IEC TS 60695-11-11:2016

IEC TS 60695-11-11 ®
Edition 2.0 2016-02
TECHNICAL
SPECIFICATION
SPECIFICATION
TECHNIQUE
colour
inside
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ

Fire hazard testing –
Part 11-11: Test flames – Determination of the characteristic heat flux for ignition
from a non-contacting flame source

Essais relatifs aux risques du feu –
Partie 11-11: Flammes d'essai – Détermination du flux de chaleur caractéristique
pour l'allumage à partir d'une flamme source sans contact

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 Fax: +41 22 919 03 00
CH-1211 Geneva 20 info@iec.ch
Switzerland www.iec.ch
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 corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing 20 000 terms and definitions in
Technical Specifications, Technical Reports and other English and French, with equivalent terms in 15 additional
documents. Available for PC, Mac OS, Android Tablets and languages. Also known as the International Electrotechnical
iPad. Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a 65 000 electrotechnical terminology entries in English and
variety of criteria (reference number, text, technical French extracted from the Terms and Definitions clause of
committee,…). It also gives information on projects, replaced IEC publications issued since 2002. Some entries have been
and withdrawn publications. collected from earlier publications of IEC TC 37, 77, 86 and

CISPR.
IEC Just Published - webstore.iec.ch/justpublished

Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: csc@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.

Catalogue IEC - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
Application autonome pour consulter tous les renseignements
Le premier dictionnaire en ligne de termes électroniques et
bibliographiques sur les Normes internationales,
électriques. Il contient 20 000 termes et définitions en anglais
Spécifications techniques, Rapports techniques et autres
et en français, ainsi que les termes équivalents dans 15
documents de l'IEC. Disponible pour PC, Mac OS, tablettes
langues additionnelles. Egalement appelé Vocabulaire
Android et iPad.
Electrotechnique International (IEV) en ligne.

Recherche de publications IEC - www.iec.ch/searchpub
Glossaire IEC - std.iec.ch/glossary
La recherche avancée permet de trouver des publications IEC 65 000 entrées terminologiques électrotechniques, en anglais
en utilisant différents critères (numéro de référence, texte, et en français, extraites des articles Termes et Définitions des
comité d’études,…). Elle donne aussi des informations sur les publications IEC parues depuis 2002. Plus certaines entrées
projets et les publications remplacées ou retirées. antérieures extraites des publications des CE 37, 77, 86 et

CISPR de l'IEC.
IEC Just Published - webstore.iec.ch/justpublished

Service Clients - webstore.iec.ch/csc
Restez informé sur les nouvelles publications IEC. Just
Published détaille les nouvelles publications parues. Si vous désirez nous donner des commentaires sur cette
Disponible en ligne et aussi une fois par mois par email. publication ou si vous avez des questions contactez-nous:
csc@iec.ch.
IEC TS 60695-11-11 ®
Edition 2.0 2016-02
TECHNICAL
SPECIFICATION
SPECIFICATION
TECHNIQUE
colour
inside
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ

Fire hazard testing –
Part 11-11: Test flames – Determination of the characteristic heat flux for ignition

from a non-contacting flame source

Essais relatifs aux risques du feu –

Partie 11-11: Flammes d'essai – Détermination du flux de chaleur caractéristique

pour l'allumage à partir d'une flamme source sans contact

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 13.220.40, 29.020 ISBN 978-2-8322-3177-7

– 2 – IEC TS 60695-11-11:2016  IEC 2016
CONTENTS
FOREWORD . 4
INTRODUCTION . 7
1 Scope . 8
2 Normative references. 8
3 Terms and definitions . 8
4 Principle of the test . 9
5 Apparatus . 9
5.1 Test arrangement . 9
5.2 Burner and test flame . 10
5.3 Heat flux meter . 10
5.4 Data acquisition system . 11
5.5 Dummy test specimen board . 11
5.6 Masking board . 11
5.7 Timing device . 12
5.8 Conditioning . 12
5.9 Test specimen support . 12
5.10 Burner support . 12
5.11 Observation mirror . 12
6 Test specimen . 12
6.1 Specimen preparation . 12
6.2 Test specimen dimensions . 12
6.3 Testing ranges in formulations . 13
6.3.1 General . 13
6.3.2 Density, melt flows and filler/reinforcement . 13
6.3.3 Colour . 13
6.4 Conditioning of test specimens . 13
7 Testing conditions . 13
8 Test procedure . 13
8.1 Determination of incident heat flux calibration curve . 13
8.2 Determination of ignition times . 14
8.3 Repetition of the test at different heat flux values . 14
9 Evaluation of test results . 15
9.1 Average ignition time t . 15
ig
9.2 Report format for CHFI . 15
9.3 Precision data . 15

