IEC 60695-9-2:2021

IEC 60695-9-2 ®
Edition 2.0 2021-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
HORIZONTAL PUBLICATION
PUBLICATION HORIZONTALE
Fire hazard testing –
Part 9-2: Surface spread of flame – Summary and relevance of test methods

Essais relatifs aux risques du feu –
Partie 9-2: Propagation des flammes en surface – Résumé et pertinence
des méthodes d'essai
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform IEC online collection - oc.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews. With a subscription you will always
committee, …). It also gives information on projects, replaced have access to up to date content tailored to your needs.
and withdrawn publications.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 000 terminological entries in English
details all new publications released. Available online and
and French, with equivalent terms in 18 additional languages.
once a month by email.
Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc
If you wish to give us your feedback on this publication or
need further assistance, please contact the Customer Service
Centre: sales@iec.ch.
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.

Recherche de publications IEC - IEC online collection - oc.iec.ch
webstore.iec.ch/advsearchform Découvrez notre puissant moteur de recherche et consultez
La recherche avancée permet de trouver des publications IEC gratuitement tous les aperçus des publications. Avec un
en utilisant différents critères (numéro de référence, texte, abonnement, vous aurez toujours accès à un contenu à jour
comité d’études, …). Elle donne aussi des informations sur adapté à vos besoins.
les projets et les publications remplacées ou retirées.

Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
Le premier dictionnaire d'électrotechnologie en ligne au
Restez informé sur les nouvelles publications IEC. Just
monde, avec plus de 22 000 articles terminologiques en
Published détaille les nouvelles publications parues.
anglais et en français, ainsi que les termes équivalents dans
Disponible en ligne et une fois par mois par email.
16 langues additionnelles. Egalement appelé Vocabulaire

Electrotechnique International (IEV) en ligne.
Service Clients - webstore.iec.ch/csc

Si vous désirez nous donner des commentaires sur cette
publication ou si vous avez des questions contactez-nous:
sales@iec.ch.
IEC 60695-9-2 ®
Edition 2.0 2021-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
HORIZONTAL PUBLICATION
PUBLICATION HORIZONTALE
Fire hazard testing –
Part 9-2: Surface spread of flame – Summary and relevance of test methods

Essais relatifs aux risques du feu –

Partie 9-2: Propagation des flammes en surface – Résumé et pertinence

des méthodes d'essai
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 13.220.40; 29.020 ISBN 978-2-8322-9997-5

– 2 – IEC 60695-9-2:2021 © IEC 2021
CONTENTS
FOREWORD . 3
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Summary of published test methods . 12
4.1 General . 12
4.2 The physical fire model . 12
4.3 Small-scale fire tests. 14
4.3.1 Horizontal and vertical 50 W and 500 W flame tests – IEC 60695-11-10
and IEC 60695-11-20 . 14
4.3.2 Fire hazard testing – Part 11-21: Test flames – 500 W vertical flame
test method for tubular polymeric materials – IEC TS 60695-11-21 [5] . 14
4.3.3 Flexible insulating sleeving – Part 2: Methods of test, Clause 26: Flame
propagation tests – IEC 60684-2:2011 [7], Clause 26 . 15
4.3.4 Vertical burning test for cables – IEC 60332-1 [9] . 16
4.3.5 Vertical burning test for cables – IEC 60332-2 [10] . 17
4.3.6 Flexible cellular polymeric materials – Laboratory assessment of horizontal
burning characteristics of small specimens subjected to a small flame –
ISO 3582 [11] . 18
4.3.7 Horizontal burning rate for road vehicle materials – ISO 3795 [12]. . 19
4.3.8 Cellular plastics – Determination of horizontal burning characteristics of
small specimens subjected to a small flame – ISO 9772 [13] . 19
4.3.9 Plastics – Determination of burning behaviour of thin flexible vertical
specimens in contact with a small-flame ignition source – ISO 9773 [15] . 20
4.3.10 Fire propagation apparatus – ISO 12136 [16] . 21
4.3.11 Plastics – Vertical flame spread determination for film and sheet –
ISO 12992 [27] . 23
4.3.12 Vertical burning test for aircraft materials – FAR 25 [29] . 23
4.4 Medium and intermediate-scale fire tests . 24
4.4.1 Lateral flame spread on building and transport products – ISO 5658-2 [30] . 24
4.4.2 Intermediate-scale fire test of vertical flame spread – ISO 5658-4 [33]. 25
4.4.3 Plastics – Reaction to fire – Test method for flame spread and combustion
product release from vertically oriented specimens – ISO 21367 [35] . 26
4.5 Intermediate and large-scale fire tests for cables . 26
4.5.1 General . 26
4.5.2 Vertical burning tests for cables (ladder tests) . 27
4.5.3 Vertical burning test for cables – NF C 32-070 [60] . 31
4.6 Real-scale fire tests for cables . 31
4.6.1 Standard for test for flame propagation height of electrical and optical-
fiber cables installed vertically in shafts – UL 1666 [61] . 31
4.6.2 Horizontal flame spread test for cables – EN 50289-4-11 [62] . 32
5 Overview of methods and relevance of data . 33
Bibliography . 38

