Guidance for assessing the validity of physical fire models for obtaining fire effluent toxicity data for fire hazard and risk assessment

This document assesses the utility of physical fire models that have been standardized, are commonly used, and/or are cited in national or international standards, for generating fire effluent toxicity data of known accuracy. This is achieved by using the criteria established in ISO 16312-1 and the guidelines established in ISO 19706. The aspects of the models that are considered are: the intended application of the model, the combustion principles it manifests, the fire stage(s) that the model attempts to replicate, the types of data generated, the nature and appropriateness of the combustion conditions to which test specimens are exposed, and the degree of validity established for the model.

Lignes directrices pour évaluer la validité des modèles de feu physiques pour l'obtention de données sur les effluents du feu en vue de l'évaluation des risques et dangers

Le présent document évalue l'utilité des modčles de feu physiques qui ont été normalisés, sont couramment utilisés et/ou sont cités dans des normes nationales ou internationales, pour la génération de données sur la toxicité des effluents du feu dont la précision est connue. Pour ce faire, les critčres établis dans l'ISO 16312-1 et les lignes directrices établies dans l'ISO 19706 sont utilisés. Les aspects des modčles pris en compte sont: l'application prévue du modčle, les principes de combustion qu'il manifeste, le ou les stades de développement d'un feu que le modčle tente de reproduire, les types de données générées, la nature et l'adéquation des conditions de combustion auxquelles les éprouvettes sont exposées, et le degré de validité établi pour le modčle.

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Published
Publication Date
21-Jan-2021
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5060 - Close of voting Proof returned by Secretariat
Start Date
23-Oct-2020
Completion Date
23-Oct-2020
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TECHNICAL ISO/TR
REPORT 16312-2
Second edition
2021-01
Guidance for assessing the validity of
physical fire models for obtaining fire
effluent toxicity data for fire hazard
and risk assessment —
Part 2:
Evaluation of individual physical fire
models
Lignes directrices pour évaluer la validité des modèles de feu
physiques pour l'obtention de données sur les effluents du feu en vue
de l'évaluation des risques et dangers —
Partie 2: Évaluation des différents modèles de feu physiques
Reference number
ISO/TR 16312-2:2021(E)
ISO 2021
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ISO/TR 16312-2:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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 the requester.
ISO copyright office
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Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
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ISO/TR 16312-2:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 General principles ............................................................................................................................................................................................... 2

4.1 Physical fire model............................................................................................................................................................................... 2

4.2 Model validity .......................................................................................................................................................................................... 2

4.3 Test specimens ........................................................................................................................................................................................ 2

4.4 Combustion conditions .................................................................................................................................................................... 2

4.5 Effluent characterization ................................................................................................................................................................ 2

5 Significance and use .......................................................................................................................................................................................... 3

6 Physical fire models .......................................................................................................................................................................................... 3

6.1 Smoke chambers - Closed cabinet toxicity tests (international) ................................................................. 3

6.1.1 NBS smoke chamber ..................................................................................................................................................... 3

6.1.2 ISO smoke chamber ....................................................................................................................................................... 5

6.2 NES 713 (United Kingdom) .......................................................................................................................................................... 7

6.2.1 Application ............................................................................................................................................................................ 7

6.2.2 Principle .................................................................................................................................................................................. 7

6.2.3 Fire stage(s) ......................................................................................................................................................................... 8

6.2.4 Types of data ....................................................................................................................................................................... 8

6.2.5 Presentation of results ................................................................................................................................................ 8

6.2.6 Apparatus assessment ................................................................................................................................................ 8

6.2.7 Toxicological results .................. ......................................................................................................................... ........... 8

6.2.8 Miscellaneous ..................................................................................................................................................................... 9

6.2.9 Validation ............................................................................................................................................................................... 9

6.2.10 Conclusion ............................................................................................................................................................................. 9

6.3 Rotative cages smoke toxicity tests ....................................................................................................................................10

6.3.1 Japanese and Korean methods..........................................................................................................................10

6.3.2 Chinese method .............................................................................................................................................................12

6.4 Cone calorimeter (international) .........................................................................................................................................14

6.4.1 Application .........................................................................................................................................................................14

6.4.2 Principle ...............................................................................................................................................................................15

6.4.3 Fire stage(s) ......................................................................................................................................................................15

6.4.4 Types of data ....................................................................................................................................................................15

6.4.5 Presentation of results .............................................................................................................................................15

6.4.6 Apparatus assessment .............................................................................................................................................15

6.4.7 Toxicological results .................. ......................................................................................................................... ........16

6.4.8 Validation ............................................................................................................................................................................16

6.4.9 Conclusion ..........................................................................................................................................................................16

6.5 Flame propagation apparatus (International) .........................................................................................................17

6.5.1 Application .........................................................................................................................................................................17

6.5.2 Principle ...............................................................................................................................................................................17

6.5.3 Fire stage(s) ......................................................................................................................................................................18

6.5.4 Types of data ....................................................................................................................................................................18

6.5.5 Presentation of results .............................................................................................................................................18

6.5.6 Apparatus assessment .............................................................................................................................................18

6.5.7 Toxicological results .................. ......................................................................................................................... ........19

6.5.8 Miscellaneous ..................................................................................................................................................................19

6.5.9 Validation ............................................................................................................................................................................19

6.5.10 Conclusion ..........................................................................................................................................................................19

6.6 Tube furnace methods ...................................................................................................................................................................20

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ISO/TR 16312-2:2021(E)

6.6.1 Static tube furnace (International) ...............................................................................................................20

6.6.2 Tube furnace (Germany) ........................................................................................................................................23

6.6.3 ISO/TS 19700 Tube furnace (International) ........................................................................................26

7 Summary of test methods ........................................................................................................................................................................29

Annex A (informative) Deprecated methods .............................................................................................................................................33

Bibliography .............................................................................................................................................................................................................................43

iv © ISO 2021 – All rights reserved
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ISO/TR 16312-2:2021(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 of 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 www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 3, Fire

threat to people and environment.

This second edition cancels and replaces the first edition (ISO/TR 16312-2:2007) which has been

technically revised.
The main changes compared to the previous edition are as follows:

— fire models have been updated following the publication of certain other standards, including

ISO/TS 19021 and ISO/TS 5660-5;
— deprecated methods have been moved to Annex A.
A list of all parts in the ISO 16312 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO 2021 – All rights reserved v
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ISO/TR 16312-2:2021(E)
Introduction

Providing the desired degree of life safety for an occupancy increasingly involves an explicit fire hazard

or risk assessment. This assessment includes such components as information on the room/building

properties, the nature of the occupancy, the nature of the occupants, the types of potential fires, the

outcomes to be avoided, etc.

