ISO/TR 10093:2017

Plastics - Fire tests - Standard ignition sources

ISO/TR 10093:2017 describes and classifies a range of laboratory ignition sources for use in fire tests on plastics and products consisting substantially of plastics. These sources vary in intensity and area of impingement. They are suitable for use to simulate the initial thermal abuse to which plastics are potentially exposed in certain actual fire risk scenarios. Different standards developing organizations have issued many standard test methods, specifications and regulations to assess fire properties of plastics or of products containing plastic materials. Many of those standards contain ignition sources associated with flaming and non-flaming ignition. This document describes the ignition sources and references the associated standard. This compilation of ignition sources does not discuss the application of the standard where the ignition source is described and is likely not to be a fully comprehensive list of ignition sources. ISO/TR 10093:2017 does not address detailed test procedures.

Plastiques — Essais au feu — Sources d'allumage normalisées

General Information

• Status: Withdrawn
• Publication Date: 29-Nov-2017
• Withdrawal Date: 29-Nov-2017
• ICS: 13.220.40 - Ignitability and burning behaviour of materials and products
• ICS: 83.080.01 - Plastics in general
• Technical Committee: ISO/TC 61/SC 4 - Burning behaviour
• Drafting Committee: ISO/TC 61/SC 4/WG 8 - Ignitability and fire growth
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 11-Sep-2018
• Completion Date: 13-Dec-2025

Relations

• Consolidates: ISO 16201:2006 - Technical aids for persons with disability - Environmental control systems for daily living
• Effective Date: 06-Jun-2022
• Consolidated By: ISO 10088:2022 - Small craft - Permanently installed fuel systems
• Effective Date: 06-Jun-2022
• Revised: ISO/TR 10093:2018 - Plastics - Fire tests - Standard ignition sources
• Effective Date: 27-Jan-2018
• Revises: ISO 10093:1998 - Plastics - Fire tests - Standard ignition sources
• Effective Date: 01-Nov-2014

Standards Content (Sample)

TECHNICAL ISO/TR
REPORT 10093
First edition
2017-11
Plastics — Fire tests — Standard
ignition sources
Plastiques — Essais au feu — Sources d'allumage normalisées
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, 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.
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ii © ISO 2017 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Ignition processes . 3
5 Characteristics of ignition sources . 4
6 General principles . 4
6.1 Flaming ignition sources . 4
6.1.1 Diffusion flame ignition source . 4
6.1.2 Premixed flame source . 4
6.2 Issues associated with flaming ignition sources . 4
6.3 Non-flaming ignition sources . 5
7 Smouldering (cigarette) ignition sources . 6
7.1 Traditional cigarettes . 6
7.2 Non-reduced ignition propensity cigarettes . 7
8 Non-flaming electrical ignition sources . 7
8.1 Glow-wire ignition . 7
8.2 Hot-wire ignition . 9
9 Radiant ignition sources .10
9.1 Conical radiant ignition sources .10
9.1.1 General.10
9.1.2 Cone calorimeter ignition source .10
9.1.3 Smoke chamber conical heater .13
9.1.4 Periodic flaming ignition test .16
9.2 Other radiant ignition sources .17
9.2.1 Glowbars ignition source .17
9.2.2 Lateral ignition and flame spread test (LIFT) radiant panel heater. .18
9.2.3 Setchkin ignition .18
10 Infrared heating system .21
11 Diffusion flame ignition .21
11.1 Needle flame ignition .21
11.2 Burning match .22
11.3 Burners generating 50 W or 500 W flames .24
12 Premixed burners .27
12.1 Premixed burner for 1 kW flame .27
12.2 Burners for vertical cable tray tests.28
12.2.1 Venturi burners for 20 kW vertical cable tray tests .28
12.2.2 Burner for vertical riser cable tests .30
12.3 Burner for large scale horizontal tests .30
12.4 Burners for room corner tests .31
12.4.1 Burner for ISO 9705-1.31
12.4.2 Alternate burner for room corner test .32
12.5 Burners for individual product heat release tests .33
12.5.1 Burner for single fuel package calorimeter .33
12.5.2 Square tube propane burner .33
12.5.3 T-shaped propane burner .34
12.5.4 Dual T-shaped propane burner .34
13 Other ignition sources .35
13.1 Wood cribs .35
13.2 Paper bags .35
Bibliography .37
iv © ISO 2017 – All rights reserved

