ISO 17554:2005

INTERNATIONAL ISO
STANDARD 17554
First edition
2005-07-01
Reaction to fire tests — Mass loss
measurement
Essais de réaction au feu — Mesurage de la perte de masse

Reference number
©
ISO 2005
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ii © ISO 2005 – All rights reserved

Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Symbols . 2
5 Principle. 3
6 Apparatus . 3
7 Suitability of a product for testing . 7
8 Specimen construction and preparation. 8
9 Test environment. 9
10 Calibration . 10
11 Test procedure . 11
12 Calculations. 12
13 Test report . 13
Annex A (informative) Commentary and guidance notes for operators. 15
Annex B (informative) Precision and bias . 16
Annex C (informative) Calibration of the working heat flux meter. 17
Bibliography . 18

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 17554 was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 1, Fire initiation
and growth.
iv © ISO 2005 – All rights reserved

INTERNATIONAL STANDARD ISO 17554:2005(E)

Reaction to fire tests — Mass loss measurement
1 Scope
This International Standard specifies a small-scale method for assessing the mass loss rate of essentially flat
specimens exposed in the horizontal orientation to controlled levels of radiant heating with an external igniter
under well-ventilated conditions. The mass loss rate is determined by measurement of the specimen mass
and is derived numerically. The time to ignition (sustained flaming) is also measured in this test. Mass loss
rate can be used as an indirect measure of heat release rate for many products. However some products, e.g.
those with high water content, will have mass loss rates that are not so closely linked to heat release rates.
Such products need to be tested in accordance with ISO 5660-1 for correct assessment of heat release.
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 554:1976, Standard atmospheres for conditioning and/or testing — Specifications
ISO 13943:2000, Fire safety — Vocabulary
ISO/TR 14697:1997, Fire tests — Guidance on the choice of substrates for building products
ISO 5660-1, Reaction-to-fire tests — Heat release, smoke production and mass loss rate — Part 1: Heat
release rate (cone calorimeter 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
onset of sustained flaming as defined in 3.9
3.4
irradiance
〈point on a surface〉 quotient of the radiant flux incident on an infinitesimal element of surface containing the
point, and the area of that element
NOTE Convective heating is negligible in the horizontal specimen orientation. For this reason, the term “irradiance” is
used instead of “heat flux” throughout this International Standard, as it best indicates the essentially radiative mode of heat
transfer.
3.5
material
single substance or uniformly dispersed mixture
EXAMPLE Metal, stone, timber, concrete, mineral fibre and polymers.
3.6
orientation
plane in which the exposed face of the specimen is located during testing, with either the vertical or horizontal
face upwards
3.7
product
material, composite or assembly about which information is required
3.8
specimen
representative piece of the product which is to be tested together with any substrate or treatment
NOTE For certain types of product, for example products that contain an air gap or joints, it is sometimes not possible
to prepare specimens that are representative of the end-use conditions (see Clause 7).
3.9
sustained flaming
existence of flame on or over the surface of the specimen for periods of over 10 s
3.10
transitory flaming
existence of flame on or over the surface of the specimen for periods of between 1 s and 10 s
4 Symbols
Symbol Designation Unit
A
Initially exposed surface area of the specimen
m
s
M Mass of the specimen G
m
Mass of the specimen at the start of the test g
I
m
Mass of the specimen at the end of the test g
f
m
Mass of the specimen at 10 % of total mass loss g
m
Mass of the specimen at 90 % of total mass loss g
1
m
Mass loss rate of the specimen
g⋅s
–1

m
Maximum value of the mass loss rate g⋅s
max
 2 –1
m
Average mass loss rate per unit area between 10 % and 90 % of mass loss
A,10-90 g⋅m ⋅s
–1
 Average mass loss rate over the period starting at t and ending 180 s later
m
g⋅s
180 ig
 Average mass loss rate over the period starting at t and ending 300 s later
m
g⋅s
300 ig
T Time s
t
Time to ignition (onset of sustained flaming) s
ig
∆t Sampling time interval s
2 © ISO 2005 – All rights reserved

