ISO 14696:2009

INTERNATIONAL ISO
STANDARD 14696
First edition
2009-05-01
Reaction-to-fire tests — Determination of
fire and thermal parameters of materials,
products and assemblies using an
intermediate-scale calorimeter (ICAL)
Essais de réaction au feu — Détermination, à l'aide d'un calorimètre à
échelle intermédiaire (ICAL), des paramètres thermiques et relatifs au
feu des matériaux, produits et ouvrages

Reference number
©
ISO 2009
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©  ISO 2009
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ii © ISO 2009 – All rights reserved

Contents Page
Foreword. v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and units . 2
3.1 Terms and definitions. 2
3.2 Symbols and units. 3
4 Principle. 5
5 Apparatus . 5
5.1 General. 5
5.2 Radiant panel . 5
5.3 Radiant panel constant irradiance controller .6
5.4 Specimen holder assembly components. 7
5.5 Other major components . 7
6 Significance and use . 10
7 Test specimens . 11
7.1 Size and preparation. 11
7.2 Conditioning. 11
8 Calibration of apparatus . 11
8.1 General. 11
8.2 Heat flux uniformity . 11
8.3 Heat flux/distance relationship. 11
8.4 Heat release. 12
8.5 Mass loss. 13
8.6 Smoke obscuration. 13
8.7 Gas analysis . 13
8.8 Heat flux meter . 13
9 Test methods. 14
9.1 Preparation . 14
9.2 Procedure . 14
10 Calculations. 15
11 Test report . 15
11.1 Descriptive information. 15
11.2 Table of numerical results . 16
11.3 Graphical results. 16
11.4 Descriptive results. 16
12 Test limitations. 17
13 Hazards . 17
14 Precision and bias . 17
Annex A (normative) Design of exhaust system . 40
Annex B (normative) Instrumentation in exhaust duct . 41
Annex C (informative) Considerations for heat release measurements. 44
Annex D (normative) Measurement equations. 48
Annex E (informative) Commentary. 51
Annex F (informative) Measurement and determination of other parameters and values needed in
computer fire models. 53
Annex G (informative) Determination of the precision and bias of the test method. 56
Bibliography . 58

iv © ISO 2009 – 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.
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.
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 14696 was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 1, Fire initiation
and growth.
This first edition cancels and replaces ISO/TR 14696:1999, which has been technically revised.
INTERNATIONAL STANDARD ISO 14696:2009(E)

Reaction-to-fire tests — Determination of fire and thermal
parameters of materials, products and assemblies using an
intermediate-scale calorimeter (ICAL)
1 Scope
This International Standard provides a method for measuring the response of materials, products and
assemblies exposed in vertical orientation to controlled levels of radiant heating with a piloted ignition source.
This test method is used to determine the ignitability, heat release rates, mass loss rates and visible smoke
development of materials, products and assemblies under well-ventilated conditions.
The heat release rate is ascertained by measurement of the oxygen consumption as determined by the
oxygen concentration and flow in the exhaust product stream as specified in 5.5.8. Smoke development is
quantified by measuring the obscuration of light by the combustion product stream.
2 2
Specimens are exposed to heating fluxes ranging from 0 kW/m to 50 kW/m . Hot wires are used as the
ignition source.
This test method has been developed for material, product or assembly evaluations, mathematical modelling
and design purposes. The specimen shall be tested in thicknesses and configurations representative of actual
end product or system uses.
[13]
The test method in this International Standard is based on the apparatus described in ASTM E1623 .
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 9705, Fire tests — Full-scale room test for surface products
ISO 13943: 2000, Fire safety — Vocabulary
ISO 14934-3, Fire tests — Calibration and use of heat flux meters — Part 3: Secondary calibration method
ISO 24473, Fire tests — Open calorimetry — Measurement of the rate of production of heat and combustion
products for fires of up to 40 MW
3 Terms, definitions, symbols and units
3.1 Terms and definitions
For the purposes of this document, the definitions given in ISO 13943 and the following apply.
3.1.1
composite
combination of materials which are generally recognized in building construction as discrete entities
EXAMPLE Coated or laminated materials.
3.1.2
flashing
existence of flame on or over the surface of the specimen for periods of less than 1 s
3.1.3
heating flux
incident flux imposed externally from the heater on the specimen at the initiation of the test
3.1.4
heat release rate
heat evolved from the specimen, per unit of time
3.1.5
ignition
onset of sustained flaming as defined in 3.1.13
3.1.6
irradiance
〈at a point on a surface〉 the density of radiant flux incident on a surface
3.1.7
material
single substance or uniformly dispersed mixture, for example metal, stone, timber, concrete, mineral fibre,
polymers
3.1.8
orientation
plane in which the exposed face of the specimen is located during testing, either vertical or horizontal, facing
up
NOTE The orientation of the specimen in this International Standard is vertical and there are no provisions for testing
horizontal specimens.
3.1.9
oxygen consumption principle
proportional relationship between the mass of oxygen consumed during combustion and the heat released
3.1.10
product
material, composite or assembly, about which information developed by this test method is required
3.1.11
specimen
representative piece of the product which is to be tested together with any substrate or treatment
2 © ISO 2009 – All rights reserved

