ISO 12136:2011

INTERNATIONAL ISO
STANDARD 12136
First edition
2011-08-15

Reaction to fire tests — Measurement of
material properties using a fire
propagation apparatus
Essais de réaction au feu — Mesurage des propriétés des matériaux au
moyen d'un appareillage de propagation du feu




Reference number
ISO 12136:2011(E)
©
ISO 2011

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ISO 12136:2011(E)

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©  ISO 2011
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Published in Switzerland

ii © ISO 2011 – All rights reserved

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ISO 12136:2011(E)
Contents Page
Foreword . v
Introduction . vi
1  Scope . 1
2  Normative references . 1
3  Terms and definitions . 1
4  Symbols . 2
5  Principle . 3
6  Apparatus . 4
6.1  General . 4
6.1.1  Dimensions . 4
6.1.2  Components . 4
6.2  Infrared (IR) heating system . 4
6.3  Load cell system . 5
6.4  Ignition pilot flame . 5
6.5  Ignition timer . 5
6.6  Gas analysis system . 5
6.6.1  Gas sampling . 5
6.6.2  Carbon dioxide/carbon monoxide analysers . 6
6.6.3  Inlet air oxygen analyser. 6
6.6.4  Optional product analysers for the combustion test . 6
6.7  Combustion air distribution system . 6
6.7.1  General . 6
6.7.2  Air distribution chamber . 6
6.7.3  Air supply pipes . 6
6.8  Water-cooled shield . 6
6.9  Exhaust system . 7
6.10  Measuring section instruments . 7
6.10.1  Measuring section thermocouple probe . 7
6.10.2  Averaging Pitot probe and pressure transducer . 7
6.11  Heat flux gauge . 7
6.12  Digital data acquisition system . 7
7  Hazards . 8
7.1  Laboratory safety . 8
7.2  Safety precautions . 8
7.3  Exhaust system operation . 8
8  Test specimen . 8
8.1  Specimen holders . 8
8.2  Specimen size and preparation . 8
8.2.1  Ignition, pyrolysis and combustion tests of horizontal specimens . 8
8.2.2  Fire propagation test of vertical, rectangular specimens . 9
8.2.3  Fire propagation test of vertical, cable specimens . 9
9  Calibration . 9
9.1  Radiant-flux heater . 9
9.1.1  Routine calibration . 9
9.1.2  Positioning of radiant-flux heaters . 10
9.2  Gas-analyser calibration . 10
9.2.1  Carbon dioxide/carbon monoxide analysers . 10
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ISO 12136:2011(E)
9.2.2  Oxygen analyser .10
9.2.3  Optional hydrocarbon gas analyser .10
9.3  Load cell .10
9.4  Heat release calibration .11
10  Specimen conditioning .11
11  Procedure .11
11.1  Procedure 1 — Ignition test method .11
11.2  Procedure 2 — Combustion test method .12
11.3  Procedure 3 — Pyrolysis test method .13
11.4  Procedure 4 — Fire propagation test method .14
12  Calculation .15
13  Test report .16
13.1  Procedure 1 — Ignition test method .16
13.2  Procedure 2 — Combustion test method .17
13.3  Procedure 3 — Pyrolysis test method .17
13.4  Procedure 4 — Fire propagation test method .17
Annex A (informative) Laser smoke measuring system .31
Annex B (informative) Rationale .34
Annex C (informative) Comparison of results – vertical and horizontal exhaust ducts .41
Annex D (informative) Heat of gasification .44
Bibliography .46

