SIST-TS CEN ISO/TS 21911-2:2022
(Main)Solid recovered fuels - Determination of self-heating - Part 2: Basket heating tests (ISO/TS 21911-2:2022)
Solid recovered fuels - Determination of self-heating - Part 2: Basket heating tests (ISO/TS 21911-2:2022)
This document gives guidance on basket heating tests for characterization of self-heating properties of
solid recovered fuels (SRFs).
This document includes:
a) a compilation of basket heating test methods;
b) guidance on the applicability and use of basket heating tests for SRF;
c) information on the application of basket heating test data for calculations of critical conditions in
storage.
Data on spontaneous heat generation determined using this document is only associated with the
specific quality and age of the sample material.
The information derived using this document is intended for use in quality control and in hazard and
risk assessments related to the procedures given in ISO 21912.
Biogene Festbrennstoffe - Bestimmung der Selbsterhitzung - Teil 2: Warmlagerungsprüfungen im Drahtnetzkorb (ISO/TS 21911-2:2022)
Dieses Dokument enthält Anleitungen zu Warmlagerungsprüfungen im Korb zur Charakterisierung der Selbsterhitzungseigenschaften fester Sekundärbrennstoffe (SRF).
Dieses Dokument umfasst
a) eine Zusammenstellung der Verfahren von Warmlagerungsprüfungen im Korb;
b) Anleitungen zur Anwendbarkeit und Anwendung von Warmlagerungsprüfungen im Korb für SRF;
c) Angaben zur Verwendung von Daten aus Warmlagerungsprüfungen im Korb für Berechnungen kritischer Bedingungen in Lagern.
Die unter Anwendung dieses Dokuments ermittelten Daten zur spontanen Wärmeerzeugung stehen lediglich mit der spezifischen Qualität und dem Alter des Probenmaterials in Zusammenhang.
Die Informationen, die unter Anwendung dieses Dokuments abgeleitet werden, sind zur Verwendung bei der Qualitätssteuerung und bei der Beurteilung von Gefährdungen und Risiken im Zusammenhang mit den in ISO 21912 angegebenen Verfahren bestimmt.
Combustibles solides de récupération - Détermination de l'auto-échauffement - Partie 2: Essais utilisant la méthode du point de croisement (ISO/TS 21911-2:2022)
Trdno alternativno gorivo - Določanje samosegrevanja - 2. del: Preskusi ogrevanja košare (ISO/TS 21911-2:2022)
Ta dokument podaja smernice za preskuse ogrevanja košare za karakterizacijo lastnosti samosegrevanja trdnega alternativnega goriva (SRF).
Dokument vsebuje:
a) zbirko preskusnih metod ogrevanja košare;
b) smernice o namenu in uporabi preskusov ogrevanja košare za trdno alternativno gorivo;
c) informacije o uporabi podatkov o preskušanju ogrevanja košare za izračun kritičnih pogojev v skladišču.
Podatki o spontanem nastajanju toplote, določeni s tem dokumentom, so povezani le s specifično kakovostjo in starostjo vzorčnega materiala.
Informacije, pridobljene na podlagi tega dokumenta, so namenjene uporabi pri nadzoru kakovosti ter pri ocenah nevarnosti in tveganj, povezanih s postopki, navedenimi v standardu ISO 21912.
General Information
Buy Standard
Standards Content (Sample)
SLOVENSKI STANDARD
SIST-TS CEN ISO/TS 21911-2:2022
01-oktober-2022
Trdno alternativno gorivo - Določanje samosegrevanja - 2. del: Preskusi ogrevanja
košare (ISO/TS 21911-2:2022)
Solid recovered fuels - Determination of self-heating - Part 2: Basket heating tests
(ISO/TS 21911-2:2022)
Biogene Festbrennstoffe - Bestimmung der Selbsterhitzung - Teil 2:
Warmlagerungsprüfungen im Drahtnetzkorb (ISO/TS 21911-2:2022)
Combustibles solides de récupération - Détermination de l'auto-échauffement - Partie 2:
Essais utilisant la méthode du point de croisement (ISO/TS 21911-2:2022)
Ta slovenski standard je istoveten z: CEN ISO/TS 21911-2:2022
ICS:
75.160.10 Trda goriva Solid fuels
SIST-TS CEN ISO/TS 21911-2:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST-TS CEN ISO/TS 21911-2:2022
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SIST-TS CEN ISO/TS 21911-2:2022
CEN ISO/TS 21911-2
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
July 2022
TECHNISCHE SPEZIFIKATION
ICS 75.160.10
English Version
Solid recovered fuels - Determination of self-heating - Part
2: Basket heating tests (ISO/TS 21911-2:2022)
Combustibles solides de récupération - Détermination Biogene Festbrennstoffe - Bestimmung der
de l'auto-échauffement - Partie 2: Essais utilisant la Selbsterhitzung - Teil 2: Warmlagerungsprüfungen im
méthode du point de croisement (ISO/TS 21911- Drahtnetzkorb (ISO/TS 21911-2:2022)
2:2022)
This Technical Specification (CEN/TS) was approved by CEN on 3 July 2022 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to
submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS
available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in
parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye 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
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN ISO/TS 21911-2:2022 E
worldwide for CEN national Members.
