SIST EN 60695-5-1:2003

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

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. The structure of this second edition remains essentially the same as the first edition with the following additions: - Information on fire scenarios and fire models has been added along with an update on the latest advances in the analysis of the fire effluent. - The general classification of fires from ISO TR 9122-1 has been added. - A new clause on the general aspects of the corrosivity of fire effluent which describes the types of corrosion damage effects and the factors affecting corrosivity. - A new clause on the principles of corrosion damage measurement has been added describing the assessment of the corrosive potential and the consideration of the corrosivity test methods. - A new table describing a summary of corrosion test methods. - A new flowchart detailing the evaluation and consideration of corrosion damage test methods. - The bibliography has been expanded. Has the status of a basic safety publication in accordance with IEC guide 104.

Prüfungen zur Beurteilung der Brandgefahr -- Teil 5-1: Korrosionsschädigung durch Rauch und/oder Brandgase - Allgemeiner Leitfaden

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

Fournit un guide concernant: a) les aspects généraux des méthodes d'essai des dommages provoqués par la corrosion; b) les méthodes de mesure des dommages provoqués par la corrosion; c) la prise en compte des méthodes d'essai; d) la pertinence des données concernant les dommages de corrosion pour l'évaluation des risques. La structure de la deuxième édition demeure pratiquement inchangée, à l'exception des éléments importants suivants qui ont été ajoutés: - Information relative aux scénarios et aux modèles de feu ainsi qu'une mise à jour des dernières avancées réalisées dans l'analyse des effluents du feu. - Classification générale des feux selon l'ISO TR 9122-1. - Nouvel article relatif aux aspects généraux de la corrosivité des effluents du feu, décrivant les types d'effets des dommages de la corrosion et les facteurs affectant la corrosivité. - Nouvel article relatif aux principes de mesure des dommages de la corrosion, décrivant l'évolution du potentiel corrosif et la prise en compte des méthodes d'essai de la corrosivité. - Nouveau tableau résumant les méthodes d'essai de la corrosivité. - Nouvel organigramme présentant en détail l'évaluation et la prise en compte des méthodes d'essai des dommages de la corrosion. - Elargissement de la bibliographie. A le statut d'une publication fondamentale de sécurité conformément au Guide 104 de la CEI.

Preskušanje požarne ogroženosti - 5-1. del: Poškodbe zaradi korozijskega učinka izžarevanja ognja - Splošno navodilo

General Information

• Status: Published
• Publication Date: 30-Jun-2003
• ICS: 13.220.40 - Ignitability and burning behaviour of materials and products
• ICS: 29.020 - Electrical engineering in general
• Technical Committee: I09 - Imaginarni 09
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Jul-2003
• Due Date: 01-Jul-2003
• Completion Date: 01-Jul-2003
• Ref Project: EN 60695-5-1:2003 - Fire hazard testing - Part 5-1: Corrosion damage effects of fire effluent - General guidance

Relations

• Replaced By: SIST EN IEC 60695-5-1:2022 - Fire hazard testing - Part 5-1: Corrosion damage effects of fire effluent - General guidance (IEC 60695-5-1:2021)
• Effective Date: 07-Dec-2021
• Replaces: SIST EN 60695-5-1:2001 - Fire hazard testing -- Part 5: Assessment of potential corrosion damage by fire effluent -- Section 1: General guidance
• Effective Date: 06-May-2014
• Revised: SIST EN IEC 60695-5-1:2022 - Fire hazard testing - Part 5-1: Corrosion damage effects of fire effluent - General guidance (IEC 60695-5-1:2021)
• Effective Date: 26-Feb-2019
• Replaces: SIST EN 60695-5-1:2001 - Fire hazard testing -- Part 5: Assessment of potential corrosion damage by fire effluent -- Section 1: General guidance
• Effective Date: 28-Jan-2023
• Replaces: SIST EN 60695-5-1:2001 - Fire hazard testing -- Part 5: Assessment of potential corrosion damage by fire effluent -- Section 1: General guidance
• Effective Date: 07-Jun-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 60695-5-1:2003
01-julij-2003
1DGRPHãþD
SIST EN 60695-5-1:2001
3UHVNXãDQMHSRåDUQHRJURåHQRVWLGHO3RãNRGEH]DUDGLNRUR]LMVNHJDXþLQND
L]åDUHYDQMDRJQMD6SORãQRQDYRGLOR
Fire hazard testing -- Part 5-1: Corrosion damage effects of fire effluent - General
guidance
Prüfungen zur Beurteilung der Brandgefahr -- Teil 5-1: Korrosionsschädigung durch
Rauch und/oder Brandgase - Allgemeiner Leitfaden
Essais relatifs aux risques du feu -- Partie 5-1: Effets des dommages de corrosion des
effluents du feu - Guide général
Ta slovenski standard je istoveten z: EN 60695-5-1:2003
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 60695-5-1:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

