SIST EN ISO 25762:2012

SLOVENSKI STANDARD
01-marec-2012
Polimerni materiali - Navodila za ocenjevanje požarnih lastnosti in požarne
odpornosti polimernih kompozitov, okrepljenih z vlakni (ISO 25762:2009)
Plastics - Guidance on the assessment of the fire characteristics and fire performance of
fibre-reinforced polymer composites (ISO 25762:2009)
Kunststoffe - Anleitung für die Bewertung der Eigenschaften und des Verhaltens von
faserverstärkten Polymerverbundstoffen bei Brandeinwirkung (ISO 25762:2009)
Plastiques - Lignes directrices pour l'évaluation des caractéristiques au feu et des
performances au feu de polymères composites renforcés de fibres (ISO 25762:2009)
Ta slovenski standard je istoveten z: EN ISO 25762:2012
ICS:
13.220.40 Sposobnost vžiga in Ignitability and burning
obnašanje materialov in behaviour of materials and
proizvodov pri gorenju products
83.120 2MDþDQLSROLPHUL Reinforced plastics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 25762
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2012
ICS 13.220.40; 83.080.01
English Version
Plastics - Guidance on the assessment of the fire characteristics
and fire performance of fibre-reinforced polymer composites
(ISO 25762:2009)
Plastiques - Lignes directrices pour l'évaluation des Kunststoffe - Anleitung für die Bewertung der
caractéristiques au feu et des performances au feu de Eigenschaften und des Verhaltens von faserverstärkten
composites polymères renforcés de fibres (ISO Polymerverbundstoffen bei Brandeinwirkung (ISO
25762:2009) 25762:2009)
This European Standard was approved by CEN on 24 December 2011.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 25762:2012: E
worldwide for CEN national Members.

Contents Page
Foreword .3

Foreword
The text of ISO 25762:2009 has been prepared by Technical Committee ISO/TC 61 “Plastics” of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 25762:2012 by
Technical Committee CEN/TC 249 “Plastics” the secretariat of which is held by NBN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by July 2012, and conflicting national standards shall be withdrawn at the
latest by July 2012.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 25762:2009 has been approved by CEN as a EN ISO 25762:2012 without any modification.

INTERNATIONAL ISO
STANDARD 25762
First edition
2009-07-01
Plastics — Guidance on the assessment
of the fire characteristics and fire
performance of fibre-reinforced polymer
composites
Plastiques — Lignes directrices pour l'évaluation des caractéristiques
au feu et des performances au feu de polymères composites renforcés
de fibres
Reference number
ISO 25762:2009(E)
©
ISO 2009
ISO 25762:2009(E)
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ii © ISO 2009 – All rights reserved

ISO 25762:2009(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 2
3.1 General. 2
3.2 Types of material . 3
4 Fibre reinforcement . 4
4.1 Form . 4
4.2 Fibre content . 4
4.3 Core materials . 4
4.4 Production methods. 4
5 Fire characteristics. 5
5.1 Reaction to fire. 5
5.1.1 General. 5
5.1.2 Combustibility. 5
5.1.3 Ignitability . 5
5.1.4 Rate of heat release. 5
5.1.5 Flame spread. 5
5.1.6 Smoke . 6
5.1.7 Toxicity . 6
5.2 Structural performance . 6
5.2.1 General. 6
5.2.2 Walls and ceilings. 7
5.2.3 Floors . 7
5.2.4 Structural integrity of fibre-reinforced composites on exposure to fire. 7
6 Fire test methods. 8
6.1 Assessment of fire hazard . 8
6.2 Fire tests for determining performance requirements. 8
6.3 Applicability of standard fire test methods to FRP composites. 8
6.4 Large-scale tests. 9
6.5 Standard fire tests for conformity purposes .9
Annex A (informative) Heat release measurements on FRP composites. 10
Annex B (informative) Typical results given for glass-fibre-reinforced polymer composites by ISO
and EN fire test methods . 12
Annex C (informative) Recommendations for the handling and storage of fibre-reinforced polymer
composites . 20
Annex D (informative) Procedure in the event of fire involving fibre-reinforced polymer
composites . 22
Annex E (informative) Mounting and fixing of test specimens of fibre-reinforced polymer
composites . 23
Bibliography . 27