This type of determination also requires information on the potential for harm to people due to the

effluent produced in the fire. Because of the prohibitive cost of real-scale product testing under the

wide range of fire conditions, most estimates of the potential harm from the fire effluent depend on

data generated from a physical fire model, a reduced-scale test apparatus and procedure for its use.

The role of a physical fire model for generating accurate toxic effluent composition is to simulate the

essential features of the complex thermal and reactive chemical environment in full-scale fires. These

environments vary with the physical characteristics of the fire scenario and with time during the

course of the fire, and close representation of some phenomena occurring in full-scale fires can be

difficult or even not possible on a small scale. The accuracy of the physical fire model, then, depends on

two features:

a) the degree to which the combustion conditions in the bench-scale apparatus mirror those in the

fire stage being simulated;

b) the degree to which the yields of the important combustion products obtained from the burning

of the commercial product at full scale are matched by the yields from burning specimens of the

product in the small-scale model. This measure is generally performed for a small set of products,

and the derived accuracy is then presumed to extend to other test subjects. Since the publication of

the first edition of this document, in which a methodology for effecting this comparison was cited

in Reference [1], ISO 29903-1 has been developed.

This document provides a set of technical criteria for evaluating physical fire models used to obtain

composition and toxic potency data on the effluent from products and materials under fire conditions

relevant to life safety. This document covers the application by experts of these criteria to currently

used test methods that are used for generating data on smoke effluent from burning materials and

commercial products.

There are 10 physical fire models discussed in this document, plus 4 depreciated methods in Annex A.

Additional apparatus can be added as they are developed or adapted with the intent of generating

information regarding the toxic potency of smoke.

For all models in this document, several are closed systems. In these, no external air is introduced and

the combustion (or pyrolysis) products remain within the apparatus except for the fraction removed

for chemical analysis. The second seven are open apparatus, with air continuously flowing past the

combusting sample and exiting the apparatus, along with the combustion products.

Reference documents useful for discussions of analytical methods, bioassay procedures, and prediction

of the toxic effects of fire effluents are listed in the Bibliography at the end of this document.

vi © ISO 2021 – All rights reserved
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TECHNICAL REPORT ISO/TR 16312-2:2021(E)
Guidance for assessing the validity of physical fire models
for obtaining fire effluent toxicity data for fire hazard and
risk assessment —
Part 2:
Evaluation of individual physical fire models
1 Scope

This document assesses the utility of physical fire models that have been standardized, are commonly

used, and/or are cited in national or international standards, for generating fire effluent toxicity data

of known accuracy. This is achieved by using the criteria established in ISO 16312-1 and the guidelines

established in ISO 19706. The aspects of the models that are considered are: the intended application of

the model, the combustion principles it manifests, the fire stage(s) that the model attempts to replicate,

the types of data generated, the nature and appropriateness of the combustion conditions to which test

specimens are exposed, and the degree of validity established for the model.
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.

ISO 13943, Fire safety — Vocabulary

ISO 19703, Generation and analysis of toxic gases in fire — Calculation of species yields, equivalence ratios

and combustion efficiency in experimental fires
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 13943 and ISO 19703 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
vitiation-controlled

type of conditions under which the volume concentration of oxygen is intentionally controlled or

reduced in the combustion environment

Note 1 to entry: Vitiation controlled conditions represent an oxygen depleted fire environment.

[SOURCE: ISO/TS 5660-5:2020, 3.3, modified.]
© ISO 2021 – All rights reserved 1
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ISO/TR 16312-2:2021(E)
3.2
ventilation-controlled

type of conditions un which the supply rate of (ambient or vitiated) air to the combustion environment

is intentionally controlled or limited

Note 1 to entry: Ventilation-controlled conditions represent a fire environment with limited fresh air supply.

[SOURCE: ISO/TS 5660-5:2020, 3.4, modified.]
4 General principles
4.1 Physical fire model

A physical fire model is characterized by the requirements placed on the form of the test specimen, the

operational combustion conditions and the capability of analysing the products of combustion.

4.2 Model validity

For use in providing data for effluent toxicity assessment, the validity of a physical fire model is

determined by the degree of accuracy with which it reproduces the yields of the principal toxic

components in real-scale fires.

ISO 12828-1, ISO 12828-2 and ISO/TS 12828-3 are guidance documents for model validity. This

includes limits of detection and quantification, range of application, trueness and fidelity in terms of

repeatability and reproducibility.
4.3 Test specimens

Fire safety engineering requires data on commercial products or product components. In a reduced-

scale test, the manner in which a specimen of the product is composed can affect the nature and yields

of the combustion products. This is especially the case for products of non-uniform composition, such

as those consisting of layered materials.
4.4 Combustion conditions

The yields of combustion products depend on such apparatus conditions as the fuel/air equivalence

ratio, whether the decomposition is flaming or non-flaming, the persistence of flaming of the sample,

the temperature of the specimen and the effluent produced, the thermal radiation incident on the

specimen, the stability of the decomposition conditions and the interaction of the apparatus with the

decomposition process, with the effluent and the flames.

The conditions of pyrolysis and combustion may differ locally and globally in a physical fire model,

leading to difficulties in scale with real-fire conditions in reduced experiments.

The experimental conditions may be vitiation-controlled and/or ventilation-controlled, or may be

unknown and vary during the test.

It is essential that the physical fire model enable accurate determinations of chemical effluent

composition. Validation of the method according to ISO 12828-2 is a suitable way to validate the

chemical analysis.
4.5 Effluent characterization

For the effluent from most common materials, the major acute toxic effects have been shown to depend

upon a small number of major asphyxiant gases and a somewhat wider range of inorganic and organic

irritants. In ISO 13571, a base set of combustion products has been identified for routine analysis.

Novel materials may evolve previously unidentified toxic products. Thus, a more detailed chemical

2 © ISO 2021 – All rights reserved
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ISO/TR 16312-2:2021(E)

analysis may be needed in order to provide a full assessment of acute effects and to assess chronic or

environmental toxicants.

A bioassay can provide guidance on the importance of toxicants not included in the base set. ISO 19706

contains a fuller discussion of the utility of integrating assays. It is desirable that the physical fire

model accommodate a bioassay method. However, due to bioethics practices, such use and comparisons

are limited. The use of laboratory animals as test subjects or living tissues are means of insuring

inclusion of the impact of all combustion gases. However, it is recognized that the adoption and use of

such protocols may be prohibited in some jurisdictions and tend to disappear. An animal-free protocol

can capture the effects of known combustion gases, but can miss the impact of any unexpected or

uncommon and highly toxic species, the smoke components of which are most in need of identification.

5 Significance and use

Most computational models of fire hazard and risk require information regarding the potential of

fire effluent (gases, heat and smoke) to cause harm to people and to affect their ability to escape or to

seek refuge.

