Fire hazard testing - Part 5-1: Corrosion damage effects of fire effluent - General guidance (IEC 60695-5-1:2021)

This part of IEC 60695 provides guidance on the following: a) general aspects of corrosion damage test methods; b) methods of measurement of corrosion damage; c) consideration of test methods; d) relevance of corrosion damage data to hazard assessment. 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. 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.

Prüfungen zur Beurteilung der Brandgefahr - Teil 5-1: Korrosionsschädigung durch Rauch und/oder Brandgase - Allgemeiner Leitfaden (IEC 60695-5-1:2021)

Essais relatifs aux risques du feu - Partie 5-1: Effets des dommages de corrosion des effluents du feu - Guide general (IEC 60695-5-1:2021)

IEC 60695-5-1:2021 est disponible sous forme de IEC 60695-5-1:2021 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente. L'IEC 60695-5-1:2021 fournit des recommandations concernant: a) les aspects généraux des méthodes d’essai des dommages de corrosion; b) les méthodes de mesure des dommages de corrosion; c) la prise en considération des méthodes d’essai; d) la pertinence des données concernant les dommages de corrosion pour l’estimation du danger. La présente publication fondamentale de sécurité est essentiellement 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. Elle n'est pas destinée à être utilisée par des fabricants ou des organismes de certification. 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 troisième édition annule et remplace la deuxième édition, parue en 2002 et constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: a) les références à l’IEC TS 60695-5-3 (supprimée en 2014) ont été supprimées; b) les références à l’IEC 60695-1-1 correspondent désormais aux normes suivantes: IEC 60695-1-10 et IEC 60695-1-11; c) l’ISO/TR 9122-1 a été révisée par l’ISO 19706; d) le Tableau 1 a été mis à jour; e) les références à l’ISO 11907-2 et à l’ISO 11907-3 ont été supprimées; f) les termes et définitions ont été mis à jour; g) le texte de 6.4 a été mis à jour; h) les références bibliographiques ont été mises à jour.

Preskušanje požarne ogroženosti - 5-1. del: Poškodbe zaradi korozijskega učinka izžarevanja ognja - Splošno navodilo (IEC 60695-5-1:2021)

Ta del standarda IEC 60695 podaja smernice glede:
a) splošnih vidikov preskusnih metod za poškodbe zaradi korozije;
b) metod za merjenje poškodb zaradi korozije;
c) upoštevanja preskusnih metod;
d) ustreznosti podatkov o poškodbah zaradi korozije za oceno ogroženosti.
Ta osnovna varnostna publikacija je namenjena predvsem tehničnim odborom za pripravo standardov v skladu z načeli vodil IEC 104 in ISO/IEC 51. Ni namenjena proizvajalcem ali certifikacijskim organom.
Ena od dolžnosti tehničnega odbora je, da med pripravo publikacij uporablja osnovne varnostne publikacije, kadar je to primerno. Zahteve, preskusne metode ali preskusni pogoji iz te osnovne varnostne publikacije se ne uporabljajo, razen če so izrecno navedeni ali zajeti v ustreznih publikacijah.

General Information

Status
Published
Publication Date
19-Dec-2021
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
10-Dec-2021
Due Date
14-Feb-2022
Completion Date
20-Dec-2021

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SLOVENSKI STANDARD
SIST EN IEC 60695-5-1:2022
01-februar-2022
Nadomešča:
SIST EN 60695-5-1:2003
Preskušanje požarne ogroženosti - 5-1. del: Poškodbe zaradi korozijskega učinka
izžarevanja ognja - Splošno navodilo (IEC 60695-5-1:2021)

Fire hazard testing - Part 5-1: Corrosion damage effects of fire effluent - General

guidance (IEC 60695-5-1:2021)
Prüfungen zur Beurteilung der Brandgefahr - Teil 5-1: Korrosionsschädigung durch
Rauch und/oder Brandgase - Allgemeiner Leitfaden (IEC 60695-5-1:2021)