3.1.12
smoke obscuration
reduction of light transmission by smoke, as measured by light attenuation
3.1.13
sustained flaming
existence of flame on or over most of the specimen surface for periods of over 10 s
3.1.14
transitory flaming
existence of flame on or over the surface of the specimen for periods of between 1 s and 10 s
3.2 Symbols and units
The symbols and units are the following.
Symbol Term Unit
A Cross-sectional area of exhaust duct m
A Exposed specimen area m
s
E Net heat released for complete combustion, per unit of oxygen consumed 13,1 MJ/kg O
E Net heat released per unit mass of oxygen consumed for combustion of CO 17,6 MJ/kg O
CO 2
to CO
E Net heat released for complete combustion of propane, per unit of oxygen 12,78 MJ/kg O
propane 2
consumed
E Net heat released for complete combustion of methane, per unit of oxygen 12,51 MJ/kg O
methane 2
consumed
F Relative optical density dimensionless
OD
f Yield of gas x kg/kg
x
f Reynolds number correction for bi-directional probe differential pressure —
(Re)
measurement
∆H Net heat released per unit mass of natural gas MJ/kg
c,ng
I Intensity of transmitted light beam cd
I Intensity of light beam before attenuation cd
−1
k Smoke extinction coefficient m
k Exhaust duct flow velocity profile shape factor dimensionless
c
L Path length of light m
p
M Relative molecular mass of incoming air kg/kmol
a
M Relative molecular mass of carbon monoxide 28 kg/kmol
CO
M Relative molecular mass of carbon dioxide 44 kg/kmol
CO
M Relative molecular mass of dry air 29 kg/kmol
dry
M Relative molecular mass of exhaust gases kg/kmol
e
M Relative molecular mass of water 18 kg/kmol
H O
M Relative molecular mass of nitrogen 28 kg/kmol

N
M Relative molecular mass of oxygen 32 kg/kmol
O
m Specimen mass kg

m Mass flow in exhaust duct kg/s
e

m Mass flow of natural gas to the radiant panel kg/s
ng
∆p Pressure drop across the orifice plate or bi-directional probe Pa

q Heat release rate kW
 ′′
q Average heat release rate per unit area of specimen for the first 60 s after kW/m
A,60
ignition

q′′ Average heat release rate per unit area of specimen for the first 180 s after kW/m
A,180
ignition

q′′ Peak heat release rate per unit area of specimen kW/m
peak
′′
q Total heat released per unit area of specimen MJ/m
s

