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

IEC 60695-11-11:2021 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, sub-assemblies or their parts. 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 part of IEC 60695 can be used in the fire hazard assessment and fire safety engineering procedures described in IEC 60695-1-10, IEC 60695-1-11 and IEC 60695-1-12.
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.
This international standard is to be used in conjunction with IEC 60695-11-4.
It has the status of a basic safety publication in accordance with IEC Guide 104 and ISO/IEC Guide 51.

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

IEC 60695-11-11:2021 décrit une méthode d’essai utilisée pour déterminer la densité de flux de chaleur caractéristique pour l’allumage (CHFI) à partir d’une flamme source sans contact pour les matériaux utilisés dans les produits et les sous-ensembles électrotechniques ou leurs composants. Elle donne une relation entre le temps d'allumage et la densité de flux de chaleur incident. Une éprouvette d’essai prélevée sur un produit fini ou un sous-ensemble peut être soumise à l’essai selon la présente méthode d’essai.
La présente partie de l’IEC 60695 peut être utilisée dans l'évaluation des dangers d’incendie et les procédures d’ingénierie de la sécurité incendie décrites dans l’IEC 60695-1-10, l’IEC 60695 1 11 et l’IEC 60695-1-12.
La présente publication fondamentale de sécurité est destinée à être utilisée par les comités d'études dans le cadre de l'élaboration de normes conformément aux principes établis dans le Guide IEC 104 et le Guide ISO/IEC 51.
L'une des responsabilités d'un comité d'études consiste, le cas échéant, à utiliser les publications fondamentales de sécurité dans le cadre de l'élaboration de ses publications. Les exigences, les méthodes ou les conditions d'essai de la présente publication fondamentale de sécurité s'appliquent seulement si elles sont spécifiquement citées en référence ou incluses dans les publications correspondantes.
Cette Norme internationale doit être utilisée conjointement avec l’IEC 60695-11-4.
Elle a le statut d'une publication fondamentale de sécurité conformément au Guide IEC 104 et au Guide ISO/IEC 51.

General Information

Status
Published
Publication Date
26-May-2021
Technical Committee
Current Stage
PPUB - Publication issued
Completion Date
27-May-2021
Ref Project

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IEC 60695-11-11
Edition 1.0 2021-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
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 de la densité de flux de chaleur
caractéristique pour l'allumage à partir d'une flamme source sans contact
IEC 60695-11-11:2021-05(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 60695-11-11
Edition 1.0 2021-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
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 de la densité de 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 978-2-8322-1045-9

Warning! Make sure that you obtained this publication from an authorized distributor.

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® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 60695-11-11:2021 © IEC 2021
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

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 ............................................................................................ 11

5.3 Heat flux meter ..................................................................................................... 11

5.4 Data acquisition system ........................................................................................ 11

5.5 Heat flux meter mounting board ............................................................................ 11

5.6 Masking board ...................................................................................................... 12

5.7 Timing device ....................................................................................................... 12

5.8 Conditioning chamber ........................................................................................... 12

5.9 Test specimen support .......................................................................................... 12

5.10 Burner support ...................................................................................................... 12

5.11 Observation mirror ................................................................................................ 13

5.12 Flow controller ...................................................................................................... 13

5.13 Heat flux meter supporting device ......................................................................... 13

6 Test specimen ............................................................................................................... 13

6.1 Dimensions of test specimen ................................................................................ 13

6.2 Testing ranges in formulations .............................................................................. 14

6.2.1 General ......................................................................................................... 14

6.2.2 Density, melt flows and filler/reinforcement .................................................... 14

6.2.3 Colour ........................................................................................................... 14

6.3 Conditioning of test specimens ............................................................................. 14

7 Testing conditions ......................................................................................................... 14

8 Test procedure .............................................................................................................. 14

8.1 Determination of incident heat flux calibration curve ............................................. 14

8.2 Determination of ignition time................................................................................ 15

8.3 Repetition of the test at different heat flux values .................................................. 16

9 Evaluation of test results ............................................................................................... 16

9.1 Average ignition time ........................................................................................ 16

9.2 Report format for CHFI ......................................................................................... 16

9.3 Analysis on CHFI (optional) .................................................................................. 17

10 Precision data ............................................................................................................... 17

11 Test report ..................................................................................................................... 17

Annex A (informative) An example of the calibration curve of incident heat flux, Q,

versus the distance, D, between the top of the burner tube and the lower surface of the

test specimen ....................................................................................................................... 18

A.1 Calibration curve ................................................................................................... 18

Annex B (informative) Examples of ignition times with various materials of 3 mm

thickness .............................................................................................................................. 20

B.1 Materials – Examples of measurements ................................................................ 20

Annex C (informative) Precision data ................................................................................... 23

---------------------- Page: 4 ----------------------
IEC 60695-11-11:2021 © IEC 2021 – 3 –

C.1 General ................................................................................................................. 23

C.2 Heat flux versus distance at different gas flow rates .............................................. 23

C.3 Repeatability ......................................................................................................... 24

C.4 Calculations and plots ........................................................................................... 25

Annex D (informative) Method of positioning the heat flux meter .......................................... 28

D.1 General ................................................................................................................. 28

