EN ISO 17225-8:2023

Solid biofuels - Fuel specifications and classes - Part 8: Graded thermally treated and densified biomass fuels for commercial and industrial use (ISO 17225-8:2023)

This document determines the fuel quality classes and specifications of graded densified solid biofuels produced from thermally treated biomass for commercial applications and industrial use. This document covers pellets and briquettes produced from the following raw materials (see ISO 17225‑1:2021, Table 1):
—    woody biomass;
—    herbaceous biomass;
—    fruit biomass;
—    aquatic biomass;
—    blends and mixtures.
Subcategories of these raw materials are included.
This document does not consider products which are marketed as charcoal or as charcoal products. For these products, see ISO 17225‑1:2021, Table 14.
NOTE      Health, safety and environmental issues for solid biofuels are important and need special attention; however, they are outside the scope of this document.

Biogene Festbrennstoffe - Brennstoffspezifikationen und -klassen - Teil 8: Klassifizierung von thermisch behandelten und gepressten Brennstoffen aus Biomasse für gewerbliche und industrielle Verwendung (ISO 17225-8:2023)

Dieses Dokument legt die qualitätsbezogenen Brennstoffklassen und  spezifikationen für klassifizierte gepresste biogene Festbrennstoffe, hergestellt aus thermisch behandelter Biomasse, für gewerbliche Verwendung und industrielle Verwendung fest. Dieses Dokument umfasst Pellets und Briketts, die aus folgenden Rohmaterialien hergestellt wurden (siehe ISO 17225 1:2021, Tabelle 1):
   holzartige Biomasse;
   halmgutartige Biomasse;
   Biomasse von Früchten;
   aquatische Biomasse;
   definierte und undefinierte Mischungen.
Unterkategorien dieser Rohmaterialien sind eingeschlossen.
Dieses Dokument berücksichtigt keine Produkte, die als Holzkohle oder Holzkohleprodukte vermarktet werden. Bezüglich dieser Produkte siehe ISO 17225 1:2021, Tabelle 14.
ANMERKUNG   Mit biogenen Festbrennstoffen verbundene Aspekte hinsichtlich Gesundheit, Sicherheit und Umwelt sind wichtig und bedürfen besonderer Aufmerksamkeit; sie fallen jedoch nicht in den Anwendungsbereich dieses Dokuments.
Dieses Dokument legt die qualitätsbezogenen Brennstoffklassen und  spezifikationen für klassifizierte gepresste biogene Festbrennstoffe, hergestellt aus thermisch behandelter Biomasse, für gewerbliche Verwendung und industrielle Verwendung fest. Dieses Dokument umfasst Pellets und Briketts, die aus folgenden Rohmaterialien hergestellt wurden (siehe ISO 17225 1:2021, Tabelle 1):
   holzartige Biomasse;
   halmgutartige Biomasse;
   Biomasse von Früchten;
   aquatische Biomasse;
   definierte und undefinierte Mischungen.
Unterkategorien dieser Rohmaterialien sind eingeschlossen.
Dieses Dokument berücksichtigt keine Produkte, die als Holzkohle oder Holzkohleprodukte vermarktet werden. Bezüglich dieser Produkte siehe ISO 17225 1:2021, Tabelle 14.
ANMERKUNG   Mit biogenen Festbrennstoffen verbundene Aspekte hinsichtlich Gesundheit, Sicherheit und Umwelt sind wichtig und bedürfen besonderer Aufmerksamkeit; sie fallen jedoch nicht in den Anwendungsbereich dieses Dokuments.

