SIST EN ISO 11925-2:2026

SLOVENSKI STANDARD
01-april-2026
Nadomešča:
SIST EN ISO 11925-2:2020
Preskusi odziva na ogenj - Sposobnost vžiga gradbenih proizvodov v
neposrednem stiku s plamenom - 2. del: Preskus z enim gorilnikom (ISO 11925-
2:2026)
Reaction to fire tests - Ignitability of products subjected to direct impingement of flame -
Part 2: Single-flame source test (ISO 11925-2:2026)
Prüfungen zum Brandverhalten-Entzündbarkeit von Produkten bei direkter
Flammeneinwirkung-Teil2: Einzelflammentest (ISO 11925-2:2026)
Essais de réaction au feu - Allumabilité de produits soumis à l'incidence directe de la
flamme - Partie 2: Essai à l'aide d'une source à flamme unique (ISO 11925-2:2026)
Ta slovenski standard je istoveten z: EN ISO 11925-2:2026
ICS:
13.220.50 Požarna odpornost Fire-resistance of building
gradbenih materialov in materials and elements
elementov
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 11925-2
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2026
EUROPÄISCHE NORM
ICS 13.220.50; 13.220.99 Supersedes EN ISO 11925-2:2020
English Version
Reaction to fire tests - Ignitability of products subjected to
direct impingement of flame - Part 2: Single-flame source
test (ISO 11925-2:2026)
Essais de réaction au feu - Allumabilité de produits Prüfungen zum Brandverhalten - Entzündbarkeit von
soumis à l'incidence directe de la flamme - Partie 2: Produkten bei direkter Flammeneinwirkung - Teil 2:
Essai à l'aide d'une source à flamme unique (ISO Einzelflammentest (ISO 11925-2:2026)
11925-2:2026)
This European Standard was approved by CEN on 12 January 2026.

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, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11925-2:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 11925-2:2026) has been prepared by Technical Committee ISO/TC 92 "Fire
safety" in collaboration with Technical Committee CEN/TC 127 “Fire safety in buildings” the secretariat
of which is held by BSI.
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 2026, and conflicting national standards shall be
withdrawn at the latest by July 2026.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 11925-2:2020.
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
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, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 11925-2:2026 has been approved by CEN as EN ISO 11925-2:2026 without any
modification.
International
Standard
ISO 11925-2
Fifth edition
Reaction to fire tests — Ignitability
2026-01
of products subjected to direct
impingement of flame —
Part 2:
Single-flame source test
Essais de réaction au feu — Allumabilité de produits soumis à
l’incidence directe de la flamme —
Partie 2: Essai à l’aide d’une source à flamme unique
Reference number
ISO 11925-2:2026(en) © ISO 2026

ISO 11925-2:2026(en)
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 11925-2:2026(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test apparatus . 2
5 Test specimen . 4
5.1 Preparation .4
5.2 Dimensions .4
5.3 Products which are not essentially flat .4
5.4 Number of specimens .4
5.5 Substrates .5
6 Conditioning . 5
7 Test procedure . 5
7.1 General .5
7.2 Preliminary operations .5
7.3 Testing operations .5
7.4 Duration of test .7
8 Expression of results . 7
9 Test report . 8
Annex A (informative) Precision of test method .22
Annex B (normative) Testing not essentially flat end-use products .25
Annex C (normative) Testing perforated end-use products .26
Bibliography .27

iii
ISO 11925-2:2026(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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 1, Fire
initiation and growth, in collaboration with the European Committee for Standardization (CEN) Technical
Committee CEN/TC 127, Fire safety in buildings, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
This fifth edition cancels and replaces the fourth edition (ISO 11925-2:2020), which has been technically
revised.
The main changes are as follows:
— note on the evaluation of the flame tip;
— revision of all figures.
A list of all parts in the ISO 11925 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
ISO 11925-2:2026(en)
Introduction
This fire test method has been developed to define reaction to fire performance of products. The method
specifies a test for determining the ignitability of products by direct small-flame impingement under zero
impressed irradiance using vertically oriented test specimens.
Although the method is designed to assess ignitability, this is addressed by measuring the spread of a small
flame up the vertical surface of a specimen following application of a small flame to either the surface or
edge of a specimen for either 15 s or 30 s. The determination of the production of flaming droplets/particles
depends on whether the filter paper placed beneath the specimen ignites.
Details on the precision of the test method is given in Annex A.
Details on testing not essentially flat end-use products is given in Annex B.
Details on testing perforated end-use products is given in Annex C.

