EN ISO 13943:2017

SLOVENSKI STANDARD
01-november-2017
1DGRPHãþD
SIST EN ISO 13943:2011
Požarna varnost - Slovar (ISO 13943:2017)
Fire safety - Vocabulary (ISO 13943:2017)
Brandschutz - Vokabular (ISO 13943:2017)
Sécurité au feu - Vocabulaire (ISO 13943:2017)
Ta slovenski standard je istoveten z: EN ISO 13943:2017
ICS:
01.040.13 Okolje. Varovanje zdravja. Environment. Health
Varnost (Slovarji) protection. Safety
(Vocabularies)
13.220.01 Varstvo pred požarom na Protection against fire in
splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 13943
EUROPEAN STANDARD
NORME EUROPÉENNE
August 2017
EUROPÄISCHE NORM
ICS 01.040.13; 13.220.01 Supersedes EN ISO 13943:2010
English Version
Fire safety - Vocabulary (ISO 13943:2017)
Sécurité au feu - Vocabulaire (ISO 13943:2017) Brandschutz - Vokabular (ISO 13943:2017)
This European Standard was approved by CEN on 14 July 2017.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
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 CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 13943:2017 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 13943:2017) has been prepared by Technical Committee ISO/TC 92 “Fire
safety” in collaboration with Technical Committee CEN/TC 127 “Fire safety in buildings” the secretariat
of which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by February 2018, and conflicting national standards
shall be withdrawn at the latest by February 2018.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 13943:2010.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 13943:2017 has been approved by CEN as EN ISO 13943:2017 without any modification.
INTERNATIONAL ISO
STANDARD 13943
Third edition
2017-07
Fire safety — Vocabulary
Sécurité au feu — Vocabulaire
Reference number
ISO 13943:2017(E)
©
ISO 2017
ISO 13943:2017(E)
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
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ii © ISO 2017 – All rights reserved

ISO 13943:2017(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
Bibliography .52
Index of deprecated terms .52
ISO 13943:2017(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO’s adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see the following
URL: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 92, Fire safety.
This third edition cancels and replaces the second edition (ISO 13943:2008), which has been technically
revised.
iv © ISO 2017 – All rights reserved

ISO 13943:2017(E)
Introduction
Over the last two decades, there has been a significant growth in the field of fire safety. There has been
a considerable development of fire safety engineering design, especially as it relates to construction
projects, as well as the development of concepts related to performance-based design. With this
continuing evolution, there is an increasing need for agreement on a common language in the broad and
expanding area of fire safety, beyond what traditionally has been limited to the field of fire testing.
The first edition of this vocabulary, ISO 13943:2000, contained definitions of about 180 terms. However,
the areas of technology that are related to fire safety have continued to evolve rapidly and this edition
contains many new terms and their definitions, as well as revised definitions of some of the terms that
were in earlier editions.
This document defines general terms to establish a vocabulary applicable to fire safety, including fire
safety in buildings and civil engineering works and other elements within the built environment. It will
be updated as terms and definitions for further concepts in the field of fire safety are agreed upon and
developed.
It is important to note that, it is possible that, when used for regulation, some fire safety terms may have
a somewhat different interpretation than the one used in this document and, in that case, the definition
given in this document may not apply.
The terms in this document are
— fundamental concepts,
— more specific concepts, such as those used specifically in fire testing or in fire safety engineering
and may be used in ISO or IEC fire standards, and
— related concepts, as exemplified by terms used in building and civil engineering.
Annex A provides an index of deprecated terms.
The layout is designed according to ISO 10241-1, unless otherwise specified. The terms are presented in
English alphabetical order and are in bold type except for deprecated terms, which are in normal type.
Use of the term “item”
For the purposes of this document, in the English version, the term “item” (and in French “objet”) is
used in a general meaning to represent any single object or assembly of objects, and may cover, for
example, material, product, assembly, structure or building, as required in the context of any individual
definition.
If the “item” under consideration is a test specimen, then the term “test specimen” is used.