5 Principle
The test method is used to assess the mass loss rate that the product undergoes under the test conditions.
This rate is determined on small representative specimens burning in a well-ventilated environment.
6 Apparatus
6.1 General
The test apparatus shall consist essentially of the following components:
6.1.1 Cone-shaped radiant electrical heater.
6.1.2 Weighing device for measuring specimen mass.
6.1.3 Specimen holder.
6.1.4 Spark ignition circuit.
6.1.5 Heat flux meters.
6.1.6 Data collection and analysis system.
A schematic representing the assembly is given in Figure 1. The apparatus should be located under a suitable
exhaust system with a flow rate of less than 0,5 m /s. The individual components are described in detail in the
following sections.
Key
1 cone heater
2 spark igniter
3 specimen
4 load cell
Figure 1 — Schematic of apparatus
6.2 Cone-shaped radiant electrical heater
The active element of the heater shall consist of an electrical heater rod, capable of delivering 5 000 W at the
operating voltage, tightly wound into the shape of a truncated cone (see Figure 2). The heater shall be
encased on the outside with a double-wall stainless steel cone, filled with a refractory fibre blanket of nominal
thickness 13 mm and nominal density 100 kg/m . The irradiance from the heater shall be maintained at a
preset level by controlling the average temperature of three thermocouples, (type K, stainless-steel sheathed
1)
thermocouples, have proved suitable, but Inconel or other high performance materials are also acceptable)
symmetrically disposed and in contact with, but not welded to, the heater element (see Figure 2). Either
3,0 mm outside-diameter sheathed thermocouples with an exposed hot junction or 1,0 mm to 1,6 mm outside-
diameter sheathed thermocouples with an unexposed hot junction shall be used. The heater shall be capable
of producing irradiances on the surface of the specimen of up to 100 kW/m . The irradiance shall be uniform
within the central 50 mm × 50 mm area of the exposed specimen surface, to within ± 2 %.
Dimensions in millimetres
Key
1 inner shell
2 refractory fibre packing
3 thermocouple
4 outer shell
5 spacer block
6 heating element
Figure 2 — Conical heater assembly
6.3 Radiation shield
The cone heater shall be provided with a removable radiation shield to protect the specimen from the
irradiance prior to the start of a test. The shield shall be made of non-combustible material, with a total
thickness not exceeding 12 mm. The shield shall be one of the following:
a) water cooled and coated with a durable matt black finish of surface emissivity, ε = 0,95 ± 0,05, or

1) Inconel is an example of a suitable product available commercially. This information is given for the convenience of
users of ISO 17554 and does not constitute an endorsement by ISO of this product.
4 © ISO 2005 – All rights reserved

b) not water-cooled, which may be either metal with a reflective top surface or ceramic in order to minimize
radiation transfer.
The shield shall be equipped with a handle or other suitable means for quick insertion and removal. The cone
heater base plate shall be equipped with a mechanism for introducing the shield into position.
6.4 Irradiance control
The irradiance control system shall be properly tuned so that it maintains the average temperature of the
heater thermocouples during the calibration described in 10.1.1 at the preset level to within ± 10 °C.
6.5 Weighing device
The weighing device shall have an accuracy of ± 0,1 g or better, measured according to the calibration
procedure described in 10.2.1. The weighing device shall be capable of measuring the mass of specimens of
at least 500 g. The weighing device shall have a 10 % to 90 % response time of 1 s to 4 s as determined
according to the calibration described in 10.1.2. The output of the weighing device shall not drift by more than
1 g over a 30 min period, as determined with the calibration described in 10.1.3.
6.6 Specimen holder and retainer frame
6.6.1 The specimen holder is shown in Figure 3. The specimen holder shall have the shape of a square pan
with an opening of (106 ± 1) mm × (106 ± 1) mm at the top, and a depth of (25 ± 1) mm. The holder shall be
constructed of stainless steel with a thickness of (2,4 ± 0,15) mm. It shall include a handle to facilitate insertion
and removal, and a mechanism to ensure central location of the specimen under the heater and proper
alignment with the weighing device. The bottom of the holder shall be lined with a layer of low-density
(nominal density equals 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 specimen shall be adjusted to be
(25 ± 1) mm except when testing dimensionally unstable materials for which the distance is (60 ± 1) mm
(see 7.5).
Dimensions in millimetres
The thickness should be 2,4 ± 0,15.
Figure 3 — Specimen holder
6.6.2 All specimens shall be tested with the retainer frame shown in Figure 4. The frame shall be
constructed of stainless steel with a thickness of (1,9 ± 0,1) mm in the shape of a box with the inside
dimension of each side (111 ± 1) mm and a height of (54 ± 1) mm. The opening for the specimen face shall be
a square with the dimension of each side (94,0 ± 0,5) mm, as shown in Figure 4. The retainer frame shall
have an appropriate means to secure to the specimen holder with a specimen in position.
Dimensions in millimetres
Key
1 10 × 32 tapped holes (X4)
Figure 4 — Specimen retainer frame
6.7 Ignition circuit
External ignition is accomplished by a spark plug powered from a 10 kV transformer or spark igniter. The
spark plug shall have a gap of (3,0 ± 0,5) mm. The electrode length and location of the spark plug shall be
such that the spark gap is located (13 ± 2) mm above the centre of the specimen except when testing
dimensionally unstable materials for which the distance is (48 ± 2) mm (see 7.5).
6.8 Ignition timer
The ignition timer shall be capable of recording elapsed time to the nearest second and shall be accurate to
within 1 s in 1 h.
6 © ISO 2005 – All rights reserved