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 documents 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).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on 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 the following
URL: www.iso.org/iso/foreword.html.
The committee responsible for this document is Technical Committee ISO/TC 61, Plastics, Subcommittee
SC 4, Burning behaviour.
This first edition of ISO/TR 10093 cancels and replaces ISO 10093:1998, which has been technically
revised.
The main changes compared to the previous edition are as follows:
— the document has been updated and converted from an International Standard to a Technical Report;
— several additional ignition sources have been added, including some that originate in standards that
have not been issued by ISO or IEC;
— no details of wood crib and paper bag ignition sources are included;
— Annex A and Annex B have been deleted;
— the information that used to be in Annex A on confirmatory procedure for evaluating test flames is
described in IEC 60695-11 and in ASTM D5207;
— the bibliography formerly contained in Annex B has been extended.
Introduction
Fires are caused by a wide range of possible ignition sources. Statistical analysis of fires has identified
the main primary and secondary sources, especially for fires in buildings. The most frequent sources of
fires have been found to be as follows:
a) cooking appliances;
b) space-heating appliances;
c) electric wiring, connectors and terminations;
d) other electrical appliances (such as washing machines, bedwarmers, televisions, water heaters);
e) cigarettes;
f) matches and smokers' gas lighters;
g) blow-lamps, blow-torches and welding torches;
h) rubbish burning; and
i) candles.
The above list covers the major primary ignition sources for accidental fires. Other sources can be
involved in fires raised maliciously. Research into causes of fires has shown that primary ignition
sources (e.g. glowing cigarettes or dropped flaming matches) can set fire to waste paper, which then
acts as a secondary ignition source of greater intensity.
When analysing and evaluating the various ignition sources for applications involving plastics
materials, it is important to answer the following questions on the basis of detailed fire statistics.
1) What is the significance of the individual ignition sources in various fire risk situations?
2) What proportion is attributable to secondary ignition sources?
3) Where does particular attention have to be paid to secondary ignition sources?
4) To what extent are different ignition sources responsible for fatal fire accidents?
The following laboratory ignition sources are intended to simulate actual ignition sources that have
been shown to be the cause of real fires involving plastics. Laboratory ignition sources are preferred
over actual ignition sources due to their consistency, which results in greater data repeatability within
a laboratory and greater reproducibility between laboratories.
These laboratory ignition sources can be used to develop new test procedures.
vi © ISO 2017 – All rights reserved

TECHNICAL REPORT ISO/TR 10093:2017(E)
Plastics — Fire tests — Standard ignition sources
1 Scope
This document describes and classifies a range of laboratory ignition sources for use in fire tests on
plastics and products consisting substantially of plastics. These sources vary in intensity and area
of impingement. They are suitable for use to simulate the initial thermal abuse to which plastics are
potentially exposed in certain actual fire risk scenarios.
Different standards developing organizations have issued many standard test methods, specifications
and regulations to assess fire properties of plastics or of products containing plastic materials. Many
of those standards contain ignition sources associated with flaming and non-flaming ignition. This
document describes the ignition sources and references the associated standard.
This compilation of ignition sources does not discuss the application of the standard where the ignition
source is described and is likely not to be a fully comprehensive list of ignition sources.
This document does not address detailed test procedures.
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
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:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
afterflame
persistence of flaming of a material after the ignition source has been removed
3.2
afterflame time
duration of flame
length of time for which a material continues to flame, under specified test conditions, after the ignition
source has been removed
3.3
afterglow
persistence of glowing of a material after cessation of flaming or, if no flaming occurs, after the ignition
source has been removed
3.4
afterglow time
length of time for which a material continues to glow, under specified test conditions, after the ignition
source has been removed and/or cessation of flaming
3.5
combustion
exothermic reaction of a substance with an oxidizer, generally accompanied by flames and/or glowing
and/or emission of smoke
3.6
ease of ignition
ease with which a material can be ignited under specified test conditions
3.7
exposed surface
surface subjected to the heating conditions of the test
3.8
flame
rapid, self-sustaining, sub-sonic propagation of combustion (3.5) in a gaseous medium, usually with
emission of light
3.9
flame
to produce flame (3.8)
3.10
flaming debris
material separating from the specimen during the test procedure and falling below the initial lower
edge of the specimen and continuing to flame (3.9) as it falls
3.11
glowing combustion
combustion (3.5) of a material in the solid phase without flame (3.8) but with emission of light from the
combustion zone
3.12
ignitability
measure of the ease with which a specimen can be ignited (3.13) due to the influence of an external heat
source under specified test conditions
3.13
ignite, transitive verb
initiate combustion (3.5)
3.14
ignite, intransitive verb
catch fire with or without the application of an external heat source
3.15
ignition
initiation of combustion (3.5)
3.16
ignition source
applied source of heat which is used to ignite (3.13) combustible materials or products
2 © ISO 2017 – All rights reserved

