prEN ISO 10840

SLOVENSKI STANDARD
01-december-2025
Polimerni materiali – Smernice za uporabo standardnih požarnih preskusov
(ISO/DIS 10840:2025)
Plastics - Guidance for the use of standard fire tests (ISO/DIS 10840:2025)
Kunststoffe - Leitfaden für die Verwendung von Standard-Brandprüfungen (ISO/DIS
10840:2025)
Plastiques - Lignes directrices pour l'utilisation d'essais au feu normalisés (ISO/DIS
10840:2025)
Ta slovenski standard je istoveten z: prEN ISO 10840
ICS:
13.220.40 Sposobnost vžiga in Ignitability and burning
obnašanje materialov in behaviour of materials and
proizvodov pri gorenju products
83.080.01 Polimerni materiali na Plastics in general
splošno
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 10840
ISO/TC 61/SC 4
Plastics — Guidance for the use of
Secretariat: BSI
standard fire tests
Voting begins on:
Plastiques — Lignes directrices pour l'utilisation d'essais au feu
2025-08-25
normalisés
Voting terminates on:
ICS: 13.220.40; 83.080.01 2025-11-17
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
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Reference number
ISO/DIS 10840:2025(en)
DRAFT
ISO/DIS 10840:2025(en)
International
Standard
ISO/DIS 10840
ISO/TC 61/SC 4
Plastics — Guidance for the use of
Secretariat: BSI
standard fire tests
Voting begins on:
Plastiques — Lignes directrices pour l'utilisation d'essais au feu
normalisés
Voting terminates on:
ICS: 13.220.40; 83.080.01
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
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Published in Switzerland Reference number
ISO/DIS 10840:2025(en)
ii
ISO/DIS 10840:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Enclosure fire scenarios . 2
4.1 General .2
4.2 Initiation and early growth of fire .3
4.3 Development of fire .3
4.4 Fully developed fire .3
4.5 Decay .3
5 Categories of fire tests . 4
5.1 Material characterisation tests .4
5.1.1 Tests done on behalf of customers undertaking no further reaction-to-fire
testing .4
5.1.2 Tests done on behalf of customers seeking compliance with reaction-to-fire
tests on a finished product .4
5.2 Quality-control tests .4
5.3 Pre-selection tests .5
5.4 End-product tests .5
5.5 Fire test based on the fire scenario .6
5.6 Use of Fire safety engineering (FSE) .6
5.6.1 basics of fire safety engineering .6
5.6.2 Fire tests for fire safety engineering on plastic products .6
6 Important considerations in the fire testing of plastics materials and products . 8
6.1 Influence of the chemical or physical nature of the test specimen .8
6.2 Sample and test specimen preparation and conditioning .8
6.3 Influence of test procedures .8
6.3.1 Test apparatus .8
6.3.2 Burning effluence .9
6.4 burning behaviours of specimens .9
6.5 Operation of tests .9
6.6 Other critical factors .10
6.7 Characteristics of ignition sources .10
6.8 Operating procedures in the event of specimen collapse or deformation .10
6.9 Debris of specimen .11
7 Advantages and disadvantages of scale in fire tests .11
8 Potentially problematical specimen behaviour .13
8.1 Test developed for materials other than plastics . 13
8.2 Shrinking .14
8.3 Bubbling . .14
8.4 Intumescence .14
8.5 Extinguishing of pilot flames by highly flame retarded plastics .14
8.6 Slumping of thermoplastic sheets . 15
8.7 Detection of flaming drips . 15
8.8 Edge effects . 15
8.9 Profiles products . 15
Annex A (Informative) End-user relevant preparation of test specimens .16
Annex B (informative) Environmental-impact Assessment .25
Bibliography .27

iii
ISO/DIS 10840:2025(en)
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 [or Project Committee] ISO/TC [or ISO/PC] 61, Plastics,
Subcommittee SC 4, Burning behaviour.
This third edition cancels and replaces the second edition (ISO 10840:2008), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— reference documents are reviewed and collected
— Terms and definitions are reviewed and collected
— Clause for fire safety engineering is added
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.

