SIST EN ISO 21656:2021
(Main)Solid recovered fuels - Determination of ash content (ISO 21656:2021)
Solid recovered fuels - Determination of ash content (ISO 21656:2021)
This Standard specifies a method for the determination of ash content of all solid recovered fuels.
Feste Sekundärbrennstoffe - Bestimmung des Aschegehaltes (ISO 21656:2021)
Dieses Dokument legt Verfahren zur Bestimmung des Aschegehaltes sämtlicher festen Sekundärbrennstoffe fest.
Combustibles solides de récupération - Détermination de la teneur en cendres (ISO 21656:2021)
Le présent document spécifie des méthodes de détermination de la teneur en cendres pour tous les combustibles solides de récupération.
Trdna alternativna goriva - Določevanje vsebnosti pepela (ISO 21656:2021)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 21656:2021
01-junij-2021
Nadomešča:
SIST EN 15403:2011
Trdna alternativna goriva - Določevanje vsebnosti pepela (ISO 21656:2021)
Solid recovered fuels - Determination of ash content (ISO 21656:2021)
Feste Sekundärbrennstoffe - Bestimmung des Aschegehaltes (ISO 21656:2021)
Combustibles solides de récupération - Détermination de la teneur en cendres (ISO
21656:2021)
Ta slovenski standard je istoveten z: EN ISO 21656:2021
ICS:
75.160.10 Trda goriva Solid fuels
SIST EN ISO 21656:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 21656:2021
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SIST EN ISO 21656:2021
EN ISO 21656
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2021
EUROPÄISCHE NORM
ICS 75.160.10 Supersedes EN 15403:2011
English Version
Solid recovered fuels - Determination of ash content (ISO
21656:2021)
Combustibles solides de récupération - Détermination Feste Sekundärbrennstoffe - Bestimmung des
de la teneur en cendres (ISO 21656:2021) Aschegehaltes (ISO 21656:2021)
This European Standard was approved by CEN on 6 March 2021.
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, 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, 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
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21656:2021 E
worldwide for CEN national Members.
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SIST EN ISO 21656:2021
EN ISO 21656:2021 (E)
Contents Page
European foreword . 3
2
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SIST EN ISO 21656:2021
EN ISO 21656:2021 (E)
European foreword
This document (EN ISO 21656:2021) 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 Fuels” the secretariat of which is held by SFS.
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 September 2021, and conflicting national standards
shall be withdrawn at the latest by September 2021.
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 15403:2011.
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, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 21656:2021 has been approved by CEN as EN ISO 21656:2021 without any modification.
3
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SIST EN ISO 21656:2021
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SIST EN ISO 21656:2021
INTERNATIONAL ISO
STANDARD 21656
First edition
2021-02
Solid recovered fuels — Determination
of ash content
Combustibles solides de récupération — Détermination de la teneur
en cendres
Reference number
ISO 21656:2021(E)
©
ISO 2021
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SIST EN ISO 21656:2021
ISO 21656:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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 2021 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 21656:2021
ISO 21656:2021(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 2
6 Sampling and sample preparation . 3
6.1 General . 3
6.2 Pre-drying . 3
6.3 Removed ash contributors (rac) . 3
7 Procedure. 3
7.1 General . 3
7.2 Method A – ash content at 550 °C . 3
7.3 Method B – ash content at 815 °C . 4
8 Calculation . 5
8.1 General analysis sample . 5
8.2 Calculation of total ash content including removed ash contributors, on an as
received and dry basis . 5
9 Precision . 6
9.1 Repeatability limit . 6
9.2 Reproducibility limit . 6
10 Test report . 6
Annex A (informative) Interlaboratory test results . 8
Annex B (informative) Environmental aspects .11
Bibliography .13
© ISO 2021 – All rights reserved iii
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SIST EN ISO 21656:2021
ISO 21656:2021(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 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).
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 © ISO 2021 – All rights reserved
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SIST EN ISO 21656:2021
ISO 21656:2021(E)
Introduction
This document covers the determination of ash content of solid recovered fuels. It is primarily geared
toward laboratories, producers, suppliers and purchasers of solid recovered fuels but is also useful for
the authorities and inspection organizations.