D.2 Positioning the heat flux meter .............................................................................. 28

Bibliography .......................................................................................................................... 30

Figure 1 – Arrangement and position of test specimen and burner ........................................ 10

Figure 2 – Heat flux meter mounting board ........................................................................... 11

Figure 3 – Structure of the masking board ............................................................................ 12

Figure 4 – Heat flux meter supporting device ........................................................................ 13

Figure A.1 – Calibration curve (example) .............................................................................. 18

Figure B.1 – Example of ignition times of PMMA ................................................................... 20

Figure B.2 – Ignition times for ABS (example) ....................................................................... 21

Figure B.3 – Ignition times for HIPS (example) ...................................................................... 21

Figure C.1 – Incident heat flux calibration curve (gas flow rate 105 cm /min) ........................ 23

Figure C.2 – Incident heat flux calibration curve (gas flow rate 160 cm /min) ........................ 24

Figure C.3 – Plot of 1/ t for material A ................................................................................ 26

Figure C.4 – Plot of 1/t for material B ................................................................................. 26

Figure C.5 – Plot of 1/ t for material C ................................................................................ 27

Figure C.6 – Plot of 1/ t for material D ................................................................................ 27

Figure D.1 – Positioning the heat flux meter .......................................................................... 28

Figure D.2 – Correct position of the test specimen support and the heat flux meter............... 29

Table A.1 – Calibration data (examples of actual measured data as shown

in Figure A.1) ........................................................................................................................ 19

Table A.2 – Calibration data (examples of interpolated values) ............................................. 19

Table B.1 – Value of Figure B.1 ............................................................................................ 20

Table B.2 – Value of Figure B.2 ............................................................................................ 21

Table B.3 – Value of Figure B.3 ............................................................................................ 22

Table B.4 – Description example of tabulated test results ..................................................... 22

Table C.1 – Precision data of ignition time ............................................................................ 25

---------------------- Page: 5 ----------------------
– 4 – IEC 60695-11-11:2021 © IEC 2021
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.

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any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.

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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.

IEC 60695-11-11 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.
The text of this International Standard is based on the following documents:
CDV Report on voting
89/1482/CDV 89/1507/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.
---------------------- Page: 6 ----------------------
IEC 60695-11-11:2021 © IEC 2021 – 5 –

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.
This international standard 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 non-

contacting flame source
Part 11-20: Test flames – 500 W flame test methods
Part 11-30: Test flames – History and development from 1979 to 1999
Part 11-40: Test flames – Confirmatory tests – Guidance

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.

IMPORTANT – The "colour inside" logo on the cover page of this document indicates

that it contains colours which are considered to be useful for the correct understanding

of its contents. Users should therefore print this document using a colour printer.

---------------------- Page: 7 ----------------------
– 6 – IEC 60695-11-11:2021 © IEC 2021
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, to acceptable levels, the

potential risks of fire even in the event of foreseeable abnormal use, malfunction or failure.

IEC 60695-1-10, IEC 60695-1-11 and IEC 60695-1-12 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 international standard 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 or heat source under controlled laboratory conditions which is

characterized by quantitative heat input (heat flux) to the materials. Results of this test may be

used as elements of a fire risk 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

an end-product or sub-assembly can be tested by this test method.

This international standard 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 60695-11-5 [1] , IEC 60695-11-10 [2], IEC 60695-11-20 [3]

and ISO 4589-2 [4].

This is the first test method to determine the characteristic heat flux for ignition (CHFI) of

materials used for electrotechnical products, sub-assemblies or parts 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 or heat 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.
---------------------- Page: 8 ----------------------
IEC 60695-11-11:2021 © IEC 2021 – 7 –
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 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, sub-assemblies or their parts. 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 part of IEC 60695 can be used in the fire hazard assessment and fire safety engineering

procedures described in IEC 60695-1-10, IEC 60695-1-11 and IEC 60695-1-12.

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 60695-1-11, Fire hazard testing – Part 1-11: Guidance for assessing the fire hazard of

electrotechnical products – Fire hazard assessment

IEC 60695-1-12, Fire hazard testing – Part 1-12: Guidance for assessing the fire hazard of

electrotechnical products – Fire safety engineering

IEC 60695-4, Fire hazard testing – Part 4: Terminology concerning fire tests for electrotechnical

products

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, Safety aspects – Guidelines for their inclusion in standards
---------------------- Page: 9 ----------------------
– 8 – IEC 60695-11-11:2021 © IEC 2021
ISO 13943:2017, Fire safety – Vocabulary
ISO 291, Plastics – Standard atmospheres for conditioning and testing

ISO/TS 14934-4, 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 13943:2017 and

IEC 60695-4, some of which are reproduced below for the user’s convenience, as well as 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
average ignition time, t
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 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 quantitative 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 13943:2017, 3.83]
3.4
heat flux

amount of thermal energy emitted, transmitted or received per unit area and per unit of time

Note 1 to entry: the typical unit is W/m
[SOURCE ISO 13943:2017, 3.201]
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: ISO 13943:2017, 3.226]
---------------------- Page: 10 ----------------------
IEC 60695-11-11:2021 © IEC 2021 – 9 –
4 Principle of the test
...

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