3.17
ignition temperature
minimum temperature of a material at which sustained combustion (3.5) can be initiated under
specified test conditions
3.18
irradiance
ratio of the radiant flux incident on a small but measurable element of surface containing the point, by
the area of that element
3.19
minimum ignition time
minimum time of exposure of a material to an ignition source (3.16) to obtain sustained combustion
(3.5) under specified test conditions
3.20
primary ignition source
first applied ignition source (3.16)
3.21
punking
propagation of a smouldering combustion (3.5) front after removal of the ignition source (3.16)
3.22
secondary ignition source
heat source which is activated following ignition (3.15) from a primary source
3.23
sustained flaming
flame (3.8), on or over the surface of a test specimen, which persists for longer than a defined
period of time
3.24
transitory flaming
flame (3.8), on or over the surface of a test specimen, which persists for a defined short period of time
Note 1 to entry: Compare with the term sustained flaming (3.23).
4 Ignition processes
4.1 When plastics are exposed to thermal energy, flammable vapours are often generated from
their surface. Under suitable conditions (especially high temperatures), it is possible that a critical
concentration of flammable vapour will form and spontaneous ignition will result. If a flame is present
as the sole energy source, or as a supplementary source, the ignition process will be assisted; this
mechanism is sometimes known as piloted ignition.
4.2 A specimen of plastic is regarded as ignited when flames appear on the surface of the plastic or
when glowing combustion is evident.
4.3 After ignition has occurred, some burning plastics create additional fire hazards by forming flaming
debris or drips. If this flaming debris falls on to combustible material, it is possible that secondary
ignition will occur and the fire will spread more rapidly.
4.4 The localized application of a heat source to some plastics results in glowing combustion. With
some thermoplastic foams and foams from thermosetting materials, the localized application of a heat
source results in punking which produces a carbonaceous char.
5 Characteristics of ignition sources
5.1 The following factors are the main characteristics describing ignition sources and their relation to
the test specimen:
a) intensity of the ignition source, which is a measure of the thermal load on the specimen resulting
from the combined conduction, convection and radiation effects caused by the ignition source;
b) area of impingement of the ignition source on the specimen;
c) duration of exposure of the specimen and whether it is continuous or intermittent;
d) presentation of the ignition source to the specimen and whether or not it impinges;
e) orientation of the specimen in relation to the ignition source;
f) ventilation conditions in the vicinity of the ignition source and exposed surface of the specimen;
NOTE Factors c) to f) are often a function of the specific fire test conditions.
5.2 Several of the ignition sources provide a range of intensities and areas of impingement to be
considered for use in fire tests of plastics.
6 General principles
6.1 Flaming ignition sources
6.1.1 Diffusion flame ignition source
To form a diffusion flame ignition source, a gas (usually propane, methane or butane) flows through
metallic tubes without ingress of air prior to the base of the flame. These flames simulate natural flames
well but they often fluctuate and are not convenient to direct if any angular presentation is required
towards the specimen.
6.1.2 Premixed flame source
To form a premixed flame source, a gas burner (usually using propane, methane or butane) fitted with
air inlet ports or an air intake manifold is used. Premixed flame sources are typically more directional
than diffusion flame sources and are generally hotter than diffusion flame sources.
6.2 Issues associated with flaming ignition sources
Gas burners are always set up to conform to precise gas flow rates and/or flame heights. Periodic
checks of flame temperature or heat flux precede the setup, but criteria on these parameters are not
necessarily an essential part of the laboratory procedure. After setting up the burner for a particular
test (i.e. often at an acute angle to the test specimen), it is desirable to leave the burner in this orientation
throughout a series of experiments. This objective is conveniently satisfied if the operator only has to
maintain the gas flow constant to the burner.
The gas burners are connected to the gas supply by flexible tubing via a cylinder regulator providing an
outlet pressure, on-off valve, fine-control valve and flowmeter.
Difficulties sometimes occur with the supply and measurement of butane or propane when the cylinders
have been stored in an environment cooler than the defined test conditions and/or some distance
from the test rig. When difficulties occur, a sufficient length of tubing is used inside the controlled
4 © ISO 2017 – All rights reserved

