ISO/FDIS 6940

ISO/DISFDIS 6940
ISO/TC 38
Secretariat: JISCSAC
Date: 2025-12-082026-01-16
Textile fabrics — Burning behaviour — Determination of ease of
ignition of vertically oriented specimens
DISÉtoffes textiles — Comportement au feu — Détermination de la facilité d'allumage d'éprouvettes orientées
verticalement
FDIS stage
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Voting begins on: 2025-05-19
Voting terminates on: 2025-08-11

ISO/DISFDIS 6940:20252026(en)
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ii
ISO/DISFDIS 6940:20252026(en)
Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 2
5.6 Timing devices . 2
6 Cautionary measure . 6
6.1 Construction of testing equipment . 6
6.2 Location of test apparatus . 6
6.3 Health and safety of test operators . 6
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 Procedure 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 Calculation of the mean ignition time . 13
12 Precision . 13
13 Test report . 13
Annex A (normative) Description and construction of the burner . 15
Annex B (informative) Calculation of mean ignition time — Work example . 16
Annex C (informative) Experimental techniques . 18
Bibliography . 19

iii
ISO/DISFDIS 6940:20252026(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
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/had not] received notice of (a)
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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 6940:2004), which has been technically
revised.
The main changes are as follows:
0— this revisin aims to clarifies without any structural changes;
— — Figure 1 b) ofhas been corrected with the second edition is incorrect for theproper angular dimension
line and the shape of the tip of the gas jet, and is revised to follow the Ammendment of the first edition;
— — Figure 3 a) and 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.
iv
ISO/DISFDIS 6940:20252026(en)
Introduction
This method is one of two closely related methods of test for the inflammability of textile fabrics. It determines
the ease of ignition, as defined in 0; the. The other method measures flame spread time 0(see).
v
Textile fabrics — Burning behaviour — Determination of ease of
ignition of vertically oriented specimens
1 Scope
This document specifies a method for the measurement of ease of ignition of vertically oriented textile fabrics
and industrial products in the form of single or multi-component textile fabrics (coated, quilted, multilayered,
sandwich constructions, and similar combinations), when subjected to a small, defined flame.
The method specified 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 thein 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 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 6940:20252026(en)
Textile fabrics — Burning behaviour — Determination of ease of
ignition of vertically oriented specimens
1 Scope
This document specifies a method for the measurement of ease of ignition of vertically oriented textile fabrics
and industrial products in the form of single or multi-component textile fabrics (coated, quilted, multilayered,
sandwich constructions, 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
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 (3.3) flame is applied to the test specimen
3.2
afterflame time
length of time for which a material continues to flame under specified test conditions, after the ignition (3.3)
source has been removedNote removed
Note 1 to entry: Afterflame time is measured to the nearest second and afterflame times of less than 1,0 s is recorded as
zero.
3.3
ignition
initiation of combustion
3.4
sustained combustion
flaming of the test specimen which gives an after-flameafterflame time (3.2) of 5 s or more or which reaches
the top or vertical edges in less than 5 s
4 Principle
A defined flame from a specified burner is applied to the surface or bottom edge of textile test specimens which
are vertically oriented.
ISO/DISFDIS 6940:20252026(en)
The mean ignition time is determined as the weighted mean of the measured flame application times to obtain
ignition of the test specimens.
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 (5.3(5.3,, see 0Figure 2)) in the specified relative orientation (see 0Figure 3).).
5.2 Gas burner, as 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 a test specimen support
pin at each corner of a rectangle of length 190 mm by width 70 mm (see 0Figure 2).). The pins for supporting
the test specimen have a maximum diameter of 2 mm and a length of at least 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 four pins.
5.4 Template, flat and rigid, made of a suitable material and a size corresponding to the size of the test
specimen (200 mm × 80 mm).
Holes approximately 4 mm in diameter are drilled in each corner of the template and positioned so that the
distances between the centres of the holes correspond to the distances 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 is generally used.
5.6 Timing devices
5.6.1 A timing device to control and measure the flame application time, which can be set at 1 s and adjusted
at 1 s intervals to 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 afterflame time. This device
is started, preferably automatically, at the instant of test flame termination or removal, and is stopped
manually.
ISO/DISFDIS 6940:20252026(en)
Dimensions in millimetres
ISO/DISFDIS 6940:20252026(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
a Fitted during assembly.
b Deburring.
NOTE Tolerance according to ISO 2768-1-m (see 0 m) if not otherwise indicated.
Figure 1 — Gas burner
ISO/DISFDIS 6940:20252026(en)
ISO/DISFDIS 6940:20252026(en)
Key
1 test specimen
2 spacer stub
3 mounting pin
NOTE Tolerance according to ISO 2768-1-m (see 0) if not otherwise indicated.
Figure 2 — Test specimen holder
6 Cautionary measuresmeasure
6.1 Construction of testing equipment
Some products of combustion are corrosive. The equipment shall be constructed of material that will not be
adversely affected by the fumes.
6.2 Location of test apparatus
The volume of air surrounding the test location shall not have any influence on testing. Where an open-fronted
cabinet is used for the test, provision shall be made to allow the test specimen to be mounted at least 300 mm
from any wall.
6.3 Health and safety of test operators
Burning of materials can produce smoke and toxic gases that can affect the health of operators. Between tests,
the atmosphere of the testing location, which shall be of adequate dimensions to avoid endangering the health
of operators, shall be cleared of smoke and fumes by an extractor fan or other means of ventilation (see
6.26.2).).
ISO/DISFDIS 6940:20252026(en)
NOTE Smoke and fume emission can be subjected to national regulations concerning atmospheric pollution
control.
7 Sampling
7.1 Number of test specimens
Mark out a set of twelve test specimens, using the template (5.4(5.4),), to allow for at least five instances of
ignition and five instances of non-ignition to occur.
testTest specimens should normally be tested with the length direction vertical and the outer face towards
the igniting flame. If the test material is non-homogeneous and preliminary testing indicates dissimilar
inflammability characteristics, length and width test specimens should be tested separately. For surface
ignition, where the two surfaces of the sample are visually dissimilar and preliminary testing indicates
dissimilar inflammability characteristics, each surface shall be tested and the results reported separately.
An iterative procedure is used and the exact number of test specimens cannot be stated. A minimum of 10 test
specimens is needed for each orientation. An extra test specimen is required for the setting-up procedure (see
9.19.1 and 9.29.2).).
7.2 Test specimen h
...