ISO/TS 19706:2004

TECHNICAL ISO/TS
SPECIFICATION 19706
First edition
2004-11-15

Guidelines for assessing the fire threat to
people
Lignes directrices pour l'évaluation des dangers du feu pour les
personnes




Reference number
ISO/TS 19706:2004(E)
©
ISO 2004

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ISO/TS 19706:2004(E)
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ISO/TS 19706:2004(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 1
3 Terms and definitions. 2
4 General principles. 3
4.1 Fire effluent and escape time . 3
4.2 Effects of fire effluent on people . 3
4.3 Use of fire effluent data . 3
4.4 Data accuracy and uncertainty. 4
5 Significance and use . 4
6 Generation and nature of effluent . 4
7 Sources of data on fire effluent . 6
7.1 Laboratory data . 6
7.2 Effluent potency . 7
7.3 Large-scale fire tests . 7
7.4 Bench-scale combustion devices . 8
7.5 Evolution of the effluent. 8
8 Effects of fire effluent on people . 8
Annex A (informative) Factors affecting fire threat to people. 10
Bibliography . 11

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ISO/TS 19706:2004(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
In other circumstances, particularly when there is an urgent market requirement for such documents, a
technical committee may decide to publish other types of normative document:
— an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in
an ISO working group and is accepted for publication if it is approved by more than 50 % of the members of
the parent committee casting a vote;
— an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical
committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting a
vote.
An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a
further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is
confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an
International Standard or be withdrawn.
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.
ISO/TS 19706 was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 3, Fire threat
to people and environment.
This first edition of ISO/TS 19706 cancels and replaces ISO/TR 9122-1:1989 and ISO/TR 9122-6:1994, which
have been technically revised.
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ISO/TS 19706:2004(E)
Introduction
All fires produce toxic gases, smoke and heat. Whether the fire occurs in a residence, a commercial building,
or a transportation vehicle, exposure to this effluent can have serious consequences for the occupants,
responding fire safety personnel, and for larger fires, people in the environment surrounding the structure.

The anticipation of a fire impacts the design and construction of all occupancies. Building codes and
equivalent documents for transportation vehicles generally provide for the egress or refuge of occupants: the
time available for escape should exceed the time required for escape. Underestimating the effects of fire
effluent on the former could result in not providing the intended degree of safety or in overestimating the
impact of fire mitigation tactics, whereas overestimating the threat could inappropriately limit the use of
construction, finish and furnishing materials and products, as well as constrain occupancy design options and
escalate costs.
Thus, it is important in the fire safety engineering of facilities to include the effects of fire effluent and to
include them accurately and in full awareness of available knowledge. From a complementary perspective,
information on fire effluent must be combined with additional consideration of design fire scenarios, the
occupancy and the occupants themselves in a fire hazard or risk assessment, rather than selecting, banning
or demeaning a construction or furnishing material or product based on its smoke production and toxic
potency alone.
All measurements, calculations, and assumptions are characterized by a degree of uncertainty. The utility of
the outcome of a fire hazard or risk assessment depends on knowing the uncertainties in the assessment
methodology and the uncertainties in the input data. This Technical Specification addresses the uncertainty in
the characterization of fire effluent, the measurement of effluent effects, and the accuracy of the
measurements.
The purpose of this Technical Specification is to provide general guidelines for estimating the fire threat to
people and to the development of quantitative information on effluent potency for use in fire hazard and risk
assessment.

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TECHNICAL SPECIFICATION ISO/TS 19706:2004(E)