environment (15 °C to 30 °C) to ensure that the gas equilibrates to the appropriate temperature before
flow measurement.
NOTE One way to facilitate this equilibration is to pass the gas (before flow measurement) through a metal
tube immersed in water maintained at 25 °C.
It is important to exercise great care with the measurement and setting of the flow rate of the gas and to
check direct-reading flowmeters, even those obtained with a direct calibration for the gas used initially,
at regular intervals during testing, with a method capable of measuring accurately the absolute gas
flow at the burner tube.
NOTE One way of doing this is to connect the burner tube with a short length of tubing (about 7 mm internal
diameter) to a soap bubble flowmeter. Passage of a soap film meniscus in a glass tube (e.g. a calibrated burette)
over a known period of time gives an absolute measurement of the flow. Also, fine-control valves that can each be
pre-set to one of the desired gas flow rates, with simple means for switching from one to the other, have proved
helpful.
6.3 Non-flaming ignition sources
The following clauses/subclauses describe ignition sources as follows (see Table 1):
Clause 7: smouldering (cigarette)
Clause 8: Non-flaming electrical ignition sources
8.1 Glow-wire ignition
8.2 Hot-wire ignition
Clause 9: Radiant ignition sources
9.1 Conical radiant ignition
9.2 Other radiant ignition
Clause 10: Infrared heating ignition
Clause 11: Diffusion flame ignition
11.1 Needle flame ignition
11.2 Burning match
11.3 Burners generating 50 W or 500 W flames
Clause 12: Premixed flame ignition
12.1 Premixed burner for 1 kW flame
12.2 Vertical cable tray burners
12.3 Burners for large scale horizontal tests
12.4 Burners for room corner tests
12.5 Burners for individual product heat release tests
Clause 13: Other ignition sources
13.1 Wood cribs
13.2 Paper bags
Table 1 — Classification of ignition sources
Type of ignition source Standard(s) using ignition source Clause/subclause
Smouldering (cigarette) ISO 8191-1, NFPA 260, NFPA 261 7
Non flaming electrical ignition sources 8
Glow-wire ignition IEC 60695–2-10, IEC 60695–2-11, 8.1
ASTM D6194
Hot-wire ignition IEC/TS 60695–2-20, ASTM D3874 8.2
Radiant ignition sources 9
Conical radiant ignition ISO 5657, ISO 5659-2, ISO 5660-1, 9.1
ASTM E1354, ASTM E1995, NFPA 270
Other radiant ignition ISO 871, ASTM D1929, ASTM E906, 9.2
ASTM E1321
Infrared heating ignition sources ASTM E2058, NFPA 287 10
+
Diffusion flame ignition sources 11
Needle flame ignition IEC 60695–11–5 11.1
Burning match ISO 8191-2, ISO 11925-2 11.2
Burners generating 50 W or 500 W flames IEC/TS 60695–11–3, IEC/TS 60695–11–4, 11.3
ASTM D635, ASTM D5025, UL 94
Premixed flame ignition sources 12
Premixed burner for 1 kW flame IEC 60695–11–2, IEC 60332–1–2, 12.1
IEC 60332–2–1
Vertical cable tray burners IEC 60332–3–10, ASTM D5424, ASTM D5537, 12.2
UL 1666, UL 1685, UL 2556
Burners for large scale horizontal tests ASTM E84, NFPA 262 12.3
Burners for room corner tests ISO 9705,-1 ASTM E2257, NFPA 265, 12.4
NFPA 286
Burners for individual product heat release tests ASTM E1537, ASTM E1590, ASTM E1822, 12.5
NFPA 289
Other ignition sources 13
Wood cribs 13.1
Paper bags 13.2
7 Smouldering (cigarette) ignition sources
7.1 Traditional cigarettes
7.1.1 This source is typical of a common commercial cigarette, which is known to cause many fires
involving upholstered furniture and bedding as discussed in ISO 8191-1. The untipped (unfiltered)
cigarette meets the following:
— length: (70 ± 4) mm
— diameter: (8,0 ± 0,5) mm
— mass: (1,0 ± 0,1) g
— smouldering rate: (12,0/50 ± 3,0/50) min/mm
6 © ISO 2017 – All rights reserved