The German version uses terminology such as material, product, kit, assembly and/or building to clarify
the meaning of each definition.
INTERNATIONAL STANDARD ISO 13943:2017(E)
Fire safety — Vocabulary
1 Scope
This document defines terminology relating to fire safety as used in ISO and IEC fire standards.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
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
abnormal heat
heat that is additional to that resulting from use under normal conditions, up to and
including that which causes a fire (3.114)
3.2
absorptivity
ratio of the absorbed radiant heat flux (3.319) to the incident radiative heat flux (3.321)
Note 1 to entry: The absorptivity is dimensionless.
3.3
acceptance criteria
criteria that form the basis for assessing the acceptability of the safety of a design of a built
environment (3.32)
Note 1 to entry: The criteria can be qualitative, quantitative or a combination of both.
3.4
accuracy
closeness of the agreement between the result of a measurement and the true value of the measurand
[SOURCE: ASTM E176: 2015]
3.5
activation time
time interval from response by a sensing device until the suppression system (3.375), smoke (3.347)
control system, alarm system or other fire safety system is fully operational
3.6
active fire protection
method(s) used to reduce or prevent the spread and effects of fire (3.114), heat or smoke (3.347) by
virtue of detection and/or suppression of the fire and which require a certain amount of motion and/or
response to be activated
EXAMPLE The application of agents (e.g. halon gas or water spray) to the fire or the control of ventilation
and/or smoke.
ISO 13943:2017(E)
Note 1 to entry: Compare with the terms passive fire protection (3.293) and suppression systems (3.375).
3.7
actual delivered density
ADD
volumetric flow rate of water per unit area that is delivered onto the top horizontal surface of a
simulated burning combustible (3.52) array
Note 1 to entry: ADD is typically determined relative to a specific heat release rate (3.206) of a fire (3.114).
Note 2 to entry: ADD can be measured according to ISO 6182-7.
−1
Note 3 to entry: The typical unit is mm⋅min .
3.8
acute toxicity
toxicity (3.405) that causes rapidly occurring toxic (3.399) effects
Note 1 to entry: Compare with the term toxic potency (3.402).
3.9
aerosol
suspension of droplets (3.84) and/or solid particles in a gas phase which are generated by fire (3.114)
Note 1 to entry: The size of the droplets or particles typically ranges from under 10 nm to over 10 μm.
Note 2 to entry: Compare with the term droplets.
3.10
aerosol particle
individual piece of solid material that is part of the dispersed phase in an aerosol (3.9)
Note 1 to entry: There are two categories of fire aerosol particles: unburned or partially burned particles
containing a high proportion of carbon (i.e. “soot”), and relatively completely combusted, small particle sized
“ashes”. Soot (3.354) particles of small diameter, (i.e. about 1 μm), typically consist of small elementary spheres
of between 10 nm and 50 nm in diameter. Formation of soot particles is dependent on many parameters including
nucleation, agglomeration and surface growth. Oxidation (3.289) of soot particles, i.e. further combustion (3.55),
is also possible.
3.11
afterflame
flame (3.159) that persists after the ignition source (3.219) has been removed
3.12
afterflame time
length of time for which an afterflame (3.11) persists under specified conditions
Note 1 to entry: Compare with the term duration of flaming (3.85).
3.13
afterglow
persistence of glowing combustion (3.197) after both removal of the ignition source (3.219) and the
cessation of any flaming combustion (3.175)
3.14
afterglow time
length of time for which an afterglow (3.13) persists under specified conditions
3.15
agent outlet
orifice of a piping system by means of which an extinguishing fluid can be applied towards the source
of a fire (3.114)
2 © ISO 2017 – All rights reserved

ISO 13943:2017(E)
3.16
alarm time
time interval between ignition (3.217) of a fire (3.114) and activation of an alarm
Note 1 to entry: The time of ignition may be known, e.g. in the case of a fire model (3.136) or a fire test (3.157), 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 when the alarm time is specified.