Essais relatifs aux risques du feu - Partie 5-1: Effets des dommages de corrosion des

effluents du feu - Guide general (IEC 60695-5-1:2021)
Ta slovenski standard je istoveten z: EN IEC 60695-5-1:2021
ICS:
13.220.40 Sposobnost vžiga in Ignitability and burning
obnašanje materialov in behaviour of materials and
proizvodov pri gorenju products
29.020 Elektrotehnika na splošno Electrical engineering in
general
SIST EN IEC 60695-5-1:2022 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN IEC 60695-5-1:2022
---------------------- Page: 2 ----------------------
SIST EN IEC 60695-5-1:2022
EUROPEAN STANDARD EN IEC 60695-5-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2021
ICS 29.020 Supersedes EN 60695-5-1:2003 and all of its
amendments and corrigenda (if any)
English Version
Fire hazard testing - Part 5-1: Corrosion damage effects of fire
effluent - General guidance
(IEC 60695-5-1:2021)

Essais relatifs aux risques du feu - Partie 5-1: Effets des Prüfungen zur Beurteilung der Brandgefahr - Teil 5-1:

dommages de corrosion des effluents du feu - Korrosionsschädigung durch Rauch und/oder Brandgase -

Recommandations générales Allgemeiner Leitfaden
(IEC 60695-5-1:2021) (IEC 60695-5-1:2021)

This European Standard was approved by CENELEC on 2021-12-02. CENELEC members are bound to comply with the CEN/CENELEC

Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC

Management Centre or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation

under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the

same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,

Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the

Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN IEC 60695-5-1:2021 E
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SIST EN IEC 60695-5-1:2022
EN IEC 60695-5-1:2021 (E)
European foreword

The text of document 89/1539/FDIS, future edition 3 of IEC 60695-5-1, prepared by IEC/TC 89 “Fire

hazard testing” was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as

EN IEC 60695-5-1:2021.
The following dates are fixed:

• latest date by which the document has to be implemented at national (dop) 2022–09–02

level by publication of an identical national standard or by endorsement

• latest date by which the national standards conflicting with the (dow) 2024–12–02

document have to be withdrawn

This document supersedes EN 60695-5-1:2003 and all of its amendments and corrigenda (if any).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Any feedback and questions on this document should be directed to the users’ national committee. A

complete listing of these bodies can be found on the CENELEC website.
Endorsement notice

The text of the International Standard IEC 60695-5-1:2021 was approved by CENELEC as a

European Standard without any modification.

In the official version, for Bibliography, the following notes have to be added for the standards

indicated:
IEC 60695-1-12 NOTE Harmonized as EN IEC 60695-1-12
IEC 60754-1 NOTE Harmonized as EN 60754-1
IEC 60754-2 NOTE Harmonized as EN 60754-2
IEC 60754-3 NOTE Harmonized as EN IEC 60754-3
ISO 7384 NOTE Harmonized as EN ISO 7384
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SIST EN IEC 60695-5-1:2022
EN IEC 60695-5-1:2021 (E)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the

relevant EN/HD applies.

NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available

here: www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60695-1-10 - Fire hazard testing - Part 1–10: Guidance EN 60695-1-10 -
for assessing the fire hazard of
electrotechnical products - General
guidelines
IEC 60695-1-11 - Fire hazard testing - Part 1–11: Guidance EN 60695-1-11 -
for assessing the fire hazard of
electrotechnical products - Fire hazard
assessment
IEC/TS 60695-5-2 Fire hazard testing - Part 5–2: Corrosion - -
damage effects of fire effluent - Summary
and relevance of test methods
IEC Guide 104 - The preparation of safety publications and - -
the use of basic safety publications and
group safety publications
ISO/IEC Guide 51 Safety aspects - Guidelines for their - -
inclusion in standards
ISO 11907-1 2019 Plastics - Smoke generation - - -
Determination of the corrosivity of fire
effluents - Part 1: General concepts and
applicability
ISO 13943 2017 Fire safety - Vocabulary EN ISO 13943 2017
ISO 19706 2011 Guidelines for assessing the fire threat to - -
people
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SIST EN IEC 60695-5-1:2022
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SIST EN IEC 60695-5-1:2022
IEC 60695-5-1
Edition 3.0 2021-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
HORIZONTAL PUBLICATION
PUBLICATION HORIZONTALE
Fire hazard testing –
Part 5-1: Corrosion damage effects of fire effluent – General guidance
Essais relatifs aux risques du feu –
Partie 5-1: Effets des dommages de corrosion des effluents du feu –
Recommandations générales
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.020 ISBN 978-2-8322-1011-3

