ISO 5657:1986

International Standard 5657
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION*MEI/lYHAPO~HAR OPrAHHBAUMR fl0 CTAH/lAPTH3AUHH.ORGANISATION INTERNATIONALE DE NORMALISATION
Fire tests - Reaction to fire - Ignitability of building
~
, products
Essais au feu - Réaction au feu - Allumabilité des produits de bâtiment
First edition - 1986-12-15
- UDC 669.81 : 691 : 620.1 Ref. No. ISO5657-1986(E)
Descriptors : buildings, construction materials, tests, fire tests, flammability testing, test equipment.
@
Price based on 32 pages
Ei
IS0 (the International Organization for standardization) is a worldwide federation of
national standards bodies (IS0 member bodies). The work of preparing International
Standards is normally carried out through IS0 technical committees. Each member
body interested in a ct for which a technical committee has been established has
the right to be rep d on that committee. International organizations, govern-
mental and non-governmental, in liaison with ISO, also take part in the work.
*
Draft International Standards adopted by the technical committees are circulated to
the member bodies for approval before their acceptance as International Standards by
IS0 Council. They are approved in accordance with IS0 procedures requiring at
the
least 75 % approval by the member bodies voting.
International Standard IS0 5657 was prepared by Technical Committee ISO/TC 92,
Fire tests on building materials, components and structures.
Users should note that all International Standards undergo revision from time to time
and that any reference made herein to any other International Standard implies its
latest edition, unless otherwise stated.
O International Organization for Standardization, 1986 0
Printed in Switzerland
ii
IS0 5657-1986 (E)
Contents Page
O Introduction . 1
1 Scope and field of application . 1
2 References. . . . . 1
3 Definitions . .
........ ......... 1
4 . . 2
Principles of the test .
5 Suitability of a product for testing . 2
Specimen construction and preparation .
7 Test apparatus. .
8 Test environment .
9 Additional equipment . . 5
10 Setting-up procedure and requirements . 6
11 Calibration .
12 Testprocedure . 7
............................
13 Expression of results. .
14 Testreport .
Annexes
A Commentary on the text and guidance notes for operators. .
B Summary test report . .
Applications and limitations of test .
C
D Variability in time to sustained surface ignition . 15
Figures
1 Wrapping of the specimen .
2 lgnitability test apparatus - General view .
3al Specimen support framework -
Part sectional elevation along B-B [figure 3b)l . 19
...
III
3b) Specimen support framework -
Part sectional plan along A-A [figure 3a)l . . 20
4a) Specimen support framework and radiator cone . . 21
4b) Radiator cone. . .
4c) Methods for attachment of thermocouples to heater coil .
4d) Grids of readings for irradiance distribution . . 23
5 Pilot flame nozzle. .
...................
6a) Pilot flame application mechanism - Pilot flame arm .
6b) Pilot flame application mechanism - Baseplate . 26
6c) Pilot flame application mechanism - Cam geometry. . 27
7 Specimen insertion and location tray . . 28
8 Specimen screening plate. .
Extraction hood and draught screen for ignitability apparatus .
10 Diagrammatic arrangement of apparatus and additional equipment . 31
11 Dummy specimen board. . 32
I iv
INTERNATIONAL STANDARD IS0 5657-1986 (E)
Fire tests - Reaction to fire - Ignitability of building
O Introduction 2 References
IS0 291, Plastics - Standard atmospheres for conditioning
0.1 Fire is a complex phenomenon : its behaviour and its ef-
and testing.
fects depend upon a number of interrelated factors. The
behaviour of materials and products depends upon the
IS0 3261, Fire tests - Vocabulary.
characteristics of the fire, the method of use of the materials
and the environment in which they are exposed. The
ISOITR 3814, The development of tests for measuring "reac-
philosophy of "reaction to fire" tests is explained in
tion to fire" of building materials.
0 ISOiTR 3814.
IS0 5725, Precision of test methods - Determination of
0.2 A test such as is specified in this International Standard
repeatability and reproducibility by inter-laboratory tests.
deals only with a simple representation of a particular aspect of
a radiant heat source and
the potential fire situation typified by
ISOiTR 6585, Fire hazard and the design and use of fire tests.
a flame; it cannot alone provide any direct guidance on
behaviour or safety in fire. A test of this type may, however, be
used for comparative purposes or to ensure the existence of a
3 Definitions
certain quality of performance (in this case ignitability) con-
sidered to have a bearing on fire performance generally. It
(See also clause A.l in annex A.)
would be wrong to attach any other meaning to performance in
th is test.