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SIST-TS CEN ISO/TS 21911-2:2022
CEN ISO/TS 21911-2:2022 (E)
Contents Page
European foreword . 3
2
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SIST-TS CEN ISO/TS 21911-2:2022
CEN ISO/TS 21911-2:2022 (E)
European foreword
This document (CEN ISO/TS 21911-2:2022) has been prepared by Technical Committee ISO/TC 300
"Solid recovered materials, including solid recovered fuels" in collaboration with Technical Committee
CEN/TC 343 “Solid recovered materials, including solid recovered fuels” the secretariat of which is held
by SFS.
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.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
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, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO/TS 21911-2:2022 has been approved by CEN as CEN ISO/TS 21911-2:2022 without any
modification.
3
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SIST-TS CEN ISO/TS 21911-2:2022
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SIST-TS CEN ISO/TS 21911-2:2022
TECHNICAL ISO/TS
SPECIFICATION 21911-2
First edition
2022-07
Solid recovered fuels — Determination
of self-heating —
Part 2:
Basket heating tests
Combustibles solides de récupération — Détermination de l'auto-
échauffement —
Partie 2: Essais utilisant la méthode du point de croisement
Reference number
ISO/TS 21911-2:2022(E)
© ISO 2022
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SIST-TS CEN ISO/TS 21911-2:2022
ISO/TS 21911-2:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022
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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
© ISO 2022 – All rights reserved
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SIST-TS CEN ISO/TS 21911-2:2022
ISO/TS 21911-2:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Basket heating tests .3
6 Tests for product classification . 4
6.1 UN classification. 4
6.1.1 General . 4
6.1.2 Test method for self-heating substances – MTC Test N.4 . 4
6.1.3 Classification criteria — GHS . 4
6.2 Classification criteria — IMO . 5
6.3 Applicability of MTC Test N.4 for solid recovered fuels . 5
7 Tests for determination of reaction kinetics . 6
7.1 General . 6
7.2 Isoperibolic test methods . 6
7.2.1 General . 6
7.2.2 Test procedure. 6
7.2.3 Determination of reaction kinetics . 7
7.2.4 Applicability for solid recovered fuels . 7
7.3 Crossing-point method . 8
7.3.1 General . 8
7.3.2 Test procedure. 8
7.3.3 Determination of reaction kinetics . 9
7.3.4 Applicability for solid recovered fuels . 9
7.4 Adiabatic hot storage tests . 10
7.4.1 General . 10
7.4.2 Test procedure. 10
7.4.3 Determination of reaction kinetics . 11
7.4.4 Applicability for solid recovered fuels .12
8 Sample handling .12
8.1 General .12
8.2 Sampling . 13
8.3 Sample transport and storage .13
8.4 Sample preparation . 13
8.5 Sample disposal .13
9 Test report .13
Annex A (informative) Self-ignition behaviour of selected materials suitable to be used as
solid recovered fuels .15
Annex B (informative) Example of calculating kinetic parameters from crossing point
method tests .22
Annex C (normative) Use of data for calculations of critical conditions in storage .25
Bibliography .30
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SIST-TS CEN ISO/TS 21911-2:2022
ISO/TS 21911-2:2022(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 of 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
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 300, Solid recovered materials, including
solid recovered fuels, in collaboration with the European Committee for Standardization (CEN) Technical
Committee CEN/TC 343, Solid recovered materials, including solid recovered fuels, in accordance with the
Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
A list of all parts in the ISO 21911 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
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SIST-TS CEN ISO/TS 21911-2:2022
ISO/TS 21911-2:2022(E)
Introduction
There is continuous global growth in trading and use of solid recovered fuels (SRFs). Therefore,
intensive investigations about the risk of fires within SRF production, handling and storing have been
conducted, see ÖNORM S 2098. Recommendations are given in ISO 21912.
