ISO/TS 5660-3:2012

Reaction-to-fire tests — Heat release, smoke production and mass loss rate — Part 3: Guidance on measurement

ISO/TS 5660-3:2012 examines the measurement limitations and applications of the cone calorimeter data as currently used for building products, and recommends ways in which some of these may be overcome for other types of products for other application areas. It compiles information from a large body of experience with regard to the use of the instrument. This information is presented as a set of guidelines, which will help to standardize the use of the cone calorimeter in this wider scope. Particular guidance is given on aspects of specimen preparation and on the behaviour, such as melting, spalling and intumescing, of specimens exposed to radiant heat. The relevance of specimen thickness and the use of substrate, and methods of fixing to substrate, are also discussed. Advice is given on approaches to testing a variety of "non-standard" products. Recommendations are made on techniques of calibration of the apparatus, selection of appropriate heat flux levels and ignition protocols.

Essais de réaction au feu — Débit calorifique, taux de dégagement de fumée et taux de perte de masse — Partie 3: Lignes directrices relatives au mesurage

General Information

• Status: Published
• Publication Date: 05-Dec-2012
• ICS: 13.220.50 - Fire-resistance of building materials and elements
• Technical Committee: ISO/TC 92/SC 1 - Fire initiation and growth
• Drafting Committee: ISO/TC 92/SC 1/WG 5 - Small and bench scale fire test methods
• Current Stage: 9093 - International Standard confirmed
• Completion Date: 12-Jul-2022

Relations

• Revises: ISO/TR 5660-3:2003 - Reaction-to-fire tests — Heat release, smoke production and mass loss rate — Part 3: Guidance on measurement
• Effective Date: 13-Jun-2009

Standards Content (Sample)

TECHNICAL ISO/TS
SPECIFICATION 5660-3
First edition
2012-12-01
Reaction-to-fire tests — Heat release,
smoke production and mass loss rate —
Part 3:
Guidance on measurement
Essais de réaction au feu — Débit calorifique, taux de dégagement de
fumée et taux de perte de masse —
Partie 3: Lignes directrices relatives au mesurage
Reference number
ISO/TS 5660-3:2012(E)
©
ISO 2012

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ISO/TS 5660-3:2012(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2012
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any
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Published in Switzerland
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ISO/TS 5660-3:2012(E)

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Capability and limitations of the cone calorimeter . 1
4 Calibration of the cone calorimeter . 2
4.1 General . 2
4.2 Heat flux meter calibration (see 6.12 and 10.3.1 of ISO 5660-1:2002) . 2
4.3 Calibration frequency . 2
4.4 Oxygen analyser calibration (see 10.1.5, 10.1.6 and 10.2.3 of ISO 5660-1:2002) . 3
4.5 Determining orifice plate calibration factor . 4
4.6 Additional comments on the orifice calibration factor . 4
4.7 Calibration of smoke measurement system . 5
4.8 Precautions in relation to water/CO removal . 6
2
4.9 Routine maintenance . 6
5 Test specimen preparation and presentation .6
5.1 General . 6
5.2 Specimen trays and edge retainer frame . 8
6 Selection of heat flux .9
7 Ignition protocols .11
8 Guidance on the testing of non-standard products .11
8.1 General .11
8.2 Non-planar products .11
8.3 Radiation transfer considerations .13
8.4 Thermally mobile specimens.19
9 Composites and layered products .20
9.1 General .20
9.2 Non-homogeneous products.20
9.3 Specimens with short test duration .20
10 Liquids .21
10.1 General .21
10.2 Testing without the radiant heater .21
10.3 Testing with the radiant heater .22
11 The theory of oxygen consumption calorimetry .22
11.1 General .22
11.2 Silicones .23
11.3 Effect of additives and fillers .24
12 Start and end of test .25
12.1 Start of test .25
12.2 End of test .25
13 Recommendations for presentation of data .25
13.1 Current situation .25
13.2 Additional useful data .26
13.3 Recommendations .29
Annex A (informative) Predictive methods from ISO 5660-1 data .30
Annex B (informative) Effect of additives and fillers .37
Annex C (informative) Measurements at low levels of heat release .40
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ISO/TS 5660-3:2012(E)

Bibliography .42
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ISO/TS 5660-3:2012(E)