v
International Standard ISO 11925-2:2026(en)
Reaction to fire tests — Ignitability of products subjected to
direct impingement of flame —
Part 2:
Single-flame source test
1 Scope
This document specifies a method of test for determining the ignitability of products by direct small flame
impingement under zero impressed irradiance using vertically oriented test specimens.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 13943, Fire safety — Vocabulary
ISO 14697, Reaction-to-fire tests — Guidance on the choice of substrates for building and transport products
EN 13238, Reaction to fire tests for building products — Conditioning procedures and general rules for selection
of substrates
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/
3.1
product
material, element or component about which information is required
[SOURCE: ISO 1716:2018, 3.1]
3.2
essentially flat product
product having one of the following characteristics:
a) a planar exposed surface;
b) a planar exposed surface with a surface irregularity that is evenly distributed over the exposed surface,
provided that:
— at least 50 % of the surface of a representative square area of 250 mm × 250 mm lies within a depth
of 6 mm from a plane taken across the highest points on the exposed surface, or

ISO 11925-2:2026(en)
— for a surface containing cracks, fissures or holes, these do not exceed 6,5 mm in width or 10 mm in
depth, and that the total area of such cracks, fissures or holes at the surface does not exceed 30 % of
a representative square area of 250 mm × 250 mm of the exposed surface
3.3
flaming droplet/particle
material separating from the specimen during the fire test procedure and igniting the filter paper beneath
the specimen
3.4
multi-layered product
product composed of two or more layers of different materials, which can be either substantial and/or non-
substantial
3.5
sustained flaming
persistence of flame for a period greater than 3 s
3.6
ignition
presence of sustained flaming
4 Test apparatus
4.1 Test room, capable of providing an environment at (23 ± 5) °C and a relative humidity of (50 ± 20) %.
NOTE It has been found that a partially darkened room assists with the perception of small surface flames.
4.2 Combustion chamber, consisting of an enclosure constructed from stainless steel sheets with heat-
resistant, glazed doors provided for access and observation in at least the front and one lateral side (see
Figure 1). Ventilation of the enclosure shall be free through the square box section base in the bottom of the
chamber. This shall be made of stainless steel of 1,5 mm thickness, 50 mm in height, with the open square
area being 25 mm × 25 mm. To make free ventilation possible, the chamber shall stand on 40 mm high
supports which provide a gap on the lateral sides of the combustion chamber. The air velocity measured
on the central axis in the chimney of the combustion chamber shall be (0,7 ± 0,1) m/s, measured with the
burner only ignited and with the ventilation hood “on”. The combustion chamber shall be situated under a
suitably ventilated hood.
4.3 Ignition source, consisting of burner constructed as shown in Figure 2 and designed so that it can
be used vertically or be tilted at 45° with respect to the vertical axis. The burner shall be mounted onto a
horizontal plate so that it moves smoothly forwards and backwards in a horizontal plane along the centreline
of the combustion chamber.
The burner shall be fitted with a fine adjustment valve to ensure accurate control of the flame height.
4.4 Fuel, consisting of commercial propane of 95 % minimum purity. In order to obtain flame stability
with the burner tilted at 45°, the gas pressure shall be between 10 kPa and 50 kPa.
4.5 Specimen holder, consisting of two stainless steel U-shaped frames. The thickness of the frames shall
be (5 ± 1) mm. The dimensions of the frame shall be as shown in Figure 3. The frame shall hang vertically
from the support (see 4.6 and Figure 7) such that the underside of the specimen is exposed directly to the