ISO 25762:2009(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 25762 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 4, Burning
behaviour.
iv © ISO 2009 – All rights reserved

ISO 25762:2009(E)
Introduction
The information given in this International Standard is in accordance with the principles recommended in
ISO 10840 which was established to develop a general policy and philosophy for the development and use of
fire tests for plastics.
Fibre-reinforced polymer (FRP) composites are produced in a wide variety of chemical and physical forms,
some of which cause difficulties for fire laboratories since the specimens required for some tests are not
representative of the FRP composite in its end-use configuration.
This International Standard identifies those tests which can be used for determining the fire characteristics of
various FRP composites and provides guidance on how to assess the fire performance of FRP composites in
different applications. Since FRP composites can be used as lightweight construction materials, the
experience of users in transport applications has been valuable in the preparation of this International
Standard. Test data from methods that are specified by regulators of marine and rail products have been
provided to exemplify the fire performance of some FRP composites.

INTERNATIONAL STANDARD ISO 25762:2009(E)

Plastics — Guidance on the assessment of the fire
characteristics and fire performance of fibre-reinforced polymer
composites
1 Scope
This International Standard gives guidelines for the assessment of the fire characteristics and fire performance
of fibre-reinforced polymer (FRP) composites, particularly in structural applications in buildings and transport.
It is applicable to FRP composites prepared from thermosetting or thermoplastic resins and reinforced with
inorganic fibres greater than 7,5 mm in length.
This International Standard gives guidelines on:
⎯ the applicability of product types (e.g. sheets, laminates, profiled sections and some sandwich
constructions) to end-use performance;
⎯ the test methods and performance criteria for different physical forms of FRP test specimen.
NOTE 1 FRP composites vary widely in their physical form (e.g. in thickness, density and shape).
NOTE 2 FRP composites can also be assembled products containing other materials (such as metals or inorganic non-
fibrous fillers) and as systems containing air-gaps, joints and fixing attachments.
NOTE 3 Handling and storage recommendations for the fire safety management of FRP composites are given in
Annex C. In addition, some guidance on how to tackle fires involving FRP composites is provided in Annex D.
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 472, Plastics — Vocabulary
ISO 13943, Fire safety — Vocabulary
ISO 25762:2009(E)
3 Terms, definitions and abbreviated terms
For the purposes of this document, the terms, definitions and abbreviated terms given in ISO 13943 and
ISO 472 and the following apply.
3.1 General
3.1.1
fibre-reinforced polymer composite
polymer matrix composite consisting of thermosetting resin or thermoplastic materials and fibres of greater
than 7,5 mm in length prior to processing
NOTE Plastics compositions containing fibres of 7,5 mm or less in length are treated as plastics.
3.1.2
load-bearing capacity
R
ability of an element to maintain its structural stability despite exposure to fire on one or more faces for a
period of time
3.1.3
integrity
E
ability of an element with a separating function to withstand fire exposure on one side only without the
transmission of fire to the non-fire side as a result of the passage of significant quantities of flames or hot
gases from the fire to the non-fire side thereby causing ignition either of the unexposed surface or of any
material adjacent to that surface
NOTE This may include the ability of an element to withstand delamination (the layers of the material separating from
each other) when under load and exposed to fire.
3.1.4
insulating capacity
I
ability of an element to withstand fire exposure on one side only without significant transfer of heat from the
exposed to the unexposed side
3.1.5
product
material, composite or assembly about which information is required
3.1.6
composite
structured combination of two or more discrete materials, with one of the materials (the matrix) forming a
continuous phase
NOTE 1 The structure of a composite can be made up of one or more layers.
NOTE 2 For the purposes of this International Standard, at least one of the materials is a plastic or an organic-based
polymer.
3.1.7
ARHE(t )
n
average rate of heat emission at time t
integrated heat emission from time 0 to time t, divided by t
NOTE It is expressed in kW/m for cone calorimeter results (see ISO 5660-1).
2 © ISO 2009 – All rights reserved

