IEC 60695-1-12:2015

IEC 60695-1-12 ®
Edition 1.0 2015-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
Fire hazard testing –
Part 1-12: Guidance for assessing the fire hazard of electrotechnical products –
Fire safety engineering
Essais relatifs aux risques du feu –
Partie 1-12: Lignes directrices pour l'évaluation des risques du feu des produits
électrotechniques – Ingénierie de la sécurité incendie

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IEC 60695-1-12 ®
Edition 1.0 2015-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ

Fire hazard testing –
Part 1-12: Guidance for assessing the fire hazard of electrotechnical products –

Fire safety engineering
Essais relatifs aux risques du feu –

Partie 1-12: Lignes directrices pour l'évaluation des risques du feu des produits

électrotechniques – Ingénierie de la sécurité incendie

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 13.220.40; 29.020 ISBN 978-2-8322-1960-7

– 2 – IEC 60695-1-12:2015 © IEC 2015
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative References . 7
3 Terms and Definitions . 8
4 The fire safety engineering process . 14
4.1 General . 14
4.2 Fire safety engineering calculations . 15
4.3 Validity of methods . 15
5 Benefits of fire safety engineering . 16
6 Objectives, requirements and performance . 17
6.1 Fire safety engineering objectives. 17
6.1.1 General . 17
6.1.2 Safety of life . 17
6.1.3 Conservation of property . 17
6.1.4 Continuity of operations . 17
6.1.5 Protection of the natural environment . 18
6.1.6 Preservation of heritage . 18
6.2 Functional requirements . 18
6.3 Performance criteria . 18
6.3.1 General . 18
6.3.2 Explicit performance criteria . 18
6.3.3 Implicit performance criteria . 19
7 Design fire scenarios and design fires . 19
7.1 Design fire scenarios . 19
7.2 Design fires. 20
8 Data for fire safety engineering . 20
9 Tests on electrotechnical products . 21
9.1 General . 21
9.2 Conditions for evaluation in fire tests . 21
9.3 Electrotechnical product evaluations . 21
9.3.1 As the source of ignition of a fire . 21
9.3.2 As the victim of a fire . 22
9.4 Test selection and/or development . 22
Annex A (informative) A probabilistic fire risk assessment . 24
A.1 The assessment of a fire risk in accordance with the Russian national
standard GOST 12.1.004-91 [38] . 24
A.1.1 Introduction . 24
A.1.2 Probability Q . 24
fc
A.1.3 Probability Q . 25
fv
A.1.4 Probability Q . 25
pf
A.1.5 Probability Q . 25
ign
A.2 Example. 26
A.2.1 General . 26
A.2.2 Test data . 27

A.2.3 Calculation . 27
Bibliography . 29

Figure 1 – Flowchart illustrating an example of the fire safety engineering process as
applied to a major project in the built environment . 16

Table 1 – Examples of design fire scenarios . 19
Table 2 – Common ignition phenomena encountered in electrotechnical products . 23
Table A.1 – Long start-up mode: enclosure (shell) temperatures in the most heated up-
point . 27
Table A.2 – The enclosure temperature at the most heated point when working under
abnormal conditions . 28
Table A.3 – Failure data for abnormal operation . 28

