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

IEC 60695-6-2:2018 provides a summary of commonly used test methods for 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 gives recommendations on their use.
This basic safety publication is primarily 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. It is not intended for use by manufacturers or certification bodies.
It has the status of a basic safety publication in accordance with IEC Guide 104 and ISO/IEC Guide 51.
This standard is to be used in conjunction with IEC 60695-6-1.
This standard cancels and replaces IEC 60695-6-2 published in 2011. This second 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) new text in 4.1;
d) deletion of references to IEC 60695-6-30 and -31 (withdrawn)
e) updates with respect to ISO 5659-2;
f) deletion of references to BS 6853 and CEI 20-37-3 (superseded);
g) deletion of references to ISO/TR 5924 (withdrawn);
h) updated text with respect to EN 50399;
i) updated text with respect to ISO 5660-1;
j) addition of new Subclause 7.5
k) deletion of Annex B;
l) deletion of Annex E;
m) additional bibliographic references.
Key words: Fire Hazard, Smoke Obscuration

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

IEC 60695-6-2:2018 La présente partie de l’IEC 60695 donne un résumé des méthodes d'essais couramment utilisées pour évaluer l’obscurcissement par la fumée. Elle présente un résumé des méthodes d'essais dynamiques et statiques communément utilisées, aussi bien comme normes internationales que nationales ou en tant que normes industrielles. Elle inclut des observations particulières relatives à leur pertinence par rapport aux produits électrotechniques et leurs matériaux et à des scénarios d’incendie, et donne des recommandations pour leur utilisation.
Cette publication fondamentale de sécurité doit être utilisée par les comités d’études pour l’établissement de leurs normes conformément aux principes exposés dans le Guide 104 de l’IEC et dans le Guide ISO/IEC 51.
Elle a le statut d’une publication fondamentale de sécurité conformément au Guide IEC 104 et au Guide ISO/IEC 51.
Cette norme doit être utilisée conjointement avec l’IEC 60695-6-1.
Cette norme annule et remplace l’IEC 60695-6-2 parue en 2011. Cette deuxième édition constitue une révision technique.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) mise à jour de l’introduction;
b) mise à jour des références normatives;
c) nouveau texte au 4.1;
d) suppression des références aux IEC 60695-6-30 et -31 (supprimées)
e) mises à jour en fonction de l’ISO 5659-2;
f) suppression des références à la BS 6853 et la CEI 20-37-3 (remplacées);
g) suppression des références à l’ISO/TR 5924 (supprimée);
h) mise à jour du texte en fonction de l’EN 50399;
i) mise à jour du texte en fonction de l’ISO 5660-1;
j) ajout d’un nouveau Paragraphe 7.5
k) suppression de l’Annexe B;
l) suppression de l’Annexe E;
m) ajout de références bibliographiques.
Mots clés: risques du feu, Opacité des fumées

General Information

Status
Published
Publication Date
04-Jun-2018
Technical Committee
Current Stage
PPUB - Publication issued
Completion Date
05-Jun-2018
Ref Project

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IEC 60695-6-2
Edition 2.0 2018-06
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 60695-6-2:2018-06(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 60695-6-2
Edition 2.0 2018-06
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
INTERNATIONALE
ICS 13.220.99; 29.020 ISBN 978-2-8322-5780-7

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

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 60695-6-2:2018 © IEC 2018
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 The physical fire model ......................................................................................... 11

4.3 Static test methods ............................................................................................... 12

4.4 Dynamic test methods ........................................................................................... 12

5 Types of test specimen .................................................................................................. 14

6 Published static test methods ........................................................................................ 14

6.1 General ................................................................................................................. 14

6.2 Determination of smoke opacity in a 0,51 m chamber .......................................... 14

6.2.1 Standards which use a vertically oriented test specimen ................................ 14

6.2.2 Standard which uses a horizontally oriented test specimen ............................ 16

6.3 Determination of smoke density in a 27 m smoke chamber ................................. 18

6.3.1 Standards ...................................................................................................... 18