The quality of the data on fire effluent has a profound effect on the accuracy of the prediction of the

degree of life safety offered by an occupancy design. Uncertainty in such predictions commonly leads to

the use of safety factors that can compromise functionality and increase cost.

Fire safety engineering requires data on commercial products. Real-scale tests of such products

generally provide accurate fire effluent data. However, due to the large number of available products,

the high cost of performing real-scale tests of products and the small number of large-scale test

facilities, information on effluent toxicity is most often obtained from physical fire models.

There are numerous physical fire models cited in national regulations. These models vary in design

and operation, as well as in their degree of characterization. The assessments of these models in this

document provide product manufacturers, regulators and fire safety professionals with insight into

appropriate and inappropriate sources of fire effluent data for their defined purposes.

The assessments of physical fire models in this document do not address means for combining

the effluent component yields to estimate the effects on laboratory animals (see ISO 13344) or for

extrapolating the test results to people (see ISO 13571).

The methods that do not include animal exposure and are not amenable to such an adaptation might

not allow identification of extreme and/or unusual toxicity.
Note that four depreciated methods are detailed in Annex A.
6 Physical fire models
6.1 Smoke chambers - Closed cabinet toxicity tests (international)
6.1.1 NBS smoke chamber
6.1.1.1 Application

This physical fire model is described in ASTM E662, with a vertically-orientated sample and heat

flux limited to 25 kW/m . It was first designed to generate smoke optical density data. The physical

fire model has also been implemented by the European Union in EN 2824, EN 2825, and EN 2826 for

determination of smoke density and gas components in smoke. It is also used in ABD-0031 (Airbus) and

BSS 7239 (Boeing) for smoke in passenger aircraft.
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ISO/TR 16312-2:2021(E)
6.1.1.2 Principle

A vertically mounted specimen, 76 mm square and up to 25 mm thick, is exposed to a radiant heater

for a minimum of 10 min. Tests are conducted at 25 kW/m with and without pilot flame. The gases are

sampled through probes positioned at various positions in the smoke box depending on the standard

applied.
6.1.1.3 Fire stage(s)

The fire stage(s) according to ISO 19706 are not clearly defined and may change during the test.

6.1.1.4 Types of data

The standard procedure includes measurement of smoke obscuration and specific effluent gas

concentrations (CO , CO, HCN, HCl, HF, HBr, NO , SO ) with a large number of analytical techniques.

2 x 2

Depending on the standard applied, gas data can be provided continuously during test or at the time

when the maximum smoke concentration is reached. In the two aircraft tests, the specific optical

density of the smoke and the gas concentrations are determined at 90 s and 240 s.

6.1.1.5 Presentation of results

The specific optical density of the smoke and the combustion fire gas concentrations are compared to

specified values.
6.1.1.6 Apparatus assessment
6.1.1.6.1 Advantages

The apparatus is simple to use and widely available. The test specimen can be a reasonable

representation of a finished product.
6.1.1.6.2 Disadvantages

The combustion conditions are not well characterized as they are linked to oxygen consumption inside

the chamber. At the beginning of the test, they are well-ventilated if it is flaming but their evolution

depends on sample behaviour. Vitiation can occur and affects the yields of combustion products.

The test specimen is vertical and melting materials can flow into the trough below the specimen holder

or even onto the floor of the test chamber, thereby altering the combustion mode or even reducing the

amount of specimen destroyed.

The gases are mixed by natural convection and possible stratification can lead to non-representative

sampling of the combustion gases.
6.1.1.6.3 Repeatability and reproducibility
No data reported.
6.1.1.7 Toxicological results
6.1.1.7.1 Advantages
The initial conditions are few and well prescribed.
6.1.1.7.2 Disadvantages

Possible vitiation could lead to time dependent generation of toxicants, which are only sampled at a

specified time in some applications of the standard.
4 © ISO 2021 – All rights reserved
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ISO/TR 16312-2:2021(E)

Condensation could occur on the wall of the chamber leading to removal of some gases from the sampled

environment. The prescribed
...

RAPPORT ISO/TR
TECHNIQUE 16312-2
Deuxième édition
2021-01
Lignes directrices pour évaluer la
validité des modèles de feu physiques
pour l'obtention de données sur les
effluents du feu en vue de l'évaluation
des risques et dangers —
Partie 2:
Évaluation des différents modèles de
feu physiques
Guidance for assessing the validity of physical fire models for
obtaining fire effluent toxicity data for fire hazard and risk
assessment —
Part 2: Evaluation of individual physical fire models
Numéro de référence
ISO/TR 16312-2:2021(F)
ISO 2021
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ISO/TR 16312-2:2021(F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2021

Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette

publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique,

y compris la photocopie, ou la diffusion sur l’internet ou sur un intranet, sans autorisation écrite préalable. Une autorisation peut

être demandée à l’ISO à l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.

ISO copyright office
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Web: www.iso.org
Publié en Suisse
ii © ISO 2021 – Tous droits réservés
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ISO/TR 16312-2:2021(F)
Sommaire Page

Avant-propos ................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Domaine d’application ................................................................................................................................................................................... 1

2 Références normatives ................................................................................................................................................................................... 1

3 Termes et définitions ....................................................................................................................................................................................... 1

4 Principes généraux ............................................................................................................................................................................................ 2

4.1 Modèle de feu physique ................................................................................................................................................................... 2

4.2 Validité des modèles ........................................................................................................................................................................... 2

4.3 Éprouvettes ................................................................................................................................................................................................ 2

4.4 Conditions de combustion ............................................................................................................................................................ 2

4.5 Caractérisation d’un effluent ...................................................................................................................................................... 2

5 Portée et utilisation ........................................................................................................................................................................................... 3

6 Modèles de feu physiques ........................................................................................................................................................................... 4

6.1 Enceintes d’essai de fumée ‒ Essais de toxicité dans une enceinte fermée (international) 4

6.1.1 Enceinte d’essai de fumée NBS ............................................................................................................................ 4

6.1.2 Enceinte d’essai de fumée ISO .............................................................................................................................. 5

6.2 NES 713 (Royaume-Uni) ................................................................................................................................................................. 8

6.2.1 Application ............................................................................................................................................................................ 8

6.2.2 Principe .................................................................................................................................................................................... 8

6.2.3 Stade(s) de développement d’un feu .............................................................................................................. 9

6.2.4 Types de données ............................................................................................................................................................ 9

6.2.5 Présentation des résultats ....................................................................................................................................... 9

6.2.6 Évaluation de l’appareillage ................................................................................................................................... 9

6.2.7 Résultats toxicologiques ........................................................................................................................................... . 9

6.2.8 Divers ......................................................................................................................................................................................10

6.2.9 Validation ............................................................................................................................................................................10

6.2.10 Conclusion ..........................................................................................................................................................................10