Table 1 – Characteristics of fire stages (ISO 19706:2011) . 13
a)
Table 2 – Summary and comparison of IEC 60332 vertical ladder test methods [37] . 28
Table 3 – Summary and comparison of non-IEC vertical ladder test methods . 29
Table 4 – Overview of flame spread methods . 34

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIRE HAZARD TESTING –
Part 9-2: Surface spread of flame –
Summary and relevance of test methods

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60695-9-2 has been prepared by IEC technical committee 89: Fire
hazard testing.
It has the status of a basic safety publication in accordance with IEC Guide 104.
This second edition cancels and replaces the first edition of IEC 60695-9-2 published in 2014.
This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Updated introduction
b) Updated normative references
c) Updated terms and definitions
d) New Subclauses 4.1 and 4.2
– 4 – IEC 60695-9-2:2021 © IEC 2021
e) Reference to fire stages as defined in ISO 19706 (Table 1)
f) New sub-division of tests into the following subclauses:
4.3 Small-scale fire tests
4.4 Medium and intermediate-scale fire tests
4.5 Intermediate and large-scale fire tests for cables
4.6 Real-scale fire tests for cables
g) Updated text in parts of Clause 4
h) Addition of the following test methods:
IEC TS 60695-11-21
IEC 60684-2:2011, Clause 26
ISO 3582
ISO 9772
ISO 9773
ISO 12992
ISO 21367
i) New Clause 5 and Table 4 giving an overview of test methods
j) Deletion of all the Annexes
k) Updated bibliography
The text of this International Standard is based on the following documents:
Draft Report on voting
89/1469/CDV 89/1505/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement,
available at www.iec.ch/members_experts/refdocs. The main document types developed by
IEC are described in greater detail at www.iec.ch/standardsdev/publications.
A list of all parts in the IEC 60695 series, published under the general title Fire hazard testing,
can be found on the IEC website.
This International Standard is to be used in conjunction with IEC 60695-1.
In this standard, the following print types are used:
terms referred to in Clause 3: in italic type.

The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 60695-9-2:2021 © IEC 2021