– 4 – IEC 60695-1-12:2015 © IEC 2015
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIRE HAZARD TESTING –
Part 1-12: Guidance for assessing
the fire hazard of electrotechnical products –
Fire safety engineering
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 60695-1-12 Ed 1.0 has been prepared by IEC technical committee
89: Fire hazard testing.
It has the status of a basic safety publication in accordance with IEC Guide 104 and
ISO/IEC Guide 51.
The text of this standard is based on the following documents:
FDIS Report on voting
89/1237A/FDIS 89/1242/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.
A list of all the parts in the 60695 series, under the general title Fire hazard testing, can be
found on the IEC web site.
IEC 60695-1 consists of the following parts:
Part 1-10: Guidance for assessing the fire hazard of electrotechnical products – General
guidelines
Part 1-11: Guidance for assessing the fire hazard of electrotechnical products – Fire
hazard assessment
Part 1-12: Guidance for assessing the fire hazard of electrotechnical products – Fire safety
engineering
Part 1-30: Guidance for assessing the fire hazard of electrotechnical products –
Preselection testing process – General guidelines
Part 1-40: Guidance for assessing the fire hazard of electrotechnical products – Insulating
liquids.
This standard is to be used in conjunction with IEC 60695-1-10 and IEC 60695-1-11.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 60695-1-12:2015 © IEC 2015
INTRODUCTION
Fire safety engineering
Fire safety engineering concerns the 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. This is in order to achieve fire safety engineering objectives, which typically are:
a) to protect life safety,
b) to protect property,
c) to maintain the continuity of operations,
d) to protect the natural environment, and
e) to preserve heritage.
The analysis is based on calculations that use input data obtained principally from
quantitative fire tests.
Fire safety engineering (FSE) is a discipline increasingly being used in support of
performance-based national fire safety regulations in many countries and regional
jurisdictions throughout the world. The eight parts of ISO/TR 13387 (see Clause 2 and
[1] to [6]) and ISO 23932 outline the fundamental methodologies and uses of FSE. Further
detailed aspects of FSE are covered in ISO 16730 [7], ISO/TS 16732 [8], ISO/TS 16733,
ISO 16734 [9], ISO 16735 [10], ISO 16736 [11], ISO 16737 [12] and ISO/TR 16738.
In addition to purely performance-based regulations, many countries are also using FSE to
supplement prescriptive regulations by applying FSE principles to specific design aspects,
where reduced costs, alternative practices, improved performance and improved safety are
the objectives.
The International Maritime Organization (IMO) is using FSE and the ISO standards mentioned
above to develop fire safety designs for ships. These are considered to be an improvement on
designs based on prescriptive fire safety requirements.
Qualitative and quantitative fire tests
Many standardised fire test methods give information on the performance of a material or end
product as measured in the test, which may or may not be related to a real fire scenario or
real installation practices. These qualitative fire test methods result in a “pass” or “fail” and/or
a product or material ranking. They play an important role in prescriptive regulations, and the
results of a qualitative test can be used indirectly in fire hazard assessment of
electrotechnical products, but they are not suitable for directly supporting performance-based
design.
Most standardized test methods developed by the IEC for electrotechnical products are of the
qualitative type. It is agreed within ISO and the IEC that this type of fire test will continue to
be maintained and, where necessary, developed. It is recognised that, even if the use of
these standards is in prescriptive codes, product data from many of these standards may be
potentially adaptable for fire safety engineering purposes.
In contrast, quantitative fire tests are increasingly being used and developed, and these do
provide data that can be input to fire safety engineering calculations.
Various quantitative fire tests have been developed by ISO, some of which can be used to
assess the performance of electrotechnical products (see 9.4).