q′′ Heat release rate per unit area of specimen kW/m
s
′′
q Heat released per unit area of specimen, in incoming air MJ/m
s,i
R Instantaneous rate of production of light-obscuring smoke m /s
inst
R Total amount of smoke m
tot
T Combustion gas temperature at the bi-directional probe or orifice plate K
e
T Combustion gas temperature near the smoke meter K
s
t Time s
t Time to ignition s
ig
 3
V Volumetric flow in exhaust duct (at measuring location of mass flow) m /s
e
 3
V Volumetric flow at location of smoke meter (value adjusted for smoke m /s
s
measurement calculations)
∆t Sampling time interval s
X Measured mole fraction of CO in exhaust flow dimensionless

CO,e
X Measured mole fraction of CO in incoming air dimensionless
CO,i
X Measured mole fraction of CO in exhaust flow dimensionless
CO ,e 2
X Measured mole fraction of CO in incoming air dimensionless
CO ,i 2
X Measured mole fraction of O in exhaust flow dimensionless
O ,e 2
X Measured mole fraction of O in incoming air dimensionless
O ,i 2
[x] Relative mass fraction of gas x kg/kg
α Combustion expansion factor (an average value of 1,105 is used for mixed dimensionless
fuels or when the exact factor is unknown)
ρ Density of air at the temperature in exhaust duct kg/m
ρ Density of air at 273,15 K: 1,293 kg/m
φ Oxygen depletion factor dimensionless
4 © ISO 2009 – All rights reserved