Guidelines for assessing the fire threat to people
1 Scope
This Technical Specification is to serve as general guidelines for assessment of the fire threat to people. It
encompasses the development, evaluation and use of relevant quantitative information for use in fire hazard
and risk assessment. This information, generally obtained from fire incidence investigation, fire statistics,
real-scale fire tests and from physical fire models, is to be used in conjunction with computational models for
analysis of the initiation and development of fire, fire spread, smoke formation and movement, chemical
species generation, transport and decay and people movement, as well as fire detection and suppression
(ISO/TR 13387). Aspects of the methodology described here are further amplified in ISO/TS 13571 and
ISO 13344.
This Technical Specification is intended to facilitate addressing the consequences of a single acute human
exposure to fire effluent. Other effects of the heat, gases and aerosols (such as effects on electronic
equipment and effects of frequent, multiple environmental exposures of people), which are of importance in
fire safety design, are to be addressed elsewhere.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO/TR 9122-1:1989, Toxicity testing of fire effluents — Part 1: General
ISO/TR 9122-2:1993, Toxicity testing of fire effluents –– Part 2: Guidelines for biological assays to determine
the acute inhalation toxicity of fire effluents (basic principles, criteria and methodology)
ISO/TR 9122-3:1993, Toxicity testing of fire effluents –– Part 3: Methods for the analysis of gases and
vapours in fire effluents
ISO/TR 9122-4:1993, Toxicity testing of fire effluents –– Part 4: The fire model (furnaces and combustion
apparatus used in small-scale testing)
ISO/TR 9122-5:1993, Toxicity testing of fire effluents –– Part 5: Prediction of toxic effects of fire effluents
ISO 13344:1996, Determination of the lethal toxic potency of fire effluents
ISO/TR 13387-1:1999, Fire safety engineering — Part 1: Application of fire performance concepts to design
objectives
ISO/TR 13387-2:1999, Fire safety engineering — Part 2: Design fire scenarios and design fires
ISO/TR 13387-3:1999, Fire safety engineering — Part 3: Assessment and verification of mathematical fire
models
ISO/TR 13387-4:1999, Fire safety engineering — Part 4: Initiation and development of fire and generation of
fire effluents
ISO/TR 13387-5:1999, Fire safety engineering — Part 5: Movement of fire effluents
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ISO/TS 19706:2004(E)
ISO/TR 13387-6:1999, Fire safety engineering — Part 6: Structural response and fire spread beyond the
enclosure of origin
ISO/TR 13387-7:1999, Fire safety engineering — Part 7: Detection, activation and suppression
ISO/TR 13387-8:1999, Fire safety engineering — Part 8: Life safety — Occupant behaviour, location and
condition
ISO/TS 13571:2002, Life-threatening components of fire — Guidelines for the estimation of time available for
escape using fire data
ISO 13943:2000: Fire safety — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 13943:2000 and the following apply.
3.1
asphyxiant
toxicant causing loss of consciousness and ultimately death resulting from hypoxic effects, particularly on the
central nervous and/or cardiovascular systems
3.2
concentration-time curve
plot of the concentration of a gaseous toxicant or fire effluent as a function of time
NOTE The typical units for the concentration of the toxic gas are microlitres per litre and for fire effluent, grams per
cubic metre. The units of microlitre per litre are numerically identical to parts per million (ppm), the use of which is
discouraged.
3.3
escape
effective action by occupants to accomplish their own arrival at a place of safe refuge
3.4
incapacitation
inability to take effective action to accomplish one’s own escape from a fire
3.5
EC
50
concentration of a toxic gas or fire effluent statistically calculated from concentration-response data to produce
an effect in 50 % of a population of a given species within a specified exposure and post-exposure time
NOTE 1 The concentration of the toxic gas is expressed as a volume fraction and that of the fire effluent in grams per
cubic metre.
NOTE 2 The observed effect is usually a behavioural response, incapacitation, or death. The EC for an incapacitating
50
exposure is termed the IC . The EC for a lethal exposure is termed the LC .
50 50 50
3.6
safe refuge
location where the subject is free from incurring further harm from the fire
3.7
time available for escape
interval between the time of ignition and the time after which conditions become untenable, such that
occupants are unable to take effective action to accomplish their own escape to a place of safe refuge
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ISO/TS 19706:2004(E)
NOTE The time available for escape, as used in this Technical Specification, differs from the commonly used term
ASET (Available Safe Escape Time) in that the latter implies that the occupant escapes unharmed, while the former
enables the user to define an acceptable level of personal safety.
3.8
time required for escape
time required for occupants to travel from their location at the time of ignition to a place of safe refuge
NOTE As used in this Technical Specification, time required for escape is intended to be equivalent to the commonly
