SIST EN ISO 1716:2018

SLOVENSKI STANDARD
01-september-2018
1DGRPHãþD
SIST EN ISO 1716:2010
3UHVNXVLRG]LYDSURL]YRGRYQDRJHQM8JRWDYOMDQMHVSHFLILþQHWRSORWH]JRUHYDQMD
NDORULþQHYUHGQRVWL,62
Reaction to fire tests for products - Determination of the gross heat of combustion
(calorific value) (ISO 1716:2018)
Prüfungen zum Brandverhalten von Produkten - Bestimmung der Verbrennungswärme
(des Brennwerts) (ISO 1716:2018)
Essais de réaction au feu de produits - Détermination du pouvoir calorifique supérieur
(valeur calorifique) (ISO 1716:2018)
Ta slovenski standard je istoveten z: EN ISO 1716:2018
ICS:
13.220.50 Požarna odpornost Fire-resistance of building
gradbenih materialov in materials and elements
elementov
91.100.01 Gradbeni materiali na Construction materials in
splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 1716
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2018
EUROPÄISCHE NORM
ICS 13.220.50; 91.100.01 Supersedes EN ISO 1716:2010
English Version
Reaction to fire tests for products - Determination of the
gross heat of combustion (calorific value) (ISO 1716:2018)
Essais de réaction au feu de produits - Détermination Prüfungen zum Brandverhalten von Produkten -
du pouvoir calorifique supérieur (valeur calorifique) Bestimmung der Verbrennungswärme (des
(ISO 1716:2018) Brennwerts) (ISO 1716:2018)
This European Standard was approved by CEN on 9 May 2018.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 1716:2018 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 1716:2018) has been prepared by Technical Committee ISO/TC 92 "Fire safety "
in collaboration with Technical Committee CEN/TC 127 “Fire safety in buildings” the secretariat of
which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by January 2019, and conflicting national standards shall
be withdrawn at the latest by January 2019.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 1716:2010.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 1716:2018 has been approved by CEN as EN ISO 1716:2018 without any modification.

INTERNATIONAL ISO
STANDARD 1716
Fourth edition
2018-05
Reaction to fire tests for products —
Determination of the gross heat of
combustion (calorific value)
Essais de réaction au feu de produits — Détermination du pouvoir
calorifique supérieur (valeur calorifique)
Reference number
ISO 1716:2018(E)
©
ISO 2018
ISO 1716:2018(E)
© ISO 2018
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved

ISO 1716:2018(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 3
5 Test apparatus . 3
6 Reagents and materials . 8
7 Test specimens. 8
7.1 General . 8
7.2 Sampling . 9
7.2.1 General. 9
7.2.2 Loose-fill material . 9
7.2.3 Liquid-applied products . 9
7.2.4 Thin film products . 9
7.3 Determination of surface density . 9
7.4 Grinding .10
7.5 Type of specimen .10
7.6 Conditioning .10
7.7 Number of test specimens .10
7.8 Determination of mass .10
7.9 Crucible method .11
7.10 “Cigarette” method .11
8 Test procedure .12
8.1 General .12
8.2 Calibration procedure .12
8.2.1 Determination of the water equivalent .12
8.2.2 Conditions for recalibration .12
8.3 Standard test procedure .12
9 Expression of results .14
9.1 Corrections for manual apparatus .14
9.2 Corrections for isothermal calorimeter (see Annex C) .14
9.3 Calculation of the gross heat of combustion of the specimen .15
9.4 Calculation of the gross heat of combustion of the product .16
9.4.1 General.16
9.4.2 Homogeneous product .17
9.4.3 Non-homogeneous product .17
10 Test report .18
11 Validity of test results .18
Annex A (normative) Calculation of net heat of combustion .20
Annex B (informative) Precision of test method .21
Annex C (informative) Calculation by graph of the corrective term, c, necessarybecause of
the cooling of the calorimeter .24
Annex D (informative) Example of determination of the gross heat ofcombustion of a non-
homogeneous product .25
Bibliography .30
ISO 1716:2018(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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 1, Fire
initiation and growth.