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ISO 12136:2011(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.
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 12136 was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 1, Fire initiation
and growth.
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ISO 12136:2011(E)
Introduction
[3][4][5][12]
This International Standard contains four separate test methods , which are conducted using a fire
propagation apparatus (FPA). The ignition, combustion and pyrolysis test methods involve the use of
2
horizontal specimens subjected to a controlled, external radiant heat flux, which can be set from 0 kW/m to
2
65 kW/m . The fire propagation test method involves the use of vertical specimens subjected to ignition near
the base of the specimen from an external radiant heat flux and a pilot flame. The combustion, pyrolysis and
fire propagation test methods can be performed using an inlet air supply that is either normal air or other
gaseous mixtures, such as air with added nitrogen, 100 % nitrogen or air enriched with up to 40 % oxygen.
The ignition test method is used to determine the time required for ignition, t , of horizontal specimens by a
ign
pilot flame as a function of the magnitude of a constant, externally applied radiant heat flux. Measurements
also are made of time required until initial fuel vaporization. The surface of these specimens is coated with a
thin layer of black paint to ensure complete absorption of the radiant heat flux from the infrared heating system
(note that the coating does not itself undergo sustained flaming).
The combustion test method is used to determine the chemical and convective heat release rates, and smoke
generation rate when the horizontal test specimen is exposed to an external radiant heat flux.
The pyrolysis test method with a flow of 100 % nitrogen and no ignition can be used to measure the mass loss
rate as a function of externally applied radiant heat flux for a horizontal specimen. From these measurements,
the heat of gasification of the material can be determined.
The fire propagation test method using 40 % oxygen is used to determine the chemical heat release rate of a
burning, vertical specimen during upward fire propagation and burning initiated by a heat flux near the base of
the specimen. Chemical heat release rate is derived from the release rates of carbon dioxide and carbon
monoxide. Observations also are made of the flame height on the vertical specimen during fire propagation.
As discussed in B.5 and B.6, the use of enhanced oxygen in small-scale fire tests can better simulate the
[16][18][19][20][21]
flame heat flux occurring in large-scale fires . Correlation has been developed between the
results from small-scale tests with 40 % oxygen and the results from large-scale tests for a class of materials
(see B.6).
Distinguishing features of the FPA include:
2
 tungsten-quartz external, isolated heaters to provide a radiant flux of up to 65 kW/m to the test specimen,
which remains constant whether the surface regresses or expands;
 provision for combustion or upward fire propagation in prescribed flows of normal air, air enriched with up
to 40 % oxygen, air oxygen vitiated, pure nitrogen or mixtures of gaseous suppression agents with the
preceding air mixtures;
 the capability of measuring heat release rates and exhaust product flows generated during upward fire
propagation on a vertical test specimen 0,305 m high.
[6]
The original FPA uses a vertical exhaust duct configuration , which requires laboratories to have available a
sufficient ceiling height to accommodate all the system components. Also, the original FPA has the gas
sampling and analysis system completely separate from the main apparatus. To reduce this ceiling height
constraint and to allow for a more compact arrangement, a horizontal exhaust configuration has been
developed as shown in Figures 1 and 2. The FPA with horizontal duct provides equivalent results to those
measured using the FPA with vertical duct, as described in Annex C.
The FPA is used to evaluate the flammability of materials and products. It is also designed to obtain the
transient response of such materials and products to prescribed heat fluxes in specified inert or oxidizing
environments and to obtain laboratory measurements of generation rates of fire products (CO , CO, and, if
2
desired, gaseous hydrocarbons) for use in fire safety engineering.
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ISO 12136:2011(E)
Ignition of the specimen is by means of a pilot flame at a prescribed location with respect to the specimen
surface [described in 11.1 e)].
The Fire Propagation test of vertical specimens is not suitable for materials that, on heating, melt sufficiently to
form a liquid pool.
This International Standard does not purport to address all of the safety concerns, if any, associated with its
use. It is the responsibility of the user of this International Standard to establish appropriate health and safety
practices and to determine the applicability of regulatory limitations prior to use. For specific hazard
statements, see Clause 7.
This International Standard specifies small-scale test methods for determining the performance of materials
when exposed to fire, which are based on decades of research published in the fire science literature. Parts of
this International Standard are based on information contained in ASTM E2058 and NFPA 287.
The following test methods, capable of being performed separately and independently, are included:
1) Ignition test, to determine t for a horizontal specimen;
ign
2) Combustion test, to determine Q , Q , , H , and Y from burning of a horizontal specimen;

chem c m eff s
3) Pyrolysis test, to determine and H ; and,

m g
4) Fire propagation test, to determine Q from burning of a vertical specimen.
chem

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INTERNATIONAL STANDARD ISO 12136:2011(E)