ISO 25762:2009(E)
3.1.8
MARHE
maximum average rate of heat emission
maximum value of ARHE from t = 0 to t = t
end
NOTE It is usually expressed in kW/m .
3.1.9
FIGRA index
fire growth rate index
maximum value of the quotient of the rate of heat release from the specimen and the length of time it occurs
NOTE It is usually expressed in W/s. Further details concerning its derivation are given in EN 13823.
3.1.10
SMOGRA index
smoke growth rate index
maximum value of the quotient of the rate of smoke production by the specimen and the length of time it
occurs
2 2
NOTE It is usually expressed in m /s . Further details concerning its derivation are given in EN 13823.
3.1.11
resistance to radiation
W
ability of a product/construction element to withstand fire exposure on one side only, thus reducing the
probability of the transmission of fire as a result of significant radiated heat either passing through the
product/element to adjacent materials or being radiated from its unexposed surface to adjacent materials
NOTE 1 The product/element might also need to protect people in the vicinity. A product/element which satisfies the
insulating-capacity criterion, I, is also deemed to satisfy the W requirement for the same period.
NOTE 2 Failure of integrity under the “cracks or openings in excess of given dimensions” criterion or the “sustained
flaming on the unexposed side” criterion (see 5.2.1) automatically means failure under the resistance to radiation criterion.
3.1.12
TSP
600s
total smoke production from the specimen in the first 600 s of exposure to the burner flames
3.2 Types of material
3.2.1
thermosetting material
material capable of being changed into a substantially infusible and insoluble product when cured by heat or
by other means, such as radiation and catalysts
NOTE 1 These materials are resins and include polymers such as polyesters, epoxides, acrylics, urethanes and
phenolics.
NOTE 2 The resins may incorporate non-fibrous fillers, flame-retardants, pigments and stabilizers.
3.2.2
thermoplastic material
polymeric material that becomes soft and plastic when heated
NOTE 1 These polymers include polypropylene (PP), polyetheretherketone (PEEK) and polyethersulfone (PES).
NOTE 2 The polymers can incorporate non-fibrous fillers, flame-retardants, pigments and stabilizers.
ISO 25762:2009(E)
3.2.3
reinforcing fibre
fibrous material added to a matrix resin or polymer in order essentially to improve its mechanical properties
NOTE These materials include glass, carbon, aramid, thermoplastic fibres (such as polypropylene, polyamide and
polyester) and natural fibres (such as cellulose and wood).
4 Fibre reinforcement
4.1 Form
The reinforcement can be in the form of unidirectional rovings or yarns, fabrics, chopped strands (individual or
in mats), fully aligned layers or knits, braids or continuous-filament mats.
NOTE The type of fibre and its form should be described in all test reports on the FRP composite.
4.2 Fibre content
The fibre content in the composite can be as low as 10 % by volume and as high as 75 % by volume.
4.3 Core materials
These can include:
a) honeycomb structures (aluminium, aramid, paper, polypropylene or phenolic-resin-impregnated
fibreglass);
b) plywood;
c) foam (cellulose acetate, polystyrene, polyurethane, phenolic or PVC);
d) balsa wood.
4.4 Production methods
FRP composites can be produced by a variety of processes as described in the various parts of ISO 1268, for
example:
a) pultrusion;
b) wet lay-up (by hand or spray application);
c) filament winding;
d) compression moulding;
e) moulding using prepregs;
f) resin transfer moulding;
g) vacuum infusion;
h) continuous lamination.
Some FRP composites have gel-coats on their surfaces. The gel-coat might be similar to the unreinforced
resin but, in many cases, a different resin is used.
4 © ISO 2009 – All rights reserved