This fourth edition cancels and replaces the third edition (ISO 1716:2010), which has been technically
revised.
iv © ISO 2018 – All rights reserved

INTERNATIONAL STANDARD ISO 1716:2018(E)
Reaction to fire tests for products — Determination of the
gross heat of combustion (calorific value)
WARNING — The attention of all persons concerned with managing and carrying out this test
is drawn to the fact that fire testing may be hazardous and that there is a possibility that toxic
and/or harmful gases may be evolved during the test. Operational hazards may also arise during
the testing of specimens, such as the possibility of an explosion, and during the disposal of test
residues.
WARNING — An assessment of all the potential hazards and risks to health should be made
and safety precautions should be identified and provided. Written safety instructions should
be issued. Appropriate training should be given to relevant personnel. Laboratory personnel
should ensure that they follow written instructions at all times.
1 Scope
This document specifies a method for the determination of the gross heat of combustion (Q ) of
PCS
products at constant volume in a bomb calorimeter.
This method is intended to be applied to solid products.
[1]
NOTE Liquids can be tested with similar equipment and using conditions described in ASTM D240 , as
[2] [3]
described in IEC 61039 using ISO 1928 test equipment.
Annex A specifies the calculation of the net heat of combustion, Q , when required.
PCI
Information on the precision of the test method is given in Annex B.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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, Standard atmospheres for conditioning and/or testing — Specifications
EN 13238, Reaction to fire tests for building products — Conditioning procedures and general rules for
selection of substrates
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at https: //www .electropedia .org/
3.1
product
material, element or component about which information is required
ISO 1716:2018(E)
3.2
material
single basic substance or uniformly dispersed mixture of substances
EXAMPLE Stone, timber, concrete, mineral wool with a uniformly dispersed binder and polymers.
3.3
homogeneous product
product (3.1) consisting of a single material (3.2) having uniform density and composition throughout
the product (3.1)
3.4
non-homogeneous product
product (3.1) that does not satisfy the requirements of a homogeneous product (3.3) and which is
composed of more than one component, substantial or non-substantial
Note 1 to entry: If a non-homogeneous product cannot be easily separated into its component parts, the individual
components shall be provided separately by the sponsor.
3.5
non-substantial component
material (3.2) that does not constitute a significant part of a non-homogeneous product (3.4) and that
has a layer with a mass/unit area below 1,0 kg/m and a thickness below 1,0 mm
Note 1 to entry: If the non-substantial layers do not comply with the above requirements, together they shall be
considered to be substantial.
Note 2 to entry: Two or more non-substantial layers that are adjacent to each other (i.e. with no substantial
component(s) in between the layers) are regarded as one non-substantial component when they collectively
comply with the requirements for a layer being a non-substantial component.
3.6
substantial component
material (3.2) that constitutes a significant part of a non-homogeneous product (3.4) and that has a layer
with a mass/unit area more than or equal to 1,0 kg/m or a thickness more than or equal to 1,0 mm
Note 1 to entry: Two or more non-substantial layers that are adjacent to each other (i.e. with no substantial
component(s) in between the layers) are regarded as one substantial component when they collectively comply
with the requirements for a layer being a substantial component.
3.7
internal non-substantial component
non-substantial component (3.5) that is covered on both sides by at least one substantial component (3.6)
3.8
external non-substantial component
non-substantial component (3.5) that is not covered on one side by a substantial component (3.6)
3.9
heat of combustion
DEPRECATED: calorific value
Q
thermal energy produced by combustion of unit mass of a given substance
Note 1 to entry: The heat of combustion is expressed in megajoules per kilogram.
[SOURCE: ISO 13943:2008, 4.174, modified — The Note 1 to entry was changed.]