3.17
alight, adj.
lit, adj. CA, US
lighted, adj.
undergoing combustion (3.55)
3.18
analyte
substance that is identified or quantified in a specimen during an analysis
3.19
arc resistance
ability of an electrically insulating material to resist the influence of an electric arc,
under specified conditions
Note 1 to entry: The arc resistance is identified by the length of the arc, the absence or presence of a conducting
path, and the burning or damage of the test specimen (3.384).
3.20
area burning rate
DEPRECATED: burning rate
DEPRECATED: rate of burning
area of material burned (3.34) per unit time under specified conditions
2 −1
Note 1 to entry: The typical unit is m ⋅s .
3.21
arson
crime of setting a fire (3.114), usually with intent to cause damage
3.22
ash
ashes
mineral residue resulting from complete combustion (3.59)
3.23
asphyxiant
toxicant (3.404) that causes hypoxia, which can result in central nervous system depression or
cardiovascular effects
Note 1 to entry: Loss of consciousness and ultimately, death may occur.
3.24
auto-ignition
spontaneous ignition
self-ignition
unpiloted ignition
DEPRECATED: spontaneous combustion
ignition (3.217) caused by an internal exothermic reaction
Note 1 to entry: The ignition may be caused either by self-heating (3.341) or, in the case of unpiloted ignition, by
heating from an external source, as long as the external source does not include an open flame
ISO 13943:2017(E)
Note 2 to entry: In North America, “spontaneous ignition” is the preferred term used to designate ignition
caused by self-heating.
Note 3 to entry: Compare with the terms piloted ignition (3.299) and spontaneous ignition temperature (3.363).
3.25
auto-ignition temperature
minimum temperature at which auto-ignition (3.24) is obtained in a fire test (3.157)
Note 1 to entry: The typical unit is °C.
Note 2 to entry: Compare with the term spontaneous ignition temperature (3.363).
3.26
available safe escape time
ASET
time available for escape
calculated time interval between the time of ignition (3.217) 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
(3.99) to a safe refuge (3.333) or place of safety (3.300)
Note 1 to entry: The time of ignition may be known, e.g. in the case of a fire model (3.136) or a fire test (3.157), 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 needs to be stated.
Note 2 to entry: This definition equates incapacitation (3.225) with failure to escape. Other criteria for ASET are
possible. If an alternate criterion is selected, it needs to be stated.
Note 3 to entry: Each occupant may have a different value of ASET, depending on that occupant’s personal
characteristics.
3.27
backdraft
rapid flaming combustion (3.175) caused by the sudden introduction of air into a confined oxygen-
deficient space that contains hot products of incomplete combustion (3.55)
Note 1 to entry: In some cases, these conditions may result in an explosion (3.105).
3.28
behavioural scenario
description of the behaviour of occupants during the course of a fire (3.114)
3.29
black body
form that completely absorbs any electromagnetic radiation falling upon it
3.30
black body radiation source
ideal thermal radiation source which completely absorbs all incident heat radiation, whatever
wavelength and direction
Note 1 to entry: The emissivity (3.89) of a black body radiant source is unity.
Note 2 to entry: A black body can also be an ideal radiator of energy.
[SOURCE: ISO 14934-1:2010, 3.1.7]
3.31
building element
integral part of a built environment (3.32)
Note 1 to entry: This includes floors, walls, beams, columns, doors, and penetrations, but does not include
contents.
4 © ISO 2017 – All rights reserved

ISO 13943:2017(E)
Note 2 to entry: This definition is wider in its scope than that given in ISO 6707-1.
3.32
built environment
building or other structure
EXAMPLE Off-shore platforms, civil engineering works such as tunnels, bridges and mines, and means of
transportation such as motor vehicles and marine vessels.
Note 1 to entry: ISO 6707-1 contains a number of terms and definitions for concepts related to the built
environment.
3.33
buoyant plume
convective updraft of fluid above a heat source
Note 1 to entry: Compare with the term fire plume (3.138).
3.34
burn, intransitive verb
undergo combustion (3.55)
3.35
burn, transitive verb
cause combustion (3.55)
3.36
burned area
that part of the damaged area (3.72) of a material that has been destroyed by combustion (3.55) or
pyrolysis (3.316), under specified conditions
Note 1 to entry: The typical unit is m .