[5]
The method A specified in this document is based on EN 15403 .
For information about environmental aspect, see Annex B.
© ISO 2021 – All rights reserved v
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SIST EN ISO 21656:2021
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SIST EN ISO 21656:2021
INTERNATIONAL STANDARD ISO 21656:2021(E)
Solid recovered fuels — Determination of ash content
1 Scope
This document specifies methods for the determination of ash content of all solid recovered fuels.
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 21637, Solid recovered fuels — Vocabulary
ISO 21645, Solid recovered fuels — Methods for sampling
1)
ISO 21646 , Solid recovered fuels — Sample preparation
ISO 21660-3, Solid recovered fuels — Determination of moisture content using the oven dry method —
Part 3: Moisture in general analysis sample
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 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 http:// www .electropedia .org/
3.1
ash
ash content on dry basis
total ash
A
mass of inorganic residue remaining after combustion of a fuel under specified conditions, typically
expressed as a percentage of the mass of dry matter in fuel
Note 1 to entry: Depending on the combustion efficiency the ash may contain combustibles.
Note 2 to entry: If a complete combustion is realized, ash contains only inorganic, non-combustible components.
[SOURCE: ISO 16559:2014, 4.13, modified — “Note 1 to entry” was removed and the following ones
renumbered, and symbol "A" was italicized.]
3.2
total ash content
mass of inorganic residue remaining after ignition of a fuel under specified conditions, expressed as
mass fraction in percent of the dry matter in the fuel, which also includes removed ash contributors
1) Under preparation. (Stage at the time of publication: ISO/DIS 21646:2021.)
© ISO 2021 – All rights reserved 1
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SIST EN ISO 21656:2021
ISO 21656:2021(E)
3.3
removed ash contributors
rac
coarse inert material (i.e. metals, glass, stones, tiles etc.) removed from the pre-dried sample before
preparation, in order to avoid damage to the preparation equipment
Note 1 to entry: Removed ash contributors are included in the total ash content calculations.
[SOURCE: ISO 21637:2020, 3.62, modified: Note 1 to entry was added]
3.4
total organic matter
combustible part of solid recovered fuels, which consists of the sum of volatile matter and fixed carbon
Note 1 to entry: It is calculated as: 100 - moisture content - ash content.
Note 2 to entry: It is the mass fraction of the matter lost by ignition, also known as “Loss of Ignition" (LOI).
3.5
volatile matter
relative part of the analysed sample, after moisture removal, that is lost when material is heated up
under specific conditions of temperature, time and in a reduced atmosphere (anoxic conditions)
3.6
fixed carbon
relative part of carbon contained in a material that can only be degraded in oxic conditions and high
temperature
Note 1 to entry: It is calculated as: 100 - moisture content - volatile matter content - ash content.
4 Principle
The sample is heated in air atmosphere up to a temperature of (550 ± 10) °C for Method A or (815 ± 10) °C
for Method B under rigidly controlled conditions of time, sample mass and equipment specifications.
The ash content is determined by calculation from the mass of the residue remaining after heating.
NOTE Difference in the ash content if determined at 815 °C compared to 550 °C is explained by decomposition
of carbonates forming CO , losses of volatile inorganic compounds (see also 3.5) and further oxidation of inorganic
2
[1]
compounds . In common standard practise, 550 °C is used for the determination of ash content in SRFs with a
[6]
high content of biomass. 550 °C can also be used for major elemental determination (see also EN 15410 ) and
[7]
trace elemental determination (see also EN 15411 ).
Automatic equipment (such as thermogravimetric analysers) may be used as long as the equipment is
validated by parallel measurements to the reference method. The automatic equipment shall fulfil all
the requirements regarding sample size, heating procedure, temperature, atmosphere and weighing
accuracy. Deviations from this paragraph shall be reported and justified.
5 Apparatus
5.1 Dish, consisting of inert material such as porcelain, silica or platinum, with a depth from 10 mm to
2
20 mm and such a size that the sample loading does not exceed 0,1 g/cm bottom area.
5.2 Furnace, capable of maintaining a zone of uniform temperature at the levels required in Clause 7
and to reach these levels in the specified heating rates. The ventilation rate through the furnace should
be such that no lack of oxygen arises during the heating procedure.