Depending on the kind of input wastes, the treatment technology applied, the quality of the SRF
produced and the realized storage versions, SRFs can generate heat spontaneously by exothermic
biological, chemical and physical processes. The heat build-up can be significant in large storage
volumes if the heat conduction in the material is low. During some conditions the heat generation
can lead to pyrolysis and spontaneous ignition. The potential for self-heating varies considerably for
different types and qualities of SRF and it is important to be able to identify SRF fractions with high
heat generation potential to avoid fires in stored materials.
Avoiding fires throughout the production and supply chain will have positive consequences on the
acceptance of SRFs and the costs for insurance coverage,
Application of SRF standards and the use of dedicated standards for the determination of self-heating
will help to reduce the risk of fires and to develop tailor-made recommendations for SRF producers,
logistics providers, SRF users, equipment suppliers or manufacturers, consultants, authorities and
insurance providers.
As part of the determination and the assessment of risks for SRF, defined test methods and standards
are established or need to be developed. However, ageing and degradation due to handling and storage
of SRF in actual environments affects their characteristics, so safety margins should be established in
relation to actual analysis results.
Two intrinsically different types of test methods can be used to estimate the potential of self-heating;
1)
a) In the isothermal calorimetry method described in ISO 21911-1 , the heat flow generated from the
test portion is measured directly.
b) In the basket heating tests described in this document, the temperature of the test portion is being
monitored and the critical ambient temperature (CAT), where the temperature of the test portion
does not increase significantly due to self-heating, is used for indirect assessment of self-heating.
These two methods are applied at different analysis temperature regimes. The operating temperature
for an isothermal calorimeter is normally in the range 5 °C to 90 °C, whereas basket heating tests are
conducted at higher analysis (oven) temperatures.
NOTE 1 These two types of test methods do not measure heat production from physical processes, such as
transport of moisture.
NOTE 2 It is likely that oxidation reactions taking place in the low respective high-temperature regimes for
SRFs are of different character and thus have different reaction rates and heat production rates. In such cases,
extrapolation of the data from a high-temperature test series can lead to non-conservative results and will
possibly not be applicable without taking the low-temperature reactions into account. In the general case of two
reactions with different activation energies, the high activation energy is “frozen out” at low temperatures and
[7]
the low activation energy reaction is “swamped” at higher temperatures .
Basket heating tests have been used traditionally for characterization of the tendency for spontaneous
ignition of predominantly coals, but also for other reactive organic materials, such as cottonseed meal,
[9]
bagasse and milk powder . The principle used in these types of test is to find the CAT for a self-heating
sample material of specific size and geometry.
There are several different methods described in the literature with different degrees of sophistication.
The variations span from simple pass and fail tests to more advanced tests from which data on reaction
[10]
rates can be extracted .
1) In preparation. Stage at the time of publication: ISO/FDIS 21911-1:2022.
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SIST-TS CEN ISO/TS 21911-2:2022
ISO/TS 21911-2:2022(E)
Basket heating tests are useful for assessment of self-heating of SRFs. The test method selected can be
evaluated for its applicability based on the information given in this document.
A compilation of available basket heating test methods is given in this document. Guidance on the
suitability for application of these methods for tests with SRFs is provided.
Basic theory of the use of basket heating test data for calculations of critical conditions in storage is
provided in Annex C.
The test methods presented require representative samples for the conditions prevailing in the process
(e.g. of SRF storage). Sample preparation is necessary for this purpose. The methods presented are not
suitable for assessing the fire hazard caused by impurities (disturbing materials) as they occur mainly
in the input area and the first steps of SRF production.
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SIST-TS CEN ISO/TS 21911-2:2022
TECHNICAL SPECIFICATION ISO/TS 21911-2:2022(E)
Solid recovered fuels — Determination of self-heating —
Part 2:
Basket heating tests
1 Scope
This document gives guidance on basket heating tests for characterization of self-heating properties of
solid recovered fuels (SRFs).
This document includes:
a) a compilation of basket heating test methods;
b) guidance on the applicability and use of basket heating tests for SRF;
c) information on the application of basket heating test data for calculations of critical conditions in
storage.
Data on spontaneous heat generation determined using this document is only associated with the
specific quality and age of the sample material.
The information derived using this document is intended for use in quality control and in hazard and
risk assessments related to the procedures given in ISO 21912.
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 21646, Solid recovered fuels — Sample preparation
ISO 21637:2020, Solid recovered fuels — Vocabulary
ISO 21645, Solid recovered fuels — Methods for sampling
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 21637 and the following apply.