6.3.2 Purpose and principle .................................................................................... 18

6.3.3 Test specimen ............................................................................................... 18

6.3.4 Method .......................................................................................................... 18

6.3.5 Repeatability and reproducibility .................................................................... 19

6.3.6 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 ................................................................................................... 20

7.2.1 Standards ...................................................................................................... 20

7.2.2 Purpose and principle .................................................................................... 20

7.2.3 Test specimen ............................................................................................... 20

7.2.4 Method .......................................................................................................... 20

7.2.5 Repeatability and reproducibility .................................................................... 20

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 ASTM and UL standards ................................................................................ 20

7.3.2 European standard ........................................................................................ 21

7.4 Determination of smoke using a cone calorimeter ................................................. 23

7.4.1 Standards ...................................................................................................... 23

7.4.2 Purpose and principle .................................................................................... 23

7.4.3 Test specimen ............................................................................................... 23

7.4.4 Method .......................................................................................................... 23

7.4.5 Repeatability and reproducibility .................................................................... 24

7.4.6 Relevance of test data and special observations............................................ 24

7.5 Determination of smoke generated by discrete (non-continuous) products ............ 24

7.5.1 Standards ...................................................................................................... 24

---------------------- Page: 4 ----------------------
IEC 60695-6-2:2018 © IEC 2018 – 3 –

7.5.2 Purpose and principle .................................................................................... 24

7.5.3 Test specimen ............................................................................................... 25

7.5.4 Method .......................................................................................................... 25

7.5.5 Repeatability and reproducibility .................................................................... 25

7.5.6 Relevance of test data and special observations............................................ 25

8 Overview of methods and relevance of data .................................................................. 25

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 ................ 28

Annex B (informative) Repeatability and reproducibility data – "Three metre cube"

smoke chamber – French interlaboratory tests according to IEC 61034-2 ............................. 29

Annex C (informative) Repeatability and reproducibility data – NFPA 262 ............................ 30

Bibliography .......................................................................................................................... 31

Table 1 – Characteristics of fire stages (ISO 19706:2011) .................................................... 13

Table 2 – Overview of smoke test methods ........................................................................... 26

Table A.1 – Measurement of D ........................................................................................... 28

Table B.1 – Measurement of transmission expressed as a percentage .................................. 29

Table C.1 – Measurements of Peak Optical Density .............................................................. 30

Table C.2 – Measurements of Average Optical Density ......................................................... 30

---------------------- Page: 5 ----------------------
– 4 – IEC 60695-6-2:2018 © IEC 2018
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

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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

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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

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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 60695-6-2 has been prepared by IEC technical committee 89: Fire

hazard testing.

This standard cancels and replaces IEC 60695-6-2 published in 2011. This second 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) new text in 4.1;
d) deletion of references to IEC 60695-6-30 and -31 (withdrawn)
e) updates with respect to ISO 5659-2;
---------------------- Page: 6 ----------------------
IEC 60695-6-2:2018 © IEC 2018 – 5 –
f) deletion of references to BS 6853 and CEI 20-37-3 (superseded);
g) deletion of references to ISO/TR 5924 (withdrawn);
h) updated text with respect to EN 50399;
i) updated text with respect to ISO 5660-1;
j) addition of new Subclause 7.5
k) deletion of Annex B;
l) deletion of Annex E;
m) additional bibliographic references.
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:
FDIS Report on voting
89/1399/FDIS 89/1405/RVD

Full information on the voting for the approval of this International Standard can be found in

the report on voting indicated in the above table.

This document 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 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

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.
---------------------- Page: 7 ----------------------
– 6 – IEC 60695-6-2:2018 © IEC 2018
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 [1] , IEC 60695-1-11 [2], and IEC 60695-1-12 [3] 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 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.

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 part of IEC 60695 describes smoke test methods in common use to assess the smoke

release from electrotechnical products, or from materials used in electrotechnical products. It

gives guidance to product committees wishing to incorporate test methods for smoke

obscuration in product standards.
___________
Numbers in square brackets refer to the bibliography.
---------------------- Page: 8 ----------------------
IEC 60695-6-2:2018 © IEC 2018 – 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 commonly used test methods for 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 gives recommendations on their use.