ISO 25762:2009(E)
FRP composites are often used as skins in sandwich constructions in combination with plastic foams or
honeycomb core material. When FRP composite products are manufactured or installed, the fire laboratory
performing a test or assessment should record details of the composition and assembly of the test specimen
that are typical of the end-use application of the product. These details could include the types of joint or fixing
attachment, air-gaps, edge coverings, skins or facings and metal inserts or reinforcements.
5 Fire characteristics
5.1 Reaction to fire
5.1.1 General
More than one fire test should be performed to characterize adequately the reaction-to-fire properties of FRP
composites.
NOTE Reaction-to-fire test results on some typical FRP composites are shown in Annex B. These data back up the
recommendations given in 5.1.1 to 5.1.7.
5.1.2 Combustibility
When tested in accordance with ISO 1182, all grades, types and densities of FRP composite are usually
classified as combustible due to the contribution of their polymer content.
5.1.3 Ignitability
Under certain conditions of heat, orientation and ventilation, a naked flame can ignite FRP composites. Care
should be taken to avoid contact with naked-flame sources when handling and storing these composites
before and during installation.
The ignitability of FRP composites can be tested using the standard ignition sources described in ISO 10093,
which include flaming, radiant heat and electrical sources. These sources can be used in standard fire tests
(see ISO 10840) or in ad hoc tests, some of which might provide information on the ignitability of the FRP
composites under end-use conditions.
5.1.4 Rate of heat release
The rate of heat release of FRP composites should be determined by the following standard tests:
a) For small test specimens, ISO 5660-1 or ISO 13927 should be used.
b) For intermediate-scale test specimens, the guidance in ISO 15791-1 should be followed. Tests such as
ISO 21367 or EN 13823 could be used.
c) For large test specimens, either ISO 9705 and ISO/TR 9705-2 or ISO 24473 should be used.
NOTE Additional information on rate of heat release measurements is given in Annex A.
5.1.5 Flame spread
ISO/TS 5658-1 should be referred to for guidance on the appropriateness of a flame spread test (especially
concerning the nature of the ignition source, the orientation of the test specimen and the ventilation conditions
in the vicinity of the test specimen). Lateral flame spread across a vertically oriented specimen can be
determined in accordance with ISO 5658-2, and flame spread over horizontally mounted floorings can be
determined in accordance with ISO 9239-1.
NOTE 1 The extent and rate of flame spread depend largely on the ignitability of, and rate of heat release from, a
combustible product.
ISO 25762:2009(E)
NOTE 2 Since the fire performance of products, including flame spread, is to a great extent dependent on the
composition of the product (such as the type of substrate), including any fixings or mountings relevant to the end-use
application, standard small-scale tests are not always appropriate for the evaluation of FRP composites. Large-scale test
methods, which more appropriately reflect end-use conditions for composites in structural applications, are briefly
discussed in 6.4.
5.1.6 Smoke
Burning some FRP composites can generate dense, black smoke. When assessing potential smoke emission
from FRP composites in a building or other enclosure under fire conditions, essential factors that should be
considered include the possible extent of flame spread over the surface of the composite, the ventilation
conditions and the rate of decomposition of the resin.
Smoke density can be measured in a dynamic test involving a well-ventilated fire (such as that described in
ISO 5660-2) or in a test carried out in a chamber in which the smoke accumulates (such as that in
ISO 5659-2).
NOTE Prediction of the precise smoke-producing potential of FRP composites is difficult because of the wide range
of combustion conditions likely to be met within an actual fire. Generalized conclusions from small-scale tests have been
substantiated by evidence from fire incidents. The density of the smoke produced increases with increasing temperature
and with the intensity of the heat flux incident on the material. In a smouldering fire, where decomposition occurs in
oxygen-deficient conditions, small grey spherical particles predominate and the specific optical-density values can be
lower than for flaming conditions.
5.1.7 Toxicity
ISO Technical Committee TC 92/SC 3 guidelines, as given in ISO 16312-1, ISO 16312-2, ISO 13571 and
ISO 19706, should be followed in the assessment of the likely toxic hazard of a defined scenario.
NOTE When organic materials such as wood, paper or plastics are burned, hot gases and smoke are evolved. All
combustion gases produced can prove fatal in a short time if inhaled in sufficient concentration. However, the toxicity
hazard in a fire arises through many factors, including the rate of fire growth and the ambient ventilation conditions, as well
as the inherent toxicity of the combustion products, and this philosophy is embodied in the ISO/TC 92/SC 3 guidelines.
A stepwise approach should usually be taken, including such factors as risk of ignition, rate of fire growth,
flame spread, smoke-producing potential, location and mobility of occupants and fire protection measures. An
estimation of the risk (that is, the likelihood of that hazard occurring) should also be made.
Some small-scale tests can be used to determine the composition of fire effluents from burning FRP
composites. For example, ISO 5659-2 could be used as a fire model with gas analysis performed using
Fourier transform infrared spectroscopy or another method (such as ion chromatography). From the results, a
toxicity index can be derived for up to 10 common fire gases.
5.2 Structural performance
5.2.1 General
A very important regulatory requirement in buildings and other enclosures (such as ships and trains) is the
need to ensure that fires are, wherever possible, confined to the compartment of fire origin. The required
structural performance is usually assessed by fire resistance tests on elements of the building structure.
Various levels of thermal action can be used to simulate different fire scenarios. Probably the most widely
used is the standard temperature/time curve, which serves as a simulation for a fully developed fire (see
ISO 834-1). Other test fires used in certain situations include the smouldering fire, the semi-natural fire, the
hydrocarbon fire and the external fire (such as exposure to fire emerging from a window of a building or from a
free-burning external fire).
Resistance-to-fire performance characteristics which should be assessed include load-bearing capacity, R,
integrity, E, and insulating capacity, I (see 3.1.2 to 3.1.4). Other characteristics which might be specified under
certain conditions for some elements are resistance to radiation, W (see 3.1.11), mechanical aspects, self-
closing ability and smoke leakage.
6 © ISO 2009 – All rights reserved