10 Test report. 15
Annex A (informative) An example of the calibration curve of incident heat flux versus
the distance between the top of the burner tube and the lower surface of the test
specimen . 16
A.1 Calibration curves . 16
Annex B (informative) Examples of ignition times with various materials of 3 mm
thickness . 18
B.1 Materials tested . 18
Annex C (informative) Precision data. 21
C.1 General . 21

C.2 Heat flux versus distance at different Gas flow rates . 21
C.3 Repeatability . 22
C.4 Calculations and plots . 23
Bibliography . 25

Figure 1 – Arrangement and position of test specimen and burner . 10
Figure 2 – Dummy test specimen board . 11
Figure 3 – Structure of the masking board . 12
Figure A.1 – Calibration curve (example) . 16
Figure B.1 – Example of ignition times of PMMA . 18
Figure B.2 – Ignition times for ABS (example) . 19
Figure B.3 – Ignition times for HIPS (example) . 19
Figure C.1 – Incident heat flux calibration curve (Gas flow rate = 105 cm /min) . 21
Figure C.2 – Incident heat flux calibration curve (Gas flow rate = 160 cm /min) . 22
Figure C.3 – 1/t for Material A . 23
ig
Figure C.4 – 1/t for Material B . 23
ig
Figure C.5 – 1/t for Material C . 24
ig
Figure C.6 – 1/t for Material D . 24
ig
Table A.1 – Calibration data (examples of actual measured data as shown in
Figure A.1) . 17
Table A.2 – Calibration data (examples of interpolated values) . 17
Table B.1 – Illustrative example of tabulated results . 20
Table C.1 – Precision data of ignition time . 22

– 4 – IEC TS 60695-11-11:2016  IEC 2016
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIRE HAZARD TESTING –
Part 11-11: Test flames – Determination of the characteristic
heat flux for ignition from a non-contacting flame source

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.
The main task of IEC technical committees is to prepare International Standards. In
exceptional circumstances, a technical committee may propose the publication of a technical
specification when
• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• the subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
Technical specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC TS 60695-11-11, which is a technical specification, 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 and ISO/IEC
Guide 51.
This second edition of IEC TS 60695-11-11 cancels and replaces the first edition published in
2008. It constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Fix of editiorials throughout the text;
b) Introduction updated;
c) Normative references updated;
d) Results of recent round-robin testing incorporated; and
e) Informative Annex C "Precision data" added.
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
89/1227/DTS 89/1248/RVC
Full information on the voting for the approval of this technical specification can be found in
the report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
This technical specification is to be used in conjunction with IEC 60695-11-4.
A list of all the parts in the IEC 60695 series, under the general title Fire hazard testing, can
be found on the IEC website.
Part 11 consists of the following parts:
Part 11-2: Test flames – 1 kW nominal pre-mixed flame – Apparatus, confirmatory test
arrangement and guidance
Part 11-3: Test flames – 500 W flames – Apparatus and confirmational test methods
Part 11-4: Test flames – 50 W flame – Apparatus and confirmational test method
Part 11-5: Test flames – Needle-flame test method – Apparatus, confirmatory test
arrangement and guidance
Part 11-10: Test flames – 50 W horizontal and vertical flame test methods
Part 11-11: Test flames – Determination of the characteristic heat flux for ignition from a
non-contacting flame source
Part 11-20: Test flames – 500 W flame test methods
Part 11-21: Test flames – 500 W vertical flame test method for tubular polymeric materials
Part 11-30: Test flames – History and development from 1979 to 1999
Part 11-40: Test flames – Confirmatory tests – Guidance

– 6 – IEC TS 60695-11-11:2016  IEC 2016
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• transformed into an International standard,
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The “colour inside” logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this publication using a colour printer.