2 © ISO 2018 – All rights reserved

ISO 1716:2018(E)
3.10
gross heat of combustion
Q
PCS
heat of combustion (3.9) of a substance when the combustion is complete and any produced water is
entirely condensed under specified conditions
Note 1 to entry: The gross heat of combustion is expressed in megajoules per kilogram.
Note 2 to entry: The acronym PCS is derived from the French term “pouvoir calorifique supérieur”.
3.11
net heat of combustion
Q
PCI
heat of combustion (3.9) of a substance when the combustion is complete and any produced water is in
the vapour state under specified conditions
Note 1 to entry: The net heat of combustion may be calculated from the gross heat of combustion.
Note 2 to entry: The net heat of combustion is expressed in megajoules per kilogram.
Note 3 to entry: The acronym PCI is derived from the French term “pouvoir calorifique inférieur”.
3.12
latent heat of vaporization of water
q
heat which is required to change water from a liquid to a gas
Note 1 to entry: The latent heat of vaporization is expressed in megajoules per kilogram.
3.13
surface density
mass per unit area
Note 1 to entry: The surface density is expressed in kilograms per square metre.
4 Principle
In this test, a test specimen of specified mass is burned under standardized conditions, at constant
volume, in an atmosphere of oxygen, in a bomb calorimeter calibrated by combustion of certified
benzoic acid. The heat of combustion determined under these conditions is calculated on the basis of
the observed temperature rise, taking account of heat loss and the latent heat of vaporization of water.
This is a test method for determining an absolute value of the heat of combustion for a product and it
does not take into account any inherent variability of the product.
5 Test apparatus
The test apparatus (bomb calorimeter) shall be as illustrated in Figure 1, and as detailed in 5.1 to 5.4.
Additional equipment shall be in accordance with 5.5 to 5.10.
Equipment described in 5.1 to 5.4 could also be available as automatic or semi-automatic apparatuses.
Any deviation from these subclauses has to be evaluated by the user according to requirements of
subsequent subclauses.
ISO 1716:2018(E)
Key
1 stirrer 7 calorimetric bomb
2 jacket lid 8 crucible
3 ignition leads 9 electrodes
4 temperature measuring device 10 firing wire
5 calorimetric vessel 11 crucible holder
6 jacket
Figure 1 — Test apparatus
5.1 Calorimetric bomb.
The calorimetric bomb shall be constructed with the following characteristics:
a) volume: (300 ± 50) ml;
b) mass not greater than 3,25 kg;
4 © ISO 2018 – All rights reserved

ISO 1716:2018(E)
c) casing thickness at least 1/10 of the inner diameter of the body:
The lid is intended to receive the crucible and the electric firing device. The lid, including any seals,
shall be capable of withstanding an internal pressure of 21 MPa.
NOTE These conditions define a bomb in which 1 g of coal under an initial oxygen pressure no greater than
3 MPa (pressure gauge method) is able to withstand, with a sufficient coefficient of safety, the maximum amount
of pressure created under combustion, without a need for a calorimetric bomb of overlarge mass.
The inner surface of the bomb shall be resistant to attack by products of combustion and, even when
“fuels” rich in sulfur are used, it shall resist pitting and inter-crystalline corrosion by acids produced
during combustion.
5.2 Calorimeter.
5.2.1 Jacket.
The jacket shall consist of a double-walled container, which is thermally insulated together with an
insulated lid. The jacket is filled with water. The dimensions of the jacket shall be such that there is at
least 10 mm space around the calorimetric vessel. The calorimetric vessel shall be supported on an as
small as possible area of non-conducting material, preferably a 3-point support.
For an adiabatic calorimeter system, a heater and thermometer system shall be incorporated into the
vessel such that the water temperature in the jacket is maintained at the same temperature as the water
in the calorimetric vessel.
For an isothermal calorimeter system, the temperature of the water in the jacket shall be kept constant.