INTRODUCTION
In the design of an electrotechnical product, the risk of fire and the potential hazards
associated with fire need to be considered. In this respect the objective of component, circuit
and equipment design, as well as the choice of materials, is to reduce the risk of fire to a
tolerable level even in the event of reasonably foreseeable (mis)use, malfunction or failure.
IEC 60695-1-10, IEC 60695-1-11 [1] , and IEC 60695-1-12 [2] provide guidance on how this is
to be accomplished.
Fires involving electrotechnical products can also be initiated from external non-electrical
sources. Considerations of this nature are dealt with in an overall fire hazard assessment.
The aim of the IEC 60695 series of standards is to save lives and property by reducing the
number of fires or reducing the consequences of the fire. This can be accomplished by:
• trying to prevent ignition caused by an electrically energised component part and, in the
event of ignition, to confine any resulting fire within the bounds of the enclosure of the
electrotechnical product;
• trying to minimise flame spread beyond the product’s enclosure and to minimise the
harmful effects of fire effluents including heat, smoke, and toxic or corrosive combustion
products.
Fire hazard increases as the burning area increases, leading in some cases to flashover and
a fully developed fire. This is a typical fire scenario in buildings. It is therefore useful to
measure the rate and extent of the surface spread of flame.
This part of IEC 60695-9 describes surface spread of flame test methods in common use to
assess electrotechnical products or materials used in electrotechnical products. It forms part
of the IEC 60695-9 series which gives guidance to product committees wishing to incorporate
test methods for surface spread of flame in product standards.

___________
Numbers in square brackets refer to the bibliography.

FIRE HAZARD TESTING –
Part 9-2: Surface spread of flame –
Summary and relevance of test methods

1 Scope
This part of IEC 60695-9 presents a summary of published test methods that are used to
determine the surface spread of flame of electrotechnical products or materials from which
they are formed.
It represents the current state of the art of the test methods and, where available, includes
special observations on their relevance and use.
The list of test methods is not to be considered exhaustive, and test methods that were not
developed by the IEC are not to be considered as endorsed by the IEC unless this is
specifically stated.
This summary cannot be used in place of published standards which are the only valid
reference documents.
This basic safety publication is intended for use by technical committees in the preparation of
standards in accordance with the principles laid down in IEC Guide 104 and
ISO/IEC Guide 51.
One of the responsibilities of a technical committee is, wherever applicable, to make use of
basic safety publications in the preparation of its publications. The requirements, test
methods or test conditions of this basic safety publication will not apply unless specifically
referred to or included in the relevant publications.
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.
IEC 60695-1-10, Fire hazard testing – Part 1-10: Guidance for assessing the fire hazard of
electrotechnical products – General guidelines
IEC 60695-4:2012, Fire hazard testing – Part 4: Terminology concerning fire tests for
electrotechnical products
IEC 60695-9-1, Fire hazard testing – Part 9-1: Surface spread of flame – General guidance
IEC GUIDE 104, The preparation of safety publications and the use of basic safety
publications and group safety publications
ISO/IEC Guide 51, Safety aspects – Guidelines for their inclusion in standards
ISO 13943:2017, Fire Safety – Vocabulary

– 8 – IEC 60695-9-2:2021 © IEC 2021
ISO 19706:2011, Guidelines for assessing the fire threat to people.
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60695-4:2012 and
ISO 13943:2017 (some of which are reproduced below) and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
burned length
maximum extent in a specified direction of the burned area
Note 1 to entry: The typical unit is m.
Note 2 to entry: Compare with the term damaged length (3.5).
[SOURCE: ISO 13943: 2017, definition 3.37]
3.2
char length
length of charred area
Note 1 to entry: Compare with the terms burned length (3.1) and damaged length (3.5).
Note 2 to entry: In some standards, char length is defined by a specific test method.
[SOURCE: ISO 13943: 2017, definition 3.49]
3.3
combustible, noun
item capable of combustion (3.4)
[SOURCE: ISO 13943: 2017, definition 3.53]
3.4
combustion
exothermic reaction of a substance with an oxidizing agent
Note 1 to entry: Combustion generally emits fire effluent accompanied by flames (3.11) and/or glowing.
[SOURCE: ISO 13943: 2017, definition 3.55]
3.5
damaged length
maximum extent in a specified direction of the damaged area
Note 1 to entry: Compare with the terms char length (3.2) and burned length (3.1)
[SOURCE: ISO 13943: 2017, definition 3.73]
3.6
fire
〈general〉 process of combustion (3.4) characterized by the emission of heat and fire effluent
and usually accompanied by smoke, flame (3.11), glowing or a combination thereof