3.37
burned length
maximum extent in a specified direction of the burned area (3.36)
Note 1 to entry: The typical unit is m.
Note 2 to entry: Compare with the term damaged length (3.73).
3.38
burning behaviour
response of a test specimen (3.384), when it burns under specified conditions, to examination
of reaction to fire (3.324) or fire resistance (3.141)
3.39
burning debris
burning material, other than drops, which has detached from a test specimen (3.384) during a fire test
(3.157) and continues to burn (3.34) on the floor
Note 1 to entry: Compare with the terms burning droplets (3.40), flaming debris (3.176) and flaming droplets
(3.177).
3.40
burning droplets
flaming molten or flaming liquefied drops which fall from a test specimen (3.384) during a fire test
(3.157) and continue to burn (3.34) on the floor
Note 1 to entry: Compare with the terms flaming droplet (3.177), flaming debris (3.176) and burning debris (3.39).
ISO 13943:2017(E)
3.41
bursting
violent rupture of an object due to an overpressure within it or upon it
3.42
calibration
process of adjusting modelling parameters in a computational fire model (3.136) for the
purpose of improving agreement with experimental data
3.43
calorimeter
apparatus that measures heat
Note 1 to entry: Compare with the terms heat release rate calorimeter (3.207) and mass calorimeter (3.257).
3.44
carboxyhaemoglobin
compound formed when CO combines with haemoglobin
Note 1 to entry: Haemoglobin has an affinity for binding to CO that is approximately 245 times higher than that
for binding to oxygen; thereby, the ability of haemoglobin to carry oxygen is seriously compromised during CO
poisoning.
3.45
carboxyhaemoglobin saturation
percentage of blood haemoglobin converted to carboxyhaemoglobin from the reversible reaction with
inhaled carbon monoxide
3.46
ceiling jet
gas motion in a hot gas layer near a ceiling that is generated by the buoyancy of a fire plume (3.138) that
is impinging upon the ceiling
3.47
char, noun
carbonaceous residue resulting from pyrolysis (3.316) or incomplete combustion (3.55)
3.48
char, verb
form char (3.47)
3.49
char length
length of charred area
Note 1 to entry: Compare with the terms burned length (3.37) and damaged length (3.73).
Note 2 to entry: In some standards, char length is defined by a specific test method.
3.50
chimney effect
upward movement of hot fire effluent (3.123) caused by convection (3.66) currents confined within an
essentially vertical enclosure (3.92)
Note 1 to entry: This usually draws more air into the fire (3.114).
3.51
clinker
solid agglomerate of residues formed by either complete combustion (3.59) or incomplete combustion
(3.55) and which may result from complete or partial melting
6 © ISO 2017 – All rights reserved

ISO 13943:2017(E)
3.52
combustible, adj.
capable of being ignited (3.216) and burned (3.34)
3.53
combustible, noun
item capable of combustion (3.55)
3.54
combustible load
theoretical mass that would be lost from a test specimen (3.384) when it is assumed to have undergone
complete combustion (3.59) in a fire test (3.157)
3.55
combustion
exothermic reaction of a substance with an oxidizing agent (3.290)
Note 1 to entry: Combustion generally emits fire effluent (3.123) accompanied by flames (3.159) and/or glowing
(3.196).
3.56
combustion efficiency
ratio of the amount of heat release (3.205) in incomplete combustion (3.55) to the theoretical heat of
complete combustion (3.59)
Note 1 to entry: Combustion efficiency can be calculated only for cases where complete combustion can be
defined.
Note 2 to entry: Combustion efficiency is usually expressed as a percentage.
Note 3 to entry: The combustion efficiency is dimensionless.
3.57
combustion product
product of combustion
solid, liquid and gaseous material resulting from combustion (3.55)
Note 1 to entry: Combustion products may include fire effluent (3.123), ash (3.22), char (3.47), clinker (3.51)
and/or soot (3.354).