FIRE HAZARD TESTING –
Part 1-12: Guidance for assessing
the fire hazard of electrotechnical products –
Fire safety engineering
1 Scope
This part of IEC 60695 is intended as a general guideline for IEC Product Committees and
provides:
• an explanation of the principles and uses of fire safety engineering;
• guidance on the use of fire safety engineering in the design of electrotechnical products;
• fire safety engineering terminology, and concepts;
• an indication of properties, data and tests needed for input into fire safety engineering
assessments;
• informative references.
This international standard is not intended to be a detailed technical design guide, but is
intended to provide guidance for product committees on fire safety engineering methods and
performance based test information needs for use in performance based designs and fire
hazard assessments of electrotechnical materials, assemblies, products and systems. More
detailed information on fire safety engineering is contained in the ISO/TR 13387 series of
documents (see Clause 2 and [1] to [6]) and in ISO 23932.
NOTE Further detailed aspects of FSE are covered in ISO 16730 [7], ISO/TS 16732 [8], ISO/TS 16733,
ISO 16734 [9], ISO 16735 [10], ISO 16736 [11], ISO 16737 [12] and ISO/TR 16738.
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, in whole or in part, are normatively referenced in this document and
are indispensable for its application. 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 60695-4, Fire hazard testing – Part 4: Terminology concerning fire tests for
electrotechnical products
– 8 – IEC 60695-1-12:2015 © IEC 2015
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 inclusion in standards
ISO 13943:2008, Fire safety – Vocabulary
ISO/TR 13387-2: Fire safety engineering – Part 2: Design fire scenarios and design fires
ISO/TR 13387-8, Fire safety engineering – Part 8: Life safety: Occupant behaviour, location
and condition
ISO/TS 16733, Fire safety engineering – Selection of design fire scenarios and design fires
ISO/TR 16738, Fire safety engineering – Technical information on methods for evaluating
behaviour and movement of people
ISO/TR 17252:2008, Fire tests – Applicability of reaction to fire tests to fire modelling and fire
safety engineering
ISO 23932:2009, Fire safety engineering – General principles
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 for the user’s convenience, as well
as the following apply.
3.1
absorptivity
fraction of the incident radiation that is absorbed by a surface on which it falls
Note 1 to entry: Absorptivity is dimensionless.
3.2
active fire protection
action taken to reduce or prevent the spread and effects of fire in response to the detection of
the fire
Note 1 to entry: Examples include the application of agents (e.g. halon gas or water spray) to the fire, or the
control of ventilation.
3.3
available safe escape time
ASET
time available for escape
for an individual occupant, the calculated time interval between the time of ignition and the
time at which conditions become such that the occupant is estimated to be incapacitated, i.e.
unable to take effective action to escape to a safe refuge or place of safety
see also required safe escape time (3.40).
Note 1 to entry: The time of ignition can be known, e.g. in the case of a fire model or a fire test, or it may be
assumed, e.g. it may be based upon an estimate working back from the time of detection. The basis on which the
time of ignition is determined is always stated.
Note 2 to entry: This definition equates incapacitation with failure to escape. Other criteria for ASET are possible.
If an alternate criterion is selected, it is necessary that it be stated.

Note 3 to entry: Each occupant can have a different value of ASET, depending on that occupant’s personal
characteristics.
[SOURCE: ISO 13943:2008, definition 4.20]
3.4
built environment
building or other structure
EXAMPLES (1) Off-shore platforms; (2) civil engineering works, such as tunnels, bridges and mines; and
(3) means of transportation, such as motor vehicles and marine vessels.
Note 1 to entry: ISO 6707-1 [13] contains a number of terms and definitions for concepts related to the built
environment.
[SOURCE: ISO 13943:2008, definition 4.26]
3.5
compressive strength
maximum uniaxial compressive stress experienced by a material at its moment of rupture
3.6
density
mass per unit volume
3.7
design fire
quantitative description of assumed fire characteristics within the design fire scenario
Note 1 to entry: It is typically, an idealised description of the variation with time of important fire variables such as
heat release rate, flame spread rate, smoke production rate, toxic gas yields, and temperature.
[SOURCE: ISO 13943:2008, definition 4.64]
3.8
design fire scenario
specific fire scenario on which a deterministic fire-safety engineering analysis is conducted
[SOURCE: ISO 13943:2008, definition 4.65]
3.9
emissivity
ratio of the radiation emitted by a radiant source to the radiation that would be emitted by a
black body radiant source at the same temperature
Note 1 to entry: Emissivity is dimensionless.
[SOURCE: ISO 13943:2008, definition 4.75]
3.10
environment
conditions and surroundings that can influence the behaviour of an item or persons when
exposed to fire
[SOURCE: ISO 13943:2008, definition 4.80]
3.11
escape
effective action taken to reach a safe refuge or place of safety
[SOURCE: ISO 13943:2008, definition 4.82]