This basic safety publication shall be used 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 60695-6-1, Fire hazard testing – Part 6-1: Smoke obscuration – General guidance

ISO/IEC Guide 51, Safety aspects – Guidelines for their inclusion in standards

IEC GUIDE 104, The preparation of safety publications and the use of basic safety

publications and group safety publications

ISO 5660-1:2015, Reaction-to-fire tests – Heat release, smoke production and mass loss rate

– Part 1: Heat release rate (cone calorimeter method) and smoke production rate (dynamic

measurement)
ISO 13943:2008, Fire safety – Vocabulary
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 ISO 13943:2008, some

of which are reproduced below for users’ convenience, and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
---------------------- Page: 9 ----------------------
– 8 – IEC 60695-6-2:2018 © IEC 2018
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
combustion
exothermic reaction of a substance with an oxidising agent

Note 1 to entry: Combustion generally emits fire effluent accompanied by flames and/or glowing.

[SOURCE: ISO 13943:2008, 4.46]
3.2
extinction area of smoke

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

Note 1 to entry: It is a measure of the amount of smoke, and the typical units are square metres (m ).

[SOURCE: ISO 13943:2008, 4.92]
3.3
extinction coefficient

natural logarithm of the ratio of incident light intensity to transmitted light intensity, per unit

light path length
Note 1 to entry: Typical units are reciprocal metres (m ).
[SOURCE: ISO 13943:2008, 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 1 to entry: 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.
[SOURCE: ISO 13943:2008, 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
[SOURCE: ISO 13943:2008, 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
[SOURCE: ISO 13943:2008, 4.98]
3.7
fire effluent

totality of gases and aerosols, including suspended particles, created by combustion or

pyrolysis in a fire
---------------------- Page: 10 ----------------------
IEC 60695-6-2:2018 © IEC 2018 – 9 –
[SOURCE: ISO 13943:2008, definition 4.105]
3.8
fire hazard

physical object or condition with a potential for an undesirable consequence from fire

[SOURCE: ISO 13943:2008, 4.112]
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
[SOURCE: ISO 13943:2008, 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 1 to entry: 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.

[SOURCE: ISO 13943:2008, 4.129]
3.11
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 13943:2008, 4.173]
3.12
ignition
sustained ignition (deprecated)
(general) initiation of combustion
[SOURCE: ISO 13943:2008, 4.187]
3.13
ignition
sustained ignition (deprecated)
(flaming combustion) initiation of sustained flame
[SOURCE: ISO 13943:2008, 4.188]
3.14
mass optical density of smoke

optical density of smoke multiplied by a factor, V/(∆m L), where V is the volume of the test

chamber, ∆m is the mass lost from the test specimen, and L is the light path length

2 -1
Note 1 to entry: The typical units are square metres per gram (m × g ).
[SOURCE: ISO 13943:2008, 4.225]
---------------------- Page: 11 ----------------------
– 10 – IEC 60695-6-2:2018 © IEC 2018
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 to entry: In practice, obscuration by smoke is usually measured as the transmittance, which is normally

expressed as a percentage.
Note 2 to entry: Obscuration by smoke causes a reduction in visibility.
[SOURCE: ISO 13943:2008, 4.242]
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 (3.25)
Note 1 to entry: The optical density of smoke is dimensionless.
[SOURCE: ISO 13943:2008, 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
[SOURCE: ISO 13943:2008, 4.251]
3.18
plenum

area located above false ceilings where heating, ventilating or air-conditioning ducts are

located, as well as communication cables and other utilities
3.19
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 are used in accordance with the conditions

laid down by the specifier and/or in accordance with normal practice.
[SOURCE: ISO 13943:2008, 4.273]
3.20
small-scale fire test
fire test performed on a test specimen of small dimensions

Note 1 to entry: 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.
[SOURCE: ISO 13943:2008, 4.292]
3.21
smoke
visible part of fire effluent
[SOURCE: ISO 13943:2008, 4.293]
---------------------- Page: 12 ----------------------
IEC 6
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