6.3 Essais de toxicité des fumées dans des cages rotatives ....................................................................................11

6.3.1 Méthodes japonaises et coréennes ...............................................................................................................11

6.3.2 Méthode chinoise .........................................................................................................................................................14

6.4 Calorimètre à cône (international) .....................................................................................................................................16

6.4.1 Application .........................................................................................................................................................................16

6.4.2 Principe .................................................................................................................................................................................16

6.4.3 Stade(s) de développement d’un feu ...........................................................................................................17

6.4.4 Types de données .........................................................................................................................................................17

6.4.5 Présentation des résultats ....................................................................................................................................17

6.4.6 Évaluation de l’appareillage ................................................................................................................................17

6.4.7 Résultats toxicologiques .........................................................................................................................................18

6.4.8 Validation ............................................................................................................................................................................18

6.4.9 Conclusion ..........................................................................................................................................................................18

6.5 Appareillage de mesure de la propagation des flammes (International) .........................................19

6.5.1 Application .........................................................................................................................................................................19

6.5.2 Principe .................................................................................................................................................................................19

6.5.3 Stade(s) de développement d’un feu ...........................................................................................................20

6.5.4 Types de données .........................................................................................................................................................20

6.5.5 Présentation des résultats ....................................................................................................................................20

6.5.6 Évaluation de l’appareillage ................................................................................................................................20

6.5.7 Résultats toxicologiques .........................................................................................................................................21

6.5.8 Divers ......................................................................................................................................................................................21

6.5.9 Validation ............................................................................................................................................................................21

6.5.10 Conclusion ..........................................................................................................................................................................21

6.6 Méthodes de four tubulaire ......... ..............................................................................................................................................22

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ISO/TR 16312-2:2021(F)

6.6.1 Four tubulaire statique (International) ....................................................................................................22

6.6.2 Four tubulaire (Allemagne) .................................................................................................................................25

6.6.3 Four tubulaire selon l’ISO/TS 19700 (International) ...................................................................28

7 Résumé des méthodes d’essai .............................................................................................................................................................31

Annexe A (informative) Méthodes déconseillées .................................................................................................................................37

Bibliographie ...........................................................................................................................................................................................................................48

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ISO/TR 16312-2:2021(F)
Avant-propos

L’ISO (Organisation internationale de normalisation) est une fédération mondiale d’organismes

nationaux de normalisation (comités membres de l’ISO). L’élaboration des Normes internationales est

en général confiée aux comités techniques de l’ISO. Chaque comité membre intéressé par une étude

a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,

gouvernementales et non gouvernementales, en liaison avec l’ISO participent également aux travaux.

L’ISO collabore étroitement avec la Commission électrotechnique internationale (IEC) en ce qui

concerne la normalisation électrotechnique.

Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont

décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier de prendre note des différents

critères d’approbation requis pour les différents types de documents ISO. Le présent document a été

rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2 (voir www

.iso .org/ directives).

L’attention est attirée sur le fait que certains des éléments du présent document peuvent faire l’objet de

droits de propriété intellectuelle ou de droits analogues. L’ISO ne saurait être tenue pour responsable

de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant

les références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de

l’élaboration du document sont indiqués dans l’Introduction et/ou dans la liste des déclarations de

brevets reçues par l’ISO (voir www .iso .org/ brevets).

Les appellations commerciales éventuellement mentionnées dans le présent document sont données

pour information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un

engagement.

Pour une explication de la nature volontaire des normes, la signification des termes et expressions

spécifiques de l’ISO liés à l’évaluation de la conformité, ou pour toute information au sujet de l’adhésion

de l’ISO aux principes de l’Organisation mondiale du commerce (OMC) concernant les obstacles

techniques au commerce (OTC), voir www .iso .org/ avant -propos.

Le présent document a été élaboré par le comité technique ISO/TC 92, Sécurité au feu, sous-comité SC 3,

Dangers pour les personnes et l’environnement dus au feu.

Cette deuxième édition annule et remplace la première édition (ISO/TR 16312-2:2007), qui a fait l’objet

d’une révision technique.

Les principales modifications par rapport à l’édition précédente sont les suivantes:

— les modèles de feu ont été mis à jour à la suite de la publication de certaines autres normes,

notamment l’ISO/TS 19021 et l’ISO/TS 5660-5;
— les méthodes dépreciées ont été déplacées dans l’Annexe A.

Une liste de toutes les parties de la série ISO 16312 se trouve sur le site web de l’ISO.

Il convient que l’utilisateur adresse tout retour d’information ou toute question concernant le présent

document à l’organisme national de normalisation de son pays. Une liste exhaustive desdits organismes

se trouve à l’adresse www .iso .org/ fr/ members .html.
© ISO 2021 – Tous droits réservés v
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ISO/TR 16312-2:2021(F)
Introduction

Assurer le degré souhaité de sécurité des personnes pour une occupation implique de plus en plus une

évaluation explicite des risques ou dangers du feu. Cette évaluation comprend des éléments tels que

des informations sur les propriétés d’une pièce/d’un bâtiment, la nature de l’occupation, la nature des

occupants, les types de feux potentiels, les résultats à éviter, etc.

Ce type de détermination exige également des informations sur les dommages potentiels aux personnes

en raison des effluents produits lors de l’incendie. Au vu du coût prohibitif des essais de produits en

grandeur réelle dans le large éventail de conditions d’incendie, la plupart des estimations des dommages

potentiels des effluents du feu reposent sur les données générées à partir d’un modèle de feu physique,

d’un appareillage d’essai à échelle réduite et du mode opératoire.

Le rôle d’un modèle de feu physique pour générer une composition précise d’effluents toxiques est de

simuler les caractéristiques essentielles de l’environnement chimique thermique et réactif complexe

lors de feux en grandeur réelle. Ces environnements varient selon les caractéristiques physiques du

scénario d’incendie et avec le temps au cours de l’incendie. Par conséquent, une représentation précise de

certains phénomènes se produisant lors de feux en grandeur réelle peut être difficile, voire impossible,

à petite échelle. La précision du modèle de feu physique dépend donc de deux caractéristiques:

a) la mesure dans laquelle les conditions de combustion dans l’appareillage d’essai au banc reflètent

celles du stade de développement d’un feu simulé;

b) la mesure dans laquelle les taux de production des principaux produits de combustion obtenus

à partir de la combustion du produit commercial à pleine échelle correspondent aux taux de

production découlant des éprouvettes en combustion du produit dans le modèle à petite échelle.

Cette mesure est généralement effectuée pour un petit ensemble de produits et la précision

obtenue est alors supposée s’étendre à d’autres sujets d’essai. Depuis la publication de la première

édition du présent document, dans laquelle une méthodologie de comparaison a été citée dans la

Référence [1], l’ISO 29903-1 a été élaborée.

