IEC 60695-8-1:2016

Fire hazard testing - Part 8-1: Heat release - General guidance

IEC 60695-8-1:2016 provides guidance on the measurement and interpretation of heat release from electrotechnical products and materials from which they are constructed. Heat release data can be used as part of fire hazard assessment and in fire safety engineering, as described in IEC 60695-1-11 and IEC 60695-1-12. This third edition cancels and replaces the second edition published in 2008. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- a modified Introduction;
- reference to IEC 60695-1-12;
- updated normative references;
- revised terms and definitions;
- new text in 4.2.2, 4.2.3, 6.1 and 6.4, including several mandatory statements and
- mandatory statements in a new Subclause 6.5. This standard is to be used in conjunction with IEC 60695-8-2.
Key words: Fire Hazard, Heat Release, Fire Safety Engineering

Essais relatifs aux risques du feu - Partie 8-1: Dégagement de chaleur - Guide général

L'IEC 60695-8-1:2016 fournit les lignes directrices sur le mesurage et l'interprétation du dégagement de chaleur des produits électrotechniques et des matériaux à partir desquels ils sont constitués. Les données de dégagement de chaleur peuvent être utilisées pour évaluer le danger d'incendie et pour l'ingénierie de la sécurité incendie, comme indiqué dans l'IEC 60695-1-11 et l'IEC 60695-1-12. Cette troisième édition annule et remplace la deuxième édition, parue en 2008. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- introduction modifiée;
- référence à l'IEC 60695-1-12;
- références normatives mises à jour;
- termes et définitions révisés;
- nouveau texte aux 4.2.2, 4.2.3, 6.1 et 6.4, y compris plusieurs déclarations obligatoires;
- déclarations obligatoires dans un nouveau paragraphe 6.5. La présente norme doit être utilisée conjointement avec l'IEC 60695-8-2.
Mots-clés: risques du feu, dégagement de chaleur, l'ingénierie de la sécurité incendie

General Information

• Status: Published
• Publication Date: 14-Nov-2016
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 13.220.40 - Ignitability and burning behaviour of materials and products
• ICS: 29.020 - Electrical engineering in general
• ICS: 29.060.10 - Wires
• ICS: 55.060 - Spools. Bobbins
• Technical Committee: TC 89 - Fire hazard testing
• Current Stage: PPUB - Publication issued
• Completion Date: 15-Nov-2016

Standards Content (Sample)

IEC 60695-8-1
Edition 3.0 2016-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
Fire hazard testing –
Part 8-1: Heat release – General guidance
Essais relatifs aux risques du feu –
Partie 8-1: Dégagement de chaleur – Guide général
IEC 60695-8-1:2016-11(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 60695-8-1
Edition 3.0 2016-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
Fire hazard testing –
Part 8-1: Heat release – General guidance
Essais relatifs aux risques du feu –
Partie 8-1: Dégagement de chaleur – Guide général
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 13.220.40; 29.020 ISBN 978-2-8322-3749-6

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

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

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 60695-8-1:2016  IEC 2016
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

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

4 Principles of determining heat release ........................................................................... 11

4.1 Complete combustion measured by the oxygen bomb calorimeter ......................... 11

4.2 Incomplete combustion ......................................................................................... 12

4.2.1 Measurement techniques ............................................................................... 12

4.2.2 Heat release by oxygen consumption ............................................................. 12

4.2.3 Heat release by carbon dioxide generation .................................................... 13

4.2.4 Heat release by increase of gas temperature ................................................. 13

5 Parameters used to report heat release data ................................................................. 15

5.1 Heat of combustion (gross and net) ...................................................................... 15

5.2 Heat release rate (HRR) ....................................................................................... 15

5.3 Heat release (HR) ................................................................................................. 16

5.4 Heat release rate per unit area (HRR*) ................................................................. 16

5.5 Total heat release ................................................................................................. 17

5.6 Peak heat release rate .......................................................................................... 17

5.7 Time to peak heat release rate .............................................................................. 17

5.8 Effective heat of combustion ................................................................................. 17

5.8.1 Measurement and calculation ........................................................................ 17

5.8.2 Examples....................................................................................................... 18

5.9 FIGRA index ......................................................................................................... 19