SIST EN 60695-5-1:2003

---------------------- Page: 2 ----------------------

SIST EN 60695-5-1:2003
EUROPEAN STANDARD EN 60695-5-1
NORME EUROPÉENNE
EUROPÄISCHE NORM February 2003

ICS 29.020 Supersedes EN 60695-5-1:1993


English version


Fire hazard testing
Part 5-1: Corrosion damage effects of fire effluent -
General guidance
(IEC 60695-5-1:2002)


Essais relatifs aux risques du feu Prüfungen zur Beurteilung
Partie 5-1: Effets des dommages der Brandgefahr
de corrosion des effluents du feu - Teil 5-1: Korrosionsschädigung
Guide général durch Rauch und/oder Brandgase -
(CEI 60695-5-1:2002) Allgemeiner Leitfaden
(IEC 60695-5-1:2002)





This European Standard was approved by CENELEC on 2003-02-01. 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 Central Secretariat 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 Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta,
Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels


© 2003 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 60695-5-1:2003 E

---------------------- Page: 3 ----------------------

SIST EN 60695-5-1:2003
EN 60695-5-1:2003 - 2 -
Foreword

The text of document 89/556/FDIS, future edition 2 of IEC 60695-5-1, prepared by IEC TC 89, Fire
hazard testing, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as
EN 60695-5-1 on 2003-02-01.

This European Standard supersedes EN 60695-5-1:1993

The following dates were fixed:

– latest date by which the EN has to be implemented
 at national level by publication of an identical
 national standard or by endorsement (dop) 2003-11-01

– latest date by which the national standards conflicting
 with the EN have to be withdrawn (dow) 2006-02-01

This European Standard should be read in conjunction with IEC 60695-5-2 and IEC 60695-5-3.

Annexes designated "normative" are part of the body of the standard.
In this standard, annex ZA is normative.
Annex ZA has been added by CENELEC.
__________

Endorsement notice

The text of the International Standard IEC 60695-5-1:2002 was approved by CENELEC as a
European Standard without any modification.

In the official version, for Bibliography, the following note has to be added for the standard indicated:

ISO 7384 NOTE Harmonized as EN ISO 7384:1995 (not modified).
__________

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

SIST EN 60695-5-1:2003
- 3 - EN 60695-5-1:2003
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of any
of these publications apply to this European Standard only when incorporated in it by amendment or
revision. For undated references the latest edition of the publication referred to applies (including
amendments).
NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
IEC 60695-1-1 1999 Fire hazard testing EN 60695-1-1 2000
+ corr. January 2000 Part 1-1: Guidance for assessing the
fire hazard of electrotechnical products -
General guidelines

IEC/TS 60695-5-2 2002 Part 5-2: Corrosion damage effects of - -
fire effluent - Summary and relevance of
test methods

1)
IEC/TS 60695-5-3 - Part 5-3: Corrosion damage effects of - -
fire effluent - Leakage current and metal
loss test method

2)
IEC 60754-1 1994 Test on gases evolved during - -
combustion of materials from cables
Part 1: Determination of the amount of
halogen acid gas

3)
IEC 60754-2 1991 Test on gases evolved during HD 602 S1 1992
(mod) combustion of materials from cables -
Determination of degree of acidity
(corrosivity) of gases by measuring pH
and conductivity
A1 1997 - -

ISO/TR 9122-1 1989 Toxicity testing of fire effluents - -
Part 1: General

ISO 11907-2 1995 Plastics - Smoke generation - - -
Determination of the corrosivity of fire
effluents
Part 2: Static method


1)
To be published.
2)
EN 50267-1:1998 and EN 50265-2-1:1998, which are related to IEC 60754-1:1994, apply.
3)
HD 602 S1 is superseded by EN 50267-1:1998 and EN 50267-2-3:1998.