Note 1 to entry: In the English language the term “fire” is used to designate three concepts, two of which relate to
specific types of self-supporting combustion with different meanings. Of these three, two of them are designated
using two different terms in both French and German.
[SOURCE: ISO 13943: 2017, definition 3.114]
3.7
fire
〈controlled〉 self-supporting combustion (3.4) that has been deliberately arranged to provide
useful effects and is limited in its extent in time and space
[SOURCE: ISO 13943: 2017, definition 3.115]
3.8
fire
〈uncontrolled〉 self-supporting combustion (3.4) that has not been deliberately arranged to
provide useful effects and is not limited in its extent in time and space
[SOURCE: ISO 13943: 2017, definition 3.116]
3.9
fire hazard
potential for harm associated with fire (3.8)
Note 1 to entry: Alternatively, fire hazard can be a physical object or condition with a potential for an undesirable
consequence from fire.
[SOURCE: ISO 13943: 2017, definition 3.131]
3.10
fire scenario
qualitative description of the course of a fire (3.8) with respect to time, identifying key events
that characterize the studied fire and differentiate it from other possible fires
Note 1 to entry: It typically defines the ignition (3.18) and fire growth processes, the fully developed fire (3.16)
stage, the fire decay stage, and the environment and systems that impact on the course of the fire.
Note 2 to entry: Unlike deterministic fire analysis, where fire scenarios are individually selected and used as
design fire scenarios, in fire risk assessment, fire scenarios are used as representative fire scenarios within fire
scenario clusters.
[SOURCE: ISO 13943: 2017, definition 3.152, modified – Note 1 removed as not relevant]
3.11
flame, noun
zone in which there is rapid, self-sustaining, sub-sonic propagation of combustion (3.4) in a
gaseous medium, usually with emission of light
[SOURCE: ISO 13943: 2017, definition 3.159 – modified by the addition of “zone in which
there is”]
3.12
flame front
boundary of flaming combustion at the surface of a material or propagating through a gaseous
mixture
[SOURCE: ISO 13943: 2017, definition 3.162]

– 10 – IEC 60695-9-2:2021 © IEC 2021
3.13
flame spread
propagation of a flame front (3.12)
[SOURCE: ISO 13943: 2017, definition 3.168]
3.14
flame-spread rate
DEPRECATED: burning rate
DEPRECATED: rate of burning
distance travelled by a flame front (3.12) during its propagation, divided by the time of travel,
under specified conditions
-1
Note 1 to entry: The typical unit is m.s .
[SOURCE: ISO 13943: 2017, definition 3.169]
3.15
flashover
〈stage of fire〉 transition to a state of total surface involvement in a fire (3.8) of combustible
materials within an enclosure
[SOURCE: ISO 13943: 2017, definition 3.184]
3.16
fully developed fire
state of total involvement of combustible materials in a fire (3.6)
[SOURCE: ISO 13943: 2017, definition 3.192]
3.17
heat release rate
DEPRECATED: burning rate
DEPRECATED: rate of burning
rate of thermal energy production generated by combustion (3.4)
Note 1 to entry: The typical unit is W.
[SOURCE: ISO 13943: 2017, definition 3.206]
3.18
ignition
DEPRECATED: sustained ignition
〈general〉 initiation of combustion (3.4)
[SOURCE: ISO 13943: 2017, definition 3.217]
3.19
ignition source
source of energy that initiates combustion (3.4)
[SOURCE: ISO 13943: 2017, definition 3.219]
3.20
intermediate-scale fire test
fire test performed on a test specimen of medium dimensions