3.58
common mode failure
failure involving a single source that affects more than one type of safety system simultaneously
3.59
complete combustion
combustion (3.55) in which all the combustion products (3.57) are fully oxidized
Note 1 to entry: This means that, when the oxidizing agent (3.290) 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 (3.52)
material, those elements are converted to the most stable products in their standard states at 298 K.
3.60
computerized model
operational computer programme that implements a conceptual model (3.64)
3.61
composite material
structured combination of two or more discrete materials
ISO 13943:2017(E)
3.62
concentration
mass of a dispersed or dissolved material in a given volume
−3
Note 1 to entry: For fire effluent (3.123), the typical unit is g⋅m .
Note 2 to entry: For toxic gas (3.400), concentration is usually expressed as a volume fraction (3.421) at T = 298 K
3 3 −6
and P = 1 atm, with typical units of μL/L (= cm /m = 10 ).
Note 3 to entry: The concentration of a gas at a temperature, T, and a pressure, P, can be calculated from its
volume fraction (assuming ideal gas behaviour) by multiplying the volume fraction by the density of the gas at
that temperature and pressure.
Note 4 to entry: Pascal (Pa) is the SI unit for pressure; however, atmosphere (atm) is typically used in this context,
where 1 atm = 101,3 kPa.
3.63
concentration-time curve
plot of the concentration (3.62) of a toxic gas (3.400) or fire effluent (3.123) as a
function of time
−3
Note 1 to entry: For fire effluent, concentration is usually measured in units of g⋅m .
Note 2 to entry: For toxic gas, concentration is usually expressed as a volume fraction (3.421) at T = 298 K and
3 3 −6
P = 1 atm, with typical units of μL/L (= cm /m = 10 ).
Note 3 to entry: Pascal (Pa) is the SI unit for pressure; however, atmosphere (atm) is typically used in this context,
where 1 atm = 101,3 kPa.
3.64
conceptual model
information, mathematical modelling, data, assumptions, boundary conditions and mathematical
equations that describes the (physical) system or process of interest
3.65
controlled burn
operational strategy where the application of firefighting media such as water or foam is restricted
or avoided
Note 1 to entry: Controlled burns are often conducted to minimize damage to public health and the environment.
Other motivations for controlled burn may include limited danger of fire spread, concerns about firefighter
safety, or limited capacity and resources at hand for firefighting operations.
Note 2 to entry: The strategy would normally be used to try and prevent water pollution by contaminated
firewater. It can also reduce air pollution due to the better combustion (3.55) and dispersion of pollutants. But it
may also have adverse impacts such as allowing or increasing the formation of hazardous gaseous by-products. It
may also have benefits for fire fighter safety and public health.
3.66
convection
transfer of heat by movement of a fluid
3.67
convective heat flux
heat flux (3.201) caused by convection (3.66)
3.68
convective heat transfer
transfer of heat to a surface from a surrounding fluid by convection (3.66)
Note 1 to entry: The amount of heat transfer depends on the temperature difference between the fluid and the
surface, the fluid properties and the fluid velocity and direction.
8 © ISO 2017 – All rights reserved

ISO 13943:2017(E)
Note 2 to entry: The fundamental modes of heat transfer are conduction or diffusion, convection and radiation.
3.69
corrosion damage
physical and/or chemical damage or impaired function caused by chemical action
3.70
corrosion target
sensor used to determine the degree of corrosion damage (3.69), under specified conditions
Note 1 to entry: The sensor may be a product or a component. It may also be a reference material or object used
to simulate the behaviour of a product or a component.
3.71
critical fire load
fire load (3.134) required in a fire compartment (3.120) to produce a fire (3.114) of sufficient severity
to cause failure of a fire barrier(s) (3.117) or structural member(s) located within or bounding the fire
compartment
3.72
damaged area
total of those surface areas which have been affected permanently by fire (3.114) under specified
conditions
Note 1 to entry: Compare with the term burned area (3.36).