7.1.2 The smouldering rate is verified on one specimen from each batch of 10 cigarettes used as
follows:
a) condition the cigarette before the test for 72 h in indoor ambient conditions and then for at least
16 h in an atmosphere having a temperature of (20 ± 5) °C and a relative humidity of (50 ± 20) %;
b) mark the cigarette at 5 mm and 55 mm from the end to be lit;
c) light the cigarette and draw air through it until the tip glows brightly; do not consume more than
3 mm of the cigarette in this operation;
d) impale the cigarette in draught-free air on a horizontal wire spike, inserting not more than 13 mm
of the spike into the unlit end of the cigarette; and
e) record the time taken to smoulder from the 5 mm to the 55 mm mark.
7.1.3 In many countries, including in the European Union and the United States, regulations that apply
to commercial cigarettes mean that they meet the characteristics of reduced ignition propensity (RIP)
cigarettes, by being tested in accordance with ISO 12863 or ASTM E2187. Thus, such RIP cigarettes have
become replacement commercial cigarettes for the commercial cigarettes available when ISO 8191-1 was
developed. The new commercial RIP cigarettes are less likely to provide a severe smouldering ignition
source than the traditional non-RIP cigarettes.
7.2 Non-reduced ignition propensity cigarettes
Standard reference material cigarettes (SRM 1196) were designed to simulate the ignition strength of
those cigarettes that were in commercial use in the United States before the development of ISO 12863
or ASTM E2187. They have been identified as having a strong ignition potential and do not conform to
1)
the specifications of RIP cigarettes. The cigarettes are described as NIST SRM 1196 cigarettes and
they are cigarettes without filter tips, made from natural tobacco (83 ± 2) mm long with a tobacco
packing density of (0,270 ± 0,020) g/cm and a total weight of (1,1 ± 0,1) g. These cigarettes are used in
NFPA 260 and NFPA 261.
8 Non-flaming electrical ignition sources
8.1 Glow-wire ignition
8.1.1 This ignition source is referenced in IEC 60695-2-10, IEC 60695-2-11 and ASTM D6194. It is called
a glow-wire. This source simulates overheating of electrical wiring, particularly within electrotechnical
equipment by heating the glow-wire to one of the following temperatures:
— (550 ± 10) °C
— (650 ± 10) °C
— (750 ± 10) °C
— (850 ± 15) °C
— (960 ± 15) °C
8.1.2 The glow-wire apparatus and ignition source are shown in Figure 1. The glow-wire itself consists
of a loop of nickel/chromium (80/20) wire 4 mm in nominal diameter.
1) Available from the US National Institute of Standards and Technology (NIST), http://www.nist.gov/srm/index.
cfm.
8.1.3 The temperature of the glow-wire is measured by the use of a sheathed fine-wire Type K
thermocouple [Nickel–Chromium (NiCr) or Nickel–Aluminium (NiAl)] having a nominal overall diameter
of 0,5 mm or 1,0 mm. The thermocouple sheath is constructed of a metal that will allow the thermocouple
to perform its function in air at sheath temperatures of at least 1 050 °C. The thermocouple is arranged
in a pocket hole, drilled in the tip of the glow-wire. The thermal contact between the walls of the bored
hole in the glow-wire is maintained by pinning the sheathed thermocouple in place. The thermocouple
follows the movement of the tip of the glow-wire resulting from elongation caused by thermal heating. A
temperature indicator for Type K thermocouples capable of reading up to 1 000 °C is used. It is important
that the supply circuit be capable of supplying up to 150 A at 2,1 V, with smooth continuous adjustment
of voltage to provide the appropriate current to maintain the desired glow-wire tip temperature.
8.1.4 The test apparatus positions the glow-wire in a horizontal plane while applying a force of
(1,0 ± 0,2) N to the specimen. This force is maintained when the glow-wire is moved horizontally towards
the specimen or vice versa. The movement of the tip of the glow-wire into the specimen when pressed
against it is mechanically limited to 7 mm.
Key
1 positioning clamp 6 stop
2 carriage 7 scale to measure height of flame
3 tensioning cord 8 scale for penetration
4 baseplate 9 glow-wire
5 weight 10 cut-out in base plate for particles falling from
specimen
Figure 1 — Glow-wire ignition source
8 © ISO 2017 – All rights reserved