iv
ISO/DIS 10840:2025(en)
Introduction
Many of the current reaction-to-fire tests were developed, prior to the widespread use of synthetic polymers,
to assess products incorporating materials such as wood (in the building industry), paper (in electrical wires
and cables), and naturally occurring fibres such as cotton, wool and horsehair (in many textile, furniture
and electrical applications). The reaction-to-fire characteristics of these so-cold traditional materials are
often very different from those of synthetic materials, especially thermoplastics.
ISO/TC 61/SC4 recognises the need for guidance for users of fire-test standards commonly applied to
materials and products made of, or incorporating, plastics. In 2003, the first edition of ISO10840 was
published, based on the now withdrawn ISO TR 10840:1993; Plastics – Burning behaviour – Guidance for
development and use of fire test, which listed a series of potential problems associated with the reaction-to-
fire testing of plastics materials and products. TR 10840, however, provided users of the test methods with
no practical assistance on how to cope with the listed difficulties.
Although the first edition of ISO 10840 discussed the provision of such assistance, the general guidance that
it gives on the mounting and fixing of test specimens as found in many cases to be insufficient. More specific
guidance, relevant to the various and-use conditions of plastic products, was required. This second edition
of ISO 10840 includes a new annex that provides more detail information about how to conduct standard
fire tests which are more relatable to the real conditions of plastics products in a variety of applications.
With more concerns expressed about the environmental impact of fires involving plastics, additional
guidance has been included in this second edition. This information is general at present but it is proposed
to provide further guidance as the technology develops.
Particular attention is given to the provision of guidance for inexperienced users who may need to assess
the fire performance of materials or products made of, or incorporating, plastics. This International
Standard also provides answers to frequently asked questions concerning fire tests; these cover factors
such as cost, duration, complexity, required operator skills, quality of the data produced, relevance to fire
hazard assessment as well as test repeatability and reproducibility. This International Standard contains a
bibliography of the most frequently used fire tests applied to the materials and products within the scope of
ISO/TC61/SC4.
The main focus of this International Standard is on reaction-to-fire testing. Fire resistance testing has
also been considered, in particular for the use of plastic construction of small ships, to take account of the
widespread use of advanced polymer composites and related materials with superior thermo-mechanical
stability which may be used in applications where there is a demand for some degree of fire resistance.
This International Standard also provides guidance on some standard fire tests which give data that is
applicable for assessment of the potentially adverse environmental impact of combustion products that may
be generated in large-scale fires involving plastics materials and products (see ANNEX B).
NOTE The term, ‘adverse environmental impact’, covers undesirable direct effects on the environment as well as
indirect effects on people of ISO 10840 through environmental exposure.

v
DRAFT International Standard ISO/DIS 10840:2025(en)
Plastics — Guidance for the use of standard fire tests
1 Scope
This document covers the following aspects of fire testing of plastics materials and products: -
— Selection of appropriate tests that reflect realistic end-use conditions
— Grouping of the reaction-to-fire characteristics that any given test or tests can measure
— Assessment of tests as to their relevance in areas such as material characterisation, quality control, pre-
selection, end-product testing, environmental profiling and DfE (Design for the Environment)
— Definition of potential problems that may arise when plastics are tested in standard fire tests
This document does not include specification for development or design of new fire-tests for plastics.
However, the flexibility of approach that is indicated with respect to the mounting and fixing of test
specimens is valuable when fire testing laboratories and certification bodies are considering how to evaluate
ranges of plastics that are used in different ways.
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/TS 3814, Standard tests for measuring reaction-to-fire of products and materials — Their development and
application
ISO 10093, Plastics — Fire tests — Standard ignition sources
ISO 13943, Fire safety — Vocabulary
ISO 23932-1, Fire safety engineering — General principles — Part 1: General
ISO 23948, Plastics — Intumescence properties of PVC materials and products — Test method for the
measurement of expansion with the cone calorimeter
ISO 29473, Fire tests — Uncertainty of measurements in fire tests
IEC 60695-1-11, Fire hazard testing - Part 1-11: Guidance for assessing the fire hazard of electrotechnical
products - Fire hazard assessment
IEC 60695-1-12, Fire hazard testing – Part 1-12; Guidance for assessing the fire hazard of electrotechnical
products – fire safety engineering
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 13943 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 https:// www .electropedia .org/