Note 1 to entry: A fire test performed on a test specimen for which the maximum dimension is between 1 m and
3 m is usually called an intermediate-scale fire test.
Note 2 to entry: The dimensions in Note 1 to entry usually refer to reaction-to-fire testing and not to fire
resistance testing.
Note 3 to entry: ISO 29903 considers medium dimensions to be those with a maximum dimension between 1 m
and 3 m.
[SOURCE: ISO 13943: 2017, definition 3.233]
3.21
large-scale fire test
fire test that cannot be carried out in a typical laboratory chamber, performed on a test
specimen of large dimensions
Note 1 to entry: A fire test performed on a test specimen of which the maximum dimension is greater than 3 m is
usually called a large-scale fire test.
[SOURCE: ISO 13943: 2017, definition 3.239]
3.22
medium-scale fire test
fire test performed on a test specimen of small-medium size dimensions
Note 1 to entry: A fire test performed on a test specimen of which the maximum dimension is between 0,5 m and
1,0 m is often called a medium-scale fire test.
Note 2 to entry: The dimensions referenced in Note 1 to entry usually refer to reaction-to-fire testing and not to
fire resistance testing, where a maximum dimension of 1 m corresponds to a small-scale test.
[SOURCE: ISO 13943: 2017, definition 3.269]
3.23
pyrolysis
chemical decomposition of a substance by the action of heat
Note 1 to entry: Pyrolysis is often used to refer to a stage of fire (3.6) before flaming combustion has begun.
Note 2 to entry: In fire science, no assumption is made about the presence or absence of oxygen.
[SOURCE: ISO 13943: 2017, definition 3.316]
3.24
real-scale fire test
fire test that simulates a given application, taking into account the real scale, the real way the
item is installed and used, and the environment
Note 1 to entry: Such a fire test normally assumes that the products will be used in accordance with the
conditions laid down by the specifier and/or in accordance with normal practice.
[SOURCE: ISO 13943: 2017, definition 3.325]
3.25
riser cable
cable that runs vertically between floors in a building
Note 1 to entry: This is a term used predominantly in North America
3.26
small-scale fire test
fire test performed on a test specimen of small dimensions

– 12 – IEC 60695-9-2:2021 © IEC 2021
Note 1 to entry: There is no clear upper limit for the dimensions of the test specimen in a small-scale fire test. In
some instances, a fire test performed on a test specimen with a maximum dimension of less than 1 m is called a
small-scale fire test. However, a fire test performed on a test specimen of which the maximum dimension is
between 0,5 m and 1,0 m is often called a medium-scale fire test.
[SOURCE: ISO 13943: 2017, definition 3.346]
3.27
surface spread of flame
flame spread (3.13) away from the source of ignition (3.18) across the surface of a liquid or a
solid
[SOURCE: ISO 13943: 2017, definition 3.378]
4 Summary of published test methods
4.1 General
This summary does not replace published standards, which are the only valid reference
documents.
In cases where fire tests are not yet specified, and need to be developed or altered for the
special purpose of an IEC technical committee, this shall be done in liaison with the relevant
IEC technical committee, as mandated by IEC Guide 104. The test method(s) selected shall
be relevant to the fire scenario of concern. Guidance on the selection and relevance of fire
tests for electrotechnical products is given in IEC 60695-1-10.
General guidance on surface spread of flame tests for electrotechnical products is given in
IEC 60695-9-1.
4.2 The physical fire model
Flame spread is not an inherent property of a material or product, but is critically dependent
on the conditions under which that material or product is burnt. The various factors that affect
flame spread are discussed in IEC 60695-9-1.
It is important to show that the test conditions defined in a standardised test method (the
physical fire model) are relevant to, and replicate the desired stage of a real fire. ISO has
published a general classification of fire stages in ISO 19706:2011, shown in Table 1.