8.2 Hot-wire ignition
8.2.1 This ignition source is referenced in IEC/TS 60695-2-20 and in ASTM D3874. It is an electrically
heated hot-wire that simulates the overloading of a live part in direct contact with a test specimen.
8.2.2 The heater wire is a loop of iron-free nickel/chromium wire (80 % nickel and 20 % chromium,
iron-free), 0,05 mm in nominal diameter. The wire has a nominal cold resistance of 5,28 Ω/m and has a
length-to-mass ratio of 580 m/kg. The wire length for each test is approximately 250 mm and has been
previously calibrated. Before testing, each straight length of wire is annealed by energizing the wire to
dissipate 0,26 W/mm of length for 8 s to 12 s to relieve internal wire stress.
8.2.3 The supply circuit used to electrically energize the heater wire has sufficient capacity to maintain
a continuous linear 50 Hz to 60 Hz power density of at least 0,31 W/mm over the length of the heater
wire at or near unity power factor. When the supply circuit operates at a current of 60 A with a voltage
of 1,5 V, this results in an approximate power density of 0,3 W/mm. Essential devices include those for
voltage adjustment and power measurement (within ±2 %), an easily actuated on-off switch for the test
power, and timers to record the duration of the application of test power.
8.2.4 Hot-wire ignition tests are carried out on bar-shaped specimens, of dimensions (125 ± 5) mm
long, (13,0 ± 0,3) mm wide and (3,0 ± 0,1) mm thick. Specimens are wrapped with five turns of 0,5 mm
diameter nickel/chromium (80/20) wire of approximate length 250 mm and with a nominal cold
resistance of 5,28 Ω/m, spaced (6,35 ± 0,5) mm between turns. The test apparatus and ignition source
are shown in Figure 2.
8.2.5 The specimen is tested in a horizontal position by heating the wire electrically so that 0,26 W is
generated per millimetre length of wire, and the wire has a temperature of approximately 930 °C.
Dimensions in millimetres
Key
1 test fixture
2 test specimen
3 hot-wire (five turns with 6,35 mm ± 0,5 mm between turns)
Figure 2 — Hot-wire ignition source
9 Radiant ignition sources
9.1 Conical radiant ignition sources
9.1.1 General
Table 2 compares the three conical ignition sources described below.
Table 2 — Details of radiant ignition sources with conical radiators
Heat flux range Specimen size
Pilot Specimen
Standard
ignition source orientation
2 2
kW/m cm
ISO 5657 10 to 50 154 Propane flame Horizontal
ISO 5659-2,
ASTM E1995, 10 to 50 56 Propane flame Horizontal
NFPA 270
ISO 5660-1, Horizontal
10 to at least 75 100 Spark igniter
ASTM E1354 or vertical
9.1.2 Cone calorimeter ignition source
9.1.2.1 This ignition source is described in ISO 5660-1 and in ASTM E1354. The ignition source is
composed of the following major components: a conical radiant electric heater (able to be used in the
horizontal or vertical orientations), a temperature controller, a radiation shield, an electric ignition
spark plug and a test specimen holder (which depends on the test orientation). The test specimen is
2 2
(100 × 100) mm and the heat flux range is from 0 kW/m to at least 75 kW/m . There is no pilot flame. A
schematic of the apparatus is shown in Figure 3 and one for the conical heater is shown in Figure 4.
10 © ISO 2017 – All rights reserved