For an isothermal calorimeter, the necessary corrections shall be made (see 9.2).
5.2.2 Calorimetric vessel.
The calorimetric vessel shall consist of a polished metal container designed to accommodate the bomb.
The dimensions shall be such that the bomb can be immersed in water (see 8.3.8).
5.2.3 Stirrer.
The stirrer shall be driven by a constant-speed motor. To prevent the transfer of heat to and from the
calorimeter, the driving shaft of the stirrer shall have a thermally insulated section in a gasket between
the jacket lid and the jacket. A magnetic stirring device with a similar performance is an acceptable
alternative.
5.3 Temperature measuring device.
The temperature measuring device shall be capable of giving a resolution of 0,005 K. When using a
mercury thermometer, this shall have at least 0,01 K graduations with a device, e.g. a lens, for taking
readings to within 0,005 K. A mechanical vibrator shall also be used to gently tap the thermometer to
ensure that the mercury column does not stick.
5.4 Crucible.
The crucible shall be made of metal, such as platinum, nickel, stainless steel or silica, with a flat base,
25 mm in diameter (maximum dimension if it is truncated) and 14 mm to 19 mm high. The following
wall thickness is recommended:
— metal: 1,0 mm;
— silica: 1,5 mm.
NOTE Several shapes of crucible have proved satisfactory.
ISO 1716:2018(E)
5.5 Timing device.
The timing device shall be capable of recording the time elapsed to the nearest second and accurate to
within 1 s in 1 h.
5.6 Electric power source.
The electric power source shall be designed with the voltage to the firing circuit not exceeding 20 V for
the firing.
NOTE An ammeter can be added to the circuit to indicate the breaking of the firing wire. A circuit breaker is
a useful addition to the supply circuit.
5.7 Pressure gauge and needle-valve.
A pressure gauge and a needle valve shall be attached to the oxygen-supply circuit to show the pressure
in the bomb while it is being filled; this pressure shall be indicated with a resolution of 0,1 MPa.
5.8 Balances.
Two balances shall be used with the following characteristics:
— one is an analytical balance with a resolution of 0,1 mg;
— the other is a balance with a resolution of 0,1 g.
5.9 Device for making the “cigarette”.
The device shall be designed as shown in Figure 2, and comprise a mould and a metallic mandrel (not
aluminium).
6 © ISO 2018 – All rights reserved

ISO 1716:2018(E)
Dimensions in millimetres
b)  Paper in position in the mould after the
a)  Shaping the paper over the mandrel
mandrel has been removed, ready to be filled
c)  Cigarette completed d)  Cigarette placed in the crucible
Key
1 mandrel 3 firing wire 5 electrode 7 crucible
2 mould 4 paper 6 cigarette
NOTE 1 The paper is kept in place by gluing an overlap of the paper using the preglued cigarette-making paper.
NOTE 2 The two ends of the paper are twisted.
NOTE 3 The “cigarette” is put in the crucible and the firing wire is wrapped tightly around the line of the
electrodes.
Figure 2 — Method for preparing the “cigarette”
ISO 1716:2018(E)
5.10 Device for making the pellet.
The device is suitable if prefabricated pellets are not available.
6 Reagents and materials
Use only reagents of recognized analytical grade and only distilled water or water of equivalent purity.
6.1 Distilled or demineralized water.
6.2 Pressurized oxygen.
The oxygen used shall be free from any other combustible product (purity ≥ 99,5 %).
WARNING — Oxygen prepared by electrolysis can contain a small percentage of hydrogen, which
makes it unsuitable for this use.
6.3 Powder or pellet of benzoic acid.
Benzoic acid whose gross heat of combustion is guaranteed is used as “reference standard for
calorimetry”.
6.4 Combustion aid.
Combustion aid is a combustible with a known heat of combustion, e.g. paraffin oil.
6.5 Cigarette-making paper.
The cigarette making paper shall be preglued and of minimum dimensions 55 mm × 50 mm with a
known heat of combustion.