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: 7 ----------------------
SIST EN IEC 60695-5-1:2022
– 2 – IEC 60695-5-1:2021 © IEC 2021
CONTENTS

FOREWORD ........................................................................................................................... 3

INTRODUCTION ..................................................................................................................... 5

1 Scope .............................................................................................................................. 6

2 Normative references ...................................................................................................... 6

3 Terms and definitions ...................................................................................................... 7

4 Fire scenarios and physical fire models ........................................................................... 9

5 General aspects of the corrosivity of fire effluent ........................................................... 10

5.1 Corrosion damage scenarios ................................................................................. 10

5.2 Types of corrosion damage effects ....................................................................... 12

5.2.1 Introduction ................................................................................................... 12

5.2.2 Metal loss ...................................................................................................... 12

5.2.3 Moving parts becoming immobile ................................................................... 12

5.2.4 Bridging of conductor circuits ......................................................................... 12

5.2.5 Formation of a non-conducting layer on contact surfaces............................... 12

5.3 Factors affecting corrosivity .................................................................................. 13

5.3.1 Introduction ................................................................................................... 13

5.3.2 The nature of fire effluent .............................................................................. 13

5.3.3 The corrosion environment ............................................................................ 14

6 Principles of corrosion damage measurement ................................................................ 14

6.1 Introduction ........................................................................................................... 14

6.2 Generation of the fire effluent ............................................................................... 14

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

6.2.2 Selection of the test specimen to be burned .................................................. 15

6.2.3 Selection of the physical fire model ............................................................... 15

6.3 Assessment of corrosive potential ......................................................................... 15

6.3.1 General ......................................................................................................... 15

6.3.2 Indirect assessment ....................................................................................... 15

6.3.3 Simulated product testing .............................................................................. 16

6.3.4 Product testing .............................................................................................. 16

6.4 Consideration of corrosivity test methods .............................................................. 16

7 Relevance of data to hazard assessment ....................................................................... 18

Bibliography .......................................................................................................................... 19

Figure 1 – Different stages in the development of a fire within a compartment ...................... 10

Figure 2 – Evaluation and consideration of corrosion damage test methods .......................... 17

Table 1 – Characteristics of fire stages (from Table 1 of ISO 19706:2011) ............................ 11

Table 2 – Summary of corrosivity test methods ..................................................................... 16

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SIST EN IEC 60695-5-1:2022
IEC 60695-5-1:2021 © IEC 2021 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIRE HAZARD TESTING –
Part 5-1: Corrosion damage effects of fire effluent –
General guidance
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote

international co-operation on all questions concerning standardization in the electrical and electronic fields. To

this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,

Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC

Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested

in the subject dealt with may participate in this preparatory work. International, governmental and non-

governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely

with the International Organization for Standardization (ISO) in accordance with conditions determined by

agreement between the two organizations.

2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

consensus of opinion on the relevant subjects since each technical committee has representation from all

interested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

misinterpretation by any end user.

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

transparently to the maximum extent possible in their national and regional publications. Any divergence

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

the latter.

5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of

patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60695-5-1 has been prepared by IEC technical committee 89: Fire

hazard testing.

This third edition cancels and replaces the second edition, published in 2002, and constitutes

a technical revision.

This edition includes the following significant technical changes with respect to the previous

edition:
a) References to IEC TS 60695-5-3 (withdrawn in 2014) have been removed.
b) References to IEC 60695-1-1 are now to its replacements: IEC 60695-1-10 and
IEC 60695-1-11.
c) ISO/TR 9122-1 has been revised by ISO 19706.
d) Table 1 has been updated.
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SIST EN IEC 60695-5-1:2022
– 4 – IEC 60695-5-1:2021 © IEC 2021
e) References to ISO 11907-2 and ISO 11907-3 have been removed.
f) Terms and definitions have been updated.
g) Text in 6.4 has been updated.
h) Bibliographic references have been updated.
The text of this International Standard is based on the following documents:
FDIS Report on voting
89/1539/FDIS 89/1543/RVD

Full information on the voting for its approval can be found in the report on voting indicated in

the above table.
The language used for the development of this International Standard is English.