4 Principle
4.1 This test method is designed to measure the heat release rate from a 1 m specimen in a vertical
orientation. The specimen is exposed to a uniform and constant heat flux from a gas fired radiant panel up to
50 kW/m and electrically heated wires are used for piloted ignition. Heat release measured using this test
method is based on the observation that, generally, the net heat released during combustion is directly related
[1], [2]
to the amount of oxygen required for combustion . The primary measurements are oxygen concentration
and exhaust flow rate. Burning may be either with or without ignition wires used at the top and bottom of the
specimen.
NOTE The addition of carbon monoxide and carbon dioxide concentration measurements can improve the accuracy
of the heat release rate measurement, and can also be used to provide species generation rates of both gases.
4.2 Additional measurements include the mass of the specimen, which can be used to determine the mass
loss rate, the time to sustained flaming and the light intensity of a light beam having traversed the smoky duct,
which can be used to determine the smoke-specific extinction area, the relative optical density and the smoke
release rate. The apparatus can be used to develop data relative to the other parameters discussed in
Annex F.
5 Apparatus
5.1 General
Dimensions shall have a tolerance of ± 5 mm on the radiant panel and specimen holder assemblies. An
exception to this tolerance is the placement of the screen in front of the ceramic burner which shall be
± 0,5 mm. The tolerances permitted in the exhaust system of ISO 9705 are permissible.
The apparatus shall consist of the following components.
5.1.1 Radiant panel assembly, in a vertical orientation, see Figure 1.
5.1.2 Radiant panel constant irradiance controller, capable of being held at a preset level by means of
regulating the flow of natural gas to the burners during a test.
5.1.3 Water-cooled heat shield, capable of absorbing the thermal energy from the radiant panels.
5.1.4 Specimen holder, capable of holding a specimen up to 150 mm thick, see Figure 2.
5.1.5 Weighing platform, of a range of 150 kg, capable of weighing the specimen to an accuracy of at
least 1 g.
5.1.6 Exhaust collection system, consisting of an extraction fan, steel hood, duct, bi-directional probe or
orifice plate, thermocouple(s), smoke obscuration measurement system and combustion gas sampling and
analysis system.
5.1.7 Gas flow meter, capable of measuring gas flow.
5.1.8 Data acquisition system, of a category equal to or better than that required in ISO 9705.
A general layout of the whole test apparatus assembly is shown in Figure 17.
5.2 Radiant panel
The panel (5.1.1) consists of a support frame, which supports three rows of adjustable, ceramic-faced, natural
gas burners and natural gas distribution plumbing (see Figure 1).
Hollow 50 mm × 50 mm square steel tubing or galvanized 41,3 mm × 41,3 mm × 2,7 mm “C” channel can be
1)
used for the support frame application .
Each row comprises 10 burners 385 mm tall and 172 mm wide, fastened next to each other with a 1 mm to
2 mm air gap between them. Each burner consists of four vertically stacked perforated ceramic elements
12,7 mm deep times 95 mm high times 158 mm wide, encased in a steel sheet metal can forming a plenum
space on the back of the ceramic elements. Natural gas is injected at a controlled rate by the burner’s control
system through a round 51,2 mm diameter opening (injection port) at the bottom of the can. Combustion air is
aspirated into the plenum space through the gas and air injection port.
The face of each burner is covered with stainless steel 330 floating screens for higher surface temperature
and safety. The screens shall be carefully installed to allow for thermal expansion. This prevents screen
deformation and allows the distance between the burners and screens to remain constant when heated. The
optimum distance between the surface of the burners and the outer surface of the screen is 20 mm. The rows
of gas burners on the panel shall be vertically separated by a distance of 110 mm from each other and also
attached to the support frame at the locations indicated in Figure 1. The space between the rows shall be filled
with lightweight ceramic boards installed flush with the front burner surface and extending the entire width of
the radiant panel. A 110 mm tall lightweight ceramic board shall be installed underneath the entire bottom
burner row. This ceramic board shall also be flush with the front surface of the burners and extend the entire
width of the panel. A 33 mm wide gap shall be left in the centre of the ceramic board between the top and the
middle burner rows to allow the use of an infrared (IR) pyrometer.
Natural gas with a net heating value of at least 48 MJ/kg shall be supplied to the unit through a control system
provided with a safety interlock. All gas pipe connections to the burners shall be sealed with a gas pipe
compound resistant to liquefied petroleum gases. A drip leg shall be installed in the gas supply line going to
the radiant panel to minimize the possibility of any loose scale or dirt within the gas supply line from entering
the burner’s control system. An approved flexible hose or fixed piping is used to supply natural gas to the
radiant panel constant irradiance controller (5.1.2). Fixed piping shall be provided from the controller to
individual burners. Each row of the burners is fed by a nominal 25 mm diameter horizontal steel pipe
branching from a vertical nominal 32 mm diameter steel pipe located on one side of the back of the radiant
panel. At each burner, a nominal 6 mm diameter pipe branches from the horizontal pipe to feed each burner.
Each burner-feeding pipe includes a shut-off, a fine regulating needle valve and a nozzle directed into the
injection port opening perpendicularly to the plane of the opening. The hose or piping as well as other gas line
components should be capable of delivering a quantity of gas corresponding to a heating power of 400 kW.
Ignition of the burners shall be accomplished manually or by an automatic safety system. A recommended
safety system designed to prevent accidental release of unburned natural gas is described in E.6.
5.3 Radiant panel constant irradiance controller
The irradiance from the radiant panel assembly (5.1.1) shall be capable of being held at a preset level by
means of regulating the flow of natural gas to the burners during a test (see E.2 for more information). The
flow of the gas is regulated using an automatic flow controller, a motorized valve and a thermocouple located
on the surface of a ceramic burner. The thermocouple shall be attached by ceramic cement on the exposed
surface of the burner top ceramic element located in the fourth burner (from either end) of the middle row of
the radiant panel. The irradiance is directly proportional to the temperature on the surface of the ceramic
burners. Gas flow shall be continuously measured to calculate the heat released from the radiant panel
assembly. This value is necessary in computations of the heat release rate from the specimen.
A laminar flow element was found to be suitable for the gas flow measurement. If a laminar element is used
the natural gas temperature measurement is necessary at the location of the laminar flow element in order to
calculate the flow. In order to calculate accurately the heat released from the radiant panel assembly (5.1.1), it
is necessary to account for any variation of the properties of natural gas (net heating value, net heat released
per unit mass of oxygen, expansion coefficient and density) by location and over time. It cannot be assumed