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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International
Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies
casting a vote.
In other circumstances, particularly when there is an urgent market requirement for such documents, a
technical committee may decide to publish other types of document:
— an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical
experts in an ISO working group and is accepted for publication if it is approved by more than 50 %
of the members of the parent committee casting a vote;
— an ISO Technical Specification (ISO/TS) represents an agreement between the members of a
technical committee and is accepted for publication if it is approved by 2/3 of the members of the
committee casting a vote.
An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for
a further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or
ISO/TS is confirmed, it is reviewed again after a further three years, at which time it must either be
transformed into an International Standard or be withdrawn.
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.
ISO/TS 5660-3 was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 1, Fire
initiation and growth.
This first edition of ISO/TS 5660-3 cancels and replaces ISO/TR 5660-3:2003.
ISO 5660 consists of the following parts, under the general title Reaction to fire tests — Heat release,
smoke production and mass loss rate:
— Part 1: Heat release rate (cone calorimeter method)
— Part 2: Smoke production rate (dynamic measurement)
— Part 3: Guidance on measurement [Technical Specification]
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ISO/TS 5660-3:2012(E)

Introduction
The first edition of ISO 5660-1, which describes a test method for rate of heat release from building
products by means of a cone calorimeter, was published in 1993, following approximately 10 years of
development within ISO/TC 92, Fire safety, Subcommittee SC 1, Fire initiation and growth.
The cone calorimeter is a fire test instrument in which horizontal specimens are exposed to controlled
levels of radiant heating by means of a truncated cone-shaped heater. Continuous spark ignition is
provided and the time to ignition is recorded for specimens which ignite. The rate of heat release from
the burning specimen is determined from measurements of the amount of oxygen consumed from the
air flowing through the apparatus, which has been demonstrated to equate to heat release. The mass of
the specimen is also measured throughout the burning period. The specimens are usually tested under
well ventilated conditions.
Results are expressed in terms of peak and average rates of heat release, as well as total heat released
and the effective net heat of combustion. ISO 5660-1:2002 limits the specimen type to essentially flat.
Several other groups are now utilizing the cone calorimeter, and a number of new parameters in addition
to those defined in ISO 5660-1:2002 and ISO 5660-2:2002 have been defined and used. Some of these,
including smoke measurement, require that measurements be made from the beginning of the test rather
than at the onset of ignition, which is commonly used as the starting point for heat release measurement.
The cone calorimeter is also designed to allow measurement of smoke and gases such as CO and CO .
2
Smoke measurement is the subject of ISO 5660-2:2002. Further work is under way to define a quality
control tool for measuring burning rates of building products. ISO 17554 specifies a test apparatus
similar to that of ISO 5660-1:2002 but measures only loss of mass when exposed to radiant heat. Mass
loss may be a surrogate for measurement of heat release for some classes of building materials. A similar
system which measures the temperature of combustion products generated by this apparatus has been
[23]
standardized as ISO 13927 . The cone calorimeter fire model is used to measure corrosivity of gases
[24]
products of combustion in ISO 11907-4 . The effect of the evolved gases on the resistance of a printed
circuit board target is used to assess corrosivity.
During development of the cone calorimeter it became apparent that there was considerable interest
in the use of the instrument for products other than building products. Several standards have been
developed by various national and international groups based on ISO 5660-1:2002 and ISO 5660-2:2002.
This part of ISO 5660 provides recommendations for the testing of products in the cone calorimeter
and gives guidance on application of the test results. Supplementary guidance is given in documents
referred to in References [1] and [2].
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TECHNICAL SPECIFICATION ISO/TS 5660-3:2012(E)
Reaction-to-fire tests — Heat release, smoke production
and mass loss rate —
Part 3:
Guidance on measurement
1 Scope
This part of ISO 5660 examines the measurement limitations and applications of the cone calorimeter
data as currently used for building products, and recommends ways in which some of these may be
overcome for other types of products for other application areas. It compiles information from a large
body of experience with regard to the use of the instrument. This information is presented as a set of
guidelines, which will help to standardize the use of the cone calorimeter in this wider scope.
Particular guidance is given on aspects of specimen preparation and on the behaviour, such as melting,
spalling and intumescing, of specimens exposed to radiant heat. The relevance of specimen thickness
and the use of substrate, and methods of fixing to substrate, are also discussed. Advice is given on
approaches to testing a variety of “non-standard” products. Recommendations are made on techniques
of calibration of the apparatus, selection of appropriate heat flux levels and ignition protocols.
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 5660-1:2002, Reaction-to-fire tests — Heat release, smoke production and mass loss rate — Part 1:
Heat release rate (cone calorimeter method)
ISO 5660-2:2002, Reaction-to-fire tests — Heat release, smoke production and mass loss rate — Part 2:
Smoke production rate (dynamic measurement)
ISO/TS 14934-4:2007 Fire tests — Calibration of heat flux meters — Part 4: Guidance on the use of heat
flux meters in fire tests
3 Capability and limitations of the cone calorimeter
Rate of heat release is one of the fundamental properties of fire and should almost always be taken into
account in any assessment of fire hazard. Heat release significantly affects fire growth. Considerable progress
has been made in methods of using rate of heat release and ignition time results from the cone calorimeter
to predict full scale fire characteristics. These characteristics include time to flashover in a small room lined
with the tested product and exposed to a high energy fire source such as that used in ISO 9705.
The design of the instrument also provides for measurement of smoke (both gravimetrically and
optically) and other gaseous products of pyrolysis or combustion. The instrument may thus be applied
to the assessment of real fire hazards such as smoke and toxic and corrosive gas emission in addition
to heat release, particularly when the results are expressed in terms of fundamental physically based
parameters, rather than ad hoc parameters.
When functioning as a rate of heat release apparatus, the parameter which is measured in the exhaust
from the specimen is the concentration of oxygen. Temperature measurements are made, but these are
not used to measure the heat output from the specimen in the manner of a conventional calorimeter.
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ISO/TS 5660-3:2012(E)