ISO/DIS 10840:2025(en)
3.1
End-product test
Fire hazard assessment test on a complete product, piece, part component or sub-assembly
3.2
pre-selection test
combustion characteristic test made on a standardized shape, for the process of assessing and choosing
candidate materials, components or subassemblies for making an end product
Note 1 to entry: IEC 60695-4 3.2.15 defines “preselection”
3.3
spalling
the breaking off of fragments or solid articles from a heated surface
4 Enclosure fire scenarios
4.1 General
A number of fire parameters influence the development of a fire and, moreover, the fire parameters measured
during the pre-flashover and the post-flashover conditions differ greatly.
There are four main stages of fire development within an enclosure, i.e., pre-ignition, fire growth, flash-over
and fully developed fire, which are assessed using measurements of temperature and heat release rate in
terms of time as shown in Figure 1, which shows the different phases in the development of fires, i.e. pre-
ignition phase, fire growth phase, flash-over, fully developed fire and fire decay, within an enclosure space
(ISO/TS 3814).
Pre-ignition Fire growth Fully developed fire and fire decay
Flame spread Fire penetration
Ignitability
Heat development
Smoke (loss of visibility, generation of gases, toxicity, corrosivity)

ISO/DIS 10840:2025(en)
Key
1 time
2 heat release rate (kW)
o
3 temperature ( C)
4 ignition
5 flash-over
6 heat release rate curve
7 temperature curve
Figure 1 — Development of fire in terms of temperature and heat release rate
NOTE Figure 1 shows fire development in a compartment that goes to flashover. In some cases, fire may not
go to flashover due to limited combustibles present or due to the intervention of active firefighting measures (e.g.
sprinklers, fire brigades).
4.2 Initiation and early growth of fire
This stage of fire includes the exposure of a product to a heat source, ignition and early development of
a fire. Two types of combustion may exist at this stage, smouldering and flaming. Smouldering is a slow,
flameless combustion producing very little heat, but having the potential to fill an enclosure with smoke and
toxic gases.
After ignition, the development of a flaming fire will depend on the following effects:
— fire growth on first ignited item,
— fire spread to other items,
— the effect of intervention (portable extinguishers, sprinklers, fire brigades).
— the ventilation conditions
4.3 Development of fire
As a fire develops, a hot smoke and gas layer usually builds up below the ceiling. The radiant heat transfer to
combustible items accelerates the thermal decomposition of material below the smoke layer, and the rate of
fire spread increases.
Flashover, which usually occurs at temperatures around 600 °C, corresponds to an abrupt sudden transition
from a localised fire to the ignition of the gas layer and to the sudden subsequent ignition of all exposed
flammable surfaces, leading to a fully developed fire. The rate of heat release increases rapidly, and this
leads to a rapid temperature rise within the enclosure. However, Temperature at flash-over is not always the
maximum temperature in the compartment of the fire. Flashover is uncommon in large enclosures, as the
required temperature conditions are not often reached.
4.4 Fully developed fire
A fire is regarded as fully developed when all fuel within an enclosure is burning. This stage usually follows
flashover, but some fires may become fully developed without passing through the flashover phase.
4.5 Decay
The decay stage of a fire is reached when the fire load or available air has been consumed, or when the fire
is suppressed. In the pre-flashover phase reaction to fire characteristics of products are important, while in
the post-flashover phase resistance to fire parameters of complete assemblies apply.
Fire building regulations make a distinction between these two conditions. Table 1 summarises the
important fire parameters associated with reaction to fire and resistance to fire.

