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

IEC 60695-5-1:2021 is available as IEC 60695-5-1:2021 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 60695-5-1:2021 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. This standard is to be read in conjunction with IEC TS 60695-5-2.
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a) References to IEC TS 60695-5-3 (withdrawn in 2014) have been removed.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.
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.

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

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.

General Information

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

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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
IEC 60695-5-1:2021-10(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
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

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® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 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

---------------------- Page: 4 ----------------------
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

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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.
---------------------- Page: 5 ----------------------
– 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.
---------------------- Page: 6 ----------------------
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.
---------------------- Page: 7 ----------------------
– 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
---------------------- Page: 8 ----------------------
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]
---------------------- Page: 9 ----------------------
– 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]
---------------------- Page: 10 ----------------------
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 depends on the ventilation and the heat and

mass transfer characteristics of the system. This is known as the fire decay stage.

In each of these stages, a different mixture of decomposition products may be formed and

this, in turn, influences the corrosive potential of the fire effluent produced during that stage.

Characteristics of these fire stages are given in Table 1.
---------------------- Page: 11 ----------------------
– 10 – IEC 60695-5-1:2021 © IEC 2021
Figure 1 – Different stages in the development of a fire within a compartment
5 General aspects of the corrosivity of fire effluent
5.1 Corrosion damage scenarios

With respect to electrotechnical equipment and systems, there are three corrosion damage

scenarios which are of concern:

a) within electrotechnical equipment and systems when exposed to fire effluent caused by

unusual, localized, internal sources of excessive heat and ignition;

b) within electrotechnical equipment and systems when exposed to fire effluent caused by

external sources of flame or excessive heat;

c) within building structures when exposed to fire effluent emitted from electrotechnical

equipment and systems.
---------------------- Page: 12 ----------------------
IEC 60695-5-1:2021 © IEC 2021 – 11 –
Table 1 – Characteristics of fire stages (from Table 1 of ISO 19706:2011)
Max. temperature Oxygen volume
[CO]
Heat flux to
100×[CO2]
Fuel/air %
fuel surface
[CO2]
Fire stage °C % equivalence
([CO2]+[CO])
ratio (plume)
2 efficiency
kW/m Fuel surface Upper layer Entrained Exhausted v/v
1. Non-flaming
a. self-sustaining not
450 to 800 25 to 85 20 20 – 0,1 to 1 50 to 90
(smouldering) applicable
b. oxidative pyrolysis from
b c c
externally applied – 300 to 600 a 20 20 < 1
radiation
c. anaerobic pyrolysis from
b c c
externally applied – 100 to 500
0 0 >> 1
radiation
d e

2. Well-ventilated flaming 0 to 60 350 to 650 50 to 500 ≈ 20 ≈ 20 < 1 < 0,05 > 95

3. Underventilated flaming
a. small, localized fire,
generally in a poorly 0 to 30 300 to 600 50 to 500
...

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