1) A modified MODINE high intensity burner unit, from Modine Manufacturing Company, 1500 DeKoven Avenue, Racine
Wisconsin 53403, USA, is an example of a suitable product available commercially. This information is given for the
convenience of users of ISO 14696 and does not constitute an endorsement by ISO of this product.
6 © ISO 2009 – All rights reserved

that these values are the same as the values for pure methane. In order to provide a set of appropriate values,
it is necessary to determine these properties over time based on the concentrations of the gas constituents
and their variability.
5.4 Specimen holder assembly components
5.4.1 Specimen holder
The specimen holder (5.1.4) assembly is shown in Figure 2 and is capable of holding a specimen up to
150 mm thick. (A thicker specimen holder is necessary to accommodate specimens thicker than 150 mm.)
The top portion of the assembly is removable to facilitate specimen insertion. Alternatively, the top portion is
not removable, in which case the specimen is inserted from the back. The specimen holder shall be made as
closely as possible to that shown in Figure 2 to Figure 16, to prevent bending of the holder due to non-uniform
heating. If Figure 2 to Figure 16 are not followed, then the specimen holder shall be designed so that the top
of the holder does not move towards or away from the radiant panel for more than 1 cm during a test.
Prior to starting the test, the specimen shall be protected from the radiant panel heat flux exposure by the
water-cooled shield (5.1.3). A drip tray, shown in Figure 14, shall be attached to the legs of the specimen
holder (5.1.4) directly below the specimen frame to contain limited amounts of materials that melt and drip.
Two wire igniters, described in 5.5.2, are attached to the specimen holder. An air-stream-interrupting
projection plate shown in Figure 16 is mounted at the bottom of the specimen (see 5.5.3).
5.4.2 Weighing platform
The general arrangement of the specimen holder (5.1.4) and the weighing platform (5.1.5) is indicated in
Figure 2. The weighing platform shall have a range of 150 kg, shall be capable of weighing the specimen to an
accuracy of at least 1 g, and shall have dimensions suitable to fit on the trolley and accommodate the sample
holder.
The weighing platform shall be protected from the radiant panel irradiance by an insulation board cover as
shown in Figure 2. The insulation board shall have sufficient thickness and adequate thermal properties to
protect the weighing platform from the temperature increase of any of its parts by 10 °C or more during a test.
A suitable protection of the weighing platform shall be demonstrated by temperature measurement on the
inside of the front wall of the platform cover before the apparatus is put in operation, and after any changes of
the insulation board cover. The temperature measurement shall be performed by a Type K 0,127 mm bare
wire thermocouple attached to the inside of the platform wall facing the radiant panel approximately at the
centre of the wall. If a calcium silicate or similar hygroscopic material is used for the insulation board cover, it
shall be completely water-vapour-sealed prior to use to prevent weight loss due to water evaporation during a
test. The front of the insulation board cover and the top of the specimen holder floor shall be completely
covered by aluminium foil additionally to protect the weighing platform from heat radiation. The foil shall be
installed with the shiny surface facing outward. The foil shall be replaced prior to a test if it becomes dirty,
damaged or covered with melted material so as to no longer provide reflectance of radiant heat.
5.4.3 Specimen holder trolley
A trolley, as shown in Figure 17, shall be provided to hold the specimen holder (5.1.4) and weighing platform
(5.1.5) so that the specimen can be moved to a predetermined location in front of the radiant panel at the
beginning of a test. The trolley shall be placed on rails or guides to facilitate exact specimen placement with