INTRODUCTION
In the design of any 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, together with its companion, IEC 60695-1-11, provide guidance on how this
is to be accomplished.
Fires involving electrotechnical products can 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.
This technical specification is to be used to measure and describe the properties of materials
used for electrotechnical products and sub-assemblies in response to heat from a non-
contacting flame source under controlled laboratory conditions and is to not be used to
describe or appraise the fire hazard or fire risk of materials, products, or assemblies under
actual fire conditions. However, results of this test can be used as elements of a fire hazard
assessment which takes into account all of the factors which are pertinent to an assessment
of the fire hazard of a particular end use. A test specimen cut from end-product or sub-
assembly can be tested by this test method.
This technical specification may involve hazardous materials, operations, and equipment. It
does not purport to address all of the safety problems associated with its use. It is the
responsibility of the user to establish appropriate safety and health practices and determine
the applicability of regulatory limitations prior to use.
Test methods to determine flammability by contact of flame have been developed and
standardized already, such as IEC 60695-11-10 [1] and IEC 60695-11-20 [2] and
ISO 4589-2 [3] .
This is the first test method to determine the characteristic heat flux for ignition (CHFI) of
materials used for electrotechnical products and sub-assemblies from a non-contacting flame
source. CHFI characterizes ignition behaviour in terms of incident heat flux. This test method
simulates the fire behaviour of materials used for electrotechnical products where a flame
source exists close to, but does not contact with these items. An example is a candle flame
near an electrotechnical product.
___________
Numbers in square brackets refer to the bibliography.

– 8 – IEC TS 60695-11-11:2016  IEC 2016
FIRE HAZARD TESTING –
Part 11-11: Test flames – Determination of the characteristic
heat flux for ignition from a non-contacting flame source

1 Scope
This part of IEC 60695, which is a technical specification describes a test method used to
determine the characteristic heat flux for ignition (CHFI) from a non-contacting flame source
for materials used in electrotechnical products and sub-assemblies. It provides a relationship
between ignition time and incident heat flux. A test specimen cut from an end-product or sub-
assembly can be tested by this test method.
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, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60695-11-4, Fire hazard testing – Part 11-4: Test flames – 50 W flame – Apparatus and
confirmational test method
IEC Guide 104, The preparation of safety publications and the use of basic safety publications
and group safety publications
ISO/IEC Guide 51:1999, Safety aspects – Guidelines for their inclusion in standards
ISO 291, Plastics – Standard atmospheres for conditioning and testing
ISO 293, Plastics – Compression moulding of test specimens of thermoplastic materials
ISO 294 (all parts), Plastics – Injection moulding of test specimens of thermoplastic materials
ISO 295, Plastics – Compression moulding of test specimens of thermosetting materials
ISO 13943:2008, Fire safety – Vocabulary
ISO 14934-4:2014, Fire tests – Calibration of heat flux meters – Part 4: Guidance on the use
of heat flux meters in fire tests
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 13943:2008, some
of which are reproduced below for the user’s convenience, as well as the following apply.
3.1
average ignition time, t
ig
arithmetic mean of three ignition times measured at a given heat flux

3.2
characteristic heat flux for ignition
CHFI
maximum incident heat flux which is a multiple of 5 kW/m and at which t is greater than
ig
120 s
3.3
draught-free environment
space in which the results of experiments are not significantly affected by the local air speed
Note 1 to entry: A qualitative example is a space in which a wax candle flame remains essentially undisturbed.
Quantitative examples are small-scale fire tests in which a maximum air speed of 0,1 m/s or 0,2 m/s is sometimes
specified.
[SOURCE: ISO 13943:2008, 4.70]
3.4
heat flux
amount of thermal energy emitted, transmitted or received per unit area and per unit time
Note 1 to entry: The typical units are watts per square metre (W/m ).
[SOURCE: ISO/IEC 13943:2008, 4.173]
3.5
ignition
initiation of combustion which results in a sustained flaming combustion for at least 5 s
Note 1 to entry: The term “ignition” in French has a very different meaning [state of body combustion].
3.6
incident heat flux
heat flux received by the surface of a test specimen
[SOURCE: IEC 60695-4:2012, 3.2.15]
4 Principle of the test
The incident heat flux is measured using the apparatus described in 5.3 and 5.4. The incident
heat flux value is controlled by changing the distance between the top of the burner tube and
the lower surface of the test specimen and by changing the flow rate of gas to the burner (See
Annex A). The time required to ignite the test specimen is measured as a function of the
incident heat flux. The tests are performed at different incident heat flux values until the
maximum heat flux, at which t is greater than 120 s and defined as the characteristic heat
ig
flux for ignition (CHFI), is obtained. The incident heat flux values at which the tests are
2 2
carried out are chosen within the range of 30 kW/m to 75 kW/m and shall be a multiple of
5 kW/m .
5 Apparatus
5.1 Test arrangement
The arrangement and position of the test specimen and burner are shown in Figure 1. The
test specimen and masking board shall be mounted horizontally. The burner tube shall be
mounted vertically. The centre line of the test specimen, the burner tube, the sensor of the
heat flux meter and the conical hole in the masking board shall all be aligned vertically. The
sensor of the heat flux meter shall be placed horizontally 6 mm above the upper surface of the
masking board with its sensing surface facing down.

