IEC 60695-6-2:2011

IEC 60695-6-2


®


Edition 1.0 2011-08



INTERNATIONAL



STANDARD



NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ


Fire hazard testing –

Part 6-2: Smoke obscuration – Summary and relevance of test methods

Essais relatifs aux risques du feu –
Partie 6-2: Opacité des fumées – Résumé et pertinence des méthodes d'essais

IEC 60695-6-2:2011

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IEC 60695-6-2


®


Edition 1.0 2011-08



INTERNATIONAL



STANDARD



NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ


Fire hazard testing –
Part 6-2: Smoke obscuration – Summary and relevance of test methods

Essais relatifs aux risques du feu –
Partie 6-2: Opacité des fumées – Résumé et pertinence des méthodes d'essais


INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX V
ICS 13.220.99; 29.020 ISBN 978-2-88912-625-5

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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– 2 – 60695-6-2 © IEC:2011


CONTENTS


FOREWORD . 4

INTRODUCTION . 6


1 Scope . 7

2 Normative references. 7

3 Terms and definitions . 7

4 Types of of test method . 11

4.1 General . 11

4.2 Physical fire model . 11
4.3 Static test methods . 11
4.4 Dynamic test methods . 11
5 Types of test specimen . 13
6 Published static test methods . 13
6.1 General . 13
3
6.2 Determination of smoke opacity in a 0,51 m chamber . 13
6.2.1 Standards which use a vertically oriented test specimen . 13
6.2.2 Standard which uses a horizontally oriented test specimen . 15
3
6.3 Determination of smoke density in a 27 m smoke chamber . 17
6.3.1 Standards . 17
6.3.2 Purpose and principle . 17
6.3.3 Test specimen . 17
6.3.4 Method . 17
6.3.5 Repeatability and reproducibility . 18
6.3.6 Relevance of test data and special observations . 18
6.4 Determination of specific optical density using a dual-chamber test . 18
6.4.1 Standards . 18
6.4.2 Purpose and principle . 18
6.4.3 Test specimen . 18
6.4.4 Method . 19
6.4.5 Repeatability and reproducibility . 19
6.4.6 Relevance of test data and special observations . 19
7 Published dynamic test methods . 19
7.1 General . 19

7.2 Determination of smoke density generated by electric cables mounted on a
horizontal ladder . 19
7.2.1 Standards . 19
7.2.2 Purpose and principle . 19
7.2.3 Test specimen . 19
7.2.4 Method . 19
7.2.5 Repeatability and reproducibility . 19
7.2.6 Relevance of test data and special observations . 20
7.3 Determination of smoke generated by electrical cables mounted on a vertical
ladder . 20
7.3.1 Standards . 20
7.3.2 prEN 50399 . 21
7.4 Determination of smoke using a cone calorimeter . 22
7.4.1 Standards . 22

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60695-6-2 © IEC:2011 – 3 –


7.4.2 Purpose and principle . 22

7.4.3 Test specimen . 22

7.4.4 Method . 22

7.4.5 Repeatability and reproducibility . 23

7.4.6 Relevance of test data and special observations . 23

8 Overview of methods and relevance of data . 24

Annex A (informative) Repeatability and reproducibility data – NBS smoke chamber –

Interlaboratory tests from the French standard NF C20-902-1 and NF C20-902-2 . 27

Annex B (informative) Repeatability and reproducibility data – ISO 5659-2 . 28


Annex C (informative) Repeatability and reproducibility data – "Three metre cube"
smoke chamber – French interlaboratory tests according to IEC 61034-2 . 30
Annex D (informative) Repeatability and reproducibility data – NFPA 262 . 31
Annex E (informative) Precision data of smoke measurement in ISO 5660-2 . 32
Bibliography . 33

Table 1 – Characteristics of fire stages (ISO 19706) . 12
Table 2 – Overview of smoke test methods. 25
Table A.1 – Measurement of D . 27
m
Table B.1 – Measurement of D 10 . 28
s
Table B.2 – Test results for poly-carbonate. 28
Table B.3 – Test results for PVC flooring . 29
Table C.1 – Measurement of transmission expressed as a percentage . 30
Table E.1 – Combinations of materials of upholstered furniture . 32
2
Table E.2 – Repeatability and Reproducibility of specific extinction area (m /kg). 32

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INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________



FIRE HAZARD TESTING –



Part 6-2: Smoke obscuration –

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
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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 60695-6-2 has been prepared by IEC technical committee 89: Fire
hazard testing.
This standard cancels and replaces IEC/TS 60695-6-2 published in 2005. This first edition
constitutes a technical revision.
The main changes with respect to the previous edition are listed below:
– this publication has been re-designated as an International Standard;
– updated normative references;
– updated terms and definitions;
– new test method Clause 7.3.2;
– numerous editorial changes of a technical nature throughout the publication.