respect to the radiant panel. The trolley tracks shall be located perpendicular to the plane of the radiant panel
so that the specimen is moved directly toward the radiant panel. The trolley tracks shall be long enough to
move the specimen holder to a distance of 6 m from the radiant panel. This distance makes mounting the
specimen easier.
5.5 Other major components
5.5.1 Specimen heat shield, capable of absorbing the thermal energy from the radiant panels prior to
testing.
This water-cooled heat shield (5.1.3, Figure 18) can be constructed of standard steel, and shall be designed
so that a preset water flow will maintain a shield temperature on the unexposed face below 100 °C. The shield
shall be positioned directly in front of the radiant panel assembly (5.1.1) at a distance of 75 mm. The mounting
method used shall enable the shield to be removed in less than 2 s.
5.5.2 Wire igniters, capable of being used as specimen pilot igniters.
2)
Two 0,81 mm Chromel wires (from Type K thermocouple wires) are used as specimen pilot igniters. One
wire is positioned horizontally, spanning the full width of the specimen, 80 mm above the bottom exposed
edge of the specimen and 15 mm from the specimen surface. The other wire is positioned horizontally,
spanning the full width of the specimen, 20 mm above the top exposed edge of the specimen and 15 mm from
the specimen’s vertical plane. A bracket [see Figures 15 a) and 15 b)] shall be attached to each end of each
wire to compensate for the wire expansion during the test. It shall remain under tension throughout the test so
that the igniter wire remains in position. When used, sufficient power shall be applied to the wires to produce
an orange glow. Low voltages, between 30 volts and 35 volts, shall be used for safety reasons. More
information about the choice of the wire igniters is given in E.3.
NOTE The upper wire is intended for igniting specimens that release pyrolysis gases at the top only. Examples are
sandwich panels and other specimens with a non-combustible protective skin on the exposed face.
5.5.3 Air-stream-interrupting projection plate.
A thin steel plate which projects 10 cm out from the specimen surface shall be attached to the specimen
holder (5.1.4) perpendicularly to the specimen surface along the lower exposed specimen edge (see
Figure 16). Information about the air-stream-interrupting projection plate is given in E.5.
3) 2
5.5.4 Heat flux meter, of the Schmidt-Boelter (thermopile) type, with a design range of 50 kW/m to
100 kW/m .
The target receiving radiation, and possibly to a small extent convection, shall be flat, circular, of
approximately 12,5 mm in diameter, and coated with a durable matt-black finish. The target shall be water-
cooled. Radiation shall not pass through any window before reaching the target. The instrument should be
robust, simple to set up and use, and stable in calibration. The instrument shall have an accuracy of within
± 3 % and a repeatability of within ± 0,5 %.
5.5.5 Heat flux calibration panel, capable of establishing the heat flux/distance relationship.
The panel shall be constructed from nominally 12,7 mm thick lightweight ceramic fibreboard. It shall be the
same size as a specimen (1 000 mm × 1 000 mm) and shall have holes with diameters to accommodate the
heat flux meter from 5.5.4. Five rows and columns of holes shall be symmetrically drilled with centres 167 mm
apart.
5.5.6 Digital data collection.
The data collection system (5.1.8) shall be equal to or better than that required in ISO 9705. Readings shall be
made at intervals not exceeding 2 s.
5.5.7 Exhaust collection system.
5.5.7.1 Construct the exhaust collection system (5.1.6) with the following minimum requirements: an
extraction fan, steel hood, duct, bi-directional probe (see Figure 25) or orifice plate, thermocouple(s), smoke
obscuration measurement system (white light lamp and photocell/detector or laser) and combustion gas