ISO and IEC maintain terminology 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
analysis temperature
temperature of the analysis environment, i.e. the oven temperature
1
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SIST-TS CEN ISO/TS 21911-2:2022
ISO/TS 21911-2:2022(E)
3.2
Biot number
quotient of the convective heat transfer coefficient (between the sample boundary and the surrounding
air) and the conduction in the sample material normalized by the characteristic dimension of the test
basket
3.3
critical ambient temperature
CAT
ambient temperature (the analysis temperature (3.1) or the storage temperature) where the internal
temperature of the test portion or the stored material increases significantly (due to self-heating (3.4))
Note 1 to entry: In EN 15188 the critical ambient temperature is defined as self-ignition temperature, T .
SI
3.4
self-heating
rise in temperature in a material resulting from an exothermic reaction within the material
[SOURCE: ISO 13943:2017, 3.341, modified — “” domain omitted from definition.]
3.5
spontaneous ignition
ignition caused by an internal exothermic reaction
[SOURCE: ISO 13943:2017, 3.24, modified — Notes to entry removed.]
3.6
test sample
laboratory sample (3.7) after an appropriate preparation made by the laboratory
Note 1 to entry: The test sample is here typically a representative sample from a batch of solid recovered fuel.
[SOURCE: ISO 21637:2020, 3.84, modified — Note 1 to entry added.]
3.7
laboratory sample
sample delivered to a laboratory
[SOURCE: ISO 16559:2022, 3.120, modified — Note 1 to entry removed.]
4 Symbols
Symbol Quantity Typical unit
−1
A pre-exponential factor in Arrhenius expression s
B dimensionless adiabatic temperature rise dimensionless
hL·
Bi Biot number, (Bi= ) dimensionless
λ
c ambient oxygen concentration by volume fraction dimensionless
0
−1 −1
C specific heat capacity of the reaction products J kg K
−1 −1
C specific heat capacity of the bulk material J kg K
p
d diameter of body m
2 −1
D diffusion coefficient m s
−1
E activation energy J mol
a
−1
H gross calorific value J kg
0
−2 −1
h heat transfer coefficient W m K
−2 −1
h radiative amount on heat transfer coefficient W m K
r
2
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SIST-TS CEN ISO/TS 21911-2:2022
ISO/TS 21911-2:2022(E)
Symbol Quantity Typical unit
−2 −1
h convective amount on heat transfer coefficient W m K
c
L characteristic length m
n order of reaction dimensionless
P constant dimensionless
−3
heat generation term W m
q´
−1
Q heat of reaction J kg
−3
Q heat of reaction by volume of oxygen J m
0
−1 −1
R universal gas constant J mol K
Ra Rayleight number dimensionless
2
S surface m
t time s
T temperature K
T ambient temperature K
0
T crossing point temperature K
p
T self-ignition temperature K
SI
3
V volume m
x length coordinate m
δ Frank-Kamenetskii parameter dimensionless
δ critical value of δ dimensionless
c
ε dimensionless
RT
0
activation energy parameter, ε =
E
a
Ф oxygen diffusion parameter dimensionless
−1 −1
λ thermal conductivity of sample W m K
−1 −1
λ thermal conductivity of air W m K
air
−3
ρ bulk density kg m
−2 −4
σ Stefan-Boltzmann coefficient W m K
5 Basket heating tests
The detailed test procedure varies between different isoperibolic and adiabatic methods. Isoperibolic
methods include that the test portion is put in a wire-mesh basket which is placed in an oven heated to
a fixed elevated temperature. The oven is equipped with a fan to keep the temperature uniform and to
[9] [10].
give a relatively large convective heat transfer coefficient to the test specimen For adiabatic tests,
the oven temperature is adjusted to the temperature at the centre of the sample, see EN 15188.
Basket heating tests are based on the Frank-Kamenetskii theory of criticality of a self-heating isotropic
slab (see Annex C) and have been developed to determine the reaction kinetics of the global reaction
responsible for heat production in a self-heating material. The large gap volume of pelletized material
can lead to convective heat transport in the bulk if the furnace is equipped with a fan. In this case
air flow in the vicinity of the sample should be kept at a low level and the critical Frank-Kamenetskii
parameter should be corrected (see C.1.3) or the convective transport within the sample should be
prevented by further measures (e.g. finer mesh wire of the basket).
NOTE The CAT for the test portion in a basket heating test is not equal to the CAT for spontaneous ignition
in, for example, large-scale storage. The critical size for spontaneous ignition (if only heat transfer is considered)
is directly related to the surface area-volume ratio of the self-heating specimen where heat is produced
distributed in the volume and heat is dissipated from the surface area only. The test sample in a laboratory-size
basket heating test has a very high surface area-volume ratio and, consequently, a high CAT compared to a larger
specimen.
