ISO 16312-1:2006
(Main)Guidance for assessing the validity of physical fire models for obtaining fire effluent toxicity data for fire hazard and risk assessment — Part 1: Criteria
Guidance for assessing the validity of physical fire models for obtaining fire effluent toxicity data for fire hazard and risk assessment — Part 1: Criteria
ISO 16312-1:2006 provides technical criteria and guidance for evaluating physical fire models (i.e. laboratory combustion devices and operating protocols) used in effluent toxicity studies for obtaining data on the effluent from products and materials under fire conditions relevant to life safety. Relevant analytical methods, calculation methods, bioassay procedures and prediction of the toxic effects of fire effluents can be referenced in ISO 19701, ISO 19702, ISO 19703, ISO 19706, ISO 13344, and ISO/TS 13571.
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 1: Critères
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 16312-1
First edition
2006-04-01
Guidance for assessing the validity of
physical fire models for obtaining fire
effluent toxicity data for fire hazard and
risk assessment —
Part 1:
Criteria
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 1: Critères
Reference number
ISO 16312-1:2006(E)
©
ISO 2006
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ISO 16312-1:2006(E)
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ISO 16312-1:2006(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 General principles. 2
5 Significance and use . 3
6 The ideal fire effluent toxicity test method . 3
7 Characteristics of fire stages . 4
8 Characterization of physical fire models . 5
9 Physical fire model accuracy . 7
Annex A (informative) Characteristics affecting combustion product yields. 9
Bibliography . 11
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ISO 16312-1:2006(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.
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 16312-1 was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 3, Fire threat
to people and environment.
This first edition of ISO 16312-1 cancels and replaces the first edition of the Technical Specification
(ISO/TS 16312-1:2004), with which it is technically identical, except that ISO/TS 13571:2002 is now listed as a
Normative reference and the bibliographic references have been updated.
ISO 16312 consists of the following parts, under the general title Guidance for assessing the validity of
physical fire models for obtaining fire effluent toxicity data for fire hazard and risk assessment:
⎯ Part 1: Criteria
A part 2 on the evaluation of individual physical fire models is under preparation.
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ISO 16312-1:2006(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 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 recreate 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 at the
small-scale. The accuracy of the physical fire model, then, depends on two features:
a) degree to which the combustion conditions in the bench-scale apparatus mirror those in the fire stage
being replicated;
b) degree to which the yields of the important combustion products obtained from burning of the commercial
product at full scale are replicated 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. At least one methodology for effecting this comparison has
[1]
been developed .
This part of ISO 16312 provides guidance for accuracy assessment with and without the use of laboratory
animals. Generally, accurate estimation of the toxic potency of the effluent can be obtained from analysis of a
small number of gases (the N-gas hypothesis), as described in ISO/TS 13571. This is especially true for
product formulations similar to those for which the N-gas model has been confirmed. There are, however,
cases where unusual toxicants have been generated in bench-scale apparatus. Thus, for novel commercial
product formulations, confidence in the accuracy of the toxic potency measurement in the bench-scale device
can be improved by a confirming bioassay and correlation with real-scale fire tests.
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INTERNATIONAL STANDARD ISO 16312-1:2006(E)
Guidance for assessing the validity of physical fire models for
obtaining fire effluent toxicity data for fire hazard and risk
assessment —
Part 1:
Criteria
1 Scope
This part of ISO 16312 provides technical criteria and guidance for evaluating physical fire models (i.e.
laboratory combustion devices and operating protocols) used in effluent toxicity studies for obtaining data on
[2]
the effluent from products and materials under fire conditions relevant to life safety . Relevant analytical
methods, calculation methods, bioassay procedures and prediction of the toxic effects of fire effluents can be
[3] [4] [5] [6] [7]
referenced in ISO 19701 , ISO 19702 , ISO 19703 , ISO 19706 , ISO 13344 , and ISO/TS 13571.
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/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
EC
50
concentration of a toxic gas or fire effluent statistically calculated from concentration-response data to produce
an effect in 50 % of test animals within a specified exposure and post-exposure time
3.2
fuel/air equivalence ratio
φ
ratio of the fuel concentration to oxygen concentration in the fire zone divided by the stoichiometric
fuel-to-oxygen ratio for the fuel
NOTE For φ < 1, as in small or well-ventilated fires, the fuel/air mixture is said to be fuel lean; complete combustion
(e.g. to CO and H O) will dominate. For φ = 1, the mixture is stoichiometric. For φ > 1, as in ventilation-controlled fires, the
2 2
mixture is fuel rich; relatively high concentrations of pyrolysis and incomplete combustion gases results.
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ISO 16312-1:2006(E)
3.3
global equivalence ratio
〈compartment fire tests〉 ratio of the mass lost from the combustible(s) divided by the mass of air introduced
into the compartment, normalized by the stoichiometric fuel/air ratio
NOTE Either global equivalence ratio (3.3 or 3.4) can be determined continuously or as a test average, depending on
the instrumentation in place.
3.4
global equivalence ratio
〈bench-scale devices〉 ratio of the mass lost from the test specimen divided by the mass of air in the system
(closed systems) or introduced into the system (open systems) normalized by the stoichiometric fuel/air ratio
NOTE Either global equivalence ratio (3.3 or 3.4) can be determined continuously or as a test average, depending on
the instrumentation in place.
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.
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.
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 stability of the decomposition conditions, and the
interaction of the apparatus with the decomposition process, with the effluent and the flames.
4.5 Effluent characterization
4.5.1 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/TS 13571, a base set of combustion products has been identified for routine analysis.
Novel materials can evolve previously unidentified toxic products. Thus a more detailed chemical analysis can
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.