– 10 – IEC 60695-1-12:2015 © IEC 2015
3.12
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 13943:2008, definition 4.104]
3.13
fire effluent
totality of gases and aerosols, including suspended particles, created by combustion or
pyrolysis in a fire
[SOURCE: ISO 13943:2008, definition 4.105]
3.14
fire growth
stage of fire development during which the heat release rate and the temperature of the fire
are increasing
[SOURCE: ISO 13943:2008, definition 4.111]
3.15
fire hazard
physical object or condition with a potential for an undesirable consequence from fire
[SOURCE: ISO 13943:2008, definition 4.112]
3.16
fire hazard assessment
evaluation of the possible causes of fire, the possibility and nature of subsequent fire growth,
and the possible consequences of fire
[SOURCE: IEC 60695-4:2012, definition 3.2.10]
3.17
fire model
fire simulation
calculation method that describes a system or process related to fire development, including
fire dynamics and the effects of fire
[SOURCE: ISO 13943:2008, definition 4.116]
3.18
fire resistance
ability of a test specimen to withstand fire or give protection from it for a period of time
Note 1 to entry: Typical criteria used to assess fire resistance in a standard fire test are fire integrity, fire stability,
and thermal insulation material.
Note 2 to entry: "Fire resistant" (adj.) refers only to this ability.
[SOURCE: ISO 13943:2008, definition 4.121]
3.19
fire safety design
quantitative description of the construction of a built environment intended to meet fire safety
objectives
3.20
fire safety engineering
application of engineering methods based on a 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, definition 4.126]
3.21
fire-safety objective
desired outcome with respect to the probability of an unwanted fire, relative to essential
aspects of the built environment
Note 1 to entry: The essential aspects typically relate to the issues of life safety, conservation of property,
continuity of operations, protection of the environment and preservation of heritage.
[SOURCE: ISO 13943:2008, definition 4.128]
3.22
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: It typically defines the ignition and fire growth processes, the fully developed fire stage, the fire
decay stage, and the environment and systems that impact on the course of the fire.
[SOURCE: ISO 13943:2008, definition 4.129]
3.23
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, definition 4.132]
3.24
flame spread
propagation of a flame front
[SOURCE: ISO 13943:2008, definition 4.142]
3.25
fully developed fire
state of total involvement of combustible materials in a fire
[SOURCE: ISO 13943:2008, definition 4.164]
3.26
heat of combustion
DEPRECATED: calorific potential
DEPRECATED: calorific value
thermal energy produced by combustion of unit mass of a given substance
–1
Note 1 to entry: The typical units are kilojoules per gram (kJ⋅g ).
[SOURCE: ISO 13943:2008, definition 4.174]

– 12 – IEC 60695-1-12:2015 © IEC 2015
3.27
heat of gasification
thermal energy required to change a unit mass of material from the condensed phase to the
vapour phase at a given temperature
–1
Note 1 to entry: The typical units are kilojoules per gram (kJ⋅g ).
[SOURCE: ISO 13943:2008, definition 4.175]
3.28
heat release
thermal energy released by combustion
Note 1 to entry: The typical units are joules (J).
[SOURCE: ISO 13943:2008, definition 4.176]
3.29
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, definition 4.177]
3.30
ignition
initiation of combustion
[SOURCE: ISO 13943:2008, definition 4.187]
3.31
modulus of elasticity
ratio of stress to strain within the elastic range of a material, i.e. where Hooke’s Law is
obeyed
3.32
passive fire protection
action taken to reduce or prevent the spread and effects of fire by means not requiring an
action
EXAMPLES (1) The division of a space into compartments using materials with inherent fire resistance to
fabricate walls, floors, doors and other barriers. (2) The use of materials with good fire behaviour.
3.33
performance criteria
quantitative criteria, which have been agreed with a building approval authority, and which
form an acceptable basis for assessing the safety of a design for a built environment
3.34
performance-based design
design that is engineered to achieve specified objectives and performance criteria
3.35
performance-based regulation
regulation in which compliance is specified in terms of performance criteria