– 10 – IEC TS 60695-11-11:2016  IEC 2016
Dimensions in milimetres
Plan view
ø15 ±1
45°
ø57 ±1
Side view
IEC
Key
1 Test specimen
2 Test specimen support
3 Masking board
4 Conical hole (diameter at the top side 15 mm)
5 Burner tube and test flame (inner diameter 9,5 mm)
6 Burner support (adjustable vertically)
7 Mirror
Figure 1 – Arrangement and position of test specimen and burner
5.2 Burner and test flame
The laboratory burner apparatus shall conform to IEC 60695-11-4. The flame size and the gas
flow rate will differ from that specified in IEC 60695-11-4 in order to obtain the heat flux value
necessary for the test. The flame used for each test shall be maintained throughout the test.
NOTE ISO 10093 [4] describes the burner as ignition source P/PF2 (50 W).
5.3 Heat flux meter
The heat flux meter shall be of a water-cooled thermopile type (see ISO 14934-4:2014) which
determines the incident heat flux applied to the test specimen.
6 ±0,5
3 ±0,5
24 ±1
When incident heat flux measurements are made, the heat flux meter is placed in the centre
of a dummy test specimen board, and the heat flux meter shall not have any optical filter in-
line with the sensor.
NOTE 1 The incident heat flux measurement is of critical importance to the test results. ISO 14934-3 [5] provides
the calibration method for the heat flux meter.
NOTE 2 A thermopile of the Schmidt-Boelter type, with a designed range up to 100 kW/m and a target diameter of
approximately 12,5 mm, has been found to be suitable.
5.4 Data acquisition system
The voltmeter for measuring the output of the heat flux meter shall have a resolution of
0,01 % or better for the maximum output range.
5.5 Dummy test specimen board
The dummy test specimen board shall be approximately 75 mm × 75 mm × 12 mm with a
centrally located hole whose diameter is slightly larger than the outside diameter of the heat
flux meter. The board shall be made from a heat-resistant non-combustible rigid board. The
dummy specimen board is used, together with the heat flux meter (see Figure 2), for the
determination of incident heat flux (see 8.1).
NOTE A calcium silicate board of approximately 12 mm thickness having dry density of approximately 900 kg/m
has been found suitable for the dummy test specimen board.
b
IEC
Key
1 Dummy test specimen board
2 Heat flux meter
3 Cooling water pipe
a Approximately 12 mm
b Approximately 100 mm
Figure 2 – Dummy test specimen board
5.6 Masking board
The masking board shall be made of three heat-resistant non-combustible rigid boards, each
3 3
having a density of 850 kg/m ± 50 kg/m and a thickness of 8 mm ± 0,5 mm and the total
thickness of the three non-combustible board shall be 24 mm ± 1,5 mm. One board is inserted
between the upper and lower boards and is made moveable. This moveable board is the
radiant heat shield which protects the test specimen from the heat source before the test is
started. At the centre of the masking board there shall be a conically shaped opening. The
diameter of the opening on the upper surface shall be 15 mm ± 1 mm and 57 mm ± 1 mm on
the lower surface. An illustration of the masking board and its operation is shown in Figure 3.
NOTE A calcium silicate board of the required density has a thermal conductivity of 0,14 W/m/K at 200 °C,
0,15 W/m/K at 400 °C, and 0,17 W/m/K at 600 °C.
a
– 12 – IEC TS 60695-11-11:2016  IEC 2016
a
1 3
b
IEC
Key
1 Masking board
2 Upper board
3 Moveable board (Radiant heat shield)
4 Lower board
a Position of the moveable masking board prior to a test
b Position of the moveable masking board during a test
Figure 3 – Structure of the masking board
5.7 Timing device
The timing device shall have a resolution of 0,5 s or better.
5.8 Conditioning
The conditioning chamber shall be maintained at a temperature of 23 °C ± 2 °C, with a
relative humidity of 50 % ± 10 % (see ISO 291).
5.9 Test specimen support
The test specimen support shall maintain a distance of 6 mm ± 0,5 mm between the lower
surface of the test specimen and the upper surface of the masking board.
5.10 Burner support
The burner shall be located on a support which can be adjusted in the vertical direction. The
distance between the top of the burner tube and the lower surface of the test specimen shall
be able to be determined using a suitable measuring device which has a resolution of 1 mm or
better.
5.11 Observation mirror
To observe the ignition behaviour of the test specimen, an observation mirror approximately
100 mm × 100 mm shall be positioned underneath the masking board.
6 Test specimen
6.1 Specimen preparation
Test specimens shall be fabricated using the appropriate ISO method, e.g. casting and
injection moulding in accordance with ISO 294, compression moulding in accordance with
ISO 293 or ISO 295, or transfer moulding to the necessary shape. Where this is not possible,
the test specimen shall be produced using the same fabrication process as would be normally
used to mould a part of a product; and where this is not possible, specimens are to be cut
from a representative sample of the moulded material taken from an end product.
After any cutting operation, care shall be taken to remove all dust and any particles from the
surface; cut edges shall be fine sanded to a smooth finish.
6.2 Test specimen dimensions
The dimensions of the planar sections of the test specimens shall be at least
77,5 mm ± 2,5 mm in length and width and at the thickness under consideration. The