For the purposes of this International Standard, the definitions
given in IS0 3261 apply, together with the following :
0.3 The term "ignitability" is defined in IS0 3261 as the
8 capability of a material of being ignited. It is one of the first fire
product: Material, composite or assembly about which
3.1
properties to be manifest and should almost always be taken
information is required.
into account in any assessment of fire hazard. It may not,
however, be the main characteristic of the material which af-
3.2 material : Single substance or uniformly dispersed mix-
fects the subsequent development of fire in a building.
ture, for example metal, stone, timber, concrete, minerai fibre,
polymers.
0.4 This test does not rely upon the use of asbestos-based
materials.
3.3 composite: Combination of materials which are gener-
ally recognized in building construction as discrete entities, for
0.5 The attention of all users of the test is drawn to the
example coated or laminated materials.
following warning.
assembly: Fabrication of materials andior composites,
3.4
SAFETY WARNING - So that suitable precautions may
for example sandwich panels. This may include an air gap.
be taken to safeguard health, the attention of all con-
cerned in fire tests is drawn to the possibility that toxic or
harmful gases may be evolved during exposure of test 3.5 exposed surface : That surface of the product subjected
to the heating conditions of the test.
specimens. The advice on safety given in annex A,
clause A.7 should also be noted.
3.6 specimen: Representative piece of the product which is
to be tested together with any substrate or treatment. This may
include an air gap.
1 Scope and field of application
3.7 essentially fiat surface: Surface whose irregularity
This International Standard specifies a method for examining
from a plane does not exceed k 1 mm.
the ignition characteristics of the exposed surfaces of
specimens of essentially flat materials, composites or
3.8 irradiance (at a point of a surface): Quotient of the
assemblies not exceeding 70 mm in thickness, when placed
radiant flux incident on an infinitesimal element of surface
horizontally and subjected to specified levels of thermal
containing the point, by the area of that element.
irradiance.
IS0 5657-1986 (E)
shall state that the product has been tested in a modified form
3.9 sustained surface ignition : Inception of a flame on the
and clearly describe the modification (see clause 14).
surface of the specimen which is still present at the next ap-
plication of the pilot flame.
5.2 Asymmetrical products
3.10 transitory surface ignition: Inception of any flame at
A product submitted for this test could have faces which differ
the surface of the specimen which is not sustained until the
next application of the pilot flame. or could 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, then both
3.11 plume ignition: Inception of any flame in the plume
faces shall be tested.
above the specimen, sustained or transitory.
6 Specimen construction and preparation
4 Principles of the test
(See also clause A.4 in annex A.)
(See also clause A.2 in annex A.)
6.1 Specimens
Specimens of the product are mounted horizontally and ex-
posed to thermal radiation on their upper surfaces at selected
6.1.1 Five specimens shall be tested at each level of irradiance
levels of constant irradiance within the range 1 to 5 W/cm2.
selected and for each different exposed surface.
A pilot flame is applied at regular intervals to a position 10 mm
above the centre of each specimen to ignite any volatile gases
6.1.2 The specimens shall be representative of the product,
given off. The time at which sustained surface ignition occurs is
square, with sides measuring 165 -E mm.
reported. Other types of ignition which occur are reported
in 12.5.
6.1.3 Materials and composites of normal thickness 70 mm or
less shall be tested using their full thickness.
Convection transfer may also make a very small contribution
(not more than a few per cent) to the heating at the centre of a
6.1.4 For materials and composites of normal thickness
specimen and to the reading of the radiometer during the
calibration procedure. However, the term irradiance is used greater than 70 mm, the requisite specimens shall be obtained
by cutting away the unexposed face to reduce the thickness to
throughout this International Standard as best indicating the
essentially radiative mode of heat transfer. 70 -3 mm.
6.1.5 When cutting specimens from products with irregular
surfaces, the highest point on the surface shall be arranged to
5 Suitability of a product for testing
occur at the centre of the specimen.
(See also clause A.3 in annex A.)
6.1.6 Assemblies shall be tested as specified in 6.1.3 or 6.1.4
as appropriate. However, where thin materials or composites
5.1 Surface characteristics
are used in the fabrication of an assembly, the presence of air
or an air gap andior the nature of any underlying construction
5.1.1
A product having one of the following properties is
may significantly affect the ignition characteristics of the ex-
:
suitable for testing
posed surface. The influence of the underlying layers should be
understood and care taken to ensure that the test result
a) an essentially flat exposed surface;
obtained on any assembly is relevant to its use in practice
(see A.4.1).
b) a surface irregularity which is evenly distributed over
the exposed surface provided that :
When the product is a material or composite which would nor-
mally be attached to a well-defined substrate, then it shall be
- at least 50 % of the surface of a
representative
tested in conjunction with that substrate using the recom-
150 mm diameter area lies within a depth of 10 mm from
mended fixing technique, e.g. bonded with the appropriate
a plane taken across the highest points on the exposed
adhesive or mechanically fixed.
surface, and/or
- for surfaces containing cracks, fissures or holes not
6.2 Baseboards
exceeding 8 mm in width nor 10 mm in depth, the total
area of such cracks, fissures or holes at the surface does
6.2.1 One baseboard will be required for each test specimen.
not exceed 30 % of a representative 150 mm diameter
area of the exposed surface. However, since it will sometimes be possible to re-use the
baseboard after test, the total number required will depend on
the frequency of testing and the type of product being tested.
