EN ISO 9239-1:2025

SLOVENSKI STANDARD
01-september-2025
Nadomešča:
SIST EN ISO 9239-1:2010
Preskusi odziva talnih oblog na ogenj - 1. del: Ugotavljanje obnašanja pri gorenju
z uporabo sevalnega vira toplote (ISO 9239-1:2025)
Reaction to fire tests for floorings - Part 1: Determination of the burning behaviour using
a radiant heat source (ISO 9239-1:2025)
Prüfungen zum Brandverhalten von Bodenbelägen - Teil 1: Bestimmung des
Brandverhaltens bei Beanspruchung mit einem Wärmestrahler (ISO 9239-1:2025)
Essais de réaction au feu des revêtements de sol - Partie 1: Détermination du
comportement au feu à l'aide d'une source de chaleur rayonnante (ISO 9239-1:2025)
Ta slovenski standard je istoveten z: EN ISO 9239-1:2025
ICS:
13.220.40 Sposobnost vžiga in Ignitability and burning
obnašanje materialov in behaviour of materials and
proizvodov pri gorenju products
97.150 Talne obloge Floor coverings
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 9239-1
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2025
EUROPÄISCHE NORM
ICS 13.220.40; 97.150 Supersedes EN ISO 9239-1:2010
English Version
Reaction to fire tests for floorings - Part 1: Determination
of the burning behaviour using a radiant heat source (ISO
9239-1:2025)
Essais de réaction au feu des revêtements de sol - Prüfungen zum Brandverhalten von Bodenbelägen -
Partie 1: Détermination du comportement au feu à Teil 1: Bestimmung des Brandverhaltens bei
l'aide d'une source de chaleur rayonnante (ISO 9239- Beanspruchung mit einem Wärmestrahler (ISO 9239-
1:2025) 1:2025)
This European Standard was approved by CEN on 29 June 2025.

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
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9239-1:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 9239-1:2025) 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 January 2026, and conflicting national standards shall
be withdrawn at the latest by January 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 9239-1:2010.
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 9239-1:2025 has been approved by CEN as EN ISO 9239-1:2025 without any
modification.
International
Standard
ISO 9239-1
Fourth edition
Reaction to fire tests for floorings —
2025-06
Part 1:
Determination of the burning
behaviour using a radiant heat source
Essais de réaction au feu des revêtements de sol —
Partie 1: Détermination du comportement au feu à l'aide d'une
source de chaleur rayonnante
Reference number
ISO 9239-1:2025(en) © ISO 2025

ISO 9239-1:2025(en)
© ISO 2025
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 9239-1:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Principle . 3
5 Apparatus . 3
5.1 General .3
5.2 Test chamber .3
5.3 Specimen holder .3
5.4 Sliding platform .3
5.5 Steel scale .4
5.6 Gas-fired radiant panel .4
5.7 Pilot burner.4
5.8 Exhaust system .4
5.9 Anemometer .4
5.10 Radiation pyrometer .4
5.11 Thermocouples .5
5.12 Heat flux meter .5
5.13 Dummy specimen.5
5.14 Recording equipment .5
5.15 Timing device .5
5.16 Smoke measurements .5
6 Test specimens . 5
6.1 General and number .5
6.2 Substrates .6
6.3 Adhesives .6
6.4 Underlay .6
6.5 Tiles .6
6.6 Loose laid flooring . .6
6.7 Washing and cleaning.6
6.8 Formal test .6
7 Conditioning . 7
8 Test procedure . 7
8.1 Calibration procedure .7
8.2 Standard test procedure .8
9 Expression of results . 9
10 Test report . 9
Annex A (normative) Smoke measurement .20
Annex B (informative) Precision of test method .23
Annex C (normative) Gas and air supplies .24
Annex D (informative) Template report format for this document .25
Bibliography .30

iii
ISO 9239-1:2025(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 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 fourth edition cancels and replaces the third edition (ISO 9239-1:2010), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— change in definition of HF-E/CHF (3.2, 3.3, 3.4)
— change in definition of tiles (size) (3.11)
— adding information about generic adhesives (6.3)
— defining securing method for edges of tiles (6.5)
— securing of loose laid flooring (6.6)
— calculation is now made from HF-E and/or HF-30 values (8.2.6)
— reporting of values in the HF-E and/or HF-30 values, and calculate mean CHF from these (9.2)
— adding of explanation of what to do if sample re-ignites after extinguishment (9.3)
— adding references to LED light sources (A.3.2.)