NOTE A ventilation rate from 5 air changes/min to 10
...
SLOVENSKI STANDARD
oSIST prEN ISO 21656:2020
01-marec-2020
Trdna alternativna goriva - Določevanje vsebnosti pepela (ISO/DIS 21656:2019)
Solid recovered fuels - Determination of ash content (ISO/DIS 21656:2019)
Feste Sekundärbrennstoffe - Bestimmung des Aschegehaltes (ISO/DIS 21656:2019)
Combustibles solides de récupération - Détermination de la teneur en cendres (ISO/DIS
21656:2019)
Ta slovenski standard je istoveten z: prEN ISO 21656
ICS:
75.160.10 Trda goriva Solid fuels
oSIST prEN ISO 21656:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
oSIST prEN ISO 21656:2020
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oSIST prEN ISO 21656:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 21656
ISO/TC 300 Secretariat: SFS
Voting begins on: Voting terminates on:
2019-12-19 2020-03-12
Solid recovered fuels — Determination of ash content
Combustibles solides de récupération — Détermination de la teneur en cendre
ICS: 75.160.10
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 21656:2019(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
©
PROVIDE SUPPORTING DOCUMENTATION. ISO 2019
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oSIST prEN ISO 21656:2020
ISO/DIS 21656:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
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 2019 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 21656:2020
ISO/DIS 21656:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 2
6 Sampling and sample preparation . 3
6.1 General . 3
6.2 Pre-drying . 3
6.3 Removed ash contributors (rac) . 3
7 Procedure. 3
7.1 General . 3
7.2 Method A – ash content at 550 °C . 3
7.3 Method B – ash content at 815 °C . 4
8 Calculation . 5
8.1 General analysis sample . 5
8.2 Calculation of total ash content including removed ash contributors, on dry basis . 5
8.3 Calculation of total ash content including removed ash contributors, basis as received . 6
9 Precision . 6
9.1 Repeatability limit . 6
9.2 Reproducibility limit . 7
10 Test report . 7
Annex A (informative) Interlaboratory test results . 8
Annex B (informative) Environmental aspects .11
Bibliography .13
© ISO 2019 – All rights reserved iii
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oSIST prEN ISO 21656:2020
ISO/DIS 21656:2019(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 fuels.
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 © ISO 2019 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 21656:2020
ISO/DIS 21656:2019(E)
Introduction
This document covers the determination of ash content of solid recovered fuels. It is primarily geared
toward laboratories, producers, suppliers and purchasers of solid recovered fuels but is also useful for
the authorities and inspection organizations.
The method specified in this document is based on EN 15403.
For information about environmental aspect, see Annex B.
© ISO 2019 – All rights reserved v
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oSIST prEN ISO 21656:2020
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oSIST prEN ISO 21656:2020
DRAFT INTERNATIONAL STANDARD ISO/DIS 21656:2019(E)
Solid recovered fuels — Determination of ash content
1 Scope
This document specifies methods for the determination of ash content of all solid recovered fuels.
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.
1)
EN 15442, Solid recovered fuels — Methods for sampling
2)
EN 15443, Solid recovered fuels — Methods for the preparation of the laboratory sample
ISO/DIS 21637, Solid recovered fuels — Terminology, definitions and descriptions
ISO/DIS 21660-3, Solid recovered fuels — Determination of moisture content using the oven dry method —
Part 3: Moisture in general analysis sample
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/DIS 21637 and the
following 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 http:// www .electropedia .org/
3.1
ash content on dry basis
mass of inorganic residue remaining after ignition of a fuel under specified conditions, expressed as
mass fraction in percent of the dry matter in the fuel
Note 1 to entry: For the characterisation of solid recovered fuels (SRF) it is necessary to analyse the content of
the volatile alkaline and therefore the temperature of 550°C is used for biomass SRF.
3.2
total ash content on dry basis
mass of inorganic residue remaining after ignition of a fuel under specified conditions, expressed as
mass fraction in percent of the dry matter in the fuel, which also includes removed ash contributors
1) ISO/CD 21645:2019 "Solid recovered fuels — Method for sampling" is currently being processed for the
preparation of the "DIS"-enquiry.