5.1.2 When an exposed surface does not meet the re-
quirements of either 5.1.1 a) or 5.1.1 b), the product shall, if
6.2.2 The baseboards shall be square with sides measuring
practicable, be tested in a modified form complying as nearly as
possible with the requirements given in 5.1.1. The test report 165 -5 mm and shall be made of non-combustible insulation

IS0 5657-1986 (E)
board of oven-dry density 825 + 125 kg/m3 and nominal approximately 250 OC for a period of 2 h in an attempt to
thickness 6 mm. remove any volatile residue. If there is still any doubt about the
condition, it shall be discarded.
6.2.3 Before use in a test, a baseboard shall be placed for at
least 24 h in an atmosphere at a temperature of 23 f 2 OC and
a relative humidity of (50 f 5) %, with free access of air to
7 Test apparatus
both sides.
7.1 General
6.3 Conditioning of specimens
7.1.1 All dimensions given in the following description of test
(See also sub-clause A.4.3 in annex A.)
apparatus are nominal unless tolerances are specified.
Before test the specimens shall be conditioned to constant
7.1.2 The test apparatus shall consist essentially of a support
mass') at a temperature of 23 + 2 OC, and a relative humidity
framework which clamps the test specimen horizontally be-
of (50 f 5) %.
tween a pressing plate and a masking plate such that a defined
area of the upper surface of the specimen is exposed to radia-
6.4 Preparation
tion. This radiation shall be provided by a radiator cone pos-
itioned above and supported from the specimen support
6.4.1 A conditioned specimen shall be placed on a baseboard
framework. An automated pilot flame application mechanism
treated according to 6.2.3 and the combination shall be
shall be used to bring a test flame through the radiator cone to
wrapped in one piece of aluminium foil of nominal thickness
a position above the centre of the surface of the specimen. A
0,02 mm from which a circle 140 mm diameter
specimen insertion and location tray shall be used to position
previously cut (see figure 1). The circular cut-out zo
the specimen accurately on the pressing plate of the specimen
centrally positioned over the upper surface of the specimen.
support framework and a screening plate shall be used to shield
After preparation the specimen-baseboard combination shall
the surface of the specimen during its insertion into the ap-
be returned to the conditioning atmosphere until required for
paratus.
test.
7.1.3 A general arrangement of a suitable apparatus is shown
6.4.2 Where a product will normally be backed by air (see 2, with detailed drawings in figures 3 to 6.
in figure
6.1.61, then the specimen shall, where practicable, be backed
by an air gap in the test. The air gap shall be formed by in-
7.2 Specimen support framework, masking plate
cluding a spacer between the specimen and the baseboard. The
and pressing plate
spacer shall consist of a piece of non-combustible insulation
board of the same size and density as the baseboard, from the
7.2.1 The specimen support framework and the other parts of
centre of which a circular area 140 -5 mm in diameter has been
removed. The thickness of the spacer shall correspond to the the system to hold the specimen in position shall be con-
structed from stainless steel. It shall consist of a rectangular
size of the air gap, if this is known, except that the total
base-frame made from 25 mm x 25 mm square tube of
thickness of the spacer plus specimen shall not exceed 70 mm.
1,5 mm wall thickness and shall have overall dimensions of
If the size of the air gap is not known or the total thickness of
275 mm x 230 mm. A horizontal masking plate, 220 mm
the air gap plus specimen exceeds 70 mm, then the specimen
shall be tested with a spacer which will give a total thickness for square and 4 mm thick, shall be mounted centrally and 260 mm
above the top of the base-frame on four 16 mm diameter legs
the specimen and spacer of 70 -3 mm.
positioned at the corners of the masking plate. A 150 mm
diameter circular opening shall be cut centrally in the masking
The spacer and baseboard shall be placed for at least 24 h in an
atmosphere at a temperature of 23 f 2 OC and a relative plate, the edges of the hole being chamfered on the top surface
of the plate at an angle of 45O and to a horizontal width
humidity of (50 f 5) %, with free access of air to both sides of
of 4 mm.
each. The spacer shall then be interposed between the
baseboard and the specimen and the combination shall be
wrapped in aluminium foil as described in 6.4.1. A clean spacer
7.2.2 Two vertical guide rods not less than 355 mm long of
shall be used for each specimen tested. After preparation the
20 mm diameter steel shall be mounted on the base-frame, one
combination shall be returned to the conditioning atmosphere
at the mid-length of each of the short sides of the frame. A
until required for test.