Note 2 to entry: Users of this term should specify the types of damage to be considered. This could include, for
example, loss of material, deformation, softening, melting behaviour (3.270), char (3.47) formation, combustion
(3.55), pyrolysis (3.316) or chemical attack.
Note 3 to entry: The typical unit is m .
3.73
damaged length
maximum extent in a specified direction of the damaged area (3.72)
Note 1 to entry: Compare with the terms char length (3.49) and burned length (3.37).
3.74
defend in place
life safety strategy in which occupants are encouraged to remain in their current location rather than
to attempt escape (3.99) during a fire (3.114)
3.75
deflagration
combustion (3.55) wave propagating at subsonic velocity
Note 1 to entry: If within a gaseous medium, deflagration is the same as a flame (3.159).
3.76
design density
measured volumetric flow rate of water from sprinklers, per unit area, that is delivered in the absence
of a fire (3.114)
−1
Note 1 to entry: The typical unit is mm⋅min .
3.77
design fire
quantitative description of assumed fire (3.114) characteristics within the design fire scenario (3.78)
Note 1 to entry: Design fire is, typically, an idealized description of the variation with time of important fire
variables such as heat release rate (3.206), flame spread rate (3.169), smoke production rate (3.351), toxic gas
yields, and temperature.
ISO 13943:2017(E)
3.78
design fire scenario
specific fire scenario (3.152) on which a deterministic fire safety engineering (3.149) analysis will be
conducted
3.79
detection time
time interval between ignition (3.217) of a fire (3.114) and its detection by an automatic or manual system
3.80
deterministic model
fire model (3.136) that uses science-based mathematical expressions to produce the same result each
time the method is used with the same set of input data values
3.81
detonation
reaction characterized by a shock wave propagating at a velocity greater than the local speed of sound
in the unreacted material
3.82
diffusion flame
flame (3.159) in which combustion (3.55) occurs in a zone where the fuel (3.189) and the oxidizing agent
(3.290) mix, having been initially separate
Note 1 to entry: Compare with the term pre-mixed flame (3.307).
3.83
draught-free environment
space in which the results of experiments are not significantly affected by the local air speed
Note 1 to entry: A qualitative example is a space in which a wax candle flame (3.159) remains essentially
−1
undisturbed. Quantitative examples are small-scale fire tests (3.346) in which a maximum air speed of 0,1 m⋅s
−1
or 0,2 m⋅s is sometimes specified.
3.84
droplets
aerosol droplets
liquid-phase products, typically generated through pyrolysis (3.316) (reduced oxygen combustion
conditions) from both flaming and smouldering fires and which may condense into tarrylike,
spherically-shaped liquid beads
Note 1 to entry: Water produced from combustion may also condense around particles forming aerosol droplets.
3.85
duration of flaming
length of time for which flaming combustion (3.175) persists under specified conditions
Note 1 to entry: Compare with the term afterflame time (3.12).
3.86
effective concentration 50
EC
concentration (3.62) of a toxic gas (3.400) or fire effluent (3.123), statistically calculated from
concentration-response data, that causes a specified effect in 50 % of a population of a given species
within a specified exposure time (3.108) and post-exposure time (3.302)
Note 1 to entry: Compare with the term IC (0).
−3
Note 2 to entry: For fire effluent, typical unit is g⋅m .
Note 3 to entry: For toxic gas, typical unit is μL/L (T = 298 K and P = 1 atm); see volume fraction (3.421).
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ISO 13943:2017(E)
Note 4 to entry: The observed effect is usually a behavioural response, incapacitation (3.225), or death. The EC
for incapacitation is termed the IC50 (3.211). The EC for lethality is termed the LC50 (3.241).
3.87
effective exposure dose 50
Ect
product of EC50 (3.86) and the exposure time (3.108) over which it was determined
Note 1 to entry: Compare with the term exposure dose (3.107).
−3
Note 2 to entry: For fire effluent (3.123), typical unit is g⋅min⋅m .
−1
Note 3 to entry: For toxic gas (3.400), typical unit is μL⋅min⋅L (T = 298 K and P = 1 atm); see volume fraction
(3.421).