2) ISO/CD 21646:2019 "Solid recovered fuels — Sample preparation" is currently being processed for the
preparation of the "DIS"-enquiry.
© ISO 2019 – All rights reserved 1
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oSIST prEN ISO 21656:2020
ISO/DIS 21656:2019(E)
3.3
removed ash contributors
rac
coarse inert material (i.e. metals, glass, stones, tiles etc.) removed from the pre-dried sample before
preparation, in order to avoid damage to the preparation equipment,
Note 1 to entry: Removed ash contributors are included in the ash content calculations.
3.4
total organic matter
combustible part of solid recovered fuels, which consists of the sum of volatile matter and fixed carbon
Note 1 to entry: It is calculated as: 100 - moisture content - ash content.
Note 2 to entry: It is the mass fraction of the matter lost by ignition, also known as “Loss of Ignition" (LOI).
3.5
volatile matter
relative part of the analysed sample, after moisture removal, that is lost when material is heated up
under specific conditions of temperature, time and in a reduced atmosphere (anoxic conditions)
3.6
fixed carbon
relative part of carbon contained in a material that can only be degraded in oxic conditions and high
temperature
Note 1 to entry: It is calculated as: 100 - moisture content - volatile matter content - ash content.
4 Principle
The sample is heated in air atmosphere up to a temperature of (550 ± 10) °C for Method A or (815 ± 10) °C
for Method B under rigidly controlled conditions of time, sample mass and equipment specifications.
The ash content is determined by calculation from the mass of the residue remaining after heating.
[1]
NOTE Difference in the ash content if determined at a higher temperature, 815 °C, according to Reference as
compared to 550 °C (major and minor elemental determination), is explained by the decomposition of carbonates
forming CO2, by losses of volatile inorganic compounds and further oxidation of inorganic compounds (to higher
oxidation states).
Automatic equipment (such as thermogravimetric analysers) may be used as long as the equipment is
validated by parallel measurements to the reference method. The automatic equipment shall fulfil all
the requirements regarding sample size, heating procedure, temperature, atmosphere and weighing
accuracy. Deviations from this paragraph shall be reported and justified.
5 Apparatus
5.1 Dish, consisting of inert material such as porcelain, silica or platinum, with a depth from 10 mm to
2
20 mm and such a size that the sample loading does not exceed 0,1 g/cm bottom area.
5.2 Furnace, capable of maintaining a zone of uniform temperature at the levels required in Clause 7
and to reach these levels in the specified heating rates. The ventilation rate through the furnace should
be such that no lack of oxygen arises during the heating procedure.
NOTE A ventilation rate from 5 air changes/min to 10 air changes/min should be suitable.
5.3 Balance, capable of weighing the dish containing the sample to the nearest 0,1 mg.
5.4 Desiccator, without desiccant.
2 © ISO 2019 – All rights reserved
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oSIST prEN ISO 21656:2020
ISO/DIS 21656:2019(E)
NOTE The use of a desiccator without desiccant is specified in ISO 1171 and emphasised here since ashes
from solid recovered fuels are often more hygroscopic than coal ashes.
5.5 Sieve
5.6 Container, sealed airtight.
6 Sampling and sample preparation
6.1 General
The general analysis sample shall be taken and prepared in accordance with EN 15442and EN 15443.
It shall be ground to pass through a sieve with an aperture size of ≤ 1 mm. The general analysis sample
shall be received in the laboratory in the container (5.6). The general analysis sample shall either
be oven-dried or its moisture content determined in accordance with ISO/DIS 21660-3. The general
analysis sample shall be mixed carefully before weighing (see also Clause 7).
6.2 Pre-drying
Pre-drying shall be performed according to EN 15443.
Pre-drying of wet samples is carried out to minimize moisture loss in the subsequent sample-division
processes, to facilitate the sample preparation processes, and to minimize biological activity. If it is
necessary to dry a sample by heating, it shall be dried in an oven at a temperature not exceeding the
temperature according EN 15443.
6.3 Removed ash contributors (rac)
Coarse inert material (i. e. metals, glass, stones) removed from the pre-dried sample before preparation,
in order to avoid damage to the preparation equipment.
rac from pre dried samples shall be con
...
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