NOTE A commercially available cigarette-making paper of 55 mm × 100 mm has been found suitable when
cut into two equal pieces.
6.6 Firing wire.
The firing wire shall be made of pure iron, 0,1 mm in diameter, e.g. piano wire. Other types of metal
wire (e.g. platinum, nickel or chromium) may be used, provided that they break under their own tension
when the switch is closed on the firing circuit and the exact heat of combustion for the wire is known.
When using a metal crucible (5.4), there shall be no contact between the firing wire and the crucible. It
is therefore advisable to wrap the metal wire with a cotton thread.
NOTE Some automatic or semi-automatic apparatuses are working with permanent firing wires in
combination with single use combustible crucibles. Reference has to be made to the instructions of the
manufacturer of such calorimeter systems.
6.7 Thread.
The thread shall be made of white cellulosic cotton (see 6.6).
7 Test specimens
7.1 General
In order to assess a product, each of its components shall be evaluated, taking into account the rules
for non-substantial components. If a non-homogeneous product cannot be easily separated into its
component parts, the individual components shall be provided separately by the sponsor of the test. A
8 © ISO 2018 – All rights reserved

ISO 1716:2018(E)
product can be delaminated when it is possible to separate one component from another without any
part of the other component adhering to the component to be evaluated.
Some substantial components cannot be produced without facings. If the facings cannot be delaminated,
a section shall be cut from the central part of the core avoiding the facings and any adhesive or other
non-substantial component on its surface.
If two or more non-substantial layers are adjacent to each other, and when added together they comply
with the definition for a substantial component, then each individual layer shall be tested separately
and they shall be assessed together as substantial. The total calorific value of the adjacent layers,
which are considered substantial, shall be calculated by adding together the relative percentage of the
measured calorific value for each component (see Annex D).
If two or more non-substantial layers are adjacent to each other, and when added together they
comply with the definition for a non-substantial component, then each individual layer shall be tested
separately and they shall be assessed together as non-substantial (see Annex D).
WARNING — Any aluminium or other metallic component of a product shall not be tested in
the bomb calorimeter, with the risk of serious injury to the operator due to overheating and/or
overpressure causing the bomb calorimeter to explode.
If the product tested is made of non-separable multiple layers in which one layer comprises aluminium
or other metallic foils, recommendations of Reference [4] should be applied.
7.2 Sampling
7.2.1 General
From a representative amount of a homogeneous product, or a component of a non-homogeneous
product, compose a sample from at least five randomly selected parts taken from across the thickness.
A minimum mass of 50 g shall be taken from a homogeneous product and a substantial component of a
non-homogeneous product. A minimum mass of 10 g shall be taken for a non-substantial component of
a non-homogeneous product.
7.2.2 Loose-fill material
A sample shall be taken at random from the product of a minimum mass of 50 g.
7.2.3 Liquid-applied products
A sample of a minimum mass of 10 g of dried material shall be prepared. The sample may be prepared
by applying a thin layer of the liquid-applied product to a glass sheet and taking the sample for the test
by scrapping the dried product from the glass surface.
The material shall be cured or dried in accordance with the manufacturer's instructions. Care should
be taken when drying liquid-applied components due to the potential presence of solvents. The method
of curing shall be described in the test report.
7.2.4 Thin film products
The sample shall have a minimum mass of 10 g. The film shall be cut into small pieces for the test which
shall either be tested as a cigarette (7.10) or shall be tested in the crucible. For the crucible method, it
is recommended that 0,5 g of the paraffin oil combustion aid is added to the crucible over the surface of
the film to stop the film from being ejected from the crucible.
7.3 Determination of surface density
Where required, the surface density of each sample of a product shall be determined to an accuracy of
±0,5 % from a minimum area of 250 mm × 250 mm.
ISO 1716:2018(E)
For liquid-applied products, the dried mass shall be determined.
