 8015:2011, 4.3 and 4.4.
NOTE 1 The classification can be compared with risk assessment where risk is evaluated by combining severity
and probability, see Figure 1 and ISO 12100:2010, 5.5.2.1.
Severity is the gravity of possible consequence of nonconformity.
NOTE 2 Severity is defined in ISO 24096-1:2024, 3.4.
Figure 1 — Example of a template diagram for classification evaluation
Severity of nonconformity with a requirement and susceptibility to deviation are mandatory parameters in
a classification system to be assessed in the classification of a requirement.
Due to the variety of already existing solutions, this document is supporting material which can help
individual organizations when deciding on their own classification system and how to use it in the TPD.
Referencing this document in the TPD creates awareness that a classification system for the consequences
of nonconformity has been used, and that the classification system used has been developed following the
rules and information laid out in this document. The details of the classification itself and the symbology to
indicate the classes, however, are not given in this document but in the organization-specific system which
shall be referenced in the TPD. In this way, it is possible to use any of the already existing explicit solutions
or develop a new one, perhaps by modifying an existing one.
5  Classification with severity and susceptibility
5.1 The three steps
5.1.1 General
Classification with severity and susceptibility is made in three main steps. Severity and susceptibility are
treated as separate parameters which together determine the final classification of requirements.
The three steps are described in 5.1.2 to 5.1.4 and aspects of them are described in detail in 5.2 to 5.5.

ISO 24096-2:2024(en)
5.1.2  Evaluation of severity
By starting with severity, a screening is achieved. First, it reduces the relevant number of components that
can have requirements worthy of classification higher than baseline, see ISO 41014:2020, 3.5.1. Second,
it reduces the number of requirements on which the susceptibility needs to be evaluated. Evaluation and
grading of the severity should use a severity list for consistency.
In step 1, the evaluation of severity consists of answering three questions:
— 1.1 What are the functions of the design solution?
— Describe, in detail, what it shall do. List all functions.
— 1.2 What are the effects on the product and for the customer in case of a function deviation?
— List the effects of function deviation. Remember to include all side effects.
— 1.3 What type of severity heading is each effect associated with?
— Match each effect to its relevant severity rating. The highest recommended rating is found in the
severity list.
This is a bottom-up approach to determine severity, see Annex A for two applied examples.
NOTE When the severity is determined with a top-down analysis, it modifies the analysis to a degree. If the
top-down analysis is performed correctly, it identifies the maximum severity for the analysed component. The
classification does not still continue directly to step 2, since different deviations can give different severity and be
linked to different requirements.
5.1.3  Evaluation of susceptibility
In step 2, the evaluation of susceptibility consists of answering two questions:
— 2.1 Which requirements affect the function at a nonconformity (most)?
— List (the most influential) requirements to affect the function.
— 2.2 How closely outside the requirements will the function start to deteriorate?
— Evaluate the susceptibility of each listed requirement.
5.1.4  Weighing severity and susceptibility together
In step 3, the results from step 1 and step 2 are combined. The combination of severity and susceptibility
yields the classification for each requirement. A simple diagram, as exemplified in Figure 2, can be used.

ISO 24096-2:2024(en)
a) Uniform distribution of severity –  b) Non-uniform distribution of severity –
susceptibility relation susceptibility relation
Key
[CC] critical characteristics
[SC] significant characteristics
NOTE [1], [2] and baseline, and [SC], [CC] and baseline are classes used in two different example systems.
Figure 2 — Examples of diagrams weighing severity and susceptibility together for final
classification
5.2  Severity and severity lists
5.2.1 General
Severity is the first parameter to assess. To assess it, a firm understanding of the function of the design is
required. To get a consistent assessment of severity, a normative table is needed: this is called the “severity
list”. This should be a list of affected areas with its maximum potential severity rating. This reduces the
risk for arbitrary and personal views and assessments. The grading of the severity preferably has the same
number of steps as the final classification for easy evaluation. The severity list is built up in two steps, see
5.2.2 and 5.2.3.
5.2.2  Severity description
Step 1.1 is determining how different effects are viewed, see Table 1.

ISO 24096-2:2024(en)
Table 1 — Example of severity description in three levels
Level Description
High severity level At nonconformity to requirements, there is a risk for function deviation resulting in:
— personal injury;
— considerable damage which can cause unpredictable and unforeseeable stop and
inability to complete intended task;
— financial damage;
— environmental impact.
Moderate severity level At nonconformity to requirements, there is a risk for function deviation resulting in:
— loss of product function;
— inability to continue production;
— necessity of immediate repair.
Normal severity level At nonconformity to requirements, there is no risk for the effects listed above. Little or no
(Baseline) effect on important characteristics for the customer.
5.2.3  Severity list
Step 1.2 is determining which effects different areas can have and the severity level to which each effect
correlates. Starting with a coarse survey to identify the main parameters, see Table 2, is often useful.
Table 2 — Example of a severity list
Important customer requirement Severity
and/or product requirements
Safety effect High severity level
Financial effect High severity level
Environmental effect High severity level
Comfort effect Moderate severity level
Company or product image High severity level
The severity list is a breakdown evaluation of customer demands, development targets, product
requirements, and organization business model and philosophy.
The severity list contains the highest recommended classification for a failure effect. The severity lists can
be unique for each product section and should reflect the organization business model, including aspects as
image, model for profitability and customers’ expectations.
The severity lists can need to be company internal documents (confidential) as they reflect business trade-
offs, strategies and considerations.
5.3  Function as the route to severity
5.3.1 Function description
The function description shall express what the design “does”, not what it “is”. By clarifying all functions,
they can all be evaluated and secured. This constitutes step 1.1 in 5.2.2.
5.3.2  Effects of deviating functions
Based on the function description, the effects of deviating or failing functions can be deduced and described.
This corresponds to the sum of all failure effects for the classified item in a design failure mode and effects
analysis (FMEA), see IEC 60812:2018. It is important to find all the ultim
...