Biocombustibles solides - Classes et spécifications des combustibles - Partie 8: Combustibles de biomasses traitées thermiquement et densifiées en vue d'une utilisation commerciale et industrielle (ISO 17225-8:2023)

Le présent document détermine les classes de qualité des combustibles et les spécifications des classes de biocombustibles solides densifiés produits à partir de biomasses traitées thermiquement en vue d'une application commerciale et utilisation industrielle. Le présent document traite des granulés et des briquettes produits à partir des matières premières suivantes (voir l'ISO 17225‑1:2021, Tableau 1):
—    biomasse ligneuse;
—    biomasse herbacée;
—    biomasse fruitière;
—    biomasse aquatique;
—    assortiments et mélanges.
Les sous-catégories de ces matières premières sont incluses.
Le présent document ne prend pas en compte les produits commercialisés sous forme de charbon de bois ou de produits à base de charbon de bois. Pour de tels produits, voir l'ISO 17225‑1:2021, Tableau 14.
NOTE      Les questions de santé, de sécurité et d'environnement concernant les biocombustibles solides sont importantes et nécessitent une attention particulière; toutefois, elles ne relèvent pas du domaine d'application du présent document.

Trdna biogoriva - Specifikacije goriv in razredi - 8. del: Sortirana termično obdelana in zgoščena goriva iz biomase za komercialno in industrijsko uporabo (ISO 17225-8:2023)

Ta dokument določa kakovostne razrede goriva in specifikacije razvrščenih zgoščenih trdnih biogoriv, izdelanih iz toplotno obdelane biomase, za komercialno in industrijsko uporabo. Toplotna obdelava vključuje postopke, kot so praženje, parna eksplozija, hidrotermalna karbonizacija in oglenenje, pri vseh pa gre za različno izpostavljenost vročini, kisiku, pari ali vodi. Ta dokument zajema pelete in brikete, izdelane iz naslednjih surovin (glej preglednico 1 iz standarda ISO 17225-1):
–   1. Lesna biomasa;
–   2. Zelnata biomasa;
–   3. Sadna biomasa;
–   4. Vodna biomasa;
–   5. Mešanice in zmesi.
Vključene so tudi podkategorije zgoraj navedenih surovin.
Ta dokument ne obravnava izdelkov, ki se jih trži kot oglje ali izdelke za pridobivanje oglja. Za te izdelke se uporablja preglednica 14 iz standarda ISO 17225-1.

General Information

• Status: Published
• Publication Date: 04-Apr-2023
• ICS: 27.190 - Biological sources and alternative sources of energy
• ICS: 75.160.40 - Biofuels
• Technical Committee: CEN/TC 335 - Solid biofuels
• Drafting Committee: CEN/TC 335 - Solid biofuels
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 05-Apr-2023
• Due Date: 15-Aug-2024
• Completion Date: 05-Apr-2023
• Ref Project: SIST EN ISO 17225-8:2023 - Solid biofuels - Fuel specifications and classes - Part 8: Graded thermally treated and densified biomass fuels for commercial and industrial use (ISO 17225-8:2023)

Overview

EN ISO 17225-8:2023 - "Solid biofuels - Fuel specifications and classes - Part 8" defines fuel quality classes and specifications for graded thermally treated and densified biomass fuels intended for commercial and industrial use. The standard covers pellets and briquettes made from woody, herbaceous, fruit, aquatic biomass and blends, and addresses thermally treated processes such as torrefaction, steam explosion, hydrothermal carbonization and charring. Charcoal products are excluded. The document is the 2023 ISO edition adopted by CEN and replaces previous technical specifications.

Key topics and technical requirements

• Fuel classes and specification principles for densified, thermally treated biomass (pellets and briquettes).
• Raw material categories covered: woody, herbaceous, fruit, aquatic biomass, plus blends and subcategories.
• Thermal treatment defined (chemical composition changed by heat; drying alone is not thermal treatment).
• Testing and measurement methods referenced (normative references): calorific value, moisture determination, ash content, elemental analysis (C/H/N, S/Cl), minor elements, bulk density, pellet length/diameter, mechanical durability, fines content and sampling procedures (e.g., ISO 18125, ISO 18134, ISO 18122, ISO 16948, ISO 17828, ISO 17829, ISO 17831, ISO 5370, ISO 18135).
• Specification support tools: Annex A provides a template for product specification; Annex B gives reference values for expressing threshold limits in terms of energy.
• Quality thresholds in the standard are expressed in terms of energy content (calorific basis).
• Important note: health, safety and environmental issues are recognized as important but are outside the scope of this part.