used term RSET (Required Safe Escape Time). See ISO/TR 13387-8:1999.
4 General principles
4.1 Fire effluent and escape time
4.1.1 Life safety in a fire is greatly enhanced if the time available for occupants to escape exceeds the time
required for them to escape and is threatened if the time required exceeds the time available.
4.1.1.1 As specified in ISO/TR 13387-8, the time required for escape includes the time from ignition of a
fire to its detection, the time from its detection to an evacuation warning to occupants, an occupant’s
pre-movement time (the time between becoming aware of an emergency and initiating egress) and the actual
travel time to a place of safety.
4.1.1.2 The time available for escape is the interval between the time of ignition and the time after which
conditions become untenable such that occupants are unable to take effective action to accomplish their own
escape to a place of safe refuge. Guidelines for estimation of the time available for escape are specified in
ISO/TS 13571. It involves procedures to evaluate the life threat components of fire hazard analysis, e.g. toxic
gases, heat and smoke obscuration, in terms of the status of exposed subjects at discrete time intervals. The
time at which occupants’ exposure exceeds a threshold criterion represents the time available for escape.
Users of ISO/TS 13571 have the flexibility to set such criteria according to their chosen life safety objectives.
Thus, an estimated time available for escape might or might not be equivalent to an ASET.
4.1.2 The quantity and nature of the fire effluent are prime factors in estimating the time available for
escape. The effluent nature is a function not only of the product from which it is generated, but also of the
conditions under which the product participates in the fire and the nature of the fire.
4.2 Effects of fire effluent on people
During and following a fire, the products of combustion can have lethal and sub-lethal effects on occupants of
the facility and responders to the fire. The severity of the effects depends on the composition of the effluent,
the extent of the exposure and the physical condition of the subject. Information relative to the effects on
people can be extracted from physical and chemical characterization of the effluent (e.g., using
ISO/TS 13571), from estimation of the toxic potency of fire effluent (e.g., using ISO 13344) or from accidental
exposures of people to the chemical and thermal components of the effluent.
The effects of the effluent on people are not deterministic in severity or immediacy, but fall into a distribution.
This is due to the range of sensitivity of people to the fire effluent and variations in the progress of a fire.
4.3 Use of fire effluent data
Because the effect of the fire effluent on people depends on factors beyond the combustible(s) as a source of
the effluent, the fire-effluent composition data must be combined with the additional information about the
facility, the fire and the people into a fire hazard or risk assessment, rather than being used alone as an
indicator of fire hazard or risk.
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ISO/TS 19706:2004(E)
4.4 Data accuracy and uncertainty
All measurements, calculations and assumptions are characterized by a degree of uncertainty. The utility of
the outcome of a fire hazard or risk assessment depends on knowing the uncertainties in the assessment
methodology and the uncertainties in the input data. This Technical Specification addresses the uncertainty in
the characterization of fire effluent, the measurement of effluent effects and the accuracy of the
measurements.
5 Significance and use
5.1 The projected response of people to fire effluent frequently determines the fire safety design limits for
occupancy. This Technical Specification provides guidelines on the type of effluent information needed to
enable such a projection and how to use the data.
5.2 The information derived using the guidelines in this Technical Specification is for use in fire hazard and
risk assessment, e.g., as given by ISO/TR 13387.
5.3 The methodologies developed using the guidelines in this Technical Specification cannot be validated
from fire experiments using people. Thus, there is some uncertainty in the accuracy of the quantitative
exposure/response relationship. This uncertainty is to be included in the estimation of the overall uncertainty
of a fire hazard or risk analysis. The user can then perform a sensitivity analysis and determine the
significance of the uncertainty in the human effects in the context of the problem at hand.
6 Generation and nature of effluent
6.1 Gases, liquid aerosol, soot particles and heat are generated during the flaming combustion and
non-flaming pyrolysis of products during a fire.
6.2 The yield and nature of the effluent are determined by the involved fuels and the prevalent thermal and
oxygen conditions in the current stage of the fire. These conditions affect the burning rate of the products and
the degree of oxidation of the emitted effluent. The stages of fire are characterized in Table 1.
NOTE The divisions between the fire stages are approximate.
6.3 The yield and nature of the effluent are affected by human or mechanical interventions in the fire.
These include the opening or closing of doors and windows, application of fire suppressant, movement of the
burning products, etc.
6.4 The harmful components of fire effluent are the fol
...