5.10 ARHE and MARHE ............................................................................................... 20

6 Considerations for the selection of test methods ............................................................ 22

6.1 Ignition sources .................................................................................................... 22

6.2 Type of test specimen ........................................................................................... 22

6.3 Choice of conditions ............................................................................................. 22

6.4 Test apparatus ...................................................................................................... 22

6.4.1 General ......................................................................................................... 22

6.4.2 Small-scale fire test apparatus ....................................................................... 22

6.4.3 Intermediate and large-scale fire test apparatus ............................................ 23

6.4.4 Comparison between small-scale and intermediate/large-scale fire test

methods ........................................................................................................ 23

6.5 Choice of fire tests ................................................................................................ 23

7 Relevance of heat release data ..................................................................................... 23

7.1 Contribution to fire hazard ..................................................................................... 23

7.2 Secondary ignition and flame spread .................................................................... 23

7.3 Determination of self-propagating fire thresholds .................................................. 24

7.4 Probability of reaching flash-over .......................................................................... 24

7.5 Smoke and toxic gas production ........................................................................... 24

7.6 The role of heat release testing in research and development ............................... 24

Bibliography .......................................................................................................................... 25

---------------------- Page: 4 ----------------------
IEC 60695-8-1:2016  IEC 2016 – 3 –

Figure 1 – Heat release rate (HRR) curve ............................................................................. 16

Figure 2 – Heat release (HR) curve ....................................................................................... 16

Figure 3 – Heat release rate per unit area (HRR*) curve ....................................................... 17

Figure 4 – Mass loss curve ................................................................................................... 18

Figure 5 – FIGRA curve derived from Figure 1 ...................................................................... 19

Figure 6 – Illustrative HRR curve .......................................................................................... 20

Figure 7 – FIGRA curve derived from Figure 6 ...................................................................... 20

Figure 8 – ARHE curve derived from Figure 1 ....................................................................... 21

Figure 9 – ARHE curve derived from Figure 6 ....................................................................... 21

Table 1 – Relationship between heat of combustion expressed in units of kJ·g of

fuel burned and kJ·g of oxygen consumed for a variety of fuels ........................................ 14

Table 2 – Relationship between heat of combustion expressed in units of kJ·g of

fuel burned and kJ·g of oxygen consumed for a variety of insulating liquids ...................... 15

---------------------- Page: 5 ----------------------
– 4 – IEC 60695-8-1:2016  IEC 2016
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIRE HAZARD TESTING –
Part 8-1: Heat release – 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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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 60695-8-1 has been prepared by IEC technical committee 89: Fire

hazard testing.

This third edition cancels and replaces the second edition published in 2008. This edition

constitutes a technical revision.

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

edition:
a) a modified Introduction;
b) reference to IEC 60695-1-12;
c) updated normative references;
d) revised terms and definitions;

e) new text in 4.2.2, 4.2.3, 6.1 and 6.4, including several mandatory statements;

f) mandatory statements in a new Subclause 6.5.
---------------------- Page: 6 ----------------------
IEC 60695-8-1:2016  IEC 2016 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
89/1342/FDIS 89/1348/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.

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

ISO/IEC Guide 51.
This standard is to be used in conjunction with IEC 60695-8-2.

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

be found on the IEC website.
IEC 60695-8 consists of the following parts:
Part 8-1: Heat release – General guidance
Part 8-2: Heat release – Summary of test methods

The committee has decided that the contents of this publication will remain unchanged until

the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data

related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
---------------------- Page: 7 ----------------------
– 6 – IEC 60695-8-1:2016  IEC 2016
INTRODUCTION

In the design of any electrotechnical product, the risk of fire and the potential hazards

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

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

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

IEC 60695-1-10 [1] provides guidance on how this is to be accomplished.

Fires involving electrotechnical products can be initiated from external non-electrical sources.

Considerations of this nature are dealt with in an overall risk assessment.

The aim of the IEC 60695 series of standards 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.