This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in

accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement,

available at www.iec.ch/members_experts/refdocs. The main document types developed by

IEC are described in greater detail at www.iec.ch/standardsdev/publications.

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

ISO/IEC Guide 51.
In this standard, the following print types are used:
Arial bold: terms referred to in Clause 2
This standard is to be read in conjunction with IEC TS 60695-5-2.

A list of all parts in the IEC 60695 series, published under the general title Fire hazard testing,

can be found on the IEC website.

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.
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SIST EN IEC 60695-5-1:2022
IEC 60695-5-1:2021 © IEC 2021 – 5 –
INTRODUCTION

In the design of an electrotechnical product the risk of fire and the potential hazards

associated with fire need to be considered. In this respect the objective of component, circuit

and equipment design, as well as the choice of materials, is to reduce the risk of fire to a

tolerable level even in the event of reasonably foreseeable (mis)use, malfunction or failure.

IEC 60695-1-10, IEC 60695-1-11, and IEC 60695-1-12 [1] 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.

All fire effluent is corrosive to some degree and the level of potential to corrode depends on

the nature of the fire, the combination of combustible materials involved in the fire, the nature

of the substrate under attack, and the temperature and relative humidity of the environment in

which the corrosion damage is taking place. There is no evidence that fire effluent from

electrotechnical products offers greater risk of corrosion damage than the fire effluent from

other products such as furnishings or building materials.

The performance of electrical and electronic components can be adversely affected by

corrosion damage when subjected to fire effluent. A wide variety of combinations of small

quantities of effluent gases, smoke particles, moisture and temperature may provide

conditions for electrical component or system failures from breakage, overheating or shorting.

Evaluation of potential corrosion damage is particularly important for high value and safety-

related electrotechnical products and installations.

Technical committees responsible for products will choose the test(s) and specify the level of

severity.

The study of corrosion damage requires an interdisciplinary approach involving chemistry,

electricity, physics, mechanical engineering, metallurgy and electrochemistry. In the

preparation of this part of IEC 60695-5, all of the above have been considered.

IEC 60695-5-1 defines the scope of the guidance and indicates the field of application.

IEC TS 60695-5-2 provides a summary of test methods including relevance and usefulness.

___________
Numbers in square brackets refer to the bibliography.
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SIST EN IEC 60695-5-1:2022
– 6 – IEC 60695-5-1:2021 © IEC 2021
FIRE HAZARD TESTING –
Part 5-1: Corrosion damage effects of fire effluent –
General guidance
1 Scope
This part of IEC 60695 provides guidance on the following:
a) general aspects of corrosion damage test methods;
b) methods of measurement of corrosion damage;
c) consideration of test methods;
d) relevance of corrosion damage data to hazard assessment.

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.

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 TS 60695-5-2, Fire hazard testing – Part 5-2: Corrosion damage effects of fire effluent –

Summary and relevance of test methods

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

publications and group safety publications
ISO/IEC Guide 51, Safety aspects – Guidelines for their inclusion in standards

ISO 11907-1:2019, Plastics – Smoke generation – Determination of the corrosivity of fire

effluents – Part 1: General concepts and applicability
ISO 13943:2017, Fire safety – Vocabulary
ISO 19706:2011, Guidelines for assessing the fire threat to people
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SIST EN IEC 60695-5-1:2022
IEC 60695-5-1:2021 © IEC 2021 – 7 –
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
corrosion damage
physical and/or chemical damage or impaired function caused by chemical action
[SOURCE: ISO 13943:2017, 3.69]
3.2
corrosion target

sensor used to determine the degree of corrosion damage (3.1), under specified conditions

Note 1 to entry: This sensor may be a product, a component. It may also be a reference material or object used to

simulate the behaviour of a product or a component.
[SOURCE: ISO 13943:2017, 3.70]
3.3
fire decay

stage of fire development after a fire has reached its maximum intensity and during which the

heat release rate and the temperature of the fire are decreasing
[SOURCE: ISO 13943:2017, 3.122]
3.4
fire effluent
all gases and aerosols, including suspended particles, created by combustion or
pyrolysis (3.9) and emitted to the environment
[SOURCE: ISO 13943:2017, 3.123]
3.5
fire scenario

qualitative description of the course of a fire with respect to time, identifying key events that

characterize the studied fire and differentiate it from other possible fires

Note 1 to entry: See fire scenario cluster (ISO 13943:2017, 3.154) and representative fire scenario

(ISO 13943:2017, 3.153).