ISO/DIS 10840:2025(en)
Table 1 — Phases of fire
Phase Stage Parameters
Pre-flashover Initiation Ignitability
Developing fire Fire growth (ignitability,
flame spread, heat-, smoke- and toxic effluent
release)
Post-flashover Developed fire Resistance to fire (load-bearing, integrity,
insulation)
5 Categories of fire tests
5.1 Material characterisation tests
5.1.1 Tests done on behalf of customers undertaking no further reaction-to-fire testing
This type of testing imposes an obligation on the material supplier to assess reaction-to-fire characteristics
of the material likely to be of relevance to the application of the customer’s product, or foreseeable misuse
of the product as may be imposed by product stewardship aspects of Responsible Care programmes, or
product liability litigation, or both. The objective should be to provide answers to questions such as:
1. Do the properties of the thermal decomposition products (heat release, smoke density, toxicity or
corrosivity) pose a foreseeable problem?
2. Is the thermomechanical response of the material (e.g. melting or retreating from the heat source) likely
to constitute a hazard or an advantage in the customer’s product application, or in foreseeable misuse
scenarios?
5.1.2 Tests done on behalf of customers seeking compliance with reaction-to-fire tests on a
finished product
In this case, the test method(s) used by the material manufacturer should provide an indication of the likely
influence on the product test result of material characteristics such as melting, dripping, or retreat from
heat source.
5.2 Quality-control tests
Quality control fire tests can be conducted at manufacturers of materials and products for the purpose of
examining that the quality of the products is maintained.
In order to select a quality control test, it is important to:
— decide which characteristics should be checked by the test;
— select or develop the appropriate test methodology;
— specify the required performance criteria;
— compare test result to ensure that the parameter measured by the quality-control test correlates with
the key performance parameter being investigated.
It is necessary to specify:
— the characteristics which have to be checked by test;
— the appropriate test procedure;
— the required pass (acceptance) and fail (rejection) criteria;

ISO/DIS 10840:2025(en)
and then to compare test result with the specified criterion/criteria (acceptance level).
Repeatability is of crucial importance in tests selected for the purpose of quality control; in this context the
relevance of the test to any given application of the material is of secondary importance.
5.3 Pre-selection tests
Data developed using pre-selection tests requires careful consideration to ensure their relevance in relation
to the intended application and to avoid misuse and erroneous interpretation.
The actual fire performance of a product is affected by its surroundings, design variables such as shape and
size, fabrication techniques, heat -transfer effects, the type of potential ignition source and the length of
exposure to it.
The advantages of pre-selection testing are as follows:
a) to a first approximation a material which reacts more favourably than another when tested as a standard
test specimen will usually also react more favourably when used as a finished part in the product. This
will be valid provided that no overriding, interactive, product-specific effects are present;
b) Data concerning relevant combustion characteristics can aid the selection of materials, components and
sub-assemblies during the design stage;
c) The precision of pre-selection tests is usually higher, and their sensitivity may be superior when
compared with end-product tests;
d) Pre-selection tests may be used in a decision-making process directed to minimize the fire hazard.
Where applicable for the purpose of fire hazard assessment, they may lead to a reduction in the number
of end-product tests with a consequent reduction in the total testing effort;
e) When fire hazard requirements need to be upgraded quickly it may be possible to do this by upgrading
the requirements of a pre-selection test before modifying the end-product test;
f) the grading and classification obtained from the pre-selection test results may be used to specify a basic
minimum performance of materials used in product specifications.
It should be noted that when pre-selection testing is used to replace some of the end-product testing, it is
necessary to fix an increased margin of safety in an attempt to ensure satisfactory performance of the end
product. Following a pre-selection procedure, it may be necessary to implement a value analysis on the end
product, in order not to over-specify materials where a more economical material can be used. In this case,
an end-product test may be necessary.
5.4 End-product tests
These tests should reflect the end-use application scenario as far as is possible. Important factors to consider
include relevance of configuration, orientation, ventilation and the nature of the ignition source.
Reaction-to-fire testing for fire safety and for fire hazard assessment of products should be programmed as
follows:
a) specify the fire hazard to be assessed (e.g. vision impairment by smoke);
b) define the relevant product-application (or misuse) scenario and specify the required safety criterion;
c) select the appropriate test method and specify the pass/fail criterion;
d) conduct the tests and analyse the data;
e) select acceptable or reject unacceptable candidate materials or products.