Reaction to fire tests — Measurement of material properties
using a fire propagation apparatus
1 Scope
This International Standard determines and quantifies the flammability characteristics of materials, in relation
to their propensity to support fire propagation, by means of a fire propagation apparatus (FPA). Material
flammability characteristics that are quantified in this International Standard include time to ignition, chemical
and convective heat release rates, mass loss rate, effective heat of combustion, heat of gasification and
smoke yield. These properties can be used for fire safety engineering and for fire modelling.
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 13943, Fire safety — Vocabulary
ISO 14934-3, Fire tests — Calibration and use of heat flux meters — Part 3: Secondary calibration method
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 13943 and the following apply.
3.1
essentially flat surface
surface whose irregularity from a plane does not exceed 1 mm
3.2
flashing
existence of flame on or over the surface of the specimen for periods of less than 1 s
3.3
ignition
sustained flaming on or over the surface of the specimen for periods of over 10 s
3.4
fire propagation
increase in the exposed surface area of the specimen that is actively involved in flaming combustion
3.5
smoke yield
mass of smoke particulates generated per unit mass of fuel vaporized
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ISO 12136:2011(E)
4 Symbols
2
A Exposed surface area of specimen
m
2
A Cross sectional area of test section duct
m
d
c Specific heat of air at constant pressure kJ/kg K
p
1
D Optical density per unit length
m

Consumption rate of O kg/s
2
D
o
2

Mass flow rate of CO in test section duct kg/s
G
co

Mass flow rate of CO in test section duct kg/s
2
G
co
2

Mass flow rate of compound j in test section duct kg/s
G
j
H Heat of complete combustion per unit mass of CO kJ/kg
co
H Effective heat of combustion kJ/kg
eff
H Heat of gasification kJ/kg
g
H Net heat of complete combustion per unit mass of fuel vaporized kJ/kg
T
1/2
K 
Flow coefficient of averaging Pitot tube [duct gas velocity/(2P / )]
m
k Stoichiometric CO to fuel mass ratio, for conversion of all fuel carbon to CO 
2 2
co
2
k Stoichiometric CO to fuel mass ratio, for conversion of all fuel carbon to CO 
co
k Stoichiometric ratio of mass of oxygen consumed to mass of fuel burned 
o
2
L Optical path length m
M Total mass loss in combustion test method k
loss
M Total smoke generation in combustion test method kg
s

m Mass loss rate of test specimen kg/s

m Mass generation rate of smoke kg/s
s

m Mass flow rate of gaseous mixture in test section duct kg/s
d
P Atmospheric pressure Pa
atm
P Pressure differential across averaging Pitot tube in test section duct Pa
m
Q Cumulative heat released during combustion test method kJ
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ISO 12136:2011(E)
 Chemical heat release rate kW
Q
chem
 Convective heat release rate kW
Q
c
Gas temperature in test section duct before ignition K
T
a
Gas temperature in test section duct K
T
d
t
Time s
t Ignition time s
ign
v
Total volumetric flow rate in test section duct m3/s
W
Width of a flat specimen or the circumference of a cable specimen m
Y Smoke yield 
s
X Mole fraction of carbon dioxide in test section duct 
co
2
X Mole fraction of carbon monoxide in test section duct

co

3
Gas density in test section duct
kg/m
5 Principle
The four test methods given in this International Standard are based on measurements of time to observed
ignition, mass loss rate, heat release rate and smoke generation rate. The test methods are performed using a
laboratory calorimeter known as fire propagation apparatus whereby the heat source is isolated from the test
specimen. The test methods are intended to produce flammability property measurements that will
characterize fire behaviour during reference-scale fire tests.
The ignition, combustion or fire propagation test methods, or a combination thereof, have been performed with
materials and products containing a wide range of polymer compositions and structures, as described in B.7.
The unique feature of the fire propagation test method is that it produces laboratory measurements of the
chemical heat release rate during upward fire propagation and burning (from a material's own flame after
initiation by an external radiant flux) on a vertical test specimen in normal air, oxygen-enriched air, or in
oxygen-vitiated air.
These test methods are intended for evaluation of specific flammability characteristics of materials. Materials
to be analysed consist of specimens from an end-use product or the various components used in the end-use
product. Results from the test methods provide input to flame spread and fire growth models, risk analysis
studies, building and product designs and materials research and development.
This International Standard can be used to measure and describe the response of materials, products, or
assemblies to heat and flame under controlled conditions, but does not by itself incorporate all factors required
for fire hazard or fire risk assessment of the materials, products or assemblies under actual fire conditions.
The sample size and amount should not exceed the measurement capacity of the apparatus. A sample that is
explosive in nature should not be tested in the apparatus.
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ISO 12136:2011(E)
6 Apparatus
6.1 General
6.1.1 Dimensions
Where dimensions are stated in the text or in figures, they shall be followed within a tolerance of 0,5 %
typical and 1 % maximum. An exception is the case of components which are intended to fit together, where
the joint tolerance shall be appropriate for a sliding fit.
6.1.2 Components
The apparatus (see photograph and schematic in Figures 1 and 2 respectively, and exploded view in Figure 3)
shall consist of the following components:
a) an infrared heating system;
b) a load cell system;
c) an ignition pilot flame and timer;
d) a product gas analysis system;
e) a laser smoke measuring system;
f) a combustion air distribution system;
g) a water-cooled shield;
h) an exhaust system;
i) measuring section instruments;
j) calibration instruments;
k) a digital data acquisition system.
6.2 Infrared (IR) heating system
1 )
The IR heating system shall consist of four 240 mm long, 81 mm high and 81 mm wide heaters (see
different views in Figures 1 to 3) and a power controller.
Each of the four IR heaters shall contain six tungsten filament tubular quartz lamps (each 500 watts) in a
2
compact reflector body that produces up to 510 kW/m of radiant flux in front of the quartz window that covers
the lamps. The reflector body is water cooled and the lamp chamber, between the quartz window and reflector,
is air cooled for prolonged life. The emitter of each lamp is a 127 mm long tungsten filament in an argon
atmosphere enclosed in a 9,5 mm outer diameter (o.d.) clear quartz tube. The emitter operates at
approximately 2 205 °C (4 000 °F) at rated voltage, with a spectral energy peak at 1,15 µm. Wavelength
greater than about 3,6 µm is absorbed by the quartz bulb envelope and heater front window, which are air
cooled.