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ISO/TS 21911-2:2022(E)
6 Tests for product classification
6.1 UN classification
6.1.1 General
[11]
The United Nations Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
is the international convention for hazard communication and labelling of gases and vapours, solid and
liquid substances and mixtures. GHS defines limit values, classes and categories and related measures
in relation to the level of hazards during transportation, handling and storage.
[12]
The United Nations Manual of Test and Criteria (MTC) prescribes specific test procedures in support
of GHS.
6.1.2 Tes
...
SLOVENSKI STANDARD
kSIST-TS FprCEN ISO/TS 21911-2:2022
01-maj-2022
Trdno alternativno gorivo - Določanje samosegrevanja - 2. del: Preskusi ogrevanja
košare (ISO/PRF TS 21911-2:2022)
Solid recovered fuels - Determination of self-heating - Part 2: Basket heating tests
(ISO/PRF TS 21911-2:2022)
Biogene Festbrennstoffe - Bestimmung der Selbsterhitzung - Teil 2:
Warmlagerungsprüfungen im Drahtnetzkorb (ISO/PRF TS 21911-2:2022)
Combustibles solides de récupération - Détermination de l'auto-échauffement - Partie 2:
Essais utilisant la méthode du point de croisement (ISO/PRF TS 21911-2:2022)
Ta slovenski standard je istoveten z: FprCEN ISO/TS 21911-2
ICS:
75.160.10 Trda goriva Solid fuels
kSIST-TS FprCEN ISO/TS 21911-2:2022 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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kSIST-TS FprCEN ISO/TS 21911-2:2022
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kSIST-TS FprCEN ISO/TS 21911-2:2022
TECHNICAL ISO/TS
SPECIFICATION 21911-2
First edition
Solid recovered fuels — Determination
of self-heating —
Part 2:
Basket heating tests
Combustibles solides de récupération — Détermination de l'auto-
échauffement —
Partie 2: Essais utilisant la méthode du point de croisement
PROOF/ÉPREUVE
Reference number
ISO/TS 21911-2:2022(E)
© ISO 2022
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kSIST-TS FprCEN ISO/TS 21911-2:2022
ISO/TS 21911-2:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022
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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
PROOF/ÉPREUVE © ISO 2022 – All rights reserved
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kSIST-TS FprCEN ISO/TS 21911-2:2022
ISO/TS 21911-2:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Basket heating tests .3
6 Tests for product classification . 4
6.1 UN classification. 4
6.1.1 General . 4
6.1.2 Test method for self-heating substances – MTC Test N.4 . 4
6.1.3 Classification criteria — GHS . 4
6.2 Classification criteria — IMO . 5
6.3 Applicability of MTC Test N.4 for solid recovered fuels . 5
7 Tests for determination of reaction kinetics . 6
7.1 General . 6
7.2 Isoperibolic test methods . 6
7.2.1 General . 6
7.2.2 Test procedure. 6
7.2.3 Determination of reaction kinetics . 7
7.2.4 Applicability for solid recovered fuels . 7
7.3 Crossing-point method . 8
7.3.1 General . 8
7.3.2 Test procedure. 8
7.3.3 Determination of reaction kinetics . 9
7.3.4 Applicability for solid recovered fuels . 9
7.4 Adiabatic hot storage tests . 10
7.4.1 General . 10
7.4.2 Test procedure. 10
7.4.3 Determination of reaction kinetics . 11
7.4.4 Applicability for solid recovered fuels .12
8 Sample handling .12
8.1 General .12
8.2 Sampling . 13
8.3 Sample transport and storage .13
8.4 Sample preparation . 13
8.5 Sample disposal .13
9 Test report .13
Annex A (informative) Self-ignition behaviour of selected materials suitable to be used as
solid recovered fuels .15
Annex B (informative) Example of calculating kinetic parameters from crossing point
method tests .22
Annex C (normative) Use of data for calculations of critical conditions in storage .25
Bibliography .30
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kSIST-TS FprCEN ISO/TS 21911-2:2022
ISO/TS 21911-2:2022(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 of 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
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 300, Solid recovered materials, including
solid recovered fuels, in collaboration with the European Committee for Standardization (CEN)
Technical Committee CEN/TC 343, Solid recovered fuels, in accordance with the Agreement on technical
cooperation between ISO and CEN (Vienna Agreement).