Key
1 pressure ports 8 spark plug
2 orifice plate 9 optional screens
3 thermocouple (located on stack centreline) 10 blower motor
4 hood 11 retainer frame and specimen
5 blower 12 specimen holder
6 heater 13 weighing device
7 gas sampling ring probe 14 smoke measurement section
NOTE Source: ISO 5660-1:2015, Figure 1.
Figure 3 — Cone calorimeter apparatus schematic
Dimensions in millimetres
110±0,5
90±0,5
80±0,5
177±0,5
197±0,5
Key
1 inner shell
2 refractory fibre packing
3 thermocouple
4 outer shell
5 space block
6 heating element
NOTE Source: ISO 5660-1:2015, Figure 2.
Figure 4 — Cone calorimeter conical heater schematic
9.1.2.2 The active element of the conical heater consists of an electrical heater rod, rated at 5 000 W
at 240 V, tightly wound into the shape of a truncated cone (Figure 4). The heater is encased on the
outside with a double-wall stainless steel cone, packed with a refractory fibre material of approximately
100 kg/m density. The heater is hinged so that it can be swung into either a horizontal or a vertical
orientation. The irradiance is uniform within the central (50 × 50) mm area of the test specimen to
within ±2 % in the horizontal orientation and to within ±10 % in the vertical orientation. The heater
irradiance from the heater is able to be held at a pre-set level by means of a temperature controller
and three type K stainless steel sheathed thermocouples, symmetrical around the heater element. The
thermocouples are of equal length and wired in parallel to the temperature controller.
9.1.2.3 The heater is controlled by a temperature controller capable of holding the element temperature
steady to within ±2 °C. A suitable system is a three-term controller (proportional, integral and derivative)
and a thyristor unit capable of switching currents up to 25 A at 240 V. The temperature input range of
the controller is up to 1 000 °C, with a scale capable of being read to 2 °C or better and automatic cold
junction compensation. The heater temperature is monitored by a meter capable of being read to ±2 °C
or better, which is often incorporated into the temperature controller.
12 © ISO 2017 – All rights reserved
50˚±1˚
65±0,5
46±0,5
13±0,5
9.1.2.4 A removable radiation shield protects the test specimen from the heat flux prior to the start of
a test. The shield is made of non-combustible material with a total thickness not to exceed 12 mm. The
shield is either
a) a water-cooled shield coated with a durable matte black finish of surface emissivity e = 0,95 ± 0,05, or
b) a shield that is not water-cooled but is provided with either a metallic reflective top surface or a
ceramic non-metallic top surface, in order to minimize radiation transfer.
The shield is equipped with a handle or other suitable means for quick insertion and removal. The cone
heater base plate is equipped with the means for holding the shield in position and allowing its easy and
quick removal.
9.1.2.5 The actual ignition is accomplished by a 10 kV discharge across a 3 mm spark gap located
13 mm above the centre of the test specimen (when used for the horizontal location). The sparker power
source is either a transformer designed for spark-ignition use or a spark generator. The spark discharge
operates continuously at 50 Hz to 60 Hz until sustained flaming is achieved. The igniter is removed when
sustained flaming is achieved. The sensitivity of the timing device for measuring time to ignition (also
known as time to sustained flaming) is such that it is capable of recording elapsed time to the nearest
second and is accurate to within 1 s in 1 h. In the case of testing in the vertical orientation, the spark gap
is located in the test specimen face plane and 5 mm above the top of the specimen holder.