Le présent document fournit un ensemble de critères techniques pour évaluer les modèles de feu

physiques utilisés pour obtenir des données sur la composition et le potentiel toxique des effluents

de produits et matériaux dans des conditions d’incendie pertinentes pour la sécurité des personnes.

Le présent document couvre l’application, par des experts, de ces critères aux méthodes d’essai

actuellement utilisées pour générer des données sur les effluents de fumée des matériaux et des

produits commerciaux en combustion.

Dix modèles de feu physiques sont abordés dans le présent document, ainsi que 4 méthodes dépréciées

en Annexe A. Des appareillages supplémentaires peuvent être ajoutés à mesure qu’ils seront développés

ou adaptés dans le but de générer des informations concernant le potentiel toxique de la fumée.

Plusieurs des modèles présentés dans le présent document sont des systèmes fermés. Aucun air

extérieur n’y est introduit et les produits de combustion (ou de pyrolyse) restent à l’intérieur de

l’appareillage, à l’exception de la fraction éliminée pour l’analyse chimique. Les sept restants sont des

appareillages ouverts, dans lesquels de l’air circule continuellement après l’échantillon en combustion

et sort de l’appareillage avec les produits de combustion.

Les documents de référence utiles pour les discussions sur les méthodes d’analyse, les modes

opératoires d’essai biologique et la prévision des effets toxiques des effluents du feu sont énumérés

dans la bibliographie fournie à la fin du présent document.
vi © ISO 2021 – Tous droits réservés
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RAPPORT TECHNIQUE ISO/TR 16312-2:2021(F)
Lignes directrices pour évaluer la validité des modèles de
feu physiques pour l'obtention de données sur les effluents
du feu en vue de l'évaluation des risques et dangers —
Partie 2:
Évaluation des différents modèles de feu physiques
1 Domaine d’application

Le présent document évalue l’utilité des modèles de feu physiques qui ont été normalisés, sont

couramment utilisés et/ou sont cités dans des normes nationales ou internationales, pour la génération

de données sur la toxicité des effluents du feu dont la précision est connue. Pour ce faire, les critères

établis dans l’ISO 16312-1 et les lignes directrices établies dans l’ISO 19706 sont utilisés. Les aspects

des modèles pris en compte sont: l’application prévue du modèle, les principes de combustion qu’il

manifeste, le ou les stades de développement d’un feu que le modèle tente de reproduire, les types de

données générées, la nature et l’adéquation des conditions de combustion auxquelles les éprouvettes

sont exposées, et le degré de validité établi pour le modèle.
2 Références normatives

Les documents suivants sont cités dans le texte de sorte qu’ils constituent, pour tout ou partie de leur

contenu, des exigences du présent document. Pour les références datées, seule l’édition citée s’applique.

Pour les références non datées, la dernière édition du document de référence s’applique (y compris les

éventuels amendements).
ISO 13943, Sécurité au feu — Vocabulaire

ISO 19703, Production et analyse des gaz toxiques dans le feu — Calcul des taux de production des espèces,

des rapports d'équivalence et de l'efficacité de combustion dans les feux expérimentaux

3 Termes et définitions

Pour les besoins du présent document, les termes et définitions de l'ISO 13943 et l'ISO 19703 ainsi que

les suivants s’appliquent.

L’ISO et l’IEC tiennent à jour des bases de données terminologiques destinées à être utilisées en

normalisation, consultables aux adresses suivantes:

— ISO Online browsing platform: disponible à l’adresse https:// www .iso .org/ obp

— IEC Electropedia: disponible à l’adresse http:// www .electropedia .org/
3.1
viciation contrôlée
contrôlé par viciation

type de conditions dans lesquelles la concentration en volume d’oxygène est volontairement contrôlée

ou réduite dans l’environnement de combustion

Note 1 à l'article: Les conditions de viciation contrôlée représentent un environnement au feu appauvri en

oxygène.
[SOURCE: ISO/TS 5660-5:2020, 3.3, modifiée.]
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ISO/TR 16312-2:2021(F)
3.2
ventilation contrôlée
contrôlé par ventilation

type de conditions dans lesquelles le débit d’alimentation en air (ambiant ou vicié) de l’environnement

de combustion est volontairement contrôlé ou limité

Note 1 à l'article: Les conditions de ventilation contrôlée représentent un environnement au feu avec une

alimentation en air frais limitée.
[SOURCE: ISO/TS 5660-5:2020, 3.4, modifiée.]
4 Principes généraux
4.1 Modèle de feu physique

Un modèle de feu physique est caractérisé par les exigences imposées en termes de forme de l’éprouvette,

de conditions opérationnelles de combustion et de capacité d’analyse des produits de combustion.

4.2 Validité des modèles

Utilisée pour fournir des données dans le cadre de l’évaluation de la toxicité des effluents, la validité

d’un modèle de feu physique est déterminée par le degré de précision avec lequel il reproduit les taux de

production des principaux composants toxiques lors des feux en grandeur réelle.

L’ISO 12828-1, l’ISO 12828-2 et l’ISO/TS 12828-3 sont des documents d’orientation pour la validité des

modèles. Cela comprend les limites de détection et de quantification, la plage d’application, la justesse

et la fidélité en termes de répétabilité et de reproductibilité.
4.3 Éprouvettes

L’ingénierie de la sécurité incendie exige des données sur les produits commerciaux ou les composants

des produits. Dans un essai à échelle réduite, la composition d’une éprouvette du produit peut affecter

la nature et les taux de production des produits de combustion. C’est notamment le cas des produits de

composition non uniforme, tels que ceux constitués de matériaux stratifiés.
4.4 Conditions de combustion

Les taux de production de produits de combustion dépendent des conditions de l’appareillage, telles que

le rapport d’équivalence combustible/air, si la décomposition se produit avec flammes ou sans flammes,

la persistance de flammes sur l’échantillon, la température de l’éprouvette et les effluents produits,

le rayonnement thermique appliqué à l’éprouvette, la stabilité des conditions de décomposition et

l’interaction de l’appareillage avec le processus de décomposition, les effluents et les flammes.

Les conditions de pyrolyse et de combustion peuvent différer localement et globalement dans un

modèle de feu physique, ce qui entraîne des difficultés d’échelle avec des conditions réelles de feu dans

des expériences réduites.

Les conditions expérimentales peuvent être contrôlées par viciation et/ou par ventilation, ou peuvent

être inconnues et varier au cours de l’essai.