Note 4 to entry: Ect is a measure of toxic potency (3.402).
3.88
effective heat of combustion
heat released (3.205) from a burning test specimen (3.384) in a given time interval divided by the mass
lost from the test specimen in the same time period
Note 1 to entry: Effective heat of combustion is the same as the net heat of combustion (3.280) if all the test
specimen is converted to volatile combustion products (3.57) and if all the combustion products are fully oxidized.
−1
Note 2 to entry: The typical unit is kJ⋅g .
3.89
emissivity
ratio of the radiation emitted by a radiant source to the radiation that would be emitted by a black body
radiant source (3.30) at the same temperature
Note 1 to entry: The emissivity is dimensionless.
3.90
empirical formula
chemical formula of a substance in which the relative numbers of atoms of each type are given
Note 1 to entry: Typically, the number for one type of atom is chosen to be an integer (usually C or O), e.g. a
particular sample might be represented as C H O N Cl .
6 8,9 4,1 0,3 0,01
3.91
enclosed fire
fire (3.114) which takes place and has been ignited (3.216) inside an enclosure (3.92)
Note 1 to entry: This term is particularly important when defining the ventilation conditions in the fire.
3.92
enclosure
volume defined by bounding surfaces, which may have one or more openings
3.93
enclosure
external casing protecting the electrical and mechanical parts of apparatus
Note 1 to entry: This term excludes cables.
3.94
end-use conditions
intended conditions to which an item will be subjected during its normal working life, when used in
accordance with the manufacturer’s instructions
ISO 13943:2017(E)
3.95
environment
conditions and surroundings that may influence the behaviour of an item or persons when
exposed to fire (3.114)
3.96
environmental impact
significant change to the natural environment, whether adverse or beneficial, wholly or partially
resulting from a fire (3.114)
3.97
equivalence ratio
fuel (3.189)/air ratio divided by the fuel/air ratio required for a stoichiometric mixture (3.370)
Note 1 to entry: Compare with the terms fuel-lean combustion (3.190), fuel-rich combustion (3.191), stoichiometric
combustion (3.367), and stoichiometric mixture.
Note 2 to entry: Standard dry air contains 20,95 % oxygen by volume. In practice, the oxygen concentration (3.62)
in entrained air may vary and calculation of the equivalence ratio to a standard dry air basis will be required.
Note 3 to entry: The equivalent ratio is dimensionless.
3.98
error
recognizable deficiency in any phase or activity of assessment that is not due to lack of knowledge
Note 1 to entry: Error is seen not only as an error in any calculation method, but also as measurement error.
3.99
escape
effective action taken to reach a safe refuge (3.333) or place of safety (3.300)
3.100
evacuation behaviour
behaviour which enables occupants of a building to reach a place of safety (3.300)
Note 1 to entry: Compare with the terms movement behaviour (3.276) and pre-movement behaviour (3.308).
3.101
evacuation time
time interval between the time of a warning of fire (3.114) being transmitted to the occupants and the
time at which the occupants of a specified part of a building or all of the building are able to enter a
place of safety (3.300)
Note 1 to entry: Compare with the term available safe escape time (3.26).
3.102
event tree
depiction of temporal, causal sequences of events, built around a single initiating condition
3.103
exit
designated point of departure from a building or from an enclosure (3.92)
3.104
expanded uncertainty
quantity defining an interval for the result of a measurement that may be expected to encompass a
large fraction of the distribution of values that could reasonably be attributed to the measurand
Note 1 to entry: The fraction may be viewed as the coverage probability or level of confidence of the interval.
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ISO 13943:2017(E)
Note 2 to entry: Compare with the term uncertainty (3.413). Expanded uncertainty requires explicit or implicit
assumptions regarding the probability distribution characterized by the measurement result and its combined
standard uncertainty. The level of confidence that may be attributed to this interval can be known only to the
extent to which such assumptions may be justified.
Note 3 to entry: Expanded uncertainty is termed overall uncertainty in some documents.