Fires are responsible for creating hazards to life and property as a result of the generation of

heat (thermal hazard), toxic and/or corrosive compounds and obscuration of vision due to

smoke. Fire risk increases as the heat released increases, possibly leading to a flash-over fire.

One of the most important measurements in fire testing is the measurement of heat release,

and it is used as an important factor in the determination of fire hazard; it is also used as one

of the parameters in fire safety engineering calculations.

The measurement and use of heat release data, together with other fire test data, can be

used to reduce the likelihood of (or the effects of) fire, even in the event of reasonably

foreseeable (mis)use, malfunction or failure of electrotechnical products.

When a material is heated by some external source, fire effluent can be generated and can

form a mixture with air, which can ignite and initiate a fire. The heat released in the process is

carried away by the fire effluent-air mixture, radiatively lost or transferred back to the solid

material, to generate further pyrolysis products, thus continuing the process.

Heat may also be transferred to other nearby products, which may burn, and then release

additional heat and fire effluent.

The rate at which thermal energy is released in a fire is defined as the heat release rate. Heat

release rate is important because of its influence on flame spread and on the initiation of

secondary fires. Other characteristics are also important, such as ignitability, flame spread

and the side-effects of the fire (see the IEC 60695 series of standards).
______________
Numbers in square brackets refer to the Bibliography.
---------------------- Page: 8 ----------------------
IEC 60695-8-1:2016  IEC 2016 – 7 –
FIRE HAZARD TESTING –
Part 8-1: Heat release – General guidance
1 Scope

This part of IEC 60695-8 provides guidance on the measurement and interpretation of heat

release from electrotechnical products and materials from which they are constructed.

Heat release data can be used as part of fire hazard assessment and in fire safety

engineering, as described in IEC 60695-1-11 [2] and IEC 60695-1-12 [3].

This basic safety publication is intended for use by technical committees in the preparation of

standards in accordance with the principles laid down in IEC Guide 104 and
ISO/IEC Guide 51.

One of the responsibilities of a technical committee is, wherever applicable, to make use of

basic safety publications in the preparation of its publications. The requirements, test

methods or test conditions of this basic safety publication will not apply unless specifically

referred to or included in the relevant publications.
2 Normative references

The following 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 60695-4:2012, Fire hazard testing – Part 4: Terminology concerning fire tests for

electrotechnical products

IEC 60695-8-2, Fire hazard testing – Part 8-2: Heat release – 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 13943:2008, Fire safety – Vocabulary
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 13943:2008 and

IEC 60695-4:2012 (some of which are reproduced below), as well as the following, apply.

3.1
combustion
exothermic reaction of a substance with an oxidizing agent

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

---------------------- Page: 9 ----------------------
– 8 – IEC 60695-8-1:2016  IEC 2016
[SOURCE: ISO 13943: 2008, 4.46]
3.2
combustion product
product of combustion
solid, liquid and gaseous material resulting from combustion

Note 1 to entry: Combustion products can include fire effluent, ash, char, clinker and/or soot.

[SOURCE: ISO 13943:2008, 4.48]
3.3
complete combustion
combustion in which all the combustion products are fully oxidized

Note 1 to entry: This means that, when the oxidizing agent is oxygen, all carbon is converted to carbon dioxide

and all hydrogen is converted to water.

Note 2 to entry: If elements other than carbon, hydrogen and oxygen are present in the combustible material,

those elements are converted to the most stable products in their standard states at 298 K.

[SOURCE: ISO 13943:2008, 4.50]
3.4
effective heat of combustion

heat released from a burning test specimen in a given time interval divided by the mass lost

from the test specimen in the same time period

Note 1 to entry: The value is the same as the net heat of combustion if the entire test specimen is converted to

volatile combustion products and if all the combustion products are fully oxidized.