Table 1 – Characteristics of fire stages (ISO 19706:2011)
Fire stage Heat flux to Max. temperature °C Oxygen volume % Fuel/air
[CO] 100 ×[CO2]
fuel surface equivalence
[CO2] ([CO2] + [CO])
kW/m ratio (plume)
Fuel surface Upper layer Entrained Exhausted
v/v % efficiency
1. Non-flaming
a. self-sustaining
d
n.a. 450 to 800 25 to 85 20 20 0,1 to 1 50 to 90

(smouldering)
b. oxidative pyrolysis from
a b c c
 300 to 600 20 20 < 1
externally applied radiation
c. anaerobic pyrolysis from
b c c
 100 to 500 0 0 >> 1
externally applied radiation
d e
2. Well-ventilated flaming 0 to 60 350 to 650 50 to 500 ≈ 20 ≈ 20 < 1 < 0,05 > 95
f
3. Under-ventilated flaming
a. small, localized fire,
a
generally in a poorly 0 to 30 300 to 600 50 to 500 15 to 20 5 to 10 > 1 0,2 to 0,4 70 to 80
ventilated compartment
g h i
b. post-flashover fire 50 to 150 350 to 650 > 600 < 15 < 5 > 1 0,1 to 0,4 70 to 90
a The upper limit is lower than for well-ventilated flaming combustion of a given combustible.
b The temperature in the upper layer of the fire room is most likely determined by the source of the externally applied radiation and room geometry.
c There are few data; but for pyrolysis, this ratio is expected to vary widely depending on the material chemistry and the local ventilation and thermal conditions.
d The fire’s oxygen consumption is small compared to that in the room or the inflow, the flame tip is below the hot gas upper layer or the upper layer is not yet significantly
vitiated to increase the CO yield significantly, the flames are not truncated by contact with another object, and the burning rate is controlled by the availability of fuel.
e The ratio may be up to an order of magnitude higher for materials that are fire-resistant. There is no significant increase in this ratio for equivalence ratios up to ≈ 0,75.
Between ≈ 0,75 and 1, some increase in this ratio may occur.
f The fire’s oxygen demand is limited by the ventilation opening(s); the flames extend into the upper layer.
g Assumed to be similar to well-ventilated flaming.
h The plume equivalence ratio has not been measured; the use of a global equivalence ratio is inappropriate.
i Instances of lower ratios have been measured. Generally, these result from secondary combustion outside the room vent.

– 14 – IEC 60695-9-2:2021 © IEC 2021
4.3 Small-scale fire tests
4.3.1 Horizontal and vertical 50 W and 500 W flame tests – IEC 60695-11-10
and IEC 60695-11-20
4.3.1.1 Purpose and principle
IEC 60695-11-10 [3] is a test using a 50 W flame. IEC 60695-11-20 [4] is a test using a 500 W
flame. These tests refer to solid electrical insulating materials and are intended to serve as a
preliminary indication of their behaviour when exposed to an ignition source. The results make
it possible to check the constancy of the characteristics of a material and provide an
indication of the progress in the development of the flame retardancy of insulating materials.
The results also provide a relative comparison and classification of insulating materials.
4.3.1.2 Test specimen
The relatively small test specimen is 125 mm long, 13 mm wide, and up to 13 mm thick.
4.3.1.3 Test method
These tests involve the application of an ignition source to a horizontal or vertical test
specimen and the evaluation of the linear burning rate (HB classification) and the vertical
spread of flame (V classification).
4.3.1.4 Repeatability and reproducibility
Data are available in IEC 60695-11-10:2013, Annexes A and B, and IEC 60695-11-20:2015,
Annex A.
4.3.1.5 Relevance of test data
These test methods are used to evaluate materials. The test methods provide classifications
that may be used for quality assurance, the preselection of component materials of products,
or to verify the required minimum flammability classification of materials used in end products.
The tests are not valid for determining the fire behaviour and fire hazard of complete items of
equipment, since the dimensions of the insulating systems and the design and heat transfer to
adjacent metallic parts, greatly influence the flammability of the electrical insulating materials
being used.
4.3.2 Fire hazard testing – Part 11-21: Test flames – 500 W vertical flame test method
for tubular polymeric materials – IEC TS 60695-11-21 [5]
4.3.2.1 Purpose and principle
This document describes a small-scale laboratory pass/fail procedure which is based on the
comparative burning characteristics of tubular polymeric materials. A flame is applied to test
specimens held in a vertical position, supported by a wire or mandrel. Upon removal of the
test flame, the extinguishing times and the burning characteristics are determined.
4.3.2.2 Test specimen
Test specimens are at least 450 mm long samples of tubular polymeric material.
4.3.2.3 Test method
A burner conforming to IEC 60695-11-3 [6], Method A, is used. This provides a pre-mixed
methane flame of nominal power 500 W.
The test specimen is secured by a wire or mandrel with its longitudinal axis vertical. An
indicator flag is attached to the test specimen with its lower edge (250 ± 2) mm above the

