SIST ISO 10840:2003

INTERNATIONAL ISO
STANDARD 10840
First edition
2003-03-01
Plastics — Guidance for the use of
standard fire tests
Plastiques — Lignes directrices pour l'utilisation d'essais au feu
normalisés
Reference number
©
ISO 2003
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ii © ISO 2003 — All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 1
3 Terms and definitions. 1
4 Fire scenarios. 2
5 Categories of fire test . 4
6 Important considerations in the fire testing of plastics materials and products. 5
7 Problems that may occur with plastics in standard fire tests. 11
Bibliography . 13

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 10840 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 4, Burning
behaviour.
This first edition of ISO 10840 cancels and replaces ISO/TR 10840:1993, which has been technically revised.
iv © ISO 2003 — All rights reserved

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 “traditional” or “older-generation”
materials are often very different from those of synthetic materials, especially thermoplastics.
ISO/TC 61/SC 4 has, for a number of years, recognized the need for guidance for users of fire-test standards
commonly applied to materials and products made of, or incorporating, plastics. During 1997, it decided to
develop a guidance document in the form of an International Standard using ISO/TR 10840, and particularly
its Annex A, as the basis.
Annex A of ISO/TR 10840:1993 listed a series of potential problems associated with the reaction-to-fire testing
of plastics materials and products. However, it provided users of the test methods with no practical assistance
on how to cope with the difficulties listed.

INTERNATIONAL STANDARD ISO 10840:2003(E)

Plastics — Guidance for the use of standard fire tests
1 Scope
This International Standard covers the following aspects of fire testing:
 selection of appropriate test(s);
 listing of reaction-to-fire characteristics which the test(s) can measure;
 assessment of the test(s) for their suitability for material characterization, quality control, pre-selection
and/or end-product testing;
 problems that can arise when plastics specimens are tested in standard fire tests.
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 standard fire tests; these cover factors such as
cost, test duration, complexity, required operator skills, quality of the data produced, relevance to fire hazard
assessment as well as test repeatability and reproducibility. Preparation of this International Standard has
involved a review and assessment of the most frequently used fire tests applied to the materials and products
within the scope of ISO/TC 61/SC 4.
The main focus in this International Standard is on reaction-to-fire testing. Fire-resistance testing has also
been considered, however, in order 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. Further development of such plastics composites and related
products will predictably increase the demand for fire-resistance testing.
The scope of this International Standard does not include the development or design of fire tests for plastics.
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 13943, Fire Safety — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 13943 and the following apply.
3.1
test specimen
test piece that may be cut from a sample of a product, or prepared by moulding or otherwise, as specified by
the test procedure, or a representative sample of the product itself
3.2
sample
representative part of a manufactured product or piece of material or semi-finished product
3.3
plastics end-product test
test made on a complete product, piece, part, component or sub-assembly
3.4
plastics pre-selection test
test made on a standardized shape, for example a rectangular bar prepared using standard moulding
procedures
4 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 stages differ greatly.
There are four main stages in the development of a fire within an enclosed space. These are assessed using
measurements of temperature and time as shown in Figure 1.
4.2 Initiation and early growth
This stage 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 enclosed space with smoke and toxic
gases.
After ignition, the development of a flaming fire will depend on the following factors:
 fire growth on the item first ignited;
 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 is the sudden transition from a localized fire to the ignition of the gas layer and subsequently of all
exposed flammable surfaces, and will lead to a fully developed fire. Flashover is uncommon in large enclosed
spaces, as the temperature conditions required are not often reached.
Flashover usually occurs at temperatures around 600 °C; thereafter, the rate of heat release increases rapidly
to reach a maximum value.
4.4 Fully developed fire
A fire is regarded as fully developed when all fuel within the enclosed space is burning. This stage usually
follows flashover, but some fires may become fully developed without passing through the flashover phase.
2 © ISO 2003 — All rights reserved

Key
1 time to ignition
2 T > 100 °C, I > 25 kW/m close to ignited item
3 developing fire
4 flashover
5 fully developed fire
Figure 1 — Typical course of a fire going to flashover in an enclosed space
4.5 Decay
The decay stage of a fire is reached when all the combustible material 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 summarizes the important
fire parameters associated with reaction to fire and resistance to fire.
Table 1 — Phases of a fire
Phase Stage Parameters
Pre-flashover Initiation Ignitability
Developing fire Fire growth (ignitability, flame spread, and heat,
smoke and toxic-effluent release)
Post-flashover Developed fire Resistance to fire (load-bearing capability,
integrity, insulating capability)
5 Categories of fire test
5.1 Material-characterization tests
5.1.1 Tests carried out on behalf of customers who will undertake no further reaction-to-fire testing
on the material, or on products manufactured from the material
This type of testing imposes an obligation on the material supplier to assess those 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:
a) Do the properties of thermal-decomposition products (smoke density, toxicity or corrosivity) pose a
foreseeable problem?
b) Is the thermo-mechanical 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 carried out on behalf of a customer who seeks compliance with reaction-to-fire test(s) on
the finished product
In this case, the test method(s) used by the material manufacturer should provide an indication of the likely
influence on the test result of characteristics such as melting, dripping and retreat from the heat source.
5.2 Quality-control tests
In order to select a quality-control test, it is important to
a) decide which characteristics should be checked by the test;
b) select or develop the appropriate test method;
c) specify the required performance criteria;
d) compare test results to ensure that the parameter measured by the quality-control test is correlatable with
the key performance parameter being investigated.
It is necessary to specify:
a) the characteristics which have to be checked by the test;
b) the appropriate test procedure;
c) the required pass (acceptance) and fail (rejection) criteria;
and then to compare the test results with the specified 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 inten
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