9.1.2.6 The horizontal test specimen holder has its bottom lined with a layer of low-density (nominal
density 65 kg/m ) refractory fibre blanket with a thickness of at least 13 mm. The distance between the
bottom surface of the cone heater and the top of the test specimen is adjusted to be 25 mm. The vertical
test specimen holder includes a small drip tray to contain a limited amount of molten material. A test
specimen is installed in the vertical test specimen holder by backing it with a layer of refractory fibre
blanket (nominal density 65 kg/m ), the thickness of which depends on test specimen thickness, but
the blanket is at least 13 mm thick. A layer of rigid, ceramic fibre millboard is placed behind the fibre
blanket layer. The millboard thickness is such that the entire assembly is rigidly bound together once the
retaining spring clip is inserted behind the millboard. When testing in the vertical orientation, the cone
heater height is set so the centre lines up with the test specimen centre.
9.1.3 Smoke chamber conical heater
9.1.3.1 This ignition source is described in ISO 5659-2 as well as in ASTM E1995 and in NFPA 270.
The ignition source is similar to that in the cone calorimeter (See 9.1.2) but is smaller. The following
are specified in these standards as the essential components: a conical radiant electric heater, a test
specimen holder, a radiation shield, a pilot burner and a spark igniter to reignite the pilot burner. The
2 2
test specimen is (75 × 75) mm and the heat flux range is 25 kW/m or 50 kW/m , either with or without
an external pilot flame. Schematics of the conical heater and the arrangement are found in Figure 5 and
Figure 6.
9.1.3.2 The active element of the conical heater consists of an electrical heater rod, rated at 450 W
at 240 V, tightly wound into the shape of a truncated cone. The heater is encased on the outside with a
double-wall stainless steel cone, packed with a refractory fibre material of approximately 100 kg/m
2 2
density. The heater provides irradiances on the surface of the test specimen of 10 kW/m to 50 kW/m , as
measured at the centre of the surface of the test specimen. The irradiance is also determined at positions
of (25 ± 2) mm to each side of the test specimen centre, and the irradiance at these two positions is
not less than 85 %, and not more than 115 % of the irradiance at the centre of the test specimen. The
2 2
heater irradiance is capable of being held at a pre-set level (25 kW/m and 50 kW/m ) by means of a
temperature controller and three type K stainless steel sheathed thermocouples, symmetrically disposed
and in contact with but not welded to the heater element. The thermocouples are of equal length and
wired in parallel to the temperature controller. The cone heater is secured from the vertical rods of the
support framework and located so that the lower rim of the cone heater is (25 ± 1) mm above the upper
surface of the test specimen.
Key
1 thermocouple
2 radiator cone
3 specimen holder
4 radiator shield
5 heat flux meter
6 spark ignition housing
Figure 5 — Typical arrangement of ISO 5659-2 radiator cone ignition source specimen holder
and radiator shield (side view)
14 © ISO 2017 – All rights reserved

Key
1 spark ignition housing
2 specimen holder
3 pilot burner and ignition electrode
4 propane and air
Figure 6 — Typical arrangement of ISO 5659-2 radiator cone ignition source specimen holder
and radiator shield (front view)
9.1.3.3 The heater temperature controller is capable of holding the element temperature steady to
within ±2 °C. A suitable system is a three-term controller (proportional, integral, and derivative) and a
thyristor unit capable of switching currents up to 25 A at 240 V. The controller has a temperature input
range of 0 °C to 1 0
...