A list of all parts in the ISO 21911 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
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kSIST-TS FprCEN ISO/TS 21911-2:2022
ISO/TS 21911-2:2022(E)
Introduction
There is continuous global growth in trading and use of solid recovered fuels (SRFs). Therefore,
intensive investigations about the risk of fires within SRF production, handling and storing have been
conducted, see ÖNORM S 2098. Recommendations are given in ISO 21912.
Depending on the kind of input wastes, the treatment technology applied, the quality of the SRF
produced and the realized storage versions, SRFs can generate heat spontaneously by exothermic
biological, chemical and physical processes. The heat build-up can be significant in large storage
volumes if the heat conduction in the material is low. During some conditions the heat generation
can lead to pyrolysis and spontaneous ignition. The potential for self-heating varies considerably for
different types and qualities of SRF and it is important to be able to identify SRF fractions with high
heat generation potential to avoid fires in stored materials.
Avoiding fires throughout the production and supply chain will have positive consequences on the
acceptance of SRFs and the costs for insurance coverage,
Application of SRF standards and the use of dedicated standards for the determination of self-heating
will help to reduce the risk of fires and to develop tailor-made recommendations for SRF producers,
logistics providers, SRF users, equipment suppliers or manufacturers, consultants, authorities and
insurance providers.
As part of the determination and the assessment of risks for SRF, defined test methods and standards
are established or need to be developed. However, ageing and degradation due to handling and storage
of SRF in actual environments affects their characteristics, so safety margins should be established in
relation to actual analysis results.
Two intrinsically different types of test methods can be used to estimate the potential of self-heating;
1)
a) In the isothermal calorimetry method described in ISO 21911-1 , the heat flow generated from the
test portion is measured directly.
b) In the basket heating tests described in this document, the temperature of the test portion is being
monitored and the critical ambient temperature (CAT), where the temperature of the test portion
does not increase significantly due to self-heating, is used for indirect assessment of self-heating.
These two methods are applied at different analysis temperature regimes. The operating temperature
for an isothermal calorimeter is normally in the range 5 °C to 90 °C, whereas basket heating tests are
conducted at higher analysis (oven) temperatures.
NOTE 1 These two types of test methods do not measure heat production from physical processes, such as
transport of moisture.
NOTE 2 It is likely that oxidation reactions taking place in the low respective high-temperature regimes for
SRFs are of different character and thus have different reaction rates and heat production rates. In such cases,
extrapolation of the data from a high-temperature test series can lead to non-conservative results and will
possibly not be applicable without taking the low-temperature reactions into account. In the general case of two
reactions with different activation energies, the high activation energy is “frozen out” at low temperatures and
[7]
the low activation energy reaction is “swamped” at higher temperatures .
Basket heating tests have been used traditionally for characterization of the tendency for spontaneous
ignition of predominantly coals, but also for other reactive organic materials, such as cottonseed meal,
[9]
bagasse and milk powder . The principle used in these types of test is to find the CAT for a self-heating
sample material of specific size and geometry.
There are several different methods described in the literature with different degrees of sophistication.
The variations span from simple pass and fail tests to more advanced tests from which data on reaction
[10]
rates can be extracted .
1) In preparation. Stage at the time of publication: ISO/DIS 21911-1:2022.
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kSIST-TS FprCEN ISO/TS 21911-2:2022
ISO/TS 21911-2:2022(E)
Basket heating tests are useful for assessment of self-heating of SRFs. The test method selected can be
evaluated for its applicability based on the information given in this document.
A compilation of available basket heating test methods is given in this document. Guidance on the
suitability for application of these methods for tests with SRFs is provided.
Basic theory of the use of basket heating test data for calculations of critical conditions in storage is
provided in Annex C.
The test methods presented require representative samples for the conditions prevailing in the process
(e.g. of SRF storage). Sample preparation is necessary for this purpose. The methods presented are not
suitable for assessing the fire hazard caused by impurities (disturbing materials) as they occur mainly
in the input area and the first steps of SRF production.
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kSIST-TS FprCEN ISO/TS 21911-2:2022
TECHNICAL SPECIFICATION ISO/TS 21911-2:2022(E)
Solid recovered fuels — Determination of self-heating —
Part 2:
Basket heating tests
1 Scope
This document gives guidance on basket heating tests for characterization of self-heating properties of
solid recovered fuels (SRFs).
This document includes:
a) a compilation of basket heating test methods;
b) guidance on the applicability and use of basket heating tests for SRF;
c) information on the application of basket heating test data for calculations of critical conditions in
storage.