preferred thickness for the presentation of comparative data include 0,4 mm ± 0,05 mm,
0,75 mm ± 0,1 mm, 1,5 mm ± 0,1 mm, 3,0 mm ± 0,2 mm and 6,0 mm ± 0,4 mm.
6.3 Testing ranges in formulations
6.3.1 General
The results of tests carried out on test specimen sets of different colour, thickness, density,
molecular mass, anisotropic type/direction, additives, fillers, and/or reinforcements can vary.
6.3.2 Density, melt flows and filler/reinforcement
Test specimens covering all combinations of minimum and maximum levels of density, melt
flows and filler/reinforcement content may be provided and considered representative of the
range if the test results yield the same CHFI. If the test results do not yield the same CHFI for
all test specimens representing the range, evaluation shall be limited to the materials with the
specific levels of density, melt flows and filler/reinforcement tested. In addition, test
specimens with intermediate density, melt flows, and filler/reinforcement content shall be
tested to determine the representative range for each CHFI determination. However, as an
alternative, the least favorable performance of the specific levels of density, melt flows and
filler/reinforcement tested may be considered representative of intermediate levels without
additional testing.
6.3.3 Colour
When evaluating a range of colours, uncoloured test specimens and test specimens with the
highest level of organic and inorganic pigment loading by weight are considered
representative of the colour range if the test results yield the same CHFI. When certain
pigments are known to affect flammability characteristics, the test specimens containing those
pigments shall also be tested. Test specimens which shall be tested are those that
a) contain no colouring,
b) contain the highest level of organic pigments,
c) contain the highest level of inorganic pigments,
d) contain pigments which are known to adversely affect flammability characteristics.
6.4 Conditioning of test specimens
Unless otherwise specified in the relevant specification, the test specimen shall be
conditioned for a minimum of 24 h at 23 °C ± 2 °C and a relative humidity of 50 % ± 10 %.
Once removed from the conditioning chamber, the test specimens shall be tested within 1 h.
7 Testing conditions
All test specimens shall be tested in a laboratory atmosphere in a draught free environment at
a temperature of between 15 °C and 35 °C and a relative humidity of 75 % or less.
8 Test procedure
8.1 Determination of incident heat flux calibration curve
The incident heat flux, which will be received by the surface of the test specimen, shall be
determined in terms of the distance between the top of the burner and the lower surface of the
test specimen and the gas flow rate to the burner. For this purpose, an incident heat flux
calibration curve shall be determined by the following procedures.
a) Place the heat flux meter, which is located in the centre of a dummy test specimen board,
in the test specimen position.
b) Place the burner (see 5.2) in position.
c) Place the radiation heat shield in position (see Figure 3, position a).
d) Ignite the gas and adjust the gas flow rate to an appropriate value.
2 2 3
NOTE For heat fluxes in the range 30 kW/m to 60 kW/m , a gas flow of 105 cm /min has been found to be
2 2 3
suitable. For heat fluxes in the range 55 kW/m to 75 kW/m , a gas flow of 160 cm /min has been found to be
suitable.
– 14 – IEC TS 60695-11-11:2016  IEC 2016
e) Wait for a period of at least 5 min to allow the burner conditions to reach equilibrium.
f) The radiant heat shield shall then be removed and the output of the heat flux meter shall
be recorded for 5 min (see Figure 3, position b).
g) Perform this measurement for several different distances between the lower surface of the
heat flux meter and the top of the burner tube, so as to obtain a range of incident heat flux
2 2
and 75 kW/m .
values between 30 kW/m
h) Plot a calibration curve of incident heat flux as a function of the distance, and obtain by
2 2
interpolation the distances which correspond to the heat fluxes of 30 kW/m , 35 kW/m ,
2 2 2 2 2 2 2
40 kW/m , 45 kW/m , 50 kW/m , 55 kW/m , 60 kW/m , 65 kW/m , 70 kW/m , and
75 kW/m (see Annex A).
The temperature of cooling water for the heat flux meter shall be maintained above the
ambient temperature in order to avoid water condensation on the sensing surface (see
ISO 14934-4:2014).
8.2 Determination of ignition times
The test shall be conducted under a selected incident heat flux value, in terms of the distance
between the top of the burner and the lower surface of the test specimen and the gas flow
rate to the burner, obtained in accordance with 8.1.
For the purposes of this test method, ignition is as defined in 3.5.
a) Adjust the distance between the top of the burner and lower surface of the test specimen
and gas flow rate to the burner in order to obtain the selected incident heat flux value.
b) Ignite the burner and wait for a period of at least 5 min to allow the burner conditions to
reach equilibrium.
c) Place the radiation heat shield in position (see Figure 3, position a).
d) Place the test specimen in the test specimen position (see Figure 1).
e) Pull aside the radiant heat shield (see Figure 3, position b) and simultaneously start the
timing device.
f) Observe the test specimen and note if phenomena such as deformation, cracking and
melting occur.
g) If the test specimen ignites within 120 s, observe the flaming combustion for at least 5 s,
record the time to ignition ( t ) and return the radiation shield to position a. The test can
ig
be stopped if sustained combustion has been observed for at least 5 s.
h) If the test specimen does not ignite within 120 s, record the failure to ignite, and return the
radiation shield to position a.