Il est essentiel que le modèle de feu physique permette des déterminations précises de la composition

chimique d’effluents. La validation de la méthode conformément à l’ISO 12828-2 est une manière

appropriée de valider l’analyse chimique.
4.5 Caractérisation d’un effluent

Pour les effluents des matériaux les plus courants, il a été démontré que les principaux effets

toxiques aigus dépendent d’un petit nombre de gaz asphyxiants majeurs et d’un éventail un peu plus

2 © ISO 2021 – Tous droits réservés
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ISO/TR 16312-2:2021(F)

large d’irritants organiques et inorganiques. Dans l’ISO 13571, un ensemble de base de produits de

combustion a été identifié pour une analyse de routine. Des matériaux nouveaux peuvent faire évoluer

les produits toxiques non identifiés auparavant. Ainsi, une analyse chimique plus détaillée peut être

nécessaire pour fournir une évaluation complète des effets aigus et pour évaluer les toxiques chroniques

ou environnementaux.

Un essai biologique peut fournir des recommandations sur l’importance des toxiques non inclus dans

l’ensemble de base. L’ISO 19706 contient une discussion plus complète sur l’utilité de l’intégration

des essais. Il est souhaitable que le modèle de feu physique intègre une méthode d’essai biologique.

Cependant, en raison des pratiques de bioéthique, ces types d’utilisation et de comparaisons sont

limités. L’utilisation d’animaux de laboratoire comme sujets d’essai ou comme tissus vivants permet de

garantir l’inclusion de l’impact de tous les gaz de combustion. Cependant, il est reconnu que l’adoption

et l’utilisation de tels protocoles peuvent être interdites dans certaines juridictions et tendent à

disparaître. Un protocole sans animaux peut capturer les effets des gaz de combustion connus, mais

peut passer à côté de l’impact d’une espèce inattendue ou peu commune et hautement toxique. Pourtant

ce sont les composants de la fumée générée par cette espèce qui ont le plus besoin d’être identifiés.

5 Portée et utilisation

La plupart des modèles mathématiques d’évaluation des dangers et risques du feu exigent des

informations sur les dommages potentiels que les effluents du feu (gaz, chaleur et fumée) peuvent

causer aux victimes et le potentiel de ces effluents à affecter la capacité des victimes à s’échapper ou se

mettre à l’abri.

La qualité des données sur les effluents du feu a un effet profond sur la précision de la prédiction

du degré de sécurité des personnes offerte par une conception d’occupation. L’incertitude dans ces

prévisions conduit généralement à l’utilisation de facteurs de sécurité qui peuvent compromettre la

fonctionnalité et accroître les coûts.

L’ingénierie de la sécurité incendie exige des données sur les produits commerciaux. Les essais en

grandeur réelle effectués sur ces produits fournissent généralement des données précises sur les

effluents du feu. Cependant, en raison du grand nombre de produits disponibles, du coût élevé des

essais de produits en grandeur réelle et du nombre limité d’installations d’essai à grande échelle, les

informations sur la toxicité des effluents sont le plus souvent tirées de modèles de feu physiques.

De nombreux modèles de feu physiques sont cités dans les réglementations nationales. Ces modèles

varient en termes de conception et de fonctionnement, mais aussi de degré de caractérisation. Les

évaluations de ces modèles présentées dans le présent document fournissent aux fabricants de produits,

aux organismes de réglementation et aux professionnels de la sécurité incendie un aperçu des sources

appropriées et inappropriées de données sur les effluents du feu aux fins définies.

Les évaluations des modèles de feu physiques présentées dans le présent document ne traitent pas

des moyens de combiner les taux de production des composants d’effluents pour estimer les effets

sur les animaux de laboratoire (voir ISO 13344) ou pour extrapoler les résultats des essais à l’homme

(voir ISO 13571).

Les méthodes qui n’incluent pas d’exposition animale et ne se prêtent pas à une telle adaptation

pourraient ne pas permettre l’identification d’une toxicité extrême et/ou inhabituelle.

Il est à noter que quatre méthodes dépreciées sont détaillées en Annexe A.
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ISO/TR 16312-2:2021(F)
6 Modèles de feu physiques
6.1 Enceintes d’essai de fumée ‒ Essais de toxicité dans une enceinte fermée
(international)
6.1.1 Enceinte d’essai de fumée NBS
6.1.1.1 Application

Ce modèle de feu physique est décrit dans l’ASTM E662, avec un échantillon orienté verticalement et

un éclairement énergétique limité à 25 kW/m . Il a initialement été conçu pour générer des données

sur la densité optique de la fumée. Le modèle de feu physique a également été mis en œuvre par l’Union

européenne dans les EN 2824, EN 2825, et EN 2826 pour la détermination de la densité de fumée et des

composants des gaz de fumée. Il est également utilisé dans l’ABD-0031 (Airbus) et la BSS 7239 (Boeing)

pour la fumée dans les avions de ligne.
6.1.1.2 Principe

Une éprouvette carrée de 76 mm, montée verticalement, et pouvant atteindre 25 mm d’épaisseur, est

exposée à un élément chauffant radiant pendant au moins 10 min. Les essais sont
...

TECHNICAL ISO/TR
REPORT 16312-2
Second edition
Guidance for assessing the validity of
physical fire models for obtaining fire
effluent toxicity data for fire hazard
and risk assessment —
Part 2:
Evaluation of individual physical fire
models
Recommandations pour évaluer la validité des modèles de feu
physiques pour l'obtention de données relatives à la toxicité des
effluents du feu en vue de l'évaluation des risques et dangers
d'incendie —
Partie 2: Evaluation des différents modèles de feu physiques
PROOF/ÉPREUVE
Reference number
ISO/TR 16312-2:2020(E)
ISO 2020
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ISO/TR 16312-2:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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 the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
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ISO/TR 16312-2:2020(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 General principles ............................................................................................................................................................................................... 2

4.1 Physical fire model............................................................................................................................................................................... 2

4.2 Model validity .......................................................................................................................................................................................... 2

4.3 Test specimens ........................................................................................................................................................................................ 2

4.4 Combustion conditions .................................................................................................................................................................... 2

4.5 Effluent characterization ................................................................................................................................................................ 2

5 Significance and use .......................................................................................................................................................................................... 3

6 Physical fire models .......................................................................................................................................................................................... 3

6.1 Smoke chambers - Closed cabinet toxicity tests (international) ................................................................. 3

6.1.1 NBS smoke chamber ..................................................................................................................................................... 3

6.1.2 ISO smoke chamber ....................................................................................................................................................... 5

6.2 NES 713 (United Kingdom) .......................................................................................................................................................... 7

6.2.1 Application ............................................................................................................................................................................ 7

6.2.2 Principle .................................................................................................................................................................................. 7

6.2.3 Fire stage(s) ......................................................................................................................................................................... 8

6.2.4 Types of data ....................................................................................................................................................................... 8

6.2.5 Presentation of results ................................................................................................................................................ 8

6.2.6 Apparatus assessment ................................................................................................................................................ 8

6.2.7 Toxicological results .................. ......................................................................................................................... ........... 8