Applications and who uses it

• Manufacturers of thermally treated pellets and briquettes use the standard to define product quality and label fuels for commercial/industrial markets.
• Fuel traders and procurement teams rely on EN ISO 17225-8:2023 to specify and verify fuel quality in contracts.
• Plant operators and equipment manufacturers use the classifications to ensure compatibility (the standard advises usage only in plants with manufacturer approval).
• Testing laboratories and conformity assessors apply the referenced ISO test methods to verify compliance.
• Regulators and standardization bodies use it to harmonize trade, reporting and permitting for thermally treated densified biomass fuels.

Related standards

• ISO 17225-1:2021 (general requirements and classification principles) - recommended to be used in conjunction with Part 8.
• Normative test standards listed in Part 8 (ISO 18125, ISO 18134, ISO 18122, ISO 16948, ISO 17831, etc.) for measurement methods.

Keywords: EN ISO 17225-8:2023, thermally treated biomass, densified biomass fuels, pellets, briquettes, fuel specifications, fuel classes, torrefaction, hydrothermal carbonization, ISO 17225 series.

Standards Content (Sample)

SLOVENSKI STANDARD
01-junij-2023
Trdna biogoriva - Specifikacije goriv in razredi - 8. del: Sortirana termično
obdelana in zgoščena goriva iz biomase za komercialno in industrijsko uporabo
(ISO 17225-8:2023)
Solid biofuels - Fuel specifications and classes - Part 8: Graded thermally treated and
densified biomass fuels for commercial and industrial use (ISO 17225-8:2023)
Biogene Festbrennstoffe - Brennstoffspezifikationen und -klassen - Teil 8: Klassifizierung
von thermisch behandelten und gepressten Brennstoffen aus Biomasse für gewerbliche
und industrielle Verwendung (ISO 17225-8:2023)
Biocombustibles solides - Classes et spécifications des combustibles - Partie 8:
Combustibles de biomasses traitées thermiquement et densifiées en vue d'une utilisation
commerciale et industrielle (ISO 17225-8:2023)
Ta slovenski standard je istoveten z: EN ISO 17225-8:2023
ICS:
75.160.40 Biogoriva Biofuels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 17225-8
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2023
EUROPÄISCHE NORM
ICS 27.190; 75.160.40
English Version
Solid biofuels - Fuel specifications and classes - Part 8:
Graded thermally treated and densified biomass fuels for
commercial and industrial use (ISO 17225-8:2023)
Biocombustibles solides - Classes et spécifications des Biogene Festbrennstoffe - Brennstoffspezifikationen
combustibles - Partie 8: Combustibles de biomasses und -klassen - Teil 8: Klassifizierung von thermisch
traitées thermiquement et densifiées en vue d'une behandelten und gepressten Brennstoffen aus
utilisation commerciale et industrielle (ISO 17225- Biomasse für gewerbliche und industrielle
8:2023) Verwendung (ISO 17225-8:2023)
This European Standard was approved by CEN on 27 February 2023.