horizontal adjustable bar 25 mm x 25 mm which can slide on
the rods and be locked in position by bolts capable of being
tightened by hand shall be mounted below the masking plate
6.4.3 Baseboards and/or spacers used to back the specimens
may be re-used if they are not contaminated. Immediately and between the vertical guide rods. A vertical central hole and
sleeve in the adjustable bar shall be used to locate a sliding ver-
before re-use, however, they should have been in the condi-
tical rod of 12 mm diameter and 148 mm long, surmounted by a
tioning atmosphere specified in 6.2.3 and 6.4.2 for at least 24 h.
e condition of a baseboard or 180 mm square pressing plate 4 mm thick. The pressing plate
If there is any doubt abou
shall be pushed upwards against the underside of the masking
spacer, it may be placed in a ventilated oven at a temperature of
1) Constant mass is considered to be reached when two successive weighing operations, carried out at an interval of 24 h, do not differ by more
than 0,l % of the mass of the test piece or 0,l g, whichever is the greater.
..-
IS0 5657-1986 (E)
7.3.3 The radiator cone shall be located and secured from the
plate by the counterweighted pivot arm which shall be
vertical guide rods of the specimen support framework by
mounted below the adjustable horizontal bar and shall press
clamps which position the lower rim of the radiator cone shade
against the bottom of the sliding vertical rod. This can be
22 f 1 mm above the upper surface of the masking plate.
achieved by an arm about 320 mm long.
It shall contain at one end a roller which shall bear against a
7.3.4 Details of the radiator cone are shown in figure 4b).
boss on the bottom of the sliding vertical rod and at the other
end an adjustable counterweight.
7.3.5 The temperature of the radiator cone shall be controlled
The counterweight shall be capable of compensating for dif-
by reference to the reading of a thermocouple (primary ther-
ferent masses of specimens and of maintaining a force of ap-
mocouple) (9.1) in close and stable thermal contact with the
proximately 20 N between the upper surface of the specimen
heater element tube. A second thermocouple (secondary ther-
and the masking plate. A counterweight of about 3 kg has been
mocouple) shall be attached similarly, mounted in a diametrical-
found to be suitable. An adjustable stop shall be provided to
ly opposite position. The thermocouples shall have a speed of
limit upward movement of the pressing plate, due to collapse,
response not worse than that of a thermocouple with insulated
softening or melting of the specimen during its exposure, to
hot junction in a stainless steel sheath 1 mm in diameter. Each
5 mm. Alternatively spacing blocks between the pressing plate
thermocouple shall be attached to a coil of the heater element
and the masking plate may be used.
tube which places them between one-third and half way down
from the top of the radiator cone. At least 8 mm of the end of
the thermocouple shall lie in a region of approximately uniform
7.2.3 Figure 3 shows details of the specimen support
temperature.
framework.
A description of methods of attaching thermocouples which
7.3 Radiator cone
have been found satisfactory in practice is given in annex A
(clause A.5.1).
7.3.1 The radiator cone shall consist of a heating element, of
nominal rating 3 kW, contained within a stainless steel tube,
7.4 Pilot flame application mechanism
approximately 3 500 mm in length and 8,5 mm in diameter,
coiled into the shape of a truncated cone and fitted into a
(See also clause A.5.2 in annex A.)
shade. The shade shall have an overall height of 75 f 1 mm,
an internal diameter of 66 f 1 mm and an internal base
7.4.1 The apparatus shall be provided with a mechanism
diameter of 200 f 3 mm. It shall consist of two layers of 1 mm
which is capable of bringing a pilot flame from a re-ignition
thick stainless steel with a 10 mm thickness of ceramic fibre in-
position outside the radiator cone to the test position within the
sulation of nominal density 100 kg/m3 sandwiched between
cone. The mechanism shall be capable of taking the pilot flame
them. The heating element shall be fastened to the inside face
through the radiator cone and through the aperture in the
of the shade by steel pins. Clamps shall be used to prevent ad-
masking plate to a maximum distance of 60 mm below the
ditional sagging of the lower coil below the base of the shade.
underside of the masking plate.
The upper turn of the heating element shall not obstruct the
area of the top aperture of the shade by more than 10 % when
7.4.2 The pilot flame shall issue from a nozzle made of
projected vertically.
stainless steel as specified in figure 5, attached near the end of
the pilot flame tube.