2) Chromel and Alumel are suitable products available commercially. This information is given for the convenience of
users of ISO 14696 and does not constitute an endorsement by ISO of this product.
3) This is an example of a suitable product available commercially. This information is given for the convenience of users
of ISO 14696 and does not constitute an endorsement by ISO of this product.
8 © ISO 2009 – All rights reserved

sampling and analysis system. An example of the exhaust collection system is shown in Figure 19 and
explained in Annex A. General rules of ISO 24473 shall be followed if the exhaust system differs from the one
shown in Figure 19. However, the flow through the exhaust system shall not be larger than 2,5 m /s to avoid
noisy measurements.
5.5.7.2 Ensure that the system for collecting the combustion has sufficient exhaust capacity and is
designed in such a way that all of the combustion products leaving the burning specimen plus the radiant
panel burning products are collected. Design the capacity of the evacuation system such that it will exhaust
minimally all combustion gases leaving the specimen (see A.1 and A.6).
5.5.7.3 Place probes for the sampling of combustion gas and for the measurement of flow in accordance
with 5.5.8.
5.5.7.4 Make all measurements of smoke obscuration, gas concentrations and flows at a position in the
exhaust duct where the exhaust is uniformly mixed so that there is a nearly uniform velocity across the duct
section.
5.5.7.5 If the length of the straight section before the measurement system is at least eight times the
inside diameter of the duct, the exhaust is considered to be uniformly mixed. There should also be a straight
section of duct after the measurement section of at least five duct diameters. If the straight section before the
measurement section is less than ten times the inside diameter of the duct, or less than five times the inside
duct diameter after the measurement section, demonstrate the achievement of equivalent measurement
results.
5.5.8 Instrumentation in exhaust duct.
5.5.8.1 General
The following specifications are minimum requirements for exhaust duct instrumentation. Additional
information is provided in Annex B.
5.5.8.2 Flow
Measure the flow in the exhaust duct by means of a bi-directional probe (see 5.1.6, 5.5.7.1 and Figure 25) or
an equivalent system of measurement with an accuracy of at least ± 5 % (see Annex B). The response time to
a stepwise change of the duct flow shall not exceed 5 s, to reach 90 % of the final value.
5.5.8.3 Combustion gas analysis
5.5.8.3.1 Sampling line
Construct the sampling line tubes of a material not influencing the concentration of the combustion gas
species to be analysed. The following sequence of the gas train has been shown to be acceptable: sampling
probe (see Figure 23, Figure 26, Figure 27 and Figure 28), soot filter, cold trap, gas stream pump, waste vent
regulator valve, moisture and carbon dioxide removal columns (if used), flow controller, instrument filter and
gas analysers (see Figure 20 and Annex B). Alternative designs of the sampling line shall give equivalent
results to those obtained with the above described gas train. The gas train shall also include appropriate
spanning and zeroing facilities.
4)
NOTE 1 Granular drierite and granular ascerite have been found useful for moisture removal and carbon dioxide
removal, respectively.
NOTE 2 The use of ascerite to remove carbon dioxide produces moisture and therefore a second dessicant column
should be used downstream to remove this additional moisture.