6.2.8 Miscellaneous ..................................................................................................................................................................... 9

6.2.9 Validation ............................................................................................................................................................................... 9

6.2.10 Conclusion ............................................................................................................................................................................. 9

6.3 Rotative cages smoke toxicity tests ....................................................................................................................................10

6.3.1 Japanese and Korean methods..........................................................................................................................10

6.3.2 Chinese method .............................................................................................................................................................12

6.4 Cone calorimeter (international) .........................................................................................................................................14

6.4.1 Application .........................................................................................................................................................................14

6.4.2 Principle ...............................................................................................................................................................................15

6.4.3 Fire stage(s) ......................................................................................................................................................................15

6.4.4 Types of data ....................................................................................................................................................................15

6.4.5 Presentation of results .............................................................................................................................................15

6.4.6 Apparatus assessment .............................................................................................................................................15

6.4.7 Toxicological results .................. ......................................................................................................................... ........16

6.4.8 Validation ............................................................................................................................................................................16

6.4.9 Conclusion ..........................................................................................................................................................................16

6.5 Flame propagation apparatus (International) .........................................................................................................17

6.5.1 Application .........................................................................................................................................................................17

6.5.2 Principle ...............................................................................................................................................................................17

6.5.3 Fire stage(s) ......................................................................................................................................................................18

6.5.4 Types of data ....................................................................................................................................................................18

6.5.5 Presentation of results .............................................................................................................................................18

6.5.6 Apparatus assessment .............................................................................................................................................18

6.5.7 Toxicological results .................. ......................................................................................................................... ........18

6.5.8 Miscellaneous ..................................................................................................................................................................19

6.5.9 Validation ............................................................................................................................................................................19

6.5.10 Conclusion ..........................................................................................................................................................................19

6.6 Tube furnace methods ...................................................................................................................................................................20

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ISO/TR 16312-2:2020(E)

6.6.1 Static tube furnace (International) ...............................................................................................................20

6.6.2 Tube furnace (Germany) ........................................................................................................................................23

6.6.3 ISO/TS 19700 Tube furnace (International) ........................................................................................25

7 Summary of test methods ........................................................................................................................................................................28

Annex A InformativeDeprecated methods ..................................................................................................................................................32

Bibliography .............................................................................................................................................................................................................................42

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ISO/TR 16312-2:2020(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 of 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 www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 3, Fire

threat to people and environment.

This second edition cancels and replaces the first edition (ISO/TR 16312-2:2007) which has been

technically revised.
The main changes compared to the previous edition are as follows:

— fire models have been updated following the publication of certain other standards, including

ISO/TS 19021 and ISO/TS 5660-5;
— depreciated methods have been moved to Annex A.
A list of all parts in the ISO 16312 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO 2020 – All rights reserved PROOF/ÉPREUVE v
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ISO/TR 16312-2:2020(E)
Introduction

Providing the desired degree of life safety for an occupancy increasingly involves an explicit fire hazard

or risk assessment. This assessment includes such components as information on the room/building

properties, the nature of the occupancy, the nature of the occupants, the types of potential fires, the

outcomes to be avoided, etc.

This type of determination also requires information on the potential for harm to people due to the

effluent produced in the fire. Because of the prohibitive cost of real-scale product testing under the

wide range of fire conditions, most estimates of the potential harm from the fire effluent depend on

data generated from a physical fire model, a reduced-scale test apparatus and procedure for its use.

The role of a physical fire model for generating accurate toxic effluent composition is to simulate the

essential features of the complex thermal and reactive chemical environment in full-scale fires. These

environments vary with the physical characteristics of the fire scenario and with time during the

course of the fire, and close representation of some phenomena occurring in full-scale fires can be

difficult or even not possible on a small scale. The accuracy of the physical fire model, then, depends on

two features:

a) the degree to which the combustion conditions in the bench-scale apparatus mirror those in the

fire stage being simulated;

b) the degree to which the yields of the important combustion products obtained from the burning

of the commercial product at full scale are matched by the yields from burning specimens of the

product in the small-scale model. This measure is generally performed for a small set of products,

and the derived accuracy is then presumed to extend to other test subjects. Since the publication of

the first edition of this document, in which a methodology for effecting this comparison was cited

in Reference [1], ISO 29903-1 has been developed.

This document provides a set of technical criteria for evaluating physical fire models used to obtain

composition and toxic potency data on the effluent from products and materials under fire conditions

relevant to life safety. This document covers the application by experts of these criteria to currently

used test methods that are used for generating data on smoke effluent from burning materials and

commercial products.

There are 10 physical fire models discussed in this document, plus 4 depreciated methods in Annex A.

Additional apparatus can be added as they are developed or adapted with the intent of generating

information regarding the toxic potency of smoke.

For all models in this document, several are closed systems. In these, no external air is introduced and

the combustion (or pyrolysis) products remain within the apparatus except for the fraction removed

for chemical analysis. The second seven are open apparatus, with air continuously flowing past the

combusting sample and exiting the apparatus, along with the combustion products.

Reference documents useful for discussions of analytical methods, bioassay procedures, and prediction

of the toxic effects of fire effluents are listed in the Bibliography at the end of this document.

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TECHNICAL REPORT ISO/TR 16312-2:2020(E)
Guidance for assessing the validity of physical fire models
for obtaining fire effluent toxicity data for fire hazard and
risk assessment —
Part 2:
Evaluation of individual physical fire models
1 Scope

This document assesses the utility of physical fire models that have been standardized, are commonly

used, and/or are cited in national or international standards, for generating fire effluent toxicity data

of known accuracy. This is achieved by using the criteria established in ISO 16312-1 and the guidelines

established in ISO 19706. The aspects of the models that are considered are: the intended application of

the model, the combustion principles it manifests, the fire stage(s) that the model attempts to replicate,

the types of data generated, the nature and appropriateness of the combustion conditions to which test

specimens are exposed, and the degree of validity established for the model.
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.

ISO 13943, Fire safety — Vocabulary

ISO 19703, Generation and analysis of toxic gases in fire — Calculation of species yields, equivalence ratios

and combustion efficiency in experimental fires
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 13943 and ISO 19703 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
vitiation-controlled

type of conditions under which the volume concentration of oxygen is intentionally controlled or

reduced in the combustion environment

Note 1 to entry: Note to entry 1: Vitiation controlled conditions represent an oxygen depleted fire environment.

[SOURCE: ISO/TS 5660-5:2020, 3.3, modified.]
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ISO/TR 16312-2:2020(E)
3.2
ventilation-controlled

type of conditions un which the supply rate of (ambient or vitiated) air to the combustion environment

is intentionally controlled or limited

Note 1 to entry: Ventilation-controlled conditions represent a fire environment with limited fresh air supply.