6.9 Heat-flux meter
The working heat flux meter shall be used to calibrate the heater (see 10.2.2). It shall be positioned at a location
equivalent to the centre of the specimen face during calibration.
This heat flux meter shall be of the Schmidt-Boelter (thermopile) type with a design range of (100 ± 10) kW/m .
The target receiving the heat shall be flat, circular, of approximately 12,5 mm in diameter and coated with a
durable matt black finish of surface emissivity, ε = 0,95 ± 0,05. The target shall be water-cooled. A cooling
temperature, which could cause condensation of water on the target surface of the heat flux meter, shall not
be used.
Radiation shall not pass through any window before reaching the target. The instrument shall be robust,
simple to set up and use, and stable in calibration. The instrument shall have an accuracy of within ± 3 % and
a repeatability to within ± 0,5 %.
The calibration of the working heat-flux meter shall be checked according to 10.3.1, by comparison with two
instruments of the same type as the working heat-flux meter. They shall be of similar range as the reference
standards and not used for any other purpose (see Annex C). One of the reference standards shall be fully
calibrated at a standardizing laboratory at yearly intervals.
6.10 Data collection and analysis system
This system shall have facilities for recording the output from the weighing device. It shall have an accuracy
corresponding to at least 0,01 % of the full-scale instrument output and at least 0,1 % for the measurement of
time.
7 Suitability of a product for testing
7.1 Surface characteristics
A product having one of the following properties is suitable for testing:
a) an essentially flat exposed surface;
b) a surface irregularity which is evenly distributed over the exposed surface provided that
1) at least 50 % of the surface of a representative 100 mm square area lies within a depth of 10 mm
from a plane taken across the highest points on the exposed surface, or
2) for surfaces containing cracks, fissures or holes not exceeding 8 mm in width or 10 mm in depth, the
total area of such cracks, fissures or holes at the surface does not exceed 30 % of a representative
100 mm area of the exposed surface.
When an exposed surface does not meet the requirements of either 7.1 a) or 7.1 b), the product shall be
tested in a modified form complying as nearly as possible with the requirements given in 7.1. The test report
shall state that the product has been tested in a modified form, and clearly describe the modification.
7.2 Asymmetrical products
A product submitted to this test may have faces which differ or contain laminations of different materials
arranged in a different order in relation to the two faces. If either of the faces can be exposed in use within a
room, cavity or void, both faces shall be tested.
7.3 Materials of short burning time
For specimens of short burning time (3 min or less), the measurements shall be taken at not more than 2 s
intervals. For longer burning times, 5 s intervals may be used.
7.4 Composite specimens
Composite specimens are suitable for testing, provided they are prepared as specified in 8.3 and are exposed
in a manner typical to end-use conditions.
7.5 Dimensionally unstable materials
Samples that intumesce or deform so that they contact the spark plug prior to ignition, or the underside of the
cone heater after ignition, shall be tested with a separation of 60 mm between the base plate of the cone
heater and the upper surface of the specimen. In this case, the heater calibration (10.2.2) shall be performed
with the heat-flux meter positioned 60 mm from the baseplate. The time to ignition measured with this
separation is not comparable to the one measured with the separation of 25 mm.
Other dimensionally unstable products, for example products that warp or shrink during testing, shall be
restrained against excessive movement. This shall be accomplished with four tie wires, as described in the
following paragraph. Metal wires of (1,0 ± 0,1) mm diameter and at least 350 mm long shall be used.
The sample shall be prepared in the standard way as described in Clause 8. A tie wire is then looped around
the sample holder and retainer frame assembly, so that it is parallel to and approximately 20 mm away from
one of the four sides of the assembly. The ends of the wire are twisted together such that the wire is pulled
firmly against the retainer frame. Excess wire is trimmed from the twisted section before testing. The three
remaining wires shall be fit around the specimen holder and retainer frame assembly in a similar manner,
parallel to the three remaining sides.
8 Specimen construction and preparation
8.1 Specimens
8.1.1 Unless otherwise specified, three specimens shall be tested at each level of irradiance selected and
for each different exposed surface.
8.1.2 The specimens shall be representative of the product and shall be square with sides measuring
100 mm.
()
−2
8.1.3 Products with normal thickness of 50 mm or less shall be tested using their full thickness.
8.1.4 For products with normal thickness of greater than 50 mm, the req
...