Note 1 to entry: Performance-based regulation is more flexible than prescriptive regulation because it focuses on
the overall outcome to be achieved rather than on component hazards.
3.36
prescriptive regulation
regulation in which the means and approach for compliance are completely or mostly
specified
Note 1 to entry: Prescriptive regulation is less flexible than performance based regulation because it focuses on
component hazards rather than on the overall outcome to be achieved.
Note 2 to entry: Many fire tests were originally developed to provide input for prescriptive regulation. They are
often based on simple pass/fail criteria and are usually unable to provide data suitable for input to fire safety
engineering.
3.37
qualitative fire test
fire test which is either:
a) a pass/fail test; or
b) a test which categorizes the behaviour of the test specimen by determining its position in
a rank order of performance
[SOURCE: IEC 60695-4:2012, definition 3.2.22]
3.38
quantitative fire test
fire test which takes into account the circumstances of product use in which the test
conditions are based on, or are relatable to, the circumstances of use of the test specimen,
and which measures a parameter or parameters, expressed in well defined terms and using
rational scientific units, which can be used in the quantitative assessment of fire risk
[SOURCE: IEC 60695-4:2012, definition 3.2.23]
3.39
reaction to fire
response of a test specimen when it is exposed to a fire under specified conditions in a fire
test
Note 1 to entry: Fire resistance is regarded as a special case and is not normally considered as a reaction to fire
property.
[SOURCE: ISO 13943:2008, definition 4.272]
3.40
required safe escape time
RSET
time required for escape
calculated time interval required for an individual occupant to travel from their location at the
time of ignition to a safe refuge or place of safety
cf. available safe escape time (3.3).
[SOURCE: ISO 13943:2008, definition 4.277]
3.41
smoke
visible part of fire effluent
[SOURCE: ISO 13943:2008, definition 4.293]

– 14 – IEC 60695-1-12:2015 © IEC 2015
3.42
specific heat capacity
heat capacity per unit mass
[SOURCE: ISO 13943:2008, definition 4.302]
3.43
thermal conductivity
parameter related to the rate at which heat flows through a material
Note 1 to entry: The thermal conductivity, k, is equal to (Q⋅d )/(A⋅t⋅θ ) , where Q is the amount of heat that flows in
time, t, through a material of thickness, d, and cross-sectional area, A, and which has a temperature difference, θ,
across it, and where no heat is exchanged with the surroundings.
–1 –1
Note 2 to entry: The typical units are watts per metre per kelvin (W⋅m ⋅K ).
[SOURCE: ISO 13943:2008, definition 4.322]
3.44
thermal inertia
product of thermal conductivity, density and specific heat capacity
8 2 –1 –4 –2
EXAMPLES (1) The thermal inertia of steel is 2,3 × 10 J ⋅s ⋅m ⋅K . (2) The thermal inertia of polystyrene foam
3 2 –1 –4 –2
is 1,4 × 10 J ⋅s ⋅m ⋅K .
Note 1 to entry: When a material is exposed to a heat flux, the rate of increase of surface temperature depends
strongly on the value of the thermal inertia of the material. The surface temperature of a material with a low
thermal inertia rises relatively quickly when it is heated, and vice versa.
Note 2 to entry: The typical units are joules squared per second per metre to the fourth power per kelvin squared
2 –1 –4 –2
(J ⋅s ⋅m ⋅K ).
[SOURCE: ISO 13943:2008, definition 4.326]
3.45
transverse flexural strength
maximum stress experienced by a material at its moment of rupture when measured using a
three-point test technique
3.46
ultimate tensile strength
maximum tensile stress experienced by a material during a uniaxial tensile test
4 The fire safety engineering process
4.1 General
Fire safety engineering was developed and is continuing to develop to enable the design,
implementation and maintenance of objects and structures in the built environment, using
scientific principles, so that defined fire safety engineering objectives can be met. In order to
do this, quantitative fire tests are used to provide input data for the necessary calculations.
When applied to a major project in the built environment, the fire engineering process is both
complex and comprehensive. A flow chart illustrating such a fire safety engineering process is
shown in Figure 1.
The process will probably encompass many different issues, for example; architectural design,
structural design, ventilation, plumbing and electrical infrastructure. The fire safety of
electrotechnical products is therefore only one aspect of a much larger process.