[SOURCE: ISO/TS 5660-5:2020, 3.4, modified.]
4 General principles
4.1 Physical fire model

A physical fire model is characterized by the requirements placed on the form of the test specimen, the

operational combustion conditions and the capability of analysing the products of combustion.

4.2 Model validity

For use in providing data for effluent toxicity assessment, the validity of a physical fire model is

determined by the degree of accuracy with which it reproduces the yields of the principal toxic

components in real-scale fires.

ISO 12828-1, ISO 12828-2 and ISO/TS 12828-3 are guidance documents for model validity. This

includes limits of detection and quantification, range of application, trueness and fidelity in terms of

repeatability and reproducibility.
4.3 Test specimens

Fire safety engineering requires data on commercial products or product components. In a reduced-

scale test, the manner in which a specimen of the product is composed can affect the nature and yields

of the combustion products. This is especially the case for products of non-uniform composition, such

as those consisting of layered materials.
4.4 Combustion conditions

The yields of combustion products depend on such apparatus conditions as the fuel/air equivalence

ratio, whether the decomposition is flaming or non-flaming, the persistence of flaming of the sample,

the temperature of the specimen and the effluent produced, the thermal radiation incident on the

specimen, the stability of the decomposition conditions and the interaction of the apparatus with the

decomposition process, with the effluent and the flames.

The conditions of pyrolysis and combustion may differ locally and globally in a physical fire model,

leading to difficulties in scale with real-fire conditions in reduced experiments.

The experimental conditions may be vitiation-controlled and/or ventilation-controlled, or may be

unknown and vary during the test.

It is essential that the physical fire model enable accurate determinations of chemical effluent

composition. Validation of the method according to ISO 12828-2 is a suitable way to validate the

chemical analysis.
4.5 Effluent characterization

For the effluent from most common materials, the major acute toxic effects have been shown to depend

upon a small number of major asphyxiant gases and a somewhat wider range of inorganic and organic

irritants. In ISO 13571, a base set of combustion products has been identified for routine analysis.

Novel materials may evolve previously unidentified toxic products. Thus, a more detailed chemical

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ISO/TR 16312-2:2020(E)

analysis may be needed in order to provide a full assessment of acute effects and to assess chronic or

environmental toxicants.

A bioassay can provide guidance on the importance of toxicants not included in the base set. ISO 19706

contains a fuller discussion of the utility of integrating assays. It is desirable that the physical fire

model accommodate a bioassay method. However, due to bioethics practices, such use and comparisons

are limited. The use of laboratory animals as test subjects or living tissues are means of insuring

inclusion of the impact of all combustion gases. However, it is recognized that the adoption and use of

such protocols may be prohibited in some jurisdictions and tend to disappear. An animal-free protocol

can capture the effects of known combustion gases, but can miss the impact of any unexpected or

uncommon and highly toxic species, the smoke components of which are most in need of identification.

5 Significance and use

Most computational models of fire hazard and risk require information regarding the potential of

fire effluent (gases, heat and smoke) to cause harm to people and to affect their ability to escape or to

seek refuge.

The quality of the data on fire effluent has a profound effect on the accuracy of the prediction of the

degree of life safety offered by an occupancy design. Uncertainty in such predictions commonly leads to

the use of safety factors that can compromise functionality and increase cost.

Fire safety engineering requires data on commercial products. Real-scale tests of such products

generally provide accurate fire effluent data. However, due to the large number of available products,

the high cost of performing real-scale tests of products and the small number of large-scale test

facilities, information on effluent toxicity is most often obtained from physical fire models.

There are numerous physical fire models cited in national regulations. These models vary in design

and operation, as well as in their degree of characterization. The assessments of these models in this

document provide product manufacturers, regulators and fire safety professionals with insight into

appropriate and inappropriate sources of fire effluent data for their defined purposes.

The assessments of physical fire models in this document do not address means for combining

the effluent component yields to estimate the effects on laboratory animals (see ISO 13344) or for

extrapolating the test results to people (see ISO 13571).

The methods that do not include animal exposure and are not amenable to such an adaptation might

not allow identification of extreme and/or unusual toxicity.
Note that four depreciated methods are detailed in Annex A.
6 Physical fire models
6.1 Smoke chambers - Closed cabinet toxicity tests (international)
6.1.1 NBS smoke chamber
6.1.1.1 Application

This physical fire model is described in ASTM E662, with a vertically-orientated sample and heat

flux limited to 25 kW/m . It was first designed to generate smoke optical density data. The physical

fire model has also been implemented by the European Union in EN 2824, EN 2825, and EN 2826 for

determination of smoke density and gas components in smoke. It is also used in ABD-0031 (Airbus) and

BSS 7239 (Boeing) for smoke in passenger aircraft.
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ISO/TR 16312-2:2020(E)
6.1.1.2 Principle

A vertically mounted specimen, 76 mm square and up to 25 mm thick, is exposed to a radiant heater

for a minimum of 10 min. Tests are conducted at 25 kW/m with and without pilot flame. The gases are

sampled through probes positioned at various positions in the smoke box depending on the standard

applied.
6.1.1.3 Fire stage(s)

The fire stage(s) according to ISO 19706 are not clearly defined and may change during the test.

6.1.1.4 Types of data

The standard procedure includes measurement of smoke obscuration and specific effluent gas

concentrations (CO , CO, HCN, HCl, HF, HBr, NO , SO ) with a large number of analytical techniques.

2 x 2

Depending on the standard applied, gas data can be provided continuously during test or at the time

when the maximum smoke concentration is reached. In the two aircraft tests, the specific optical

density of the smoke and the gas concentrations are determined at 90 s and 240 s.

6.1.1.5 Presentation of results

The specific optical density of the smoke and the combustion fire gas concentrations are compared to

specified values.
6.1.1.6 Apparatus assessment
6.1.1.6.1 Advantages

The apparatus is simple to use and widely available. The test specimen can be a reasonable

representation of a finished product.
6.1.1.6.2 Disadvantages

The combustion conditions are not well characterized as they are linked to oxygen consumption inside

the chamber. At the beginning of the test, they are well-ventilated if it is flaming but their evolution

depends on sample behaviour. Vitiation can occur and affects the yields of combustion products.

The test specimen is vertical and melting materials can flow into the trough below the specimen holder

or even onto the floor of the test chamber, thereby altering the combustion mode or even reducing the

amount of specimen destroyed.

The gases are mixed by natural convection and possible stratification can lead to non-representative

sampling of the combustion gases.
6.1.1.6.3 Repeatability and reproducibility
No data reported.
6.1.1.7 Toxicological results
6.1.1.7.1 Advantages
The initial conditions are few and well prescribed.
6.1.1.7.2 Disadvantages

Possible vitiation could lead to time dependent generation of toxicants, which are only sampled at a

specified time in some applications of the standard.
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