Note 2 to entry: It typically defines the ignition and fire growth processes, the fully developed fire stage, the fire

decay (3.3) stage, and the environment and systems that will impact on the course of the fire.

Note 3 to entry: Unlike deterministic fire analysis, where fire scenarios are individually selected and used as

design fire scenarios, in fire risk assessment, fire scenarios are used as representative fire scenarios within fire

scenario clusters.
[SOURCE: ISO 13943:2017, 3.152]
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SIST EN IEC 60695-5-1:2022
– 8 – IEC 60695-5-1:2021 © IEC 2021
3.6
flashover

transition to a state of total surface involvement in a fire of combustible

materials within an enclosure
[SOURCE: ISO 13943:2017, 3.184]
3.7
full developed fire
state of total involvement of combustible materials in a fire
[SOURCE: ISO 13943:2017, 3.192]
3.8
leakage current
electrical current flowing in an undesired circuit
3.9
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 13943:2017, 3.298]
3.10
pyrolysis
chemical decomposition of a substance by the action of heat

Note 1 to entry: Pyrolysis is often used to refer to a stage of fire before flaming combustion has begun.

Note 2 to entry: In fire science, no assumption is made about the presence or absence of oxygen.

[SOURCE: ISO 13943:2017, 3.316]
3.11
small-scale fire test
fire test performed on a test specimen of small dimensions

Note 1 to entry: There is no clear upper limit for the dimensions of the test specimen in a small-scale fire test. In

some instances, a fire test performed on a test specimen with a maximum dimension of less than 1 m is called a

small-scale fire test. However, a fire test performed on a test specimen of which the maximum dimension is

between 0,5 m and 1,0 m is often called a medium-scale fire test.
[SOURCE: ISO 13943:2017, 3.346]
3.12
smoke
visible part of a fire effluent
[SOURCE: ISO 13943:2017, 3.347]
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SIST EN IEC 60695-5-1:2022
IEC 60695-5-1:2021 © IEC 2021 – 9 –
4 Fire scenarios and physical fire models

During recent years, major advances have been made in the analysis of fire effluents. It is

recognized that the composition of the mixture of combustion products is particularly

dependent upon the nature of the combusting materials, the prevailing temperatures and the

ventilation conditions, especially access of oxygen to the seat of the fire. Table 1 shows how

the different stages of a fire relate to the changing atmosphere. Conditions for use in

laboratory scale tests can be derived from the table in order to correspond, as far as possible,

to full-scale fires.

Fire involves a complex and interrelated array of physical and chemical phenomena. As a

result, it is difficult to simulate all aspects of a real fire in laboratory scale apparatus. This

problem is perhaps the single most perplexing technical problem associated with all fire

testing.

General guidance for assessing the fire hazard of electrotechnical products is given in

IEC 60695-1-10. Guidance concerning fire hazard assessment is given in IEC 60695-1-11.

ISO 11907-1 defines terms related to smoke corrosivity as well as smoke acidity and smoke

toxicity. It presents the scenario-based approach that controls smoke corrosivity. It describes

the test methods to assess smoke corrosivity at laboratory scale and deals with test

applicability and post-exposure conditions.

After ignition, fire development may occur in different ways depending on the environmental

conditions, as well as on the physical arrangement of the combustible materials. However, a

general pattern can be established for fire development within a compartment, where the

general temperature-time curve shows three stages, plus a fire decay stage (see Figure 1).

Stage 1 (non-flaming decomposition) is the incipient stage of the fire prior to sustained

flaming, with little rise in the fire room temperature. Ignition and smoke generation are the

main hazards during this stage.

Stage 2 (developing fire) starts with ignition and ends with a rapid rise in fire room

temperature. Spread of flame and heat release are the main hazards in addition to smoke

during this stage.

Stage 3 (fully developed fire) starts when the surface of all of the combustible contents of the

room has decomposed to such an extent that sudden ignition occurs all over the room, with a

rapid and large increase in temperature (flashover).

At the end of Stage 3, the combustibles and/or oxygen have been largely consumed and

hence the temperature decreases at a rate which d
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