— adding of Annex D “Example of report template”
A list of all parts in the ISO 9239 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 9239-1:2025(en)
Introduction
The measurements in the test method in this document provide a basis for estimating one aspect of fire
exposure behaviour of floorings. The imposed radiant flux simulates the thermal radiation levels likely to
impinge on the floor of a corridor whose upper surfaces are heated by flames or hot gases or both, during
the early stages of a developing fire in an adjacent room or compartment under wind-opposed flame-spread
conditions.
v
International Standard ISO 9239-1:2025(en)
Reaction to fire tests for floorings —
Part 1:
Determination of the burning behaviour using a radiant
heat source
WARNING — The possibility of a gas-air fuel explosion in the test chamber should be recognized.
Suitable safeguards consistent with sound engineering practice should be installed in the panel fuel
supply system. These should include at least the following:
— a gas-feed cut-off which is immediately activated when air and/or gas supply fail;
— a temperature sensor or a flame detection unit directed at the panel surface that stops fuel flow
when the panel flame goes out.
The attention of all persons concerned with managing and carrying out this test is drawn to the fact
that fire testing can be hazardous and that there is a possibility that toxic and/or harmful gases can
be evolved during the test. Operational hazards can also arise during the testing of specimens, such
as the possibility of an explosion, and during the disposal of test residues.
An assessment of all the potential hazards and risks to health shall be made and safety precautions
shall be identified and provided. Written safety instructions shall be issued. Appropriate training
should be given to relevant personnel. Laboratory personnel shall ensure that they follow written
instructions at all times.
1 Scope
This document specifies a method for assessing the wind-opposed burning behaviour and spread of flame of
horizontally mounted floorings exposed to a heat flux radiant gradient in a test chamber, when ignited with
pilot flames. Annex A gives details of assessing the smoke development, when required.
This method is applicable to all types of flooring, e.g. textile carpet, cork, wood, rubber and plastics
coverings as well as coatings. Results obtained by this method reflect the reaction to fire performance of the
flooring, including any substrate if used. Modifications of the backing, bonding to a substrate, underlay or
other changes of the flooring can affect test results. It cannot be used alone to describe or appraise the fire
hazard or fire risk of floorings under actual fire conditions.
Information on the precision of the test method is given in Annex B.
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 554, Standard atmospheres for conditioning and/or testing — Specifications
ISO 3182, Light measuring system for smoke emission testing
ISO 13943, Fire safety — Vocabulary
ISO 14697, Reaction-to-fire tests — Guidance on the choice of substrates for building and transport products

ISO 9239-1:2025(en)
ISO 14934-2, Fire tests — Calibration and use of heat flux meters — Part 2: Primary calibration methods
ISO 14934-3, Fire tests — Calibration and use of heat flux meters — Part 3: Secondary calibration method
ISO/TS 19850, Fire tests — Use of LED (light-emitting diode) as an alternative to white light for measuring
smoke parameters
EN 13238, Reaction to fire tests for building products — Conditioning procedures and general rules for selection
of substrates
IEC 60584-1, Thermocouples — Part 1: EMF specifications and tolerances
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 terminology 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
heat flux
amount of thermal energy emitted, transmitted or received per unit area and unit time
Note 1 to entry: Heat flux is expressed in kilowatts per square metre (kW/m ).
3.2
heat flux at extinguishment
HF-E
incident heat flux (3.1), in kW/m , at the surface of a specimen at the point where the flame ceases to advance
and may subsequently go out
3.3
heat flux at X min
HF-X
heat flux (3.1), in kW/m , received by the specimen at the most distant spread of flame position observed
during the first X min of the test
3.4
critical heat flux
CHF
heat flux (3.1) at which the flame extinguishes (HF-E) or the heat flux (3.1) after the test period of 30 min
(HF-30), whichever is the lower value (i.e. the flux corresponding to the furthest extent of spread of flame
within 30 min)
3.5
heat flux profile
curve relating the heat flux (3.1) on the specimen plane to the distance from the zero point
3.6
zero point of heat flux profile
inner edge of the hottest side of the specimen holder (see Figures 6, 8 and 9)
3.7
sustained flaming
persistence of flame on or over the surface of the specimen for a period of more than 4 s
3.8
flame-spread distance
furthest extent of travel of a sustained flaming (3.7) along the length of the test specimen within a given time

ISO 9239-1:2025(en)
3.9
flooring
upper layer(s) of a floor, comprising any surface finish with or without an attached backing and with any
accompanying underlay, interlay and/or adhesive
3.10
substrate
product which is used immediately beneath the product about which information is required
Note 1 to entry: For a flooring, it is the floor on which the flooring is mounted or the material representing the floor.