---------------------- Page: 5 ----------------------

SIST EN 60695-5-1:2003
EN 60695-5-1:2003 - 4 -
Publication Year Title EN/HD Year
ISO 11907-3 1998 Part 3: Dynamic decomposition method - -
using a travelling furnace

ISO 11907-4 1998 Part 4: Dynamic decomposition method - -
using a conical radiant heater

ISO/IEC 13943 2000 Fire safety - Vocabulary EN ISO 13943 2000

ASTM D 2671-00 - Standard Test Methods for Heat- - -
Shrinkable Tubing for Electrical Use

---------------------- Page: 6 ----------------------

SIST EN 60695-5-1:2003
NORME CEI
INTERNATIONALE IEC
60695-5-1
INTERNATIONAL
Deuxième édition
STANDARD
Second edition
2002-11
PUBLICATION FONDAMENTALE DE SÉCURITÉ
BASIC SAFETY PUBLICATION
Essais relatifs aux risques du feu –
Partie 5-1:
Effets des dommages de corrosion
des effluents du feu – Guide général
Fire hazard testing –
Part 5-1:
Corrosion damage effects of fire effluent –
General guidance
 IEC 2002 Droits de reproduction réservés  Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in any
utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including
électronique ou mécanique, y compris la photo-copie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail]  Web: www.iec.ch
CODE PRIX
Q
Commission Electrotechnique Internationale
PRICE CODE
International Electrotechnical Commission
Международная Электротехническая Комиссия
Pour prix, voir catalogue en vigueur
For price, see current catalogue

---------------------- Page: 7 ----------------------

SIST EN 60695-5-1:2003
60695-5-1  IEC:2002 – 3 –
CONTENTS
FOREWORD . 5
INTRODUCTION .9
1 Scope .11
2 Normative references.11
3 Definitions .13
4 Fire scenarios and fire models .15
5 General aspects of the corrosivity of fire effluent .17
5.1 Corrosion damage scenarios .17
5.2 Types of corrosion damage effects .19
5.2.1 Metal loss .19
5.2.2 Moving parts becoming immobile .19
5.2.3 Bridging of conductor circuits.19
5.2.4 Formation of a non-conducting layer on contact surfaces.19
5.3 Factors affecting corrosivity.21
5.3.1 The nature of fire effluent.21
5.3.2 The corrosion environment.23
6 Principles of corrosion damage measurement.23
6.1 Introduction .23
6.2 Generation of the fire effluent .25
6.2.1 Selection of the test specimen which is to be burned .25
6.2.2 Selection of the fire model .25
6.3 The assessment of corrosive potential .25
6.3.1 General.25
6.3.2 Indirect assessment .25
6.3.3 Simulated product testing .27
6.3.4 Product testing.27
6.4 Consideration of corrosivity test methods.29
7 Relevance of data to hazard assessment.33
Bibliography.35
Figure 1 – Different stages in the development of a fire within a compartment.17
Figure 2 – Evaluation and consideration of corrosion damage test methods .31
Table 1 – General classification of fires (ISO/TR 9122-1) .17
Table 2 – Summary of corrosivity test methods .27

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SIST EN 60695-5-1:2003
60695-5-1  IEC:2002 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIRE HAZARD TESTING –
Part 5-1: Corrosion damage effects of fire effluent –
General guidance
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. 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. The 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 the 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 National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The 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 second edition cancels and replaces the first edition, published in 1993, and constitutes
a technical revision.
The structure of this International standard remains essentially the same with some major new
changes added:
– Information on fire scenarios and fire models has been added along with an update on the
latest advances in the analysis of the fire effluent.
– The general classification of fires from ISO TR 9122-1 has been added.
– A new clause on the general aspects of the corrosivity of fire effluent which describes the
types of corrosion damage effects and the factors affecting corrosivity.
– A new clause on the principles of corrosion damage measurement has been added
describing the assessment of the corrosive potential and the consideration of the
corrosivity test methods.
– A new table describing a summary of corrosion test methods.
– A new flowchart detailing the evaluation and consideration of corrosion damage test
methods.
– The bibliography has been expanded.