[SOURCE: ISO/IEC Guide 98-3:2008, 2.3.5]
3.105
explosion
abrupt expansion of gas which may result from a rapid oxidation (3.289) or decomposition
reaction, with or without an increase in temperature
3.106
exposed surface
surface of a test specimen (3.384) subjected to the heating conditions of a fire test (3.157)
Note 1 to entry: The surface of the test specimen could also be exposed to the heat generated by the output from
the test specimen itself.
3.107
exposure dose
measure of the maximum amount of a toxic gas (3.400) or fire effluent (3.123) which is available for
inhalation, calculated by integration of the area under a concentration-time curve (3.63)
−3
Note 1 to entry: For fire effluent, typical unit is g⋅min⋅m .
−1
Note 2 to entry: For toxic gas, typical unit is μL⋅min⋅L (T = 298 K and P = 1 atm); see volume fraction (3.421).
3.108
exposure time
length of time for which people, animals or test specimens (3.384) are exposed under specified
conditions
3.109
extent of combustion
maximum length of a test specimen (3.384) that has been destroyed by combustion
(3.55) or pyrolysis (3.316), under specified test conditions, excluding any region damaged only by
deformation
3.110
extinction area of smoke
product of the volume occupied by smoke (3.347) and the extinction coefficient (3.111) of the smoke
Note 1 to entry: The extinction area of smoke is a measure of the amount of smoke. The typical unit is m .
3.111
extinction coefficient
natural logarithm of the ratio of incident light intensity to transmitted light intensity, per unit light
path length
−1
Note 1 to entry: The typical unit is m .
3.112
F factor
minimum concentration (3.62) of a toxic gas (3.400) irritant (3.237) that is expected to seriously
compromise the ability to escape (3.99) from a fire (3.114)
Note 1 to entry: Compare with the term fractional effective concentration (3.187).
Note 2 to entry: The concentration is usually expressed as a volume fraction (3.421) (0) at T = 298 K and P = 1 atm,
3 3 −6
in which case the typical unit is μL/L (= cm /m = 10 ).
ISO 13943:2017(E)
3.113
fault tree
depiction of the logical dependencies of events on one another, built around a critical resulting event,
which usually has an unacceptable level of consequence and may be described as a failure
3.114
fire
process of combustion (3.55) characterized by the emission of heat and fire effluent (3.123)
and usually accompanied by smoke (3.347), flame (3.159) or glowing (3.196) or a combination thereof
Note 1 to entry: In the English language, the term “fire” is used to designate three concepts, two of which relate to
specific types of self-supporting combustion with different meanings. Of these three, two of them are designated
using two different terms in both French and German.
3.115
fire
self-supporting combustion (3.55) that has been deliberately arranged to provide useful
effects and is limited in its extent in time and space
3.116
fire
self-supporting combustion (3.55) that has not been deliberately arranged to provide
useful effects and is not limited in its extent in time and space
3.117
fire barrier
fire separation, noun
separating element (3.345) that exhibits fire integrity (3.133) or fire stability (3.156) or thermal insulation
(3.391), or a combination thereof, for a period of time under specified conditions
3.118
fire behaviour
change in, or maintenance of, the physical and/or chemical properties of an item and/or structure
exposed to fire (3.114)
Note 1 to entry: Compare with the term fire performance (3.137).
Note 2 to entry: This concept covers both reaction to fire (3.324) and fire resistance (3.141).
Note 3 to entry: In English, this term may also be used to describe the behaviour of a fire.
3.119
fire classification
standardized system of classifying fires (3.114) in terms of the nature of the fuel (3.189)
EXAMPLE In Europe and Australasia, there are six classes:
—  Class A: fire involving solid materials, usually of an organic nature, in which combustion (3.55) normally
takes place with the formation of glowing (3.196) embers;
—  Class B: fires involving liquids or liquefiable solids;
—  Class C: fires involving gases;
—  Class D: fires involving metals;
—  Class E: fires involving electrical hazards;
—  Class F: fires involving cooking oil or fat.
3.120
fire compartment
enclosed space, which may be subdivided, separated from adjoining spaces by fire barriers (3.117)
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