3.11
tiles
generally square flooring (3.9) with linear dimensions less than (1 050 ± 5) mm.
4 Principle
The test specimen is placed in a horizontal position below a gas-fired radiant panel inclined at 30° where it
is exposed to a defined heat flux. A pilot flame is applied to the hotter end of the specimen. The test principle
is illustrated in Figure 1. Following ignition, any flame front that develops is noted and a record is made of
the progression of the flame front horizontally along the length of the specimen in terms of the time it takes
to spread to defined distances. If required, the smoke development during the test is recorded as the light
transmission in the exhaust stack.
The results are expressed in terms of flame-spread distance versus time, the critical heat flux and smoke
density versus time.
5 Apparatus
5.1 General
The apparatus shall be as described in 5.2 to 5.8 and shall have the dimensions shown in Figures 2 to 5. The
apparatus shall be placed in a room that is sufficiently large that there is a distance of at least 0,4 m between
the apparatus and the walls and the ceiling.
5.2 Test chamber
The chamber shall be made of calcium silicate boards of (13 ± 1) mm thickness and 650 kg/m to
750 kg/m nominal density, with a tightly fitting panel of fire-resistant glass with dimensions of
(110 ± 10) mm × (1 100 ± 100) mm, situated at the front so that the whole length of the specimen can be
observed during the test. The chamber may have an outside metal cladding. Below this observation window,
an access door shall be provided through which the test specimen platform can be moved into the chamber
for the test and out of the chamber after test.
5.3 Specimen holder
The test specimen holder is fabricated from heat-resistant L-profile stainless steel of (2,0 ± 0,1) mm thickness
with the dimensions shown in Figure 6. The test specimen is exposed through an opening (200 ± 3) mm ×
(1 015 ± 10) mm. The test specimen holder is fastened to the sliding steel platform by means of two bolts on
each end.
The test specimen holder shall be provided with a means to secure the specimen (e.g. steel bar clamps); a
maximum of eight clamps shall be used. The overall thickness of the holder is (22 ± 2) mm.
5.4 Sliding platform
The bottom of the chamber shall consist of a sliding platform, which shall have provision for rigidly securing
the test specimen holder in a fixed and level position (see Figure 1). The total air access area between the

ISO 9239-1:2025(en)
chamber and the test specimen holder shall be (0,23 ± 0,03) m uniformly distributed on all sides of the test
specimen.
5.5 Steel scale
At least one steel scale marked with 10 mm and 50 mm intervals shall be mounted on one side of the test
specimen holder. A second steel scale on the other side of the specimen holder may also be used.
5.6 Gas-fired radiant panel
The source of radiant heat energy shall be a panel of porous material mounted in a metal frame, with a
radiation surface of (300 ± 10) mm × (450 ± 10) mm.
The panel shall be capable of withstanding temperatures up to 900 °C and use a fuel gas/air mixing system
with suitable instrumentation in accordance with Annex C to ensure consistent and repeatable operation.
Propane and/or butane/air mixtures have been proven to be suitable, but other fuel gas/air mixtures may
also be used.
The radiant heat panel is placed over the test specimen holder with its longer dimension at (30 ± 1)° to the
horizontal plane (see Figure 5).