ISO 11925-2:2026(en)
flame along its centreline and edges (see Figure 8). The two halves of the specimen holder shall be held
together by screws or clamps to prevent the specimen warping.
It is important that the technique of clamping used is capable of restraining the specimen for the total
duration of the test.
NOTE Small pins of approximately 1 mm in length incorporated on the surface of the frame, to which the specimen
is attached, have been found suitable.
For multi-layered products, a typical test frame as shown in Figure 4 shall be used when carrying out the
prescribed additional set of tests on multi-layer test specimens of thickness greater than 10 mm according
to 7.3.3.2.3.
For the mounting and fixing of loose fill material, the following applies.
a) A specimen holder as shown in Figure 5 shall be used.
b) When making the specimens for testing, the surface of the loose fill material specimen shall be as even
as possible.
c) A wire lacing as shown in Figure 6 shall be used to retain the specimen if material falls from the
specimen holder. A wire of 0,2 mm diameter shall be used to form 11 rows vertically in front of the
opening to hold the loose fill material in place. The wire lacing shall have the shape of a harp.
d) If the material is a mixture of various grain sizes, the release of smaller particles from the open central
surface does not justify the use of the harp.
e) It is deemed sufficient to carry out the tests with a surface flame attack. Edge flame attack tests are not
necessary.
4.6 Support, consisting of a vertical stand to which the specimen holder is attached such that it hangs
vertically and exposes its open edge containing the specimen to the burner flame (see Figure 7).
The distance between the underside of the specimen and the top of horizontal plate above the metal grid
shall be (125 ± 10) mm for edge flame impingement and (85 ± 10) mm for surface flame impingement.
4.7 Timing device, capable of recording elapsed time to the nearest second and which shall be accurate to
within 5 s in 1 h.
0 0
4.8 Template, consisting of one metal plate 250 mm long and 90 mm wide.
 
1 1
4.9 Flame checking devices
4.9.1 Flame-height measuring device, capable of indicating a flame height of 20 mm (see Figure 9) when
located against a fixed point of the burner. The tolerance on the flame-height measuring device shall be
±0,1 mm.
The flame height shall be measured from the upper edge of the burner to the yellow tip of the flame. The
outer blue halo of the flame may not be considered. This check shall be conducted before testing each
specimen.
4.9.2 Burner spacer for edge flame impingement, removable, 16 mm long, which can be mounted at the
burner orifice to check the distance from the pre-set flame contact point on the specimen (see Figure 10).
4.9.3 Burner spacer for surface flame impingement, removable, cone-shaped, which can be mounted at
the burner orifice to check the fixed distance of 5 mm between the burner edge and specimen surface (see
Figure 11).
ISO 11925-2:2026(en)
4.10 Anemometer, thermal anemometer with an accuracy of ±0,1 m/s, for measuring the airflow velocity
in the upper outlet of the combustion chamber (see 4.2 and Figure 1).
4.11 Filter paper and tray. The paper shall be new, undyed filter paper with a mass/unit area of (75 ± 15)
g/m and an ash content of less than 0,1 %. The tray shall be 100 mm × 50 mm and 10 mm deep and made of
aluminium foil. The tray is placed beneath the specimen holder and is replaced between tests.
4.12 Apparatus to allow observation of the reverse face of the specimen. For some materials, it is
sometimes necessary to observe the flame on the reverse face of the specimen as well as the exposed face.
Provision shall therefore be made to enable the operator to view both sides of the specimen at the same
time. One method by which this may be achieved is to place a mirror such that the backside of the specimen
can be monitored. The mirror shall not be placed above the specimen, in order to avoid disturbance of the
airflow. The design and location of the mirror shall be appropriate for the construction of the equipment and
the available ambient lighting. The result observed on the reverse face shall be treated as if it occurred on
the front side.
5 Test specimen
5.1 Preparation
The test specimen shall be cut from a sample which is representative of the product to be tested using the
templates specified in 4.8.
5.2 Dimensions
2 2
The dimensions of the test specimens shall be 250 mm long by 90 mm wide.
 
2 2
Specimens normally having a thickness of 60 mm or less shall be tested using their full thickness. Specimens
normally having a thickness greater than 60 mm shall be reduced to a thickness of 60 m
...