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, 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
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 17225-8:2023 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 17225-8:2023) has been prepared by Technical Committee ISO/TC 238 "Solid
biofuels" in collaboration with Technical Committee CEN/TC 335 “Solid biofuels” the secretariat of
which is held by SIS.
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 October 2023, and conflicting national standards shall
be withdrawn at the latest by October 2023.
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 17225-8:2023 has been approved by CEN as EN ISO 17225-8:2023 without any
modification.
INTERNATIONAL ISO
STANDARD 17225-8
First edition
2023-03
Solid biofuels — Fuel specifications
and classes —
Part 8:
Graded thermally treated and
densified biomass fuels for
commercial and industrial use
Biocombustibles solides — Classes et spécifications des
combustibles —
Partie 8: Combustibles de biomasses traitées thermiquement et
densifiées en vue d'une utilisation commerciale et industrielle
Reference number
ISO 17225-8:2023(E)
ISO 17225-8:2023(E)
© ISO 2023
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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO 17225-8:2023(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols and abbreviated terms.3
5 Specification of graded pellets and briquettes produced by thermal processing .4
Annex A (normative) Template for specification of densified and non-densified biomass
fuels produced by thermal processing .13
Annex B (informative) Reference values for the calculation of the limit values in terms of
energy .15
Bibliography .17
iii
ISO 17225-8:2023(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 238, Solid biofuels, in collaboration with
the European Committee for Standardization (CEN) Technical Committee CEN/TC 335, Solid biofuels, in
accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This first edition cancels and replaces the first edition (ISO/TS 17225-8:2016), which has been
technically revised.
The main changes are as follows:
— raw material basis enlarged;
— Tables 1 to 6 merged into Tables 1 to 3, to be used for pellets and briquettes;
— table for thermally treated woody biomass split in two tables (Table 1 and Table 2);
— threshold values for Tables 1 to 3 stated in terms of energy;
— Annex A has been introduced to support product specification;
— Annex B has been introduced to support the calculation of the limit values in terms of energy given
in Tables 1 to 3.
A list of all parts in the ISO 17225 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
ISO 17225-8:2023(E)
Introduction
The objective of this document is to provide unambiguous and clear classification principles for solid
biofuels, to serve as a tool, to enable efficient trading of biofuels, to enable good understanding between
seller and buyer as well as to serve as a tool for communication with equipment manufacturers. It will
also facilitate legal permission procedures and reporting.
This document supports the use of thermally treated and densified biomass in commercial and
industrial energy generation applications and in industrial processes, which require classified quality.
Thermal treatment includes processes such as torrefaction, steam explosion, hydrothermal
carbonization and charring, all of which represent different exposure to heat, oxygen, steam or water.
Thermally treated and densified biomass fuels should only be used in plants with manufacturer
approval.
For individual contracts, ISO 17225-1 can be used. ISO 17225-1 can also be used for specification of
charcoal.
Although this document may be used separately, a general understanding of the standards based on
and supporting ISO 17225-1 is required. It is recommended that ISO 17225-1 is used in conjunction
with this document.
v
INTERNATIONAL STANDARD ISO 17225-8:2023(E)
Solid biofuels — Fuel specifications and classes —
Part 8:
Graded thermally treated and densified biomass fuels for
commercial and industrial use
1 Scope
This document determines the fuel quality classes and specifications of graded densified solid
biofuels produced from thermally treated biomass for commercial applications and industrial
use. This document covers pellets and briquettes produced from the following raw materials (see
ISO 17225-1:2021, Table 1):
— woody biomass;
— herbaceous biomass;
— fruit biomass;
— aquatic biomass;
— blends and mixtures.
Subcategories of these raw materials are included.
This document does not consider products which are marketed as charcoal or as charcoal products. For
these products, see ISO 17225-1:2021, Table 14.
NOTE Health, safety and environmental issues for solid biofuels are important and need special attention;
however, they are outside the scope of this document.
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 5370, Solid biofuels — Determination of fines content in pellets
ISO 14780, Solid biofuels — Sample preparation
ISO 16559, Solid biofuels — Vocabulary
ISO 16948, Solid biofuels — Determination of total content of carbon, hydrogen and nitrogen
ISO 16968, Solid biofuels — Determination of minor elements
ISO 16994, Solid biofuels — Determination of total content of sulfur and chlorine