i) Repeat d) to h) above two additional times with a new test specimen each time and under
the same test conditions.
j) Calculate and record t , the arithmetic mean of the three ignition times.
ig
NOTE If dripping or melting occurs which adversely affect the test results, the test results would be considered
invalid.
8.3 Repetition of the test at different heat flux values

2 2
The incident heat flux shall be chosen within the range from 30 kW/m to 75 kW/m and shall
be a multiple of 5 kW/m .
The tests shall be carried out until the highest incident heat flux value at which t is greater
ig
than 120 s is determined.
NOTE It might be efficient to start the test at a incident heat flux which is in the middle of the range from
2 2 2
30 kW/m to 75 kW/m , for example 50 kW/m .

9 Evaluation of test results
9.1 Average ignition time t
ig
t for each incident heat flux value used in the tests.
Calculate the average ignition time
ig
When ignition and non-ignition occur in the three tests, the average shall not be calculated.

When all three specimens do not ignite within 120 s, record " t is greater than 120 s".
ig
9.2 Report format for CHFI
The CHFI shall be reported in the following manner.

When three test specimens of thickness X mm do not ignite after 120 s exposure, and the
heat flux H is the maximum multiple of 5 kW/m at which this occurs, then this incident heat
flux shall be determined as the CHFI, and reported in the following format:
CHFI: H kW/m / X mm
t
for example, for a test specimen of 3,0 mm thickness and the maximum heat flux, at which
ig
is greater than 120 s, is 50 kW/m :
CHFI: 50 kW/m / 3,0 mm
If the three test specimens do not ignite at the heat flux value of 75 kW/m , CHFI shall be
reported as:
CHFI: >75 kW/m / thickness
If t is less than 120 s at 30 kW/m , the CHFI shall be reported as:
ig
CHFI: <30 kW/m / thickness
Exam
...