7.3.2 The radiator cone shall be capable of providing irra-
diance in the range 1 to 5 W/cm2 at the centre of the aperture
7.4.3 The normal position of the pilot flame shall be above the
in the masking plate and in a reference plane coinciding with
radiator cone and clear of the plume of smoke or decompo-
the underside of the masking plate, when measured as de-
sition products which may rise through the top of the cone.
scribed in ll -2. The distribution of irradiance provided by the
When in this position the pilot flame nozzle shall be adjacent to
cone at the reference plane shall be such that the variation of ir-
a secondary ignition source') having a heat output not greater
radiance within a circle of 50 mm diameter, drawn from the
than 50 W which shall be capable of re-igniting the pilot flame
centre of the masking plate aperture, shall be not more than
should it be extinguished.
f 3 % of that at the centre; the variation of irradiance within a
circle of 100 mm diameter shall be not more than f5 % of that
at the centre. 7.4.4 The normal position for the pilot flame shall be such that
the flame issues horizontally over the centre point of the aper-
The distribution of irradiance shall be determined from readings
ture in the masking plate and perpendicular to the plane of
at the centres of 10 mm squares forming the grids shown in
movement of the pilot arm, with the centre of the orifice in the
figure 4d). The tolerances given shall apply to the readings
nozzle positioned 10 f 1 mm above the underside of the
within the grid comprising all the squares shown in figure 4d).
masking plate.
For these measurements, the opening in the masking plate shall
be completely filled; it is necessary to employ a number of 7.4.5 The application mechanism shall automatically bring the
pilot flame to the "normal test position" once every 4 s.
calibration boards of special horizontal shapes and sizes.
1) The secondary ignition source can be a gas flame, hot wire or spark igniter. A propane flame, 15 mm long, from a nozzle with an internal diameter
of 1 to 2 mm, has a heat output of approximately 50 W.
IS0 5657-1986 (E)
The pilot flame shall not take longer than 0,5 s to travel from effluent gases shall be extracted without causing forced ven-
the opening at the top of the radiator shade to the test position tilation over the apparatus.
where it shall remain for 1 +:ri s. The time taken for the pilot
flame to travel back over the same distance shall not exceed
8.2 A suitable design for screening the apparatus from
0,5 s.
draughts and exhausting the effluent gases is shown in
figure 9.
7.4.6 The mechanism shall be provided with an adjustable stop
which will restrict the lowest point of travel of the pilot flame to
any position within the range from 20 mm above the test position 9 Additional equipment
to 60 mm below. When operating within this range, the vertical
force exerted on the test specimen by the pilot flame nozzle shall
9.1 Temperature controller
be between 0,l and 0,2 N. This is to be measured as the static
force exerted with the mechanism stopped.
The temperature controller for the radiator cone shall be of the
proportional integral and derivative type (“3-term” controller)
7.4.7 A suitable pilot flame application mechanism” is shown with thyristor stack fast-cycle or phase angle (see A.5.3) con-
trol of not less than 15 A maximum rating. Capacity for adjust-
in figures 6a), 6b) and 6c).
ment of integral times between about 10 s and 150 s, and dif-
ferential times between about 2 s and 30 s, shall be provided to
7.5 Specimen insertion and location tray
permit reasonable matching with the response characteristics
of the heater. The temperature at which the heater is to be con-
7.5.1 The specimen insertion and location tray shall be used
trolled shall be set on a scale capable of being read to I2 OC.
to facilitate rapid insertion of the specimen on to the pressing
An input range of temperature of about O to 1 O00 OC is
plate and to locate accurately the exposed area of the specimen
suitable. (An irradiance of 5 W/cm2 will be given by a heater
in relation to the aperture in the masking plate.
temperature in the region of 800 OC.) Automatic cold junction
compensation for the thermocouple shall be provided.
7.5.2 It shall consist essentially of a flat metal plate having
Desirable features are a meter to indicate the output to the
lugs on its upper surface to position and hold the specimen.
heater and a control which, in the event of an open circuit in
Guides shall be fixed to the lower surface to locate the tray in
the thermocouple line, will cause the temperature to fall to near
the apparatus and a stop shall also be provided to bear against
the bottom of its range.
the pressing plate, thus limiting the distance of insertion. The
tray should be provided with a handle to facilitate use.
To monitor heater temperature, particularly to show the
operator when the heater has attained temperature equilibrium,
7.5.3 A suitable device is shown in figure 7.
heater temperature shall be indicated by a meter capable of be-
I2 OC. This may be incorporated in the controller
ing read to
or separate.