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SIST EN 60695-5-1:2003
60695-5-1  IEC:2002 – 7 –
It has the status of a basic safety publication in accordance with IEC Guide 104.
The text of this standard is based on the following documents:
FDIS Report on voting
89/556/FDIS 89/566/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.
This standard should be read in conjunction with IEC 60695-5-2 and IEC 60695-5-3.
This standard forms part 5-1 of IEC 60695, which is published under the general heading Fire
hazard testing. Part 5 consists of the following parts:
Part 5-1: Corrosion damage effects of fire effluent – General guidance
Part 5-2: Corrosion damage effects of fire effluent – Summary and relevance of test methods
Part 5-3: Corrosion damage effects of fire effluent – Leakage current and metal loss test
method
The committee has decided that the contents of this publication will remain unchanged
until 2008. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.

---------------------- Page: 10 ----------------------

SIST EN 60695-5-1:2003
60695-5-1  IEC:2002 – 9 –
INTRODUCTION
The risk of fire should be considered in any electrical circuit. With regard to this risk, the
circuit and equipment design, the selection of components and the choice of materials should
contribute towards reducing the likelihood of fire even in the event of foreseeable abnormal
use, malfunction or failure. The practical aim should be to prevent ignition caused by electrical
malfunction but, if ignition and fire occur, to control the fire preferably within the bounds of the
enclosure of the electrotechnical product.
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, building materials, etc.
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 the 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 pre-
paration 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 60695-5-2 provides a summary of test methods including relevance and usefulness.
IEC 60695-5-3 provides details of a small-scale test method for the measurement of leakage
current and metal loss caused by fire effluent.

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SIST EN 60695-5-1:2003
60695-5-1  IEC:2002 – 11 –
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.
One of the responsibilities of a technical committee is, wherever applicable, to make use of
basic safety publications in the preparation of its 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 60695-1-1:1999, Fire hazard testing – Part 1-1: Guidance for assessing the fire hazard
of electrotechnical products – General guidelines
IEC/TS 60695-5-2:2002, Fire hazard testing – Part 5-2: Corrosion damage effects of fire
effluent – Summary and relevance of test methods
IEC/TS 60695-5-3, Fire hazard testing – Part 5-3: Corrosion damage effects of fire effluent –
1
Leakage current and metal loss test method
IEC 60754-1:1994, Test on gases evolved during combustion of materials from cables –
Part 1: Determination of the amount of halogen acid gas
IEC 60754-2:1991, Test on gases evolved during combustion of electric cables – Part 2:
Determination of degree of acidity of gases evolved during the combustion of materials taken
from electric cables by measuring pH and conductivity
IEC 60754-2, Amendment 1 (1997)
ISO/TR 9122-1:1989, Toxicity testing of fire effluents – Part 1: General
ISO 11907-2:1995, Plastics – Smoke generation – Determination of the corrosivity of fire
effluents – Part 2: Static method
ISO 11907-3:1998, Plastics – Smoke generation – Determination of the corrosivity of fire
effluents – Part 3: Dynamic decomposition method using a travelling furnace
___________
1
 To be published.

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SIST EN 60695-5-1:2003
60695-5-1  IEC:2002 – 13 –
ISO 11907-4:1998, Plastics – Smoke generation – Determination of the corrosivity of fire
effluents – Part 4: Dynamic decomposition method using a conical radiant heater
ISO/IEC 13943:2000, Fire safety – Vocabulary
ASTM D 2671 – 00, Standard Test Methods for Heat-Shrinkable Tubing for Electrical Use
3 Terms and definitions
For the purposes of this part of IEC 60695, the following definitions, some of which have been
taken from ISO/IEC 13943, apply.
3.1
corrosion damage
physical and/or chemical damage or impaired function caused by chemical action
[ISO/IEC 13943, definition 25]
3.2
corrosion target
sensor used to determine the degree of corrosion damage, under specified conditions
NOTE This sensor may be a product, a component, or a reference material used to simulate them.
[ISO/IEC 13943, definition 26]
3.3
critical relative humidity
level of relative humidity that causes leakage current to exceed a value defined in the product
specification
3.4
fire effluent
totality of gases and/or aerosols (including suspended particles) created by combustion or
pyrolysis
[ISO/IEC 13943, definition 45]
3.5
fire effluent decay characteristics
physical and/or chemical changes in fire effluent due to time and transport
3.6
fire effluent transport
movement of fire effluent away from the location of the fire
3.7
fire scenario
detailed description of conditions, including environmental, of one or more stages from before
ignition to after completion of combustion in an actual fire at a specific location or in a real-
scale simulation
[ISO/IEC 13943, definition 58]