7.4 Grinding
The samples defined in 7.2 shall be reduced gradually to provide the final test sample. Grinding shall
be carried out in such a way that no thermal decomposition takes place. Grind the sample and reduce it
with a method of cross-reduction, grinding to a finer powder as reduction proceeds.
If the sample cannot be ground, reduce it by any appropriate method into small granules or pieces
which should be as small as possible, and treat the specimens obtained as a powder.
In the case of homogeneous material which, when ground, clearly separates into components of
different density, so that a 0,5 g sample of the product, when taken from the ground powder, is not
representative of the original product with respect to the proportion of the materials present, reduce
the sample by any appropriate method, e.g. by sawing the sample into thin discs or by cutting it with a
knife into small pieces. If this preparation is not possible, testing shall be conducted on the individual
ingredients used in the manufacture of that product. The individual Q values for these ingredients
PCS
shall be used together with the proportion by mass of the ingredients in the final product to calculate
the overall Q value for the product.
PCS
7.5 Type of specimen
If a fine powder can be obtained by grinding (see 7.4), the test specimen shall be prepared using the
crucible method (see 7.9). If a fine powder cannot be obtained by grinding and/or a complete combustion
cannot be obtained when using the crucible method, the test shall be conducted by using either the
“cigarette” method (see 7.10) or the crucible method utilizing a combustion aid, e.g. paraffin oil.
7.6 Conditioning
The powdered specimen, the benzoic acid and the cigarette-making paper shall be conditioned before
testing in accordance with EN 13238 or ISO 554.
7.7 Number of test specimens
Three test specimens shall be tested following the procedure in 8.3. Two additional test specimens
shall be tested if the requirements for validity of test results are not met (see Clause 11). More than
three specimens may be tested as required for any classification system.
7.8 Determination of mass
Weigh the following elements:
— Approximately 0,5 g of material, with a minimum precision of 0,1 mg;
— Approximatively 0,5 g of benzoic acid, with a minimum precision of 0,1 mg;
— combustion aid, with a minimum precision of 0,1 mg;
— firing wire, cotton thread and cigarette-making paper, if necessary, with a minimum precision
of 0,1 mg.
NOTE For some materials with a low heat of combustion, it can be necessary to increase the gross heat of
combustion of the specimen in order to obtain complete combustion by changing the mass ratio between the
material and the benzoic acid or by adding a combustion aid (e.g. paraffin oil). The benzoic acid and/or combustion
aid can be reduced or excluded if it’s not necessary for combustion of the material.
10 © ISO 2018 – All rights reserved

ISO 1716:2018(E)
7.9 Crucible method
The procedure shall be carried out as follows (see Figure 3).
a) Insert the previously weighed mixture of specimen and benzoic acid into the crucible.
b) Connect the previously weighed firing wire to the two electrodes.
c) Loop down the firing wire to touch the powder in the crucible.
NOTE Some automatic apparatus is supplied with a fixed firing wire. For these items of apparatus, loop
down a previously weighed cotton thread to touch the powder in the crucible.
Key
1 firing wire
2 electrodes
3 mixture of benzoic acid and product
4 crucible
5 crucible holder
Figure 3 — Test specimen preparation using the crucible method
7.10 “Cigarette” method
The procedure shall be carried out as follows (see Figure 2).
a) Place a previously weighed firing wire down the centre of the mandrel.
b) Wrap the previously weighed cigarette-making paper around the mandrel and glue the two
overlapping edges together. No additional glue shall be used since the cigarette-making paper is
preglued. Sufficient paper shall be left free at each end to allow this to be twisted around the
firing wire.
c) Twist the paper around the firing wire at the lower end of the mandrel and insert the whole
assembly into the mould. The firing wire shall project through the bottom of the mould.
NOTE A clearance of 0,5 mm between the mandrel and the mould allows for easy positioning of the
assembly.
d) Remove the mandrel.