[6]
ISO 19706 contains a fuller discussion of the utility of bioassays.
4.5.2 It is essential that the physical fire model enable accurate determinations of chemical effluent
composition.
4.5.3 It is desirable that the physical fire model accommodate a bioassay method.
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ISO 16312-1:2006(E)
5 Significance and use
5.1 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.
5.2 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.
5.3 Due to the large number of products to be included in fire safety assessments, 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.
5.4 There are numerous physical fire models cited in national regulations. These apparatus vary in design
and operation, as well as in their degree of characterization. This part of ISO 16312 defines what apparatus
characteristics should define a physical fire model, identifies the data appropriate for assessing the validity of
a physical fire model and provides technical criteria for evaluating them with regard to the accuracy of their
data relevant to life safety.
5.5 This part of ISO 16312 does not address means for combining the effluent component yields to
[7]
estimate the effects on laboratory animals (see ISO 13344 ) or for extrapolating the test results to people
(see ISO/TS 13571).
6 The ideal fire effluent toxicity test method
6.1 Fire stages
6.1.1 The combustion and/or pyrolysis conditions in the combustor section of the apparatus reproduce the
conditions in one or more stages of actual fires, including incipient, growing and fully developed fires.
6.1.2 Specimens are burned under constant, pre-selected conditions of thermal insult and oxygen
availability (ventilation). The decomposition conditions and decomposition behaviour of the specimen enable
yields to be characterized for specific condition parameters.
6.1.3 For initial and progressive smouldering, the effects of specimen bulk and thermal properties are
considered.
6.1.4 For growth and early fire simulations, including oxidative pyrolysis and well ventilated flaming, the
in-use exposed surface of a material or product is exposed to the appropriate thermal insult.
6.1.5 For simulation of the developed stages of a fire, full burning of the test specimen is required.
6.2 Applicability
This method tests homogeneous materials (both solid and cellular) and commercial products (especially
layered, non-uniform specimens), both melting and non-melting, in relevant form and under simulated fire
scenarios. The nature and quantity of the decomposition products are representative of actual fire scenarios.
6.3 Apparatus independence
The apparatus does not impose any significant influence on the results, i.e. the results reflect the burning
behaviour of the test specimen and not apparatus effects. Flame quenching on surfaces should not affect the
nature of the effluent and the effluent should not be subject to ageing effects. The combustion zone and
effluent plume treatment are designed to ensure that these are achieved.
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ISO 16312-1:2006(E)
6.4 Operational efficiency
The test equipment is as simple as possible and capable of safe operation.
6.5 Data generated
6.5.1 The method produces direct measurements of the yields of toxic gases and smoke and/or
measurements of the mass concentration of gases and smoke over time, from which the yields may be
calculated. The gases include those expected to contribute to the toxic potency of fire effluent: CO , CO, HCN,
2
HCl, HBr, HF, NO, NO , SO , acrolein and formaldehyde.
2 2
NOTE The relative importance of the various gases can depend on the harmful effect being considered.
6.5.2 The method produces a measurement of the mass of the test specimen. Preferably, this is obtained
throughout the test to determine whether the yields of the combustion products are changing as the
combustion proceeds. A determination of the final mass allows for the calculation of average yields over the
duration of the test.
6.5.3 The physical fire model is compatible with the use of bioassay methods.
6.6 Accuracy
Sufficient test data and especially gas yield data from the physical fire model have been validated against full
scale and/or real scale fire scenarios. The fire stages for which agreement is achieved and the degree of
agreement are included in Annex A. The test conditions required to achieve that agreement with the specified
fire stages are given.
6.7 Repeatability and reproducibility
Repeatability and reproducibility of data and limits of accuracy have been established by inter-laboratory trial
and are incorporated as part of the standard method.
7 Characteristics of fire stages
7.1 The stages of fire are characterized in ISO/TS 19706.
7.2 The environmental conditions that characterize the stages of a fire and in a physical fire model are
⎯ ambient temperature;
⎯ temperature at the combustion site (for non-radiation-controlled burning);
⎯ heat flux to the fuel surface (for radiation-controlled burning);
⎯ surface temperature of the test specimen;
⎯ mass loss rate;
⎯ oxygen concentration at the fuel surface and around the flame;
⎯ availability of fresh oxygen to replenish that depleted by combustion (ventilation rate and mixing).
7.2.1 The last three of these parameters are captured in the fuel/air equivalence ratio.
7.2.2 Typical values of these parameters for the various fire stages are presented in Table 1 of
ISO/TS 19706:2004.
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ISO 16312-1:2006(E)
7.3 The outcomes of the combustion process also form a basis for characterization of the fire stage:
⎯ yields of a (toxicologically important) subset of the hundreds of combustion products;
⎯ carbon monoxide to carbon dioxide ratio ([CO]/[CO ]);
2
⎯ ratios of “telltale” second-order products of incomplete combustion, such as an aldehyde to carbon
dioxide.
8 Characterization of physical fire models
8.1 Thermal environment in the test specimen
8.1.1 General
The three-dimensional temperature profile around a product undergoing combustion determines both the
burning rate and the yields of the combustion products. The nature of this profile varies with the fire type and
the time at which one is observing the burning. (See Annex A.)
8.1.2 Smouldering
This type of combustion, occurring only in porous materials, is characterized by
a) the direction in which the combustion front moves relative to the direction from which the air is arriving,
and
b) a peak fuel temperature.
8.1.3 Pyrolysis
2
Radiative pyrolysis is characterized by a radiant flux to the surface (kW/m ), a surface temperature, and the
thermal inertia of the test specimen. Conductive and convective heating are characterized by a surface
temperature and the thermal inertia of the test specimen.
8.1.4 Flaming
Fla
...
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