This is a crucial point in understanding heat release by oxygen consumption calorimetry. The theory of
oxygen consumption calorimetry is discussed in more detail in Clause 10.
The instrument is limited to bench scale specimens and it uses a simple fire model which provides
continuous free ventilation and removal of the products of combustion. Specimen behaviour during
the experiment such as shrinking and swelling can be tolerated if this happens within small margins,
but if the specimen intumesces so that it touches the igniter or the cone, or if it exhibits spalling, this
behaviour will invalidate the results generated.
4 Calibration of the cone calorimeter
4.1 General
Regular and accurate calibration of several measuring devices is essential in order for valid results
to be obtained from the cone calorimeter. The following calibration procedures are outlined in
ISO 5660-1:2002, Clause 10 (respectively 10.1 to 10.3):
— preliminary calibration;
— operating calibration;
— less frequent calibrations.
Table 1 gives details of the major calibration requirements together with recommended intervals.
Calibration procedures are to some extent controlled by the apparatus and the comments below may not
apply to all makes of cone calorimeter.
Some guidelines are given on actual operating experiences with these calibrations and follow the clause
headings given in ISO 5660-1:2002. In addition there are some additional comments on low orifice
calibration factors and the cause thereof. The clause numbers in parentheses refer to clauses given in
ISO 5660-1:2002.
4.2 Heat flux meter calibration (see 6.12 and 10.3.1 of ISO 5660-1:2002)
Detailed information on heat flux meter calibration is provided in ISO/TS 14934-4:2007.
Great care should be taken of the heat flux meter which is in regular use and care should be taken to
use this always with water cooling. It should be checked regularly against a primary meter as set out in
Annex E of ISO 5660-1:2002, to ensure its continued correct working.
4.3 Calibration frequency
The setting of the required heat flux is set out in the manuals of the various instruments. Once a steady-
state value has been obtained (fluctuations of ± 0,1°C may occur) this value should be noted for future
reference and act as an early warning of some change. In particular, users should ensure that the control
thermocouples which should be situated behind and touching the heater helix (i.e. the face remote from
the specimen) do not penetrate the heater helix and experience the temperature of the flame rather than
that of the heater winding.
Table 1 provides information on the frequency of calibration of the instrumentation for the operation of
the Cone Calorimeter.
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ISO/TS 5660-3:2012(E)

Table 1 — Frequency for calibration and maintenance procedures
a
Equipment item Prior to run Daily Monthly Occasional
Check that unused
Drying/CO
2
portion is suffi- — — —
removal columns
b
cient
Analyser flow rates
Oxygen analyser Span Pressure/zero —
time offsets
Check and replace
Main filter — — —
if needed
Soot mass filter Place in position — — Controller set up
Check loading tare
Load cell Calibrate — —
and mass
Heat flux/tempera-
ture relationship
c
Irradiance Check temperature Heat flux level —
Heat flux meter
against reference
meter
CO/CO — Zero/span — —
2
Heat release flow
rates of 5 kW and
Heat release flow
methane burner
Methane — rate of 5 kW for —
methane burner
Mass flow control-
ler
Check adjustment
Laser smoke pho- Check response Check photometer
and 100 % trans- —
tometer with filter zero
mission
Differential pres-
— Check zero — Check calibration
sure transducer
PMMA burn — — — Perform test
a
   These calibrations need only be carried out very occasionally or when alterations have been made to the system.
b
   Always before spanning the oxygen analyser.
c
   Also when required to change irradiance level.
4.4 Oxygen analyser calibration (see 10.1.5, 10.1.6 and 10.2.3 of ISO 5660-1:2002)
Few problems should be encountered when carrying out the calibration of the oxygen analyser. When
running the “zero” check using pure nitrogen with analysers equipped to measure pressure in the sensor
cell, it has been found easier to set the nitrogen flow using the analyser pressure reading. The nitrogen
flow is adjusted until the pressure reading is the same as when the analyser is fed from the atmosphere.
The oxygen analyser delay time should be determined from time to time (recommended frequency, once
every three months) as set out in 10.1.5 of ISO 5660-1:2002. It should be remembered that because of the
time offset, the amount of valid data collected would be lower than the total test time by the extent of
the delay time. Thus, start to record the oxygen analyser output at the same time the calibration burner
is placed underneath the exhaust hood and continue until 3 min after removal of the calibration burner.
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ISO/TS 5660-3:2012(E)