ISO 25762:2009(E)
The assessment of integrity should generally be made on the basis of the following three criteria:
a) cracks or openings in excess of given dimensions;
b) ignition of a cotton pad;
c) sustained flaming on the unexposed side.
The integrity should be determined by all three criteria during the test. The cotton pad should be applied until it
ignites and, once it has ignited, it should be withdrawn and the test continued until all three criteria have been
exceeded. The times taken to reach the failure point for each aspect of integrity should be recorded.
If composites are used as a sandwich structure with a thin fibre-reinforced resin laminate attached over a core
material (for example, for cabin interiors of passenger aircraft, transport vehicles or ships), the whole
assembly should be tested in an appropriate fire test.
NOTE 1 Engineering theory shows that the flexural stiffness of any panel is proportional to the cube of its thickness.
The purpose of a core in a composite laminate is therefore to increase the stiffness of the laminate by effectively
thickening it with a low-density core material. This can provide a dramatic increase in stiffness for very little additional
mass. Thus a sandwich panel comprising FRP skins bonded to one or both sides of a suitable core material can be as
little as 20 mm thick and up to 200 mm thick.
NOTE 2 Core materials can be composed of any of a large number of lightweight materials (see 4.3)
5.2.2 Walls and ceilings
The efficiency of joints and fixing attachments, especially in the case of lightweight assemblies and
mechanically fixed facings, is important in determining the overall fire resistance of an element. The joints
should be proven by testing, and the construction of the assembly or facing should not deviate from that of the
test specimen in order to ensure that the required levels of fire resistance are achieved.
The reaction-to-fire performance of an element, including its fixing attachments, can also be affected by its
structure. If the product is a wall or ceiling lining, the reaction-to-fire performance can be assessed by a room
test, such as that in ISO 9705, in which the product is installed for the test as far as possible in its end-use
condition. When testing FRP composite panels, the test specimen should be fixed to a steel framework.
5.2.3 Floors
For floors, other than those of the lowest storey of a building, fire resistance should be determined by
constructing the floor so that it resembles as closely as possible the end-use assembly. For example, floors in
aircraft can be composed of FRP skins with thick, low-density cores (such as aramid honeycomb
compositions).
In some transport applications (such as railway vehicles), the fire source can be under the floor and could be
an electrical cabinet containing a high-power supply or a traction transformer (or a reactor filled with insulation
fluid). These floors should be tested in accordance with ISO 834-1 or EN 1364-2, which are appropriate to a
non-load-bearing element. The requirements should be defined from under the floor to the top of the floor
covering.
5.2.4 Structural integrity of fibre-reinforced composites on exposure to fire
Structural-integrity evaluation is an important requirement for FRP composites used for structural applications.
Since not many standard fire test methods are available, many researchers modify mechanical tests to meet
their needs. This area of research is being actively addressed in building and transport applications.
Determination of failure criteria is difficult for some FRP composites. When the resin contained in some FRP
composites has fully burnt, the residual structure is effectively a fibre curtain. If the reinforcement is a glass
fibre mat (random or woven), the further input of heat can cause local melting of the glass fibre, and this can
result in a growing hole that is sufficient to cause the composite to fail the integrity specification of ISO 834-1.