---------------------- Page: 13 ----------------------

SIST EN 60695-5-1:2003
60695-5-1  IEC:2002 – 15 –
3.8
ignition source
source of energy that initiates combustion
([SO/IEC 13943, definition 97]
3.9
leakage current
electrical current flowing in an undesired circuit
3.10
smoke
visible part of fire effluent
[ISO/IEC 13943, definition 150]
4 Fire scenarios and 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 of fire model validity 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 60695-1-1.
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 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 decay stage.

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SIST EN 60695-5-1:2003
60695-5-1  IEC:2002 – 17 –
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.
Stage 1 Stage 2 Stage 3
Decay
Non-flaming Developing Full developed
stage
fire
decomposition fire
0 Ignition Flashover Time  t
IEC  2767/02
Figure 1 – Different stages in the development of a fire within a compartment
Table 1 – General classification of fires (ISO/TR 9122-1)
Oxygen * CO2/CO Temperature * Irradiance ***
Stages of fire
ratio **
°
−2
% C
kW⋅m
Stage 1 Non-flaming decomposition
a) Smouldering (self-sustaining) 21 Not applicable <100 Not applicable
b) Non-flaming (oxidative) 5 to 21 Not applicable <500 <25
c) Non-flaming (pyrolytic) <5 Not applicable <1 000 Not applicable
Stage 2 Developing fire (flaming) 10 to 15 100 to 200 400 to 600 20 to 40
Stage 3 Fully developed fire (flaming)
a) Relatively low ventilation 1 to 5 <10 600 to 900 40 to 70
b) Relatively high ventilation 5 to 10 <100 600 to 1 200 50 to 150
* General environmental condition (average) within compartment.
** Mean value in fire plume near to fire.
*** Incident irradiance onto test specimen (average).
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. These are where corrosion damage is caused by fire effluent
in the following situations:
a) within electrotechnical equipment and systems when exposed to fire effluent caused by
unusual, localized, internal sources of excessive heat and ignition;
Compartment
temperature

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SIST EN 60695-5-1:2003
60695-5-1  IEC:2002 – 19 –
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.
5.2 Types of corrosion damage effects
Four types of corrosion damage effect are recognized. These are
a) metal loss,
b) moving parts becoming immobile,
c) bridging of conductor circuits,
d) formation of a non-conducting layer on contact surfaces.
5.2.1 Metal loss
Metal loss is caused by oxidation of elemental metal to a positive oxidation state. One of the
simplest reactions of this type is with an acid to form a metal salt and water, and this is why
early efforts to combat potential corrosion were directed at reducing the acid gas production
in fire effluent.
However, it is not necessary for an acid to be present for oxidation to occur. If a metal is in
contact with an electrically conductive solution, the free ions of the solution can facilitate
corrosion of contacting metals by either reacting directly with the metal or by depolarizing the
area around the reacting metal. The rate of corrosion will depend on the area of metal
affected, the temperature, and on the magnitude of the difference between the electrode
potentials of the oxidizing and reducing couples. Metals higher in the electrochemical series
are more prone to corrosion.
Metal loss can cause many undesired effects. In buildings it can result in a weakening or
failure of structural elements. In electrical equipment it can cause a decrease in electrical
conductivity or ultimately the breaking of a circuit.
5.2.2 Moving parts becoming immobile
Fire effluent can cause moving parts in mechanical or electromechanical equipment to
become immobile, e.g. a ball bearing or parts in a circuit breaker. This may be because of the
deposition of sticky particulate matter or because of the formation of chemical corrosion
products between surfaces.
5.2.3 Bridging of conductor circuits
Fire effluent may contain conductive particulates, e.g. graphitic carbon or ionic species. Metal
corrosion also produces ionic species. These conductive species can bridge the small gaps
between the copper tracks on cir
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