4.5 Determining orifice plate calibration factor
4.5.1 Calibration using methane (see 10.2.4 of ISO 5660-1:2002)
It is recommended that the calibration consisting of burning methane be carried out when the heater
has been set at the required heat flux. This allows the differential pressure transducer (DPT) to warm
up. The fan is shut down and the DPT re-adjusted to zero. The fan is then set to the required air flow and
then the burning of methane is carried out.
ISO 5660-1:2002 requires that at the start of each day, one heat release calibration corresponding to a
heat release flow rate of 5 kW of the supplied methane be carried out. An orifice constant between 0,040
and 0,046 should be obtained with 99,9 % or 99,5 % methane at a flow rate of 8,37 l/min at 273 K (0°C)
and 1 atm (101,3 Pa)). Daily calibration factors should agree within approximately ±1 %.
It should be noted that the heat release calibration using methane does not constitute an absolute
calibration of the instrument, but rather that it verifies the orifice plate constant, which appears in the
calculations [see Equation (5) in 12.2, Equation (7) in 12.3.2 and Equation (9) in 12.4 of ISO 5660-1:2002].
It is not a direct measurement of heat release.
Black polymethylmethacrylate (PMMA) (with a thickness of 6 mm or greater) can also be used within
each laboratory to check repeatability of the cone calorimeter performance.
When zeroing the differential pressure transducer (DPT), ensure that the duct fan and any “decoupled”
extractor system are switched off. Air should be prevented from flowing over the open end of the stack
and across the orifice plate. If necessary, a plastic bag or equivalent should be used to block the open end
of the stack.
It is important to keep records of the values of X (oxygen analyser reading, mole fraction of oxygen),
O2
T (absolute temperature of gas at the orifice meter) and Δp (orifice meter pressure differential) which
e
lead to good calibration factors which should also be noted every time the calibration is carried out. In
this way any discrepancy is immediately identified and early correction can be carried out.
4.5.2 Calibration using liquids
It should be noted that when calibrating using liquids, which usually have low flash points, it is essential
that calibrations be performed on a cold system (the cone heater is not powered). The liquid should be
held in a stable vessel, and the vessel should be stable under the cone before ignition of the liquid. The
burning liquid should not be disturbed until it is all burned.
In addition to burning methane for calibration, users have used a variety of materials such as alcohols.
The heats of combustion of ethanol and propan-2-ol are 26,8 kJ/g and 30,2 kJ/g, respectively. It is
desirable to use propan-2-ol with a purity ≥ 99,5 %.
4.6 Additional comments on the orifice calibration factor
Some variation of the orifice plate calibration factor (also known as the methane calibration factor) may
be observed for various reasons. However, any change greater than 5 % is indicative of a malfunction. In
the majority of cases, the problem is caused by leaks into the sampling lines, in which case the recorded
factor will be higher than usual. Other items that can cause problems are
— blockages in the gas sampling line,
— connections between the orifice plate and the differential pressure transducer,
— leaks at the methane supply line,
— faulty differential pressure transducer,
— faulty methane flow meter,
— cold-trap refrigeration system clogged,
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— inactive CO removal agent. (If CO is not removed from the gas stream entering the oxygen analyser,
2 2
the heat release determined using the standard equations will be higher than expected; hence the
calibration factor will be lower.)
4.7 Calibration of smoke measurement system
Calibration using filters assumes that the system used to calibrate the filter is superior to the optical
system in the cone calorimeter. The photodiodes used in the cone calorimeter specify a high degree
of linearity. The optical density quoted for a commercially supplied filter is usually the average over a
range of wavelengths and the value at the frequency of the monochromatic laser used in the cone may
not be this average value. Therefore, the use of the filter is better confined for daily routine checking of
the proper functioning of the system rather than as a primary calibration.
The user may therefore calibrate by checking zero and 100 % values and utilizing the linearity of
the photodiode.
If filters calibrated at the correct wavelength are used, the following routine may be used. The smoke
measurement system should be checked weekly using neutral density glass filters of 0,3 nominal optical
density. This procedure assumes that the smoke system is the conventional split beam laser described
in ISO 5660-2.
Place the filter in the beam between the duct and the detector. Collect
...