5.7 Pilot burner
The pilot burner, used to ignite the test specimen, shall be of nominal internal diameter 6 mm and of outer
diameter 10 mm, and be made of stainless steel having two lines of 19 evenly spaced 0,7 mm diameter holes
drilled radially along the centre-line and 16 evenly spaced 0,7 mm diameter holes drilled radially 60° below
the centre-line (see Figure 7). In operation, the propane flow rate shall be adjusted to (0,026 ± 0,002) l/s. The
pilot burner shall be positioned so that the flames generated from the lower line of holes will impinge on the
specimen (10 ± 2) mm from the zero point (see Figure 8). The pilot burner tube shall be 3 mm above the edge of
the specimen holder when the burner is in the ignition position. When not being applied to the test specimen,
the burner shall be capable of being moved at least 50 mm away from the zero point of the test specimen. The
gas used shall be commercial-grade propane having a calorific value of approximately 83 MJ/m .
NOTE 1 It is important to keep the holes in the pilot burner clean. A soft wire brush is suitable to remove surface
contaminants. Nickel-chromium or stainless-steel wire, 0,5 mm in diameter, is suitable for opening the holes.
NOTE 2 With the propane gas flow properly adjusted and the pilot burner in the test position, the pilot flame will
vary in height from approximately 60 mm to approximately 120 mm across the width of the burner (see Figure 8).
5.8 Exhaust system
An exhaust system connected to the exhaust duct and de-coupled from the exhaust stack of the test
apparatus, shall be used to extract the products of combustion. With the gas-fired radiant panel turned
off, the dummy specimen in place and the access door closed, the air velocity in the exhaust stack shall be
(2,5 ± 0,2) m/s.
3 3
NOTE An exhaust capacity of 39 m /min to 85 m /min (at 25 °C, 1 bar) has proven to be suitable.
5.9 Anemometer
An anemometer with an accuracy of ±0,1 m/s shall be provided for measuring the air velocity in the exhaust
stack. It shall be fitted in the exhaust stack, in such a way that its measuring point coincides with the centre-
line of the exhaust stack at (250 ± 10) mm above the lower edge of the exhaust stack (see Figure 4).
5.10 Radiation pyrometer
In order to control the thermal output of the radiant panel, a radiation pyrometer with a range of 480 °C to
530 °C (black-body temperature) and an accuracy of ±5 °C suitable for viewing a circular area 250 mm in
diameter at a distance of about 1,4 m shall be used.

ISO 9239-1:2025(en)
The sensitivity of the pyrometer shall be substantially constant between the wavelengths 1 µm and 9 µm.
5.11 Thermocouples
A 3,2 mm stainless-steel sheathed type K thermocouple, in accordance with IEC 60584-1 with an insulated
measuring junction, shall be mounted in the flooring radiant test chamber. It shall be located in the
longitudinal central vertical plane of the chamber, 25 mm down from the top and 100 mm back from the
inside wall of the exhaust stack (see Figures 4 and 5).
A second thermocouple may be inserted centrally in the exhaust stack, at a distance of (150 ± 2) mm from
the top of the exhaust stack. The thermocouples shall be cleaned after each test.
5.12 Heat flux meter
The heat flux meter used to determine the heat flux profile to the test specimen shall be of the Schmidt-
Boelter type without a window and with a diameter of 25 mm. Its range shall be from 0 kW/m to 15 kW/
2 2 2
m , and shall be calibrated over the operating heat flux level range from 1 kW/m to 15 kW/m . A source of
cooling water with a temperature of 15 °C to 25 °C shall be provided for this instrument.
The heat flux meter shall have an accuracy of ±3 % of the measured value, and shall be calibrated in
accordance with ISO 14934-2 or ISO 14934-3.
5.13 Dummy specimen
The dummy specimen used for calibration shall be made of (20 ± 1) mm thick uncoated calcium silicate board
of (850 ± 100) kg/m density. It shall be (250 ± 10) mm wide and (1 050 ± 20) mm long (see Figure 6), with
(26 ± 1) mm diameter holes centred on and along the centre-line at 110 mm, 210 mm through to 910 mm
locations, measured from the zero point of the test specimen.
5.14 Recording equipment
Recording equipment shall be suitable for recording the output from the radiation pyrometer and the heat
flux meter.
5.15 Timing device
A timing device capable of recording elapsed time to the nearest second and with an accuracy of 1 s in 1 h
shall be used.
5.16 Smoke measurements
The apparatus described in Annex A shall be used if smoke measurements are required.
6 Test specimens
6.1 General and number
The test specimens shall be representative of the flooring in its end use.