ISO 1716:2018(E)
e) Insert the previously weighed mixture of specimen and benzoic acid into the cigarette-making paper.
f) Remove the filled “cigarette” from the mould and twist together the ends of the paper to seal the
“cigarette”.
g) Weigh the “cigarette” to ensure that the total mass does not vary from the masses of the constituents
by more than 10 mg.
h) Put the “cigarette” into the crucible.
i) Connect the firing wire to the two electrodes.
8 Test procedure
8.1 General
It is recommended that the test be conducted in a room where the temperature remains stable, within
±2 K. Calibration of the apparatus and subsequent testing should be conducted under similar conditions
of temperature and pressure. For manual apparatus, the difference between the room temperature and
the vessel water temperature shall not vary by more than ±2 K.
8.2 Calibration procedure
8.2.1 Determination of the water equivalent
The water equivalent, E, expressed in megajoules per kelvin, of the calorimeter, the bomb and their
accessories shall be determined by making at least five determinations of the gross heat of combustion
of pellets of 0,4 g to 1,0 g of certified benzoic acid.
The calibration procedure shall be carried out as follows.
a) Compress the previously weighed powder of benzoic acid, using a pellet-making machine, to make
a pellet or take a prefabricated pellet. Prefabricated certified pellets of benzoic acid may be used as
an alternative to benzoic acid powder. The certified value provided shall be used in any calculation
of the gross heat of combustion.
b) Weigh the pellet with a minimum precision of 0,1 mg.
c) Put the pellet into the crucible.
d) Connect the firing wire to the two electrodes.
e) Loop down the previously weighed firing wire to touch the pellet.
The test shall be carried out as specified in 8.3. The water equivalent, E, expressed in megajoules per
kelvin, shall be the average of the five determinations. Each individual result shall not deviate by more
than 0,5 % from the water equivalent.
8.2.2 Conditions for recalibration
The procedure given in 8.2.1 shall be carried out at regular intervals, not greater than two months with
continuous use of the apparatus, or when any significant part of the system is changed.
8.3 Standard test procedure
WARNING — Aluminium or other metallic components of a product shall not be tested in
the bomb calorimeter at the risk of serious injury to the operator due to overheating and/or
overpressure causing the bomb calorimeter to explode.
12 © ISO 2018 – All rights reserved

ISO 1716:2018(E)
Switch on the apparatus and wait at least 1 h before testing, or until stabilization is reached.
8.3.1 Place the specimen in the crucible.
8.3.2 Place the crucible in the holder.
8.3.3 Attach the firing wire and loop it to touch the specimen.
8.3.4 Check that a good electrical contact is ensured between the two electrodes and the firing wire.
8.3.5 Place the holder in the body of the calorimetric bomb.
1 ml of de-ionized water may be introduced into the body of the calorimetric bomb to absorb any acid
gases produced. Absorption of the acid gases can help reduce the amount of pitting within the bomb vessel.
8.3.6 Adjust the lid and tighten onto the body of the bomb. Connect the bomb to the bottle of oxygen,
then carefully open the bottle's tap and fill the bomb until a pressure of 3,0 MPa to 3,5 MPa is achieved (if
not achieved automatically), without removing the air already there.
8.3.7 Place the bomb in the calorimeter vessel.
8.3.8 Introduce into the calorimeter vessel a quantity of distilled or demineralized water that is
sufficient to cover the upper surface of the bomb cap and weigh. This quantity of water shall be the same,
to the nearest 1 g, as that used in the calibration procedure (see 8.2.1) (if not achieved automatically).
8.3.9 Check that the bomb does not leak (no continuous stream of bubbles).
8.3.10 Place the calorimeter vessel in the water jacket.
8.3.11 Proceed as follows:
a) Set the temperature-measuring device and start the stirrer and the timing device (if this is not
achieved automatically).
b) Bring the water in the calorimeter vessel to a temperature that is approximately equal to that
of the jacket. Note the
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