7.6 Specimen screening plate
7.6.1 The screening plate shall be designed to slide over the
9.2 Radiometer (heat flux meter)
top of the masking plate during the period of insertion of the
specimen, thus shielding the specimen from radiation until
The radiometer shall be of the Gardon (foil) type with a design
commencement of the test.
range of about 10 W/cm2. The target receiving radiation, and
possibly to a small extent convection, shall be flat, circular, not
more than 10 mm in diameter and coated with a durable matt
7.6.2 The plate shall be made from 2 mm thick polished
black finish. The target shall be contained within a water-
aluminium or stainless steel and shall have overall dimensions
cooled body the front face of which shall be of highly polished
which allow it to cover the masking plate. It should be provided
metal, flat, coinciding with the plane of the target and circular,
with a stop, to limit its insertion against the masking plate, and
with a diameter of about 25 mm.
a handle.
Radiation shall not pass through any window before reaching
7.6.3 A suitable design is shown in figure 8.
the target. The instrument shall be robust, simple to set up and
use, insensitive to draughts, and stable in calibration. The in-
strument shall have an accuracy of within I3 % and a
8 Test environment
repeatability within 0,5 %.
The calibration of the radiometer shall be checked whenever a
8.1 The test shall be carried out in an environment essentially
recalibration of the apparatus is carried out (see 11 -21, by com-
free of air currents and protected, where necessary, by a
parison with an instrument held as a reference standard and not
screen. The air velocity close to the test apparatus should be
used for any other purpose. The reference standard instrument
not more than 0,2 m/s. The operator should be protected from
any products of combustion generated by the specimen. The shall be fully calibrated at yearly intervals.
1) The pilot flame application mechanism should be constructed to a close tolerance since minor changes in the dimensions can lead to changes to
the timing as specified in 7.4.5. Small changes can, however, be accommodated by slight changes in the diameter of the slave roller.
IS0 5657-1986 (E)
9.3 Millivolt measuring device 9.7 Calibration board
The board shall be made of ceramic fibre of density
This shall be compatible with the output from the radiometer
specified in 9.2. It shall have a full scale deflection, sensitivity 200 f 50 kg/m3, and shall be square, with sides measuring
165 -: mm and of thickness not less than 20 mm.
and accuracy which enable the irradiance measured by the
radiometer to be resolved to 0,05 W/cm2.
A suitable hole or groove cut to fit closely around the
radiometer shall be cut in the centre of the board. The target of
the radiometer shall be in the plane of the upper surface of the
9.4 Secondary thermocouple monitoring device
board. If additional support for the radiometer is required, it
shall be provided from below the calibration board.
To monitor the secondary thermocouple, an instrument is re-
quired with a resolution equivalent to f2 OC. This may read
directly in temperature or in millivolts. Allowance or automatic
9.8 Dummy specimen board
compensation for cold junction temperature shall be made. If a
separate device is used to monitor heater temperature, this
The dummy specimen board shall be constructed as specified
may, with a suitable switch connection, also be used to
in figure 11. The necessary total thickness of ceramic fibre
monitor the secondary thermocouple.
board may be built up from a number of thinner sheets at-
tached to each other by adhesive or long fine pins.
9.5 Timing device (timer)
9.9 Extinguishing board
This shall be capable of recording elapsed time to the nearest
The extinguishing board shall be made of the same material as
second and shall be accurate to within 1 s in 1 h.
the baseboards (6.2) and shall have nominal dimensions of
300 mm x 185 mm x 6 mm.
9.6 Air and propane supplies
9.10 Oven
Air and propane shall be fed to the pilot flame (see 7.4) via
If it is necessary to meet the recommendation given in 6.4.3,
regulating valves, filters (if necessary), flow meters, non-return
then a ventilated oven capable of maintaining a temperature of
valves, a suitable junction connection and a flame arrester as
approximately 250 OC is required.
shown in figure IO.
9.11 Specimen conditioning cabinet
9.6.1 Gas regulating valves
The specimen conditioning cabinet shall be capable of main-
These shall be capable of adjusting the pressure and flow of
taining a constant temperature of 23 f 2 OC and a relative
propane and air to the pilot flame to the levels required by 10.2.
humidity of (50 f 5) %.
9.6.2 Filters
9.12 Balance
Filters may need to be installed in the propane and/or air lines
The balance shall have a nominal capacity of 5 kg and shall be
to avoid the readings of the flow-meters being affected by im-
readable and accurate to 0,l g.
purities (for example oil droplets) carried in the flow.
9.6.3 Flow-meters
10 Setting-up procedure and requirements
These shall be capable of measuring the flow-rates of propane
and air to the pilot flame to an accuracy of at least 5 %.
10.1 Siting the apparatus
9.6.4 Non-return valves
The apparatus shall be placed in an environment essentially free
of air currents (see clause 8).
A suitable non-return valve shall be included in both air and
propane lines, sited as close to the junction point as possible.
10.2 Pilot flame
9.6.5 Flame arrester
(See also clause A.5.2 in annex A.)