ISO/DIS 10840:2025(en)
In case fire safety of a large constructions made of plastics is to be considered within a scope of overall fire
safety of the constructions, fire resistance of such product may need to be evaluated.
NOTE 1 ISO 30021 gives fire resistance test method on plastics including fibre reinforced plastics (FRP) for
evaluation of fire safety of such product in small ships (crafts).
It is also possible to develop an intermediate scale reaction-to-fire test that has close relationship to large
scale reaction-to-fire test used for regulatory purposes.
NOTE 2 ISO 15791-1 and ISO 15791-2 have been developed for application of intermediate-scale reaction-to-fire tests.
5.5 Fire test based on the fire scenario
In case it becomes necessary to evaluate fire performance of plastics and/or product made of plastics in
anticipated condition of use, fire scenario-based approach can be utilized. The fire scenario-based fire
hazard assessment can be conducted in the process as described below:
a) define the target of the evaluation, i.e. plastic materials, product made of plastics;
b) identify conditions where the target is used;
c) establish fire scenario that realize the identifies conditions and existence of the target;
d) identify fire performance parameters to evaluate fire performance of the target;
e) establish criteria to decide acceptability of the target in the fire conditions;
f) develop or choose fire test method(s) that realize the identified fire conditions and provide the results
in terms of identified fire performance parameters
h) evaluate the test results in light of established criteria.
Detailed process of scenario based fore hazard assessment is given in IEC 60695-1-11.
NOTE A fire test method of plastic materials in a condition of micro gravity is given in ISO 4589-4.
Basic and overall approach fire safety evaluation based on the fire scenario and fire safety engineering is
given in ISO 23932-1 and IEC 60695-1-12.
5.6 Use of Fire safety engineering (FSE)
5.6.1 basics of fire safety engineering
Basic approach on fire safety engineering is given in ISO 23932-1.
Fire safety engineering was developed and is continuing to develop to enable the design, implementation and
maintenance of objects and structures in the built environment, using scientific principles, so that defined
fire safety engineering objectives can be met. In order to do this, quantitative fire tests are used to provide
input data for the necessary calculations.
When applied to a major project in the built environment, the fire engineering process is both complex
and comprehensive. A flow chart illustrating such a fire safety engineering process is shown in Figure 2.
Fire safety engineering should be used when safety objectives cannot adequately be met by prescriptive
requirements, and can also be used in parallel with prescriptive requirements e.g. to support, from a
scientific point of view, that such requirements are valid, or to further improve the fire safety of the product.
5.6.2 Fire tests for fire safety engineering on plastic products
Any physical or chemical tests on plastics products, to be used in fire safety engineering, should provide data
appropriate to enable ‘in-use’ plastics product performance to be assessed through utilization of predictive
methods.
ISO/DIS 10840:2025(en)
It follows that:
— performance of plastic products in a fire test shall be provided in quantitative terms for known, controlled
and varied exposure conditions over continuous intervals of time;
— exposure conditions shall be provided in quantitative form and must be representative of the fire
scenario, and actual installation and use practices;
— thermal, chemical and physical processes in the test shall be able to be well understood and prescribed
that they can be validated and modelled theoretically; and
— performance of the plastics products in the particular conditions of the test shall then be translatable by
predictive methods to design environments representative of ‘in-use’ behaviour.
Figure 2 — Typical process of Fire safety engineering approach (Figure 1 of ISO 23932-1)

ISO/DIS 10840:2025(en)
6 Important considerations in the fire testing of plastics materials and products
6.1 Influence of the chemical or physical nature of the test specimen
Various chemical and/or physical aspects of the material may affect the performance of the specimen at
the high temperatures encountered in standard fire testing procedures. These may be categorised under
various headings, depending on whether the observed phenomena are associated with the specimen itself,
and/or the test apparatus, and/or the execution of the test procedure and/or the interpretation of the test
results. Annex A provides information on basic rules which are generally valid for the mounting and fixing of
plastics products in reaction-to-fire test standards.
6.2 Sample and test specimen preparation and conditioning
The preparation of material samples and test specimens can be of extreme importance in fire-testing of
plastics materials and products; preparation covers selection, sampling, cutting-out and conditioning of
specimens. Conditioning is important because variations in moisture content of a specimen will affect test
results.
It is important to remove moulding flash and other similar residues from surfaces and edges of specimens.
The initial temperature of specimen may influence its ease of ignition in the test.
Particular attention should be paid to thermo-formed test specimens. The conditions of the thermo-forming
operation, such as injection moulding or extrusion, should be rigorously controlled to minimize and, if
possible, eliminate any specimen-to-specimen variations in residual stress, anisotropy, specific gravity and
degree of crystallinity. All of these variables influence the thermos-mechanical properties of the specimen
and, consequently, its response to the application of heat from the fire-test ignition source.
Material inhomogeneities (e.g. distribution of additives, such as flame retardant, fibres, and morphological
inhomogeneities) may influence the test results.
6.3 Influence of test procedures
6.3.1 Test apparatus
When an ignition source is applied to any plastic test specimen made from pure, compounded or laminated
material, thermal decomposition products will be generated. The ignition source to be used for appropriate
testing is one that has an intensity that is relevant to the scenario in which the material or product is to be used.
The nature of the decomposition products is not determined exclusively by the chemical composition of the
test specimen. Other determinant factors are:
a) the energy output of the ignition source;
b) the nature and intensity of the ignition source;
— flaming or non-flaming;
— impingement or non-impingement on the specimen;
c) the nature of the test apparatus;
— high or low ventilation
— high or low thermal inertia (i.e. significance of heat-sink effects).
It is also important to measure heat release rate from the specimen during the test, since heat release during
combustion feeds heat back to the specimen. Heat release is the key parameter on fire growth. There are
many ISO standard fire tests that measure heat release, such as ISO 5660-1, ISO 9705-1, ISO 12136.