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60695-6-2 © IEC:2011 – 5 –


This standard is to be used in conjunction with IEC 60695-6-1.


It has the status of a basic safety publication in accordance with IEC Guide 104 and

ISO/IEC Guide 51.


The text of this standard is based on the following documents:



Enquiry draft Report on voting

89/1057/FDIS 89/1071/RVD



Full information on the voting for the approval of this standard 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.
A list of all parts of the IEC 60695 series, under the general title of Fire hazard testing, can be
found on the IEC website.
Part 6 consists of the following parts:
Part 6-1: Smoke obscuration – General guidance
Part 6-2: Smoke obscuration – Summary and relevance of test methods
Part 6-30: Guidance and test methods on the assessment of obscuration hazard of vision
caused by smoke opacity from electrotechnical products involved in fires – Small
scale static method – Determination of smoke opacity – Description of the
apparatus
Part 6-31: Smoke obscuration – Small-scale static test – Materials
The committee has decided that the contents of this publication will remain unchanged until the
stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to
the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

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– 6 – 60695-6-2 © IEC:2011


INTRODUCTION


The risk of fire needs to be considered in any electrical circuit, and the objective of component,

circuit and equipment design, and the choice of materials, is to reduce the likelihood of fire,

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


Electrotechnical products, primarily as victims of fire, may nevertheless contribute to the fire.

One of the contributing hazards is the release of smoke, which may cause loss of vision and/or

disorientation which could impede escape from the building, or fire fighting.


This international standard describes smoke test methods in common use to assess the smoke

release from electrotechnical products, or from materials used in electrotechnical products. It
forms part of the IEC 60695-6 series which gives guidance to product committees wishing to
incorporate test methods for smoke obscuration in product standards.

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60695-6-2 © IEC:2011 – 7 –


FIRE HAZARD TESTING –



Part 6-2: Smoke obscuration –

Summary and relevance of test methods








1 Scope


This part of IEC 60695 provides a summary of the test methods that are used in the
assessment of smoke obscuration. It presents a brief summary of static and dynamic test
methods in common use, either as international standards or national or industry standards. It
includes special observations on their relevance to electrotechnical products and their
materials and to fire scenarios, and it gives recommendations on their use.
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 referenced documents are indispensable for the application 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 60695-6-1:2005, Fire hazard testing – Part 6-1: Smoke obscuration – General guidance
IEC Guide 104:, The preparation of safety publications and the use of basic safety publications
and group safety publications
ISO/IEC 13943:2008, Fire safety – Vocabulary
ISO 5725-2:1994, Accuracy (trueness and precision) of measurement methods and results –
Part 2: Basic method for the determination of repeatability and reproducibility of a standard

measurement method
1
ISO 19706:2007 , Guidelines for assessing the fire threat to people
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 13943, some of
which are reproduced below for users’ convenience, apply.
3.1
combustion
exothermic reaction of a substance with an oxidising agent
___________
1
This publication cancels and replaces ISO 9122-1:1989, Toxicity testing of fire effluents – Part 1: General.

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NOTE Combustion generally emits fire effluent accompanied by flames and/or glowing.

[ISO/IEC 13943, definition 4.46]


3.2

extinction area of smoke

product of the volume occupied by smoke and the extinction coefficient of the smoke


2
NOTE It is a measure of the amount of smoke, and the typical units are square metres (m ).

[ISO/IEC 13943, definition 4.92]



3.3
extinction coefficient
natural logarithm of the ratio of incident light intensity to transmitted light intensity, per unit light
path length
-1
NOTE Typical units are reciprocal metres (m ).
[ISO/IEC 13943, definition 4.93]
3.4
fire
(general) process of combustion characterized by the emission of heat and fire effluent and
usually accompanied by smoke, flame, glowing or a combination thereof
NOTE In the English language the term "fire" is used to designate three concepts, two of which, fire (3.5) and fire
(3.6), relate to specific types of self-supporting combustion with different meanings and two of them are designated
using two different terms in both French and German.
[ISO/IEC 13943, definition 4.96]
3.5
fire
(controlled) self-supporting combustion that has been deliberately arranged to provide useful
effects and is limited in its extent in time and space
[ISO/IEC 13943 definition 4.97]
3.6
fire
(uncontrolled) self-supporting combustion that has not been deliberately arranged to provide
useful effects and is not limited in its extent in time and space
[ISO/IEC 13943 definition 4.98]