A flame arrester [see figure 6a)l shall be mounted at the point
The pilot flame nozzle (see 7.4) shall be fed with a mixture of
of entry of the propane/air mixture to the pilot flame arm.
propane and air which is achieved by regulating the propane
flow-rate to 19 to 20 ml/min and the air flow-rate to 160 to
180 ml/min. These flow-rates shall be measured after the
9.6.6 Connections
pressure and flow regulating valves and shall be fed directly to
the pilot flame from the flow meters so that the pressure is
All connections with flexible tubing shall be firmly attached
with suitable clips. nominally atmospheric.
IS0 5657-1986
E)
10.3 Electrical requirements The values should be repeatable to within f5 OC.
Repeatability values outside these limits indicate possible
defects in control of monitoring equipment, or significant
10.3.1 The heating element of the radiometer cone (7.3) shall
changes in the test environment, which shall be corrected
be connected to the output from the thyristor of the
before further calibrations are carried out.
10. No element or
temperature controller as shown in figure
wiring in this circuit shall be changed between calibration and
testing. The primary thermocouple shall be connected to the 11.3 Calibration check
temperature controller and its temperature-monitoring device.
The irradiance produced by the temperature setting which the
The secondary thermocouple shall be connected to its monitor-
initial calibration has shown to correspond to an irradiance of
ing device (9.4).
3 W/cm2 shall be frequently checked (at least once every 50
operating hours) and the apparatus shall be recalibrated if such
10.3.2 The framework of the apparatus shall be provided with
a check reveals a deviation greater than O,% W/cm2.
a good electrical earth.
12 Test procedure
10.4 Precautions against electrical interference
12.1 Initial procedure
The radiometer shall be connected to the millivolt measuring
device (9.3) using leads which should be screened to minimize
The initial procedure shall be as follows.
any electrical interference to the signal. The radiometer shall be
earthed back to the millivolt measuring device and by no other
Set up the apparatus as described in clause IO.
a)
route (i.e. not to the earthed frame of the apparatus). All con-
b) Weigh a prepared specimen-baseboard combination
nections shall be thoroughly checked to ensure good electrical
(6.4.1 ) and return to the conditioning atmosphere.
contact.
c) Adjust the counterweight mechanism to give a force of
20 f 2 N between the upper surface of the specimen and
the underside of the masking plate (see 7.2.2 and sub-
clauses A.6.1 and A.6.2 in annex A), when the specimen-
11 Calibration
baseboard combination is positioned on the pressing plate
in the insertion and location tray. This adjustment may be
11.1 Installation of radiometer
made by the methods indicated in A.6.1 but using a dummy
of the same mass as the specimen-baseboard combination
For calibration of the apparatus, the radiometer (9.2) shall be
instead of a prepared and conditioned specimen.
installed in the hole or groove of the calibration board (9.7).
d) Insert the dummy specimen board (9.8).
11.2 Calibration procedure e) Adjust the temperature setting of the controller to thu
appropriate value established by the calibration procedure
Calibration procedure shall be as follows. to correspond to 5 W/cm2 (or other level as required).
f) Allow the apparatus to heat up to equilibrium. When the
a) Set up the apparatus as described in clause 10, except
heater has attained temperature equilibrium, as shown by
that the pilot flame mechanism shall be kept in the re-
the indicating meter of the temperature controller, a further
ignition position with gas supply turned off throughout the
5 min should be allowed to elapse before commencing ex-
0 calibration procedure.
posure of a specimen.
b) Place the calibration board (9.7) in the apparatus in the
g) Check that the reading of the secondary thermocouple
specimen position so that the target of the radiometer (9.2)
is within the equivalent of f2 OC of the value established
is located centrally within the circular opening of the mask-
during the calibration procedure (1 1.2). A deviation outside
ing plate, in the plane of the bottom face of the masking
this tolerance indicates the need for a complete re-
plate.
calibration.
c) Switch on the electricity supply and establish the
h) Remove a prepared specimen from the conditioning
temperature settings of the controller required to produce ir-
cabinet (9.1 1) and place it on the insertion and location tray
radiances at the centre of the circular opening in the mask-
(7.5).
ing plate of 1, 2, 3, 4 and 5 W/cm2. Adjustments near the
final setting for heater temperature should be followed by a i) Place the specimen screening plate on top of the mask-
ing plate.
5 min period without further adjustment to ensure that the
remainder of the apparatus has attained sufficient tem-
j) Start the pilot flame application mechanism (7.4).
perature equilibrium.
k) Lower the pressing plate, remove the dummy specimen
At each full equilibrium, read and record the secondary ther-
board and replace it with the insertion and location tray con-
mocouple monitor. These readings are to enable a close and
taining the specimen.
independent check to be made on the temperature of the
heater during testing. I) Release the pressing plate.
d) Carry out this procedure at least twice, the first time at m) When the pilot flame is at the re-ignition position,
settings of increasing temperature and the second time at simultaneously remove the specimen screening plate and
start the timer (9.5).
decreasing settings.