Data on spontaneous heat generation determined using this document is only associated with the
specific quality and age of the sample material.
The information derived using this document is intended for use in quality control and in hazard and
risk assessments related to the procedures given in ISO 21912.
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.
2)
ISO 21646 , Solid recovered fuels — Sample preparation
ISO 21637:2020, Solid recovered fuels — Vocabulary
ISO 21645, Solid recovered fuels — Methods for sampling
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 21637 and the following apply.
ISO and IEC maintain terminology 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
analysis temperature
temperature of the analysis environment, i.e. the oven temperature
2) In preparation. Stage at the time of publication: ISO/FDIS 21646:2022.
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kSIST-TS FprCEN ISO/TS 21911-2:2022
ISO/TS 21911-2:2022(E)
3.2
Biot number
quotient of the convective heat transfer coefficient (between the sample boundary and the surrounding
air) and the conduction in the sample material normalized by the characteristic dimension of the test
basket
3.3
critical ambient temperature
CAT
ambient temperature (the analysis temperature (3.1) or the storage temperature) where the internal
temperature of the test portion or the stored material increases significantly [due to self-heating (3.4)]
Note 1 to entry: In EN 15188 the critical ambient temperature is defined as self-ignition temperature, T .
SI
3.4
self-heating
rise in temperature in a material resulting from an exothermic reaction within the material
[SOURCE: ISO 13943:2017, 3.341, modified — “” domain omitted from definition.]
3.5
spontaneous ignition
ignition caused by an internal exothermic reaction
[SOURCE: ISO 13943:2017, 3.24, modified — Notes to entry removed.]
3.6
test sample
laboratory sample (3.7) after an appropriate preparation made by the laboratory
Note 1 to entry: The test sample is here typically a representative sample from a batch of solid recovered fuel.
[SOURCE: ISO 21637:2020, 3.84, modified — Note 1 to entry added.]
3.7
laboratory sample
sample delivered to a laboratory
[SOURCE: ISO 16559:2022, 3.120, modified — Note 1 to entry removed.]
4 Symbols
Symbol Quantity Typical unit
−1
A pre-exponential factor in Arrhenius expression s
B dimensionless adiabatic temperature rise dimensionless
hL·
Bi Biot number, (Bi= ) dimensionless
λ
c ambient oxygen concentration by volume fraction dimensionless
0
−1 −1
C specific heat capacity of the reaction products J kg K
−1 −1
C specific heat capacity of the bulk material J kg K
p
d diameter of body m
2 −1
D diffusion coefficient m s
−1
E activation energy J mol
a
−1
H gross calorific value J kg
0
−2 −1
h heat transfer coefficient W m K
−2 −1
h radiative amount on heat transfer coefficient W m K
r
2
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ISO/TS 21911-2:2022(E)
Symbol Quantity Typical unit
−2 −1
h convective amount on heat transfer coefficient W m K
c
L characteristic length m
n order of reaction dimensionless
P constant dimensionless
−3
heat generation term W m
q´
−1
Q heat of reaction J kg
−3
Q heat of reaction by volume of oxygen J m
0
−1 −1
R universal gas constant J mol K
Ra Rayleight number dimensionless
2
S surface m
t time s
T temperature K
T ambient temperature K
0
T crossing point temperature K
p
T self-ignition temperature K
si
3
V volume m
x length coordinate m
δ Frank-Kamenetskii parameter dimensionless
δ critical value of δ dimensionless
c
ε dimensionless
RT
0
activation energy parameter, ε =
E
a
Ф oxygen diffusion parameter dimensionless
−1 −1
λ thermal conductivity of sample W m K
−1 −1
λ thermal conductivity of air W m K
air
−3
ρ bulk density kg m
−2 −4
σ Stefan-Boltzmann coefficient W m K
5 Basket heating tests
The detailed test procedure varies between different isoperibolic and adiabatic methods. Isoperibolic
methods include that the test portion is put in a wire-mesh basket which is placed in an oven heated to
a fixed elevated temperature. The oven is equipped with a fan to keep the temperature uniform and to
[9] [10].
give a relatively large convective heat transfer coefficient to the test specimen For adiabatic tests,
the oven temperature is adjusted to the temperature at the centre of the sample, see EN 15188.
Basket heating tests are based on the Frank-Kamenetskii theory of criticality of a self-heating isotropic
slab (see Annex C) and have been developed to determine the reaction kinetics of the global reaction
responsible for heat production in a self-heating material. The large gap volume of pelletized material
can lead to convective heat transport in the bulk if the furnace is equipped with a fan. In this case
air flow in the vicinity of the sample should be kept at a low level and the critical Frank-Kamenetskii
parameter should be corrected (see C.1.3) or the convective transport within the sample should be
prevented by further measures (e.g. finer mesh wire of the basket).