ISO 25762:2009(E)
6 Fire test methods
6.1 Assessment of fire hazard
The design, construction and conditions of use of an FRP composite should be analysed to define the
individual factors likely to affect significantly the response to fire of the product. Certain parameters can then
be measured using recognized techniques. Other parameters should be identified and investigated
individually.
6.2 Fire tests for determining performance requirements
For control purposes involving building and transport products, standard fire tests are specified for the
assessment of specific reaction-to-fire and structural fire-resistance characteristics. In addition, they are
performed to determine whether given construction elements, wall linings or ceiling linings satisfy a minimum
level of performance for use in a given situation or occupancy.
NOTE Attention is drawn to the fact that there can be legal or statutory requirements for assessing the fire risk of FRP
composites.
Standard fire tests cannot, in isolation, measure the fire hazard (although they can assist in its assessment
and control) and satisfactory results in these tests cannot alone guarantee fire safety since such tests cover
only one of a number of factors that need to be taken into account.
Precise simulation of all fire conditions to which a product is likely to be exposed in practice would be
desirable, but this is impracticable and the experimental procedure uses only standardized exposure
conditions. The results of such standard tests are directly applicable in practice only when an FRP composite
product is exposed to fire conditions identical to those used in the test.
The concept of standard testing assumes that a range of FRP composite products will generally give the same
performance ranking under all combustion conditions. However, if there are significant changes in parameters
such as thickness, density or fibre content across a range of composite products, differences in performance
classification can occur. The fire performance of a new FRP composite product is often predicted by analogy
with the performance in practice of a well-known product of similar ranking in the test.
6.3 Applicability of standard fire test methods to FRP composites
Standard tests are typically carried out on small-size specimens supported often in non-typical orientations by
means other than those used in practice. This is particularly true of lining materials. Thus the test specimen
can be exposed to forces considerably different from those acting on it in an actual building or transport
vehicle, and the physical performance of the composite can be impossible to predict. In such cases, an
indicative non-standard fire test might be needed to provide a basis on which to judge the applicability and
validity of the information from standard tests.
Many of the well-established fire test procedures used for building products were originally devised for
cellulosic products. Difficulties can be experienced in conducting standard fire tests because of the widely
varying physical nature of the FRP composites available, and a proper rating might not be obtainable.
NOTE It is known that some types of FRP composite can decompose explosively when exposed to heat. For
example, some types of phenolic resin produce moisture during the cure process, which becomes trapped in the structure
of the laminate. When exposed to heat, this expands and can result in explosive delamination. This normally simply results
in small-bubble delamination. However, particularly in some small test specimens, it can cause the laminate to come apart
entirely, which can cause a safety hazard. For example, this type of delamination has been known to damage the
ISO 5660-1 cone calorimeter apparatus by throwing the retainer frame off the specimen holder. Where this is likely,
appropriate precautions should be taken, such as securing the retainer frame to the specimen holder with screws or bolts.
8 © ISO 2009 – All rights reserved