ISO/DIS 10840:2025(en)
6.3.2 Burning effluence
These may consist of:
a) toxic decomposition products;
b) corrosive decomposition products;
c) smoke and soot;
d) char and intumesced layers;
6.4 burning behaviours of specimens
The following types of effects may occur:
a) additive evaporation or sublimation;
b) out-gassing or intumescence;
c) char-layer formation;
d) delamination;
e) spalling;
f) deformation;
g) smouldering;
h) glowing combustion;
i) shrinking;
j) dripping;
k) absorption of liquified components; and
l) explosion.
6.5 Operation of tests
The following factors should be taken into account:
a) operator safety especially from fast fire-growth, as in flashovers, and from exposure to smoke and toxic
effluents, particularly in large-scale tests such as ISO 9705;
b) effects of heat on structures in large-scale test procedures (dangers of structural collapse);
c) need for personal protective equipment;
d) local environmental impacts to air, the water and the soil (see ANNEX B for information);
e) compliance with local regulations;
f) avoidance of local nuisance as required by Responsible Care commitment;
g) identification and control of effluents;
h) equipment corrosion;
i) smoke or gas explosion hazard.

ISO/DIS 10840:2025(en)
6.6 Other critical factors
It is important to define selection criteria for test specimens taken from finished products.
Influential factors include, but not limited to:
a) specimen thickness. Heat and smoke release depend on thickness; thicker specimens may release much
more heat and smoke than thin specimens. Thin specimens may ignite more easily than thick specimens
because of thermal inertia effects;
b) specimen size
c) specimen form, as determined by its structure, shape and aspect ratio;
d) edge effects: Sharp edges may ignite more readily than rounded-off edges;
e) orientation and ventilation: Flame spread will depend on the air to gas ratio and flow of gaseous species
in the vicinity of the flame;
f) specimen support including substrates and air-gaps: In case not-self standing materials, specimens shall
be supported by a relevant frame. Conductive air-flow and thermal transfer between the specimen and
its support system may affect temperature rise profile and, consequently, ignitability and flame-spread
of specimen. Limitation of specimen movement by its support system may also affect specimen response
to the ignition source;
g) Material homogeneity: material homogeneity may differ in the part of the test specimen or among
different piece of specimens;
h) Conditioning or ageing of the test specimen: burning behaviour may differ among specimens that treated
in different conditioning or ageing.
6.7 Characteristics of ignition sources
The relevance of ignition sources depends on the selection of fire scenarios in which the product is to
be evaluated for fire hazard. Fundamentally, heat flow from the heat source to the specimen is a major
parameter in such evaluation; this also depends on the relative sizes of specimen and ignition source. Thus,
the test result may depend on many design features of the test system. The following characteristics of the
ignition source should be taken into account:
a) radiant, conductive and convective effects
b) flaming or non-flaming condition;
c) impingement or non-impingement of flame;
d) precision and quantification of measurements;
e) flaming instability
ISO 10093 gives definitions of ignition sources that shall be the basis of selection of the ignition sources.
6.8 Operating procedures in the event of specimen collapse or deformation
Problems arise in the fire testing of many plastics because of common thermomechanical effects such as
specimen slumping and sagging as well as edge-effects such as the curling of the thin specimens towards or
away from the ignition source.
It is also pointed out the problem of specimens that are not self-supporting. Fire test standards should
establish a method to support such specimens during the test.
Interpreting test results can also be problematical when the operator
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