NOTE The CAT for the test portion in a basket heating test is not equal to the CAT for spontaneous ignition
in, for example, large-scale storage. The critical size for spontaneous ignition (if only heat transfer is considered)
is directly related to the surface area-volume ratio of the self-heating specimen where heat is produced
distributed in the volume and heat is dissipated from the surface area only. The test sample in a laboratory-size
basket heating test has a very high surface area-volume ratio and, consequently, a high CAT compared to a larger
specimen.
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kSIST-TS FprCEN ISO/TS 21911-2:2022
ISO/TS 21911-2:2022(E)
6 Tests for product classification
6.1 UN classification
6.1.1 General
[11]
The United Nations Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
is the international convention for hazard communication and labelling of gases and vapours, solid and
liquid substances and mixtures. GHS defines limit values, classes and categories and related measures
in relation to the level of hazards during transportation, handling and storage.
[12]
The United Nations Manual of Test and Criteria (MTC) prescribes specific test procedures in support
of GHS.
6.1.2 Test method for self-heating substances – MTC Test N.4
[12]
Test N.4 is described in the MTC, Part III, 33.3.1.6, sometimes called the basket test.
This basket heating test determines the ability of a substance to undergo oxidative self-heating with
exposure to air at temperatures of 100 °C, 120 °C or 140 °C in a 25 mm or 100 mm wire mesh cube.
The N.4 test basket heating test is not intended for determination of self-heating kinetics but rather
[11]
prescribed to classify a material (e.g. SRFs) as meeting the criteria for self-heating set out by the GHS
for hazard communication and labelling purposes.
The test set-up consists of a hot-air circulating oven, cubic sample containers with sides of 25 mm and
100 mm made of stainless-steel net with a mesh opening of 0,05 mm, and thermocouples of 0,3 mm
diameter for measurement of the oven temperature and the temperature of the centre of the sample.
The sample container is housed in a cubic container cover made from stainless-steel net with a mesh
opening of 0,60 mm and slightly larger than the test container. To avoid the effect of air circulation,
this cover is installed in a second steel cage, made from a net with a mesh size of 0,595 mm and
150 mm × 150 mm × 250 mm in size.
The normal procedure is to start with a test at 140 °C with a 100-mm sample cube. The container is
housed in the cover and hung at the centre of the oven. The oven temperature is raised to 140 °C and
kept there for 24 h. A positive result is obtained if spontaneous ignition occurs or if the temperature
of the sample exceeds the oven temperature by 60 °C. If a negative result is obtained, no further test is
necessary.
If a positive result is obtained at 140 °C with a 100-mm sample cube, the substance is classified as a self-
heating substance and further testing shall be made to find the correct classification (see 6.1.3).
The bulk density tested can influence the test results. The bulk density of the sample shall be adjusted
according to EN 15188 to the respective practical conditions (if known) and the tested bulk density
shall be recorded. The MTC contains no information on the bulk density to be tested.
6.1.3 Classification criteria — GHS
[11]
The classification criteria are given in chapter 2.11.2 of the GHS . The criteria are summarized in
Table 1.
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ISO/TS 21911-2:2022(E)
Table 1 — Criteria in GHS for self-heating substances and mixtures
Category Criteria
1 A positive result is obtained in a test using a 25-mm sample cube at 140 °C
2 a) A positive result is obtained in a test using a 100-mm sample cube at 140 °C, a negative
result is obtained in a test using a 25-mm sample cube at 140 °C and the substance or
3
mixture is packed in packages with a volume of more than 3 m ; or
b) A positive result is obtained in a test using a 100-mm sample cube at 140 °C, a negative
result is obtained in a test using a 25-mm sample cube at 140 °C, a positive result is
obtained in a test using a 100-mm sample cube at 120 °C and the substance or mixture is
packed in packages with a volume of more than 450 l; or
c) A positive result is obtained in a test using a 100-mm sample cube at 140 °C, a negative
result is obtained in a test using a 25-mm sample cube at 140 °C and a positive result is
obtained in a test using a 100-mm sample cube at 100 °C.
NOTE Hazard packing group classification is prescribed depending on flammability characteristics of the
[11]
material, see GHS, Table 32.1.
6.2 Classification criteria — IMO
Handling guidelines and hazard classifications for all cargoes, including SRFs, transported onboard
ocean vessels are specified by the International Maritime Org
...
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