1) Hi-Temp 5208-05 high density infrared heaters with model 500T3/CL/HT lamps and 664 SCR power controller; or Hi-
Temp 5209-05 with QIH240-1000R12 lamps and 3629B power controller, supplied by Research, Inc.,
http://www.researchinc.com, are examples of suitable products available commercially. This information is given for the
convenience of users of this document and does not constitute an endorsement by ISO of the product named.
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ISO 12136:2011(E)
6.3 Load cell system
The load cell system, shown in Figures 2 and 3, shall consist of a load cell with a suitable load cell signal
conditioning load cell controller, which shall have:
a) an accuracy of 0,1 g and a measuring range of 0 g to1 000 g; a 6,35 mm diameter stainless steel shaft, at
least 330 mm long, resting on the load cell support point;
b) a 100 mm diameter, 1,5 mm thick aluminium load platform connected to the upper end of the stainless
steel shaft by a collar;
c) two low friction, ball-bushing bearings that guide the shaft as it passes through the top and bottom,
respectively, of the air distribution chamber.
The stainless steel shaft shall incorporate, at the lower end, a threaded adjustment rod to compensate for
horizontal test specimens of different thicknesses.
6.4 Ignition pilot flame
The ignition pilot shall consist of an ethylene/air (60/40 by volume) flame adjusted for a 10 mm length. The
pilot flame is anchored at the 50 mm long, horizontal end of a stainless steel tube with an outer diameter of
6,35 mm and an inner diameter of 4,70 mm. In the horizontal tube section, use a four-hole ceramic insert to
produce a stable flame and prevent flashback. The pilot flame tube shall be able to be rotated and elevated to
position the horizontal flame at specified locations near the specimen [described in 11.1 e)], as shown in
Figures 2 and 3.
6.5 Ignition timer
The device for measuring time to sustained flaming shall be capable of recording elapsed time to the nearest
0,1 s and have an accuracy of better than 1 s/h.
6.6 Gas analysis system
6.6.1 Gas sampling
The gas analysis system shall consist of a gas sampling system and gas analysis instruments. The gas
sampling arrangement is shown in Figure 4. This arrangement consists of:
a) a sampling probe in the test section duct;
b) primary and secondary plastic filters (5 µm pore size) to prevent entry of soot;
c) a condenser operating at temperatures in the range 5 °C to 0 °C to remove liquids;
d) a tube containing an indicating desiccant (10 to 20 mesh) to remove most of the remaining moisture;
e) a filter to prevent soot from entering the analysers, if not already removed;
f) a sampling pump that transports the flow through the sampling line, system flow meters, needle valves
and manifolds to direct the flow to individual analysers (CO, CO , O , and hydrocarbon gas).
2 2
The sampling probe, made of stainless steel tubing (6,35 mm o.d.) with 14 holes, inserted through a test
section port, shall be positioned such that the open end of the tube is at the centre of the test section. The
sampling probe is connected to a tee fitting that allows either sa
...