point at which the blue inner cone of the test flame touches the test specimen. A flat
horizontal layer of cotton is placed below the test specimen.
The flame is applied for (15 ± 0,5) s to the side of the test specimen at a point near its lower
edge. It is then removed for (15 ± 0,5) s. The flaming time, t, is noted. This operation is
repeated until the test specimen has been subjected to five applications of the test flame.
Where flaming of the test specimen persists longer than 15 s after the previous application of
the test flame, the test flame is not reapplied until flaming of the test specimen has ceased of
its own accord. The test flame is reapplied as soon as flaming of the test specimen has
ceased.
The test specimen is considered to have passed the test if three criteria apply to all three test
specimens. These are:
a) the test specimen does not flame longer than 60 s following any of five 15 s applications of
the test flame;
b) flaming material from the test specimen does not ignite the cotton pad; and
c) the indicator flag is not more than 25 % damaged, during, between, or after the five
applications of the test flame.
4.3.2.4 Repeatability and reproducibility
No data are given.
4.3.2.5 Relevance of test data
This test method can be used to compare the burning characteristics of tubular polymeric
materials. It can be used to compare the relative performance of materials, to aid in material
selection, for quality control purposes and for quality assurance.
It is not to be used to compare the burning characteristics of any wire or cable products or
any cable management systems.
4.3.3 Flexible insulating sleeving – Part 2: Methods of test, Clause 26:
Flame propagation tests – IEC 60684-2:2011 [7], Clause 26
4.3.3.1 Purpose and principle
These are three small-scale laboratory procedures of different severities for determining the
burning characteristics of flexible insulating sleeving. Methods A and B are vertical burning
o
tests. Method C tests a sample at 20 from the vertical.
NOTE IEC 60684-3 [8] indicates which tests should be applied to a particular type or grade of sleeving.
4.3.3.2 Method A
4.3.3.2.1 Test specimen
Test specimens are at least 450 mm long. Heat-shrinkable sleeving is recovered before
testing. The bore of the sleeving is not more than 10 mm.
NOTE For heat-shrinkable sleeving, this dimension is the specified recovered bore.
4.3.3.2.2 Test method
Tests are carried out in accordance with IEC TS 60695-11-21:2005 except that the source of
heat is as defined in 26.3 of IEC 60684:2011.