ISO 25762:2009(E)
6.4 Large-scale tests
Recognizing that small-scale tests cannot adequately assess more complex building constructions, a number
of methods have been developed by ISO/TC 92 so that a composite or an assembly can be tested in its
installed state in a way that is more closely related to the end-use applications. These methods include
ISO 9705 (full-scale room test for surface products), ISO 13784-1 and ISO 13784-2 (large- and small-room
tests for sandwich panels) and ISO 13785-2 (large-scale test for façades). Large-scale tests, carried out in
isolation, can only be relied on to give information applicable to the severity of the fire conditions selected and
to the size and constructional design of the components involved.
If representative fire performance is to be achieved, the construction of full-size test specimens (that is,
structural elements of the fibre-reinforced composite and assemblies of such elements) requires careful
design of jointing systems, consideration of edge effects and (where appropriate) of air-gaps, and realistic
simulation of the method used in practice for supporting any protective facings.
Extrapolation of test results to other large-scale fire scenarios or to other composites and assemblies is
extremely difficult, and this practice should be avoided whenever possible.
6.5 Standard fire tests for conformity purposes
The reaction-to-fire tests that should be used for quality control of plastics products and FRP composites for
many conformity purposes are specified in ISO 10840 and ISO 15791-1. Most tests are intended to assess
the response of a material, product or structure to one or more aspects of fire.
When testing structural elements or other elements used in construction, test specimens should comprise a
representative section of the entire construction, including all relevant design features, such as fastenings.
Structural test specimens should ideally be either full size or, for compliance with standard fire resistance tests,
at least 3 m × 3 m or 4 m × 3 m for vertical and horizontal dividing elements, respectively.
NOTE 1 The ISO 834 series provides procedures for large-scale fire resistance testing of some FRP composites.
Intermediate-scale fire resistance tests are performed on, typically, 1 m × 1 m test specimens. The period for
which a construction element continues to perform the function for which it was designed, as determined by
conformity with specified criteria for load-bearing capacity, integrity and insulating capacity, defines the fire
resistance of the composite under test.
NOTE 2 An intermediate-scale fire resistance test for FRP composites, ISO 30021-2, is currently under development.
ISO 25762:2009(E)
Annex A
(informative)
Heat release measurements on FRP composites
A.1 General
The gross calorific value of materials influences fire severity in terms of fire duration. The rate of heat release
is of major importance for fire growth and is very dependent on the combustion conditions, especially the heat
flux incident on the exposed surface and the ventilation.
The rate of heat release directly influences many of the other reactions to fire, such as smoke and toxic-gas
production. The ability to measure accurately the heat released from items such as wall linings is viewed as
essential to fire protection engineering.
The extent and rate of heat release is limited primarily by ventilation. Complete combustion of FRP
composites is unlikely to occur, so their gross calorific value is rarely released.
Until about 1990, it was not easy to determine the rate of heat release from fires, and calculations were made
from heats of combustion. Measurement of oxygen consumption in fires now makes it possible to determine
the rate of heat release more directly, regardless of how complete the degree of combustion is.
A.2 Test methods and results
The cone calorimeter used in ISO 5660-1 is an instrument designed to measure the heat released from
burning materials. Specimens tested with the cone calorimeter can be subject to various levels of incident
heat flux and so it is possible to model different stages of a developing fire. This modelling has been shown to
correlate well with results from some large-scale fire tests, such as ISO 9705 (which simulates a fire which
starts in a corner of a small room) and ISO 24473.
Often when an FRP composite is tested in the cone calorimeter, it proves difficult to ignite at low incident heat
fluxes. A
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