Fire safety engineering should be used when safety objectives cannot adequately be met by
prescriptive requirements, and can also be used in parallel with prescriptive requirements e.g.
to support, from a scientific point of view, that such requirements are valid, or to further
improve the fire safety of the product.
4.2 Fire safety engineering calculations
These calculations can range from the solution of simple equations to very complex computer
models. For example, they could be used to calculate pipe sizes for sprinkler systems, or they
could be used to calculate the structural response of a load bearing building element, such as
a beam or a column, from a knowledge of the material properties at elevated temperatures,
the predicted temperatures reached in the fire, and the applied loads.
At another level, requiring the use of integrated computer programmes, these calculations can
be applied to the evaluation of the life safety consequences of a specified fire, which would
involve definition of the context, the product designs, the structures, the scenarios, and then
calculation of the resulting hazards.
An electrotechnical example would be to assess the risks associated with cable fires in the
built environment using quantified data of fire growth, flame spread, smoke and toxic gas
generation of electric cables as well as the prediction of people movement.
NOTE A study at Lund University [14] simulated the escape phase in an occupied furnished building considering
two different cable installations but with various fire scenarios and means of evacuation. Cables with widely
differing material properties were chosen, not necessarily representing actually installed cables. The study aimed
at illustrating the power of modelling tools (simulation and FSE approach) rather than a practical selection study.
At a more strategic level, fire safety engineering can be applied by using a package of tests
and measures to a variety of different fire scenarios. Computer fire models have been
developed with four-dimensional animations (time and space) simulating multiple fire
dynamics over a range of fire scenarios, and structure responses. (see, for example [15]).
4.3 Validity of methods
The fire safety engineering process should be based on sound fire science and engineering
practice incorporating widely accepted methods, empirical data, calculations, correlation, and
computer models as contained in engineering textbooks and technical literature. There are
numerous technical resources that may be of use in a particular fire safety design. Therefore,
it is very important that fire safety engineers and other members of the design team determine
the acceptability of the sources and methodologies used for the particular applications in
which they are used.
When determining the validity of a resource, it is helpful to know the process through which
the resource was developed, reviewed, and validated. For example, many codes and
standards are developed under an open consensus process conducted by recognised
professional societies, code-making organisations, or governmental bodies. Other technical
references are subject to a peer review process, such as many of the technical and
engineering journals available. Also, engineering handbooks and textbooks provide widely
recognised and technically valid information and calculation methods.
Some useful references are listed in the Bibliography – references [14] to [24].

– 16 – IEC 60695-1-12:2015 © IEC 2015
Definition of the scope of the fire safety project
Identification of objectives, requirements
and performance criteria
Identification of hazards
Description of the fire-safety design plan
Implementation of design plan
Selection of design fire scenarios and
behavioural scenarios
Selection of engineering methods
Evaluation of the trial fire-safety design plan
Are
No Yes
performance
Final project report
criteria
satisfied?
IEC
(Adapted from Figure 1 in ISO 23932:2009)
Figure 1 – Flowchart illustrating an example of the fire safety engineering
process as applied to a major project in the built environment
5 Benefits of fire safety engineering
The benefits of fire safety engineering include the following; it may:
a) provide design decisions based on quantitative and scientifically based principles, in order
to make safer products;
b) form an important element of the performance based design of major projects such as
airport terminals, train stations, transportation vehicles, stadiums, convention centres, tall
buildings, bridges, power generation plants, and large atrium structures, which are of such
magnitude and complexity that they cannot be optimally designed using only the currently
available prescriptive tests and technical guidance;
c) discipline the designer to follow a structured approach to fire safety design;
d
...