IS0 5657-1986 E)
12.5 Observations during test
12.2 Time permitted for test initiation
All operations detailed in 12.1 i) to m) shall be completed within
For each specimen tested, the time at which sustained
12.5.1
15 s.
surface ignition occurs shall be noted (see 3.9).
12.5.2 Observations shall be made during each test of the
general behaviour of the specimen and, in particular, note
12.3 Conduct and termination of test
should be made of the following :
12.3.1 If sustained surface ignition of the specimen occurs
a) the time, position and nature of other ignitions;
(see 3.91, the timer shall be stopped. Any flames shall im-
b) glowing decomposition of the specimen ;
mediately be extinguished by placing the extinguishing board
(9.9) on top of the masking plate and the pilot flame application
c) melting, foaming, spalling, cracking, expansion or
mechanism shall be stopped. The tray and remains of the
shrinkage of the exposed surface of the specimen.
specimen shall then be quickly removed and replaced by the
dummy specimen board. The extinguishing board shall then be
12.6 Special procedures
removed as quickly as possible (see sub-clause A.6.3 in
annex A).
12.6.1 Soft and softening products
12.3.2 If no sustained surface ignition of the specimen occurs
within 15 min, the test shall be stopped by placing the ex-
12.6.1 .I For some soft products, especially low-density
tinguishing board on top of the masking plate and the pilot
products such as glass- or mineral-fibre products with or
flame application mechanism shall be stopped. The specimen
without coatings, the pressure of the pressing plate may cause
shall then be removed and replaced by the dummy specimen
some compression of the edges of the specimen so that the ex-
board. The extinguishing board shall then be removed as
posed face of the specimen is not flat but convex upwards.
quickly as possible.
This can occur even without heating from the radiator cone.
In order that the specimen should not be subjected to an ir-
12.3.3 Transitory surface ignitions and/or plume ignitions
radiance higher than that for a flat, stable specimen, an ad-
should be noted as far as possible but should not cause the test
justable stop should be installed and operated on the pressing
to be terminated.
plate mechanism to avoid the crushing of the a!uminium foil
wrapping, to maintain the surface of the specimen flat and to
preserve the nominal thickness of the product. Alternatively,
spacing blocks between the pressing plate and the masking
12.4 Repeat tests
plate may be used.
12.4.1 Operations 12.1 h) to m) and 12.3 shall be repeated
12.6.1.2 For specimens which are likely to contract, soften or
with four more specimens at the same irradiance after allowing
melt away when heated it is necessary to prevent the pressing
sufficient time between applications to allow the apparatus to
plate (7.2.2) from unduly crushing the aluminium foil wrapping
reach thermal equilibrium (see sub-clause A.6.3 in annex A).
on the edge of the specimen. This can be accomplished by an
adjustable stop on the pressing plate mechanism or spacing
12.4.2 If sustained surface ignition occurs with any specimen
blocks between the pressing plate and the masking plate.
in a set of five at a given irradiance, a further set of five
specimens shall be tested at the next lower level of irradiance
12.6.1.3 With certain products the pilot flame application
(or at any other set lower level).
mechanism may not act satisfactorily. For example, some
materials become sticky when heated and can be drawn up in
12.4.3 Operation 12.4.2 shall be repeated as necessary until a
threads, some materials are or become soft enough for the pilot
set of five specimens has been tested at each required ir-
flame arm to bury itself, some materials intumesce and produce
radiance.
a foamed char "crust" having little mechanical strength. With
these products it will be necessary to operate the adjustable
12.4.4 If no sustained surface ignition occurs (see 12.3.2) stop on the travel of the pilot flame application mechanism to
with all specimens in a set of five at a given irradiance, tests bring it close to, but not touching, the exposed surface of the
shall not be carried out at lower irradiances, unless specifically specimen (see sub-clause A.6.4 in annex A).
required (see sub-clause A.6.2 in annex A).
12.6.1.4 Certain materials (e.g. PVC) may contain high con-
centrations of flame retardants. With these products, the
12.4.5 When adjusting the heater to the next level of ir-
copious fumes generated on irradiating can extinguish the pilot
radiance, sufficient time shall be allowed for the apparatus to
flame and prevent its re-ignition by the secondary ignition
reach thermal equilibrium following the change in temperature
source. If this situation occurs repeatedly within 15 min, when
setting (see clause A.6.3 in annex A).
reasonable attempts to re-light the pilot flame have been made,
the results should be given as "no sustained surface ignition
At full equilibrium the reading of the secondary thermocouple
under these test conditions: pilot flame repeatedly extin-
should be within f2 OC of the value establi
...