Note 2 to entry: The typical units are kilojoules per gram (kJ·g ).
[SOURCE: ISO 13943:2008, 4.74]
3.5
fire

〈general〉 process of combustion characterized by the emission of heat and fire effluent and

usually accompanied by smoke, flame, glowing or a combination thereof

Note 1 to entry: In the English language the term “fire” is used to designate three concepts, two of which, fire (3.6)

and fire (3.7), relate to specific types of self-supporting combustion with different meanings and two of them are

designated using two different terms in both French and German.
[SOURCE: ISO 13943:2008, 4.96]
3.6
fire

〈controlled〉 self-supporting combustion that has been deliberately arranged to provide useful

effects and is limited in its extent in time and space
[SOURCE: ISO 13943:2008, 4.97]
3.7
fire

〈uncontrolled〉 self-supporting combustion that has not been deliberately arranged to provide

useful effects and is not limited in its extent in time and space
[SOURCE: ISO 13943:2008, 4.98]
---------------------- Page: 10 ----------------------
IEC 60695-8-1:2016  IEC 2016 – 9 –
3.8
fire effluent

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

pyrolysis in a fire
[SOURCE: ISO 13943:2008, 4.105]
3.9
fire hazard

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

[SOURCE: ISO 13943:2008, 4.112]
3.10
fire safety engineering

application of engineering methods based on scientific principles to the development or

assessment of designs in the built environment through the analysis of specific fire scenarios

or through the quantification of risk for a group of fire scenarios
[SOURCE: ISO 13943:2008, 4.112]
3.11
fire test

test that measures behaviour of a fire or exposes an item to the effects of a fire

Note 1 to entry: The results of a fire test can be used to quantify fire severity or determine the fire resistance or

reaction to fire of the test specimen.
[SOURCE: ISO 13943:2008, 4.132]
3.12
flashover

〈stage of fire〉 transition to a state of total surface involvement in a fire of combustible materials

within an enclosure
[SOURCE: ISO 13943: 2008, 4.156]
3.13
gross heat of combustion

heat of combustion of a substance when the combustion is complete and any produced water

is entirely condensed under specified conditions
cf. complete combustion (3.3)
Note 1 to entry: The typical units are kilojoules per gram (kJ·g ).
[SOURCE: ISO 13943: 2008, 4.170]
3.14
heat of combustion
DEPRECATED: calorific potential
DEPRECATED: calorific value
thermal energy produced by combustion of unit mass of a given substance

cf. effective heat of combustion (3.4), gross heat of combustion (3.13) and net heat of

combustion (3.19)
Note 1 to entry: The typical units are kilojoules per gram (kJ·g ).
[SOURCE: ISO 13943: 2008, 4.174]
---------------------- Page: 11 ----------------------
– 10 – IEC 60695-8-1:2016  IEC 2016
3.15
heat release
thermal energy produced by combustion
Note 1 to entry: The typical units are joules (J).
[SOURCE: ISO 13943: 2008, 4.176]
3.16
heat release rate
DEPRECATED: burning rate
DEPRECATED: rate of burning
rate of thermal energy production generated by combustion
Note 1 to entry: The typical units are watts (W).
[SOURCE: ISO 13943: 2008, 4.177]
3.17
intermediate-scale fire test
fire test performed on a test specimen of medium dimensions

Note 1 to entry: A fire test performed on a test specimen for which the maximum dimension is between 1 m and

3 m is usually called an intermediate-scale fire test.
[SOURCE: ISO 13943: 2008, 4.200]
3.18
large-scale fire test

fire test, that cannot be carried out in a typical laboratory chamber, performed on a test

specimen of large dimensions

Note 1 to entry: A fire test performed on a test specimen for which the maximum dimension is greater than 3 m is

usually called a large-scale fire test.
[SOURCE: ISO 13943: 2008, 4.205]
3.19
net heat of combustion

heat of combustion when any water produced is considered to be in the gaseous state

Note 1 to entry: The net heat of combustion is always smaller than the gross heat of combustion because the

heat released by the condensation of water vapour is not included.
Note 2 to entry: The typical units are kilojoules per gram (kJ·g ).
[SOURCE: ISO 13943: 2008, 4.237]
3.20
oxidation

chemical reaction in which the proportion of oxygen or other electronegative element in a

substance is increased

Note 1 to entry: In chemistry, the term has the broader meaning of a process that involves the loss of an el

...