ISO/FDIS 6941

ISO/DISFDIS 6941
ISO/TC 38
Secretariat: JISCSAC
Date: 2025-12-082026-01-16
Textile fabrics — Burning behaviour — Measurement of flame spread
properties of vertically oriented specimens
DISÉtoffes textiles — Comportement au feu — Détermination des propriétés de propagation de flamme
d'éprouvettes orientées verticalement
FDIS stage
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Voting begins on: 2025-05-19
Voting terminates on: 2025-08-11

ISO/DISFDIS 6941:20252026(en)
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ISO/DISFDIS 6941:20252026(en)
Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
5.6 Timing device . 2
6 Precautions . 6
6.1 Construction of testing equipment . 6
6.2 Location of test apparatus . 6
6.3 Health and safety of operators . 7
7 Sampling . 7
7.1 Number of test specimens . 7
7.2 Test specimen holder pin location marks . 7
7.3 Test specimen size . 7
8 Conditioning and testing atmosphere . 7
8.1 Conditioning . 7
8.2 Testing atmosphere . 7
9 Setting up the apparatus . 8
9.1 Procedures A (Surface ignition) . 8
9.2 Procedure B (Bottom edge ignition) . 8
10 Test procedure . 12
10.1 Surface ignition . 12
10.2 Bottom edge ignition . 12
11 Precision . 12
12 Test report . 13
Annex A (normative) Description and construction of the burner . 14
Annex B (informative) Experimental techniques . 15
Bibliography . 16

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ISO/DISFDIS 6941:20252026(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
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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
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This document was prepared by Technical Committee ISO/TC 38, Textiles., in collaboration with the European
Committee for Standardization (CEN) Technical Committee CEN/TC 248, Textiles and textile products, in
accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 6941:2003), which has been technically
revised.
The main changes are as follows:
0— this revision aims to clarifies without any structural changes;
— — Figure 1 b) ofhas been corrected with the second edition is incorrect forproper angular dimension line
and the shape of the tip of the gas jet and is revised to follow the Amendment of the first edition;
— — Figure 3 a) and 0 b) have been revised to show the test specimen clear;
— this revision aims to clarify without any structural changes.
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.
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ISO/DISFDIS 6941:20252026(en)
Introduction
This method is one of two closely related methods of test for the inflammability of textile fabrics. This method
determines the “flame spread time” — vocabulary in relation to the termas defined in 0ISO 4880 — the. The
other method observes and measures “ease of ignition” (see ISO 06940).).
ThisThe method given in this document assesses the properties of textile fabrics in response to flame contact
under controlled conditions. There is a possibility that results do not apply the situations where there is
restricted air supply or exposure to large sources of intense heat.
The influence of seams on the behaviour of textile fabrics can be determined by this method, the seam being
positioned within the test specimen so as to be subjected to the test flame. Whenever practicable, trimmings
are tested as part of the textile fabric assembly on which they are or will be used.
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ISO/DISFDIS 6941:20252026(en)
Textile fabrics — Burning behaviour — Measurement of flame spread
properties of vertically oriented specimens
1 Scope
This document specifies a method for the measurement of flame spread times of vertically oriented textile
fabrics and industrial products in the form of single or multi-component textile fabrics (coated, quilted,
multilayered, sandwich combinations, and similar combinations) when subjected to a small, defined flame.
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 4880, Burning behaviour of textiles and textile products — Vocabulary
EN ISO 6940, Textile fabrics -— Burning behaviour -— Determination of ease of ignition of vertically oriented
specimens (ISO 6940:2004)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4880 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
flame application time
time for which the ignition flame is applied to the test specimen
3.2
flame spread time
time taken by a flame on a burning material to travel a specified distance under specified test conditions
4 Principle
A defined flame from a specified burner is applied for 10 s to the surface or the bottom edge of test specimens
which are vertically oriented. The flame spread times in seconds for the flame front to travel between marker
threads positioned adjacent to the surface of the test specimen and located at three distances from the igniting
flame, are recorded.
5 Apparatus
5.1 Mounting frame, constructed to a design capable of holding the gas burner (5.2(5.2),), see 0Figure 1,,
and the test specimen holder (5.2(5.3),), see 0Figure 2,, in the specified relative orientation, see 0Figure 3.
ISO/DISFDIS 6941:20252026(en)
The design shall also permit three marker threads (5.7(see 5.7)) to be attached in the positions shown in
0Figure 2. At each location the marker thread is mounted as a loop so that the two segments are spaced 1 mm
and 5 mm from the plane of the front of the test specimen. Each loop is attached to a different timing device
(5.6.2(5.6.2).).
5.2 Gas burner, as shown in 0Figure 1 and described in Annex AAnnex A,, capable of being moved from a
standby position, where the tip of the burner is at least 75 mm from the test specimen to either the horizontal
or inclined operating position, see 0Figure 3.
5.3 testTest specimen holder, consisting of a rectangular metal frame having 12 test specimen support
pins mounted along the longer edge of the rectangle of length 560 mm by width 150 mm, see 0Figure 2. The
pins for supporting the test specimen are 5 mm, 10 mm, 190 mm, 370 mm, 550 mm and 555 mm above the
bottom edge of the frame and have a minimum length of 26 mm.
NOTE Longer pins can be needed for mounting thick or multilayer test specimens.
For the purpose of locating the test specimen in a plane at least 20 mm away from the frame (see 9.1.19.1.1
and 9.2.19.2.1),), a spacer stub of 2 mm diameter and a length of at least 20 mm shall be positioned adjacent
to each of the pins, except for the upper and lower pins on each side.
5.4 Template, flat rigid, made of a suitable material and of a size corresponding to the size of the test
specimen (560 mm × 170 mm) shall be used.
Twelve holes, approximately 4 mm in diameter, are drilled along the edges of the template and positioned so
that the distances between the centres of the holes correspond to the distance between the pins on the test
specimen holder (see 0Figure 2).). The holes should be located equidistant about the vertical centreline of the
template.
5.5 Gas, commercial grade propane or butane or butane/propane mixtures.
NOTE Commercial grade propane gas is generally used.
5.6 Timing device
5.6.1 A timing device to control and measure the flame application time and which can be set at 1 s and
adjusted at 1 s intervals with an accuracy of 0,2 s or better.
5.6.2 Three timing devices reading to 0,2 s or better are required to measure the flame spread times. These
devices are started simultaneously when the igniting flame is applied and are stopped automatically when the
individual marker threads are severed.
5.7 Marker threads, white mercerized cotton thread having a linear density of 45 tex to 50 tex.
ISO/DISFDIS 6941:20252026(en)
Dimensions in millimetres
ISO/DISFDIS 6941:20252026(en)
Key
1 gas jet
2 burner tube
3 flame stabilizer
4 choke tube
5 notch
6 gas mixing zone
7 diffusion zone
8 air chamber
9 gas outlet
Tolerance according to if not otherwise indicated.
a Fitted during assembly
b Deburring
NOTE Tolerance according to ISO 2768-1-m (see 0) if not otherwise indicated.
Figure 1 — Gas burner
ISO/DISFDIS 6941:20252026(en)
Dimensions in millimetres
ISO/DISFDIS 6941:20252026(en)
Key
1 third marker thread
2 second marker thread
3 fabric test specimen
4 first marker thread
5 mounting pins
6 spacer stubs (optional)
7 burner (oriented for surface ignition)
NOTE Tolerance according to ISO 2768-1-m (see 0.).
Figure 2 — Test specimen holde
...