Cut six specimens with dimensions (1 050 ± 5) mm × (230 ± 5) mm, three in one direction (e.g. production
direction) and three in a direction perpendicular to the first direction. For products not having a directional
surface effect/production direction three test specimens are cut/cast (e.g. in situ cast epoxy floorings or
floor paints).
NOTE Under normal circumstances, 38 mm is the maximum thickness, but with modification of the specimen
holder the thickness can be greater. If the thickness of the specimen is more than 19 mm, the length can be reduced to
(1 025 ± 5) mm.
ISO 9239-1:2025(en)
6.2 Substrates
The specimen shall be mounted on a substrate that simulates the actual floor in accordance with EN 13238
or ISO 14697 and shall simulate actual installation practice.
6.3 Adhesives
The adhesive used for the specimens shall be representative of those used in practice. If in practice different
adhesives are used, the specimens shall be prepared using each of the different adhesives or without
adhesives.
If “generic” adhesives are used, the results apply for all adhesives of the same defined type, applied in similar
quantities. “Generic” refers to adhesives giving the same or higher reaction to fire performance to the
product in question, as that tested. Subject to the above, “generic” may also apply to adhesives of a defined
type (e.g. polyvinylpyrrolidone, polyvinylacetate). If specific adhesives are used, the results apply only for
the specific adhesives.
6.4 Underlay
When used as part of the specimen, underlays shall be representative of those used in practice.
6.5 Tiles
If the specimen consists of tiles, it shall be representative of the largest dimension tile. The specimen shall be
mounted so that the first joint is located the farthest possible distance from the zero point. The test results
are applicable to identical tiles of smaller dimensions.
Where the tile is not sufficiently wide to cover the width of the specimen holder, the test specimen shall be
prepared to incorporate a centre-longitudinal joint.
The edges of joints should be secured on the substrate by mechanical means.
One securing method is the use of staples at about 100 mm spacing. The staples shall be perpendicular to
the joint and be located across it. This shall be done in addition to securing the edges of the specimen by the
specimen holder.
6.6 Loose laid flooring
Loose laid flooring including tiles, when tested without adhesives, shall be fixed only by means of the
specimen holder and its clamps (see 5.3), except at the joints, which shall be secured with three staples
crosswise.
Flooring, which due to shrinkage withdraws from the specimen holder frame, can show different results
depending on the fixing. Special attention shall therefore be given to the use of good fixing techniques for
floorings with a tendency to shrink during the heat exposure.
6.7 Washing and cleaning
To determine the effect of washing or cleaning procedures on the fire performance of the flooring, the test
specimens shall be washed or cleaned in accordance with the procedures given in the relevant product
specification for the flooring.
6.8 Formal test
A formal test shall consist of the results from three specimens which are identical in all respects.
Additional details for the preparation of the test specimen shall be in accordance with the relevant product
specifications.
ISO 9239-1:2025(en)
For loose fill materials and for materials that melt forming molten pools, ensure that the sides of the
specimen holder are fully closed. No attempt should be made to increase the height of the specimen holder to
adjust the incident heat flux on the specimen.
7 Conditioning
The specimens shall be conditioned as specified in EN 13238 or ISO 554.
The curing time for flooring, which is glued to the substrate, is at least three days. This time may be part of
the conditioning.
8 Test procedure
8.1 Calibration procedure
8.1.1 The apparatus shall be calibrated using the following procedure after each essential change of the
apparatus, or at least once a month. If there are no changes in subsequent calibrations, this interval may be
extended to six months.
8.1.2 Position the sliding platform and the mounting frame together with the dummy specimen in the
chamber. Measure the air velocity in the exhaust stack with the exhaust system running and the access door
closed and, if necessary, adjust it to (2,5 ± 0,2) m/s. Ignite the radiant panel.
Allow the unit to heat for at least 1 h until the chamber temperature has stabilized (see 8.2.2). The pilot
burner shall be off during this period.
8.1.3 Measure the heat flux level at the 410 mm point with the total heat flux meter. Insert the heat flux
meter in the hole so that its detecting surface is between 2 mm and 3 mm above and parallel to the plane of
the dummy specimen. Allow the reading to stabilize over a 30 s period. Read its output over a subsequent
30 s. If the averaged level is (5,1 ± 0,2) kW/m , start the heat flux profile determination. If it is not, make the
necessary adjustments to the gas/air flows to the panel, and the in-panel fuel flow, at least 10 min before a
new reading of the heat flux is taken.