– 16 – IEC 60695-9-2:2021 © IEC 2021
4.3.3.3 Method B
4.3.3.3.1 Test specimen
Test specimens are approximately 660 mm long (recovered in the case of heat-shrinkable
sleeving) and are supported on piano wire 900 mm in length. The sleeving is closed at the top
end to prevent a chimney effect.
4.3.3.3.2 Test method
Tests are carried out in accordance with IEC TS 60695-11-21:2005 except that the source of
heat is as defined in 26.3 of IEC 60684-2:2011.
4.3.3.4 Method C
4.3.3.4.1 Test specimen
Test specimens are approximately 560 mm long (recovered in the case of heat-shrinkable
sleeving) and are supported on piano wire 800 mm in length. The sleeving is closed at the top
end to prevent a chimney effect.
4.3.3.4.2 Test method
The source of heat is as defined in 26.3 of IEC 60684-2:2011. An indicator flag is attached to
the test specimen with its lower edge (250 ± 2) mm away from the point at which the blue
inner cone of the test flame touches the test specimen. There is no cotton layer.
o
The test specimen is supported so as to be 20 from the vertical and the flame is applied at
o
45 to the test specimen. The flame is applied for 15 s to the side of the test specimen at a
point near its lower edge. After-flame time is noted as well as the length of burned specimen.
4.3.3.5 Repeatability and reproducibility
No data are given.
4.3.3.6 Relevance of test data
These test methods are used in order to determine if products meet specifications given
in IEC 60684-3. It can also be used for quality control purposes and for quality assurance.
4.3.4 Vertical burning test for cables – IEC 60332-1 [9]
4.3.4.1 Purpose and principle
This test method specifies a method of testing a single vertical wire or cable or optical cable
under fire conditions. IEC 60332-1-1 defines the apparatus. IEC 60332-1-2 defines the
procedure. The char length of a vertical test specimen, exposed to a 1 kW pre-mixed flame in
a suitable chamber, is measured. The standard includes, in an informative annex,
recommended requirements for compliance for use where these are not given in the cable
product standard. IEC 60332-1-3 is a procedure for determination of flaming
droplets/particles.
The method specified is not suitable for the testing of small single insulated conductors or
cables of less than 0,5 mm total cross-section, because the conductor melts before the test
is completed, or for the testing of small optical fibre cables because the cable is broken
before the test is completed – see 4.1.3.
NOTE The corresponding EN standards are EN 60332-1-1, EN 60332-1-2 and EN 60332-1-3.

4.3.4.2 Test specimen
The test specimen consists of a piece of finished wire or cable 600 mm ± 25 mm long.
4.3.4.3 Test method
The test specimen is held in a vertical position by means of two support arms within a three-
sided metallic screen. A calibrated burner is used to ignite the test specimen. Its flame is
continuously applied for a period of time which is related to the overall diameter of the test
specimen. The damaged length of the test specimen is then noted.
4.3.4.4 Repeatability and reproducibility
No data are known to be available.
4.3.4.5 Relevance of test data
This method is used to determine the extent of vertical burning of a single finished wire or
cable by measuring the char length.
The use of insulated wire or cable, which retards flame propagation and complies with the
requirements of this standard, cannot be assumed by itself to prevent propagation of fire
under all conditions of installation. Two examples of such conditions are:
a) vertical runs of bunched or bundled cables
b) potential ignition sources that would impose a more intense thermal environment than that
provided by the test method.
It is recommended that wherever the risk of propagation is high, special installation
precautions should be taken.
4.3.5 Vertical burning test for cables – IEC 60332-2 [10]
4.3.5.1 Purpose and principle
This test method specifies a method of testing a small insulated wire under fire conditions
when the method specified in vertical burning test IEC 60332-1 is not suitable – see 4.1.2.1.
IEC 60332-2-1 defines the apparatus. IEC 60332-2-2 defines the procedure. The char length
of a vertical test specimen, exposed to a diffusion flame of length 125 mm ± 25 mm in a
draught-free chamber, is measured. The standard includes, in an informative annex,
recommended requirements for compliance for use where these are not given in the cable
product standard.
NOTE The corresponding EN standards are EN 60332-2-1 and EN 60332-2-2.
4.3.5.2 Test specimen
The test specimen consists of a piece of finished copper wire or cable or optical cable,
600 mm ± 25 mm long.
4.3.5.3 Test method
The test specimen is held in a vertical position by means of two support arms within a three-
sided metallic screen. A load of 5 N for each mm of conductor area is attached to the lower
part of the test specimen. A calibrated burner is used to ignite the test specimen. Its flame is
continuously applied for a maximum period of 20 s. The damaged length of the test specimen
is then noted.
--
...