3.7
fire effluent
totality of gases and aerosols, including suspended particles, created by combustion or
pyrolysis in a fire
[ISO/IEC 13943, definition 4.105]
3.8
fire hazard
physical object or condition with a potential for an undesirable consequence from fire
[ISO/IEC 13943, definition 4.112]

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3.9

fire model

fire simulation

calculation method that describes a system or process related to fire development, including

fire dynamics and the effects of fire

[ISO/IEC 13943, definition 4.116]


3.10

fire scenario
qualitative description of the course of a fire with respect to time, identifying key events that
characterise the studied fire and differentiate it from other possible fires

NOTE It typically defines the ignition and fire growth processes, the fully developed fire stage, the fire decay
stage, and the environment and systems that impact on the course of the fire.
[ISO/IEC 13943 definition 4.129]
3.11
heat flux
amount of thermal energy emitted, transmitted or received per unit area and per unit time
-2
NOTE The typical units are watts per square metre (W·m ).
[ISO/IEC 13943, definition 4.173]
3.12
ignition
sustained ignition (deprecated)
(general) initiation of combustion
[ISO/IEC 13943, definition 4.187]
3.13
ignition
sustained ignition (deprecated)
(flaming combustion) initiation of sustained flame
[ISO/IEC 13943 definition 4.188]
3.14
mass optical density of smoke
/(Δm L), where V is the volume of the test
optical density of smoke multiplied by a factor, V

chamber, Δm is the mass lost from the test specimen, and L is the light path length
2 -1
NOTE The typical units are square metres per gram (m × g ).
[ISO/IEC 13943, definition 4.225]
3.15
obscuration by smoke
reduction in the intensity of light due to its passage through smoke
cf. extinction area of smoke (3.2) and specific extinction area of smoke (3.23).
NOTE 1 In practice, obscuration by smoke is usually measured as the transmittance, which is normally expressed
as a percentage.
NOTE 2 Obscuration by smoke causes a reduction in visibility.
[ISO/IEC 13943 definition 4.242]

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3.16

optical density of smoke

measure of the attenuation of a light beam passing through smoke expressed as the logarithm

to the base 10 of the opacity of smoke


cf. specific optical density of smoke (3.24)

NOTE The optical density of smoke is dimensionless.

[ISO/IEC 13943, definition 4.244]


3.17

physical fire model
laboratory process, including the apparatus, the environment and the fire test procedure
intended to represent a certain phase of a fire
[ISO/IEC 13943, definition 4.251]
3.18
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 Such a fire test normally assumes that the products are used in accordance with the conditions laid down
by the specifier and/or in accordance with normal practice.
[ISO/IEC 13943, definition 4.273]
3.19
small-scale fire test
fire test performed on a test specimen of small dimensions
NOTE A fire test performed on a test specimen of which the maximum dimension is less than 1 m is usually called
a small-scale fire test.
[ISO/IEC 13943, definition 4.292]
3.20
smoke
visible part of fire effluent
[ISO/IEC 13943, definition 4.293]
3.21
smoke production rate

amount of smoke produced per unit time in a fire or fire test
NOTE 1 It is calculated as the product of the volumetric flow rate of smoke and the extinction coefficient of the
smoke at the point of measurement.
2 -1
NOTE 2 The typical units are square metres per second (m × s ).
[ISO/IEC 13943 definition 4.295]
3.22
smoke release rate
see smoke production rate (3.21)
3.23
specific extinction area of smoke
extinction area of smoke produced by a test specimen in a given time period divided by the
mass lost from the test specimen in the same time period

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60695-6-2 © IEC:2011 – 11 –


2 -1
NOTE The typical units are square metres per gram (m ·g ).

[ISO/IEC 13943 definition 4.301]


3.24

specific optical density of smoke

optical density of smoke multiplied by a geometric factor


NOTE 1 The geometric factor is V /(A⋅L), where V is the volume of the test chamber, A is the area of the exposed

surface of the test specimen, and L is the light path length.


NOTE 2 The use of the term “specific” does not denote “per unit mass” but rather denotes a quantity associated
with a particular test apparatus and area of the exposed surface of the test specimen.

NOTE 3 The specific optical density of smoke is dimensionless.
[ISO/IEC 13943 definition 4.303]
3.25
visibility
maximum distance at which an object of defined size, brightness and contrast can be seen and
recognized
[ISO/IEC 13943 definition 4.350]
4 Types of of test method
4.1 General
Test methods are characterised by whether they are static or dynamic and/or by the nature of
the test specimen.
4.2 Physical fire model
The amount and rate of smoke released from a given material or product is not an inherent
property of that material or product, but is critically dependent on the condit
...