8.1.4 Perform the determination of the heat flux profile.
Insert the heat flux meter in each hole in turn, starting with the 110 mm location and ending with the
910 mm location. Ensure that the detecting plane of the meter and time of measurement agree with 8.1.3.
To determine whether the heat flux level has changed during these measurements, check the reading at
410 mm, after the 910 mm reading.
8.1.5 Record the heat flux data as a function of distance along the specimen plane. Carefully draw a
smooth curve through the data points. This curve is the heat flux profile curve (see Figure 9). The heat flux
value reported and used as a basis for determining the CHF is based on interpolations of this curve.
If the heat flux profile curve is within the tolerances of Table 1, the test equipment is in calibration and the
heat flux profile determination is completed. If not, carefully adjust the fuel flow and allow at least 10 min to
ensure that the chamber temperature is stabilized. Repeat the procedure until the heat flux profile is within
the specifications in Table 1.
To correct the heat flux at the hotter end of the specimen, normally only a change of gas flow is necessary. To
correct the heat flux at the colder end of the specimen, a change to both gas and air flows can be necessary.

ISO 9239-1:2025(en)
8.1.6 Remove the dummy specimen and close the door. After 5 min, measure the black-body temperature
of the radiant panel and the temperature of the chamber. Record the results.
Table 1 — Required heat flux distribution onto the dummy specimen board
Distance to zero
Heat flux Tolerances
point of specimen
2 2
mm kW/m kW/m
110 10,9 ±0,4
210 9,2 ±0,4
310 7,1 ±0,4
410 5,1 ±0,2
510 3,5 ±0,2
610 2,5 ±0,2
710 1,8 ±0,2
810 1,4 ±0,2
910 1,1 ±0,2
8.2 Standard test procedure
8.2.1 Set the air velocity in the exhaust stack in accordance with 8.1.2. Remove the dummy specimen
and close the door. Ignite the panel and allow the test apparatus to heat for at least 1 h until the chamber
temperature has stabilized.
8.2.2 Measure the black-body temperature of the radiant panel. The black-body temperature shall be
within ±5 °C of the black-body temperature recorded during the calibration in accordance with 8.1.6. The
chamber temperature shall be within ±10 °C of the chamber temperature recorded during the calibration in
accordance with 8.1.6.
If the black-body or chamber temperature differs by more than the given limits, adjust the gas/air input to
the radiant panel. Allow the test apparatus unit to stabilize for at least 15 min before the temperatures are
measured again. When the temperatures are within the limits given, the test apparatus is ready for use.
If required, adjust the smoke-measuring system so that its output value is equal to 100 %. Ensure that the
measuring system has stabilized before starting the tests. If not, adjust it further. Check the purging air to
both the lamp and the detector system and adjust if necessary.
8.2.3 Insert the test specimen, including any underlay(s) and substrate, into the specimen holder. Place
the steel bar clamps across the back of the assembly and tighten the nuts firmly or apply other fixing means.
Raise the pile of textile flooring, if applicable, using a vacuum cleaner and mount the test specimen and its
holder onto the sliding platform.
Ignite the pilot burner, keeping it at least 50 mm away from the intended zero point of the test specimen.
Move the sliding platform into the chamber and immediately close the door. This is the start of the test. Start
the timing and recording devices.
After preheating for 2 min with the pilot burner at least 50 mm away from the zero point of the test specimen,
bring the pilot burner flames into contact with the test specimen 10 mm from the edge of the holder as
specified in 5.5. Leave the pilot burner flames in contact with the test specimen for 10 min, then withdraw
the pilot burner to a position at least 50 mm away from the zero point of the test specimen. Extinguish the
pilot burner flames. During the test, both the gas and air flow to the radiant panel shall be kept constant.
8.2.4 At 10 min intervals from the start of the test and at the flame-out time, measure the distances
between the flame front and the zero point to the nearest 10 mm. Observe and record any significant

ISO 9239-1:2025(en)
phenomena such as transitory flaming, melting, blistering, time and location of glowing combustion after
flame-out, penetration of the flame through to the substrate, etc.
Additionally, note the
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