4) Drierite and ascerite are suitable products available commercially. This information is given for the convenience of
users of ISO 14696 and does not constitute an endorsement by ISO of this product.
5.5.8.3.2 Oxygen measurement
The oxygen analyser shall be of the paramagnetic type and capable of measuring at least a range of 16 % to
5)
21 % oxygen with an accuracy of at least ± 0,01 percent volume fraction of oxygen, in order to have
adequate measurements of heat release rate. The drift of the analyser shall be less than 0,01 % (100 ppm)
over a period of 30 min. The time delay of the system, including the time constant of the instrument, shall not
exceed 25 s (measured in accordance with Annex B).
5.5.8.3.3 Carbon monoxide and carbon dioxide measurement
The carbon dioxide analyser shall be of the IR type and capable of measuring at least a range of 0 % to 10 %
carbon dioxide. The accuracy of the analyser shall be at least ± 1 % of full scale or 0,1 % (1 000 ppm). The
carbon monoxide analyser shall also be of the IR type and capable of measuring at least a range of 0 % to
1 % carbon monoxide. The accuracy of the analyser shall be at least ± 1 % of full scale or 0,01 % (100 ppm).
The time delay of the system, including the time constant of the instrument, shall not exceed 25 s (measured
in accordance with Annex B).
5.5.8.4 Smoke obscuration measurement
5.5.8.4.1 Install an optical system for measurement of light obscuration across the centreline of the exhaust
duct. Determine the relative optical density of the smoke by measuring the light transmitted with a photometer
system consisting of a white light source and a photocell/detector or a laser system for measurement of light
obscuration across the centreline of the exhaust duct.
5.5.8.4.2 One photometer system found suitable consists of a lamp, lenses, an aperture and a photocell.
See Figure 21 and Annex B. Construct the system so that soot deposits on the optics during a test do not
reduce the light transmission by more than 5 %.
5.5.8.4.3 Alternatively, instrumentation can be constructed using a 0,5 mW to 2,0 mW helium-neon laser,
instead of a white light system. See Figure 22 and B.4.2. It has been shown that white light and laser systems
[15]
will give similar results .
6 Significance and use
6.1 This test method is used primarily to determine the heat release rate of materials, products and
assemblies. Other parameters determined are mass loss rate, the time to ignition, and smoke and gas
production. These properties are determined on a specimen which may be an assembly of materials or
products that are tested in their end-use thickness. Therefore, the heat release rate of a wall assembly, for
instance, can be determined.
6.2 Representative joints and other characteristics of an assembly shall be included in a specimen when
these details are part of the normal design.
6.3 This test method is applicable to end-use products not having an ideally planar external surface. The
radiant flux field shall be adjusted to be that which is desired at the average distance of the surface from the
radiant panel.
5) This is the equivalent of 100 ppm; ppm is a deprecated unit.
10 © ISO 2009 – All rights reserved

7 Test specimens
7.1 Size and preparation
7.1.1 The dimensions of test specimens shall be 1 000 mm × 1 000 mm and up to 150 mm in thickness and
shall be representative of the construction of the end-use product. Materials and assemblies of normal
thickness 150 mm or less shall be tested using their full thickness. If specimens of thickness greater than
150 mm are to be tested, a specimen holder (5.1.4) can be constructed to accommodate the desired
specimen thickness up to 500 mm.
7.1.2 If a product is designed normally to have joints in a field application, then that specimen shall
incorporate the joint detail. The joint shall be centred in the specimen’s vertical or horizontal centreline as
appropriate. The specimen shall also be tested without a joint detail if the design does not include a joint.
7.1.3 The edges of the specimen shall be covered with 12 mm ceramic wool blanket to eliminate the gap
between the holder and the specimen.
7.2 Conditioning
Specimens shall be conditioned to moisture equilibrium (constant mass) at an ambient temperature of
(23 ± 3) °C and a relative humidity of (50 ± 5) %.
NOTE Constant mass is reached when two successive weighing operations, at an interval of 24 h, do not differ by
more than 0,1 % of the mass of the test piece or 1 g, whichever is the greater.
8 Calibration of apparatus
8.1 General
Calibrate all instruments carefully with standard sources after initial installation. Among the instruments to be
calibrated are load cells or weighing platforms, smoke meters, flow or velocity transducers and gas analysers.
8.2 Heat flux uniformity
Determine the set temperature of the controller (5.1.2) using the following procedure. Ignite the radiant panel
and allow it to reach a burner surface temperature of 850 °C set on the controller. Insert the heat flux meter in
the centre hole of the calibration panel so that the sensing face of the heat flux meter extends 15 mm toward
the radiant panel from the exposed surface of the calibration panel to minimize the convective heat transfer
contribution. Move the calibration panel with the heat flux meter inserted in the centre hole to the
predetermined distance of 650 mm from the radiant panel (measure from the ceramic burner surface to the
gauge sensing surface). Adjust the burner surface temperature on the controller to a value required for the
heat flux meter to read 35 kW/m . Adjust the individual burner outputs by adjusting the needle valves to obtain
uniform irradiance over the calibration board. This is accomplished by moving the heat flux meter around all
the holes in the calibration panel and adjusting the needle valves of
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