ISO 17225-1:2021, Solid biofuels — Fuel specifications and classes — Part 1: General requirements
ISO 17828, Solid biofuels — Determination of bulk density
ISO 17829, Solid Biofuels — Determination of length and diameter of pellets
ISO 17225-8:2023(E)
ISO 17831-1, Solid biofuels — Determination of mechanical durability of pellets and briquettes — Part 1:
Pellets
ISO 17831-2, Solid biofuels — Determination of mechanical durability of pellets and briquettes — Part 2:
Briquettes
ISO 18122, Solid biofuels — Determination of ash content
ISO 18125, Solid biofuels — Determination of calorific value
ISO 18134-1, Solid biofuels — Determination of moisture content — Part 1: Reference method
ISO 18134-2, Solid biofuels — Determination of moisture content — Oven dry method — Part 2: Total
moisture — Simplified method
ISO 18135, Solid Biofuels — Sampling
ISO 21945, Solid biofuels — Simplified sampling method for small scale applications
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 16559 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
pellet made from thermally treated biomass
densified biofuel made from thermally treated solid biomass with or without additives usually with a
cylindrical form, random length typically 5 mm to 40 mm, diameter up to 25 mm and broken ends
EXAMPLE Torrefied biomass, steam exploded biomass, hydrothermally carbonized biomass, charred
biomass.
Note 1 to entry: Drying is not considered as thermal treatment in this definition.
Note 2 to entry: Fuel pellets which are produced by applying the thermal treatment after densification are also
included in this definition.
3.2
briquette made from thermally treated biomass
densified biofuel made with or without additives in pre-determined geometric form with at least two
dimensions (height width, and length) of more than 25 mm produced by compressing thermally treated
solid biomass
EXAMPLE Torrefied biomass, steam exploded biomass, hydrothermally carbonized biomass, charred
biomass.
Note 1 to entry: Drying is not considered as thermal treatment in this definition.
Note 2 to entry: Fuel briquettes which are produced by applying the thermal treatment after densification are
also included in this definition.
3.3
commercial application
facility that utilizes solid biofuel burning appliances or equipment that have similar fuel requirements
as residential appliances
Note 1 to entry: Commercial applications should not be confused with industrial applications, which can utilize a
much wider array of materials and have vastly different fuel requirements.
ISO 17225-8:2023(E)
[SOURCE: ISO 17225-1:2021, 3.2]
3.4
post-immersion durability reduction
DUR
pi
measure of the drop in the durability of thermally treated biomass fuel pellets after immersion in water
Note 1 to entry: A post-immersion durability reduction value of 0 means there was no change to the durability
of the thermally treated pelletized fuel as a result of wetting, whereas, for example, a post-immersion durability
reduction value of 3 indicates that the durability dropped by three percentage points as a result of wetting.
Note 2 to entry: The test procedure is given in ISO 23343-1.
[SOURCE: ISO 23343-1:2021, 3.2, modified — Definition revised and Note 2 to entry added.]
3.5
thermally treated biomass
biomass whose chemical composition has been changed by heat (usually by temperatures of 200 °C to
300 °C and above)
3.6
thermally treated biomass grindability index
TTBGI
measure for the tendency of a fixed volume of thermally treated biomass material to produce fine
particles after grinding under defined settings and conditions
[SOURCE: ISO/TS 21596:2021, 3.3]
3.7
water sorption
W
SORP
gain or loss of water or moisture by solid biofuels through absorption and/or adsorption when exposed
to water or varying levels of humidity
[SOURCE: ISO 16559:2022, 3.216]
4 Symbols and abbreviated terms
A designation for ash content on a dry basis [g/MJ dry]
MJ
ar as received
BD designation for bulk density as received [kg/m , (loose volume)]
C fixed carbon [% in mass dry]
f
D designation for diameter as received [mm]
d dry (dry basis)
DT designation for deformation temperature of the fuel ash [°C]
DU designation for mechanical durability as received [% in mass]
DUR designation for post-immersion durability reduction [% in mass]
pi
F designation for amount of fines (<3,15 mm) as received [% in mass]
F0.5 designation for amount of fines below 0,5 mm as received [% in mass]
ISO 17225-8:2023(E)
FT designation for flow temperature of the fuel ash [°C]
HT designation for hemisphere temperature of the fuel ash [°C]
L designation for length as received [mm]
M designation for moisture as received on a wet basis, M [% in mass]
ar
Q designation for net calorific value as received, q [MJ/kg, GJ/t, kWh/kg or MWh/t]
p,net,ar
at constant pressure
Q designation for net calorific value on a dry basis, q [MJ/kg or GJ/t or kWh/kg or
d p,net,d
MWh/t] at constant pressure
SST designation for shrinkage starting temperature of the fuel ash [°C]
TTBGI thermally treated biomass grindability index [% in mass]
VM volatile matter on a dry basis [% in mass dry]
W water sorption [% in mass]
SORP
NOTE 1 1 MJ/kg equals 0,277 8 kWh/kg (1 kWh/kg equals 1 MWh/t and 1 MWh/t equals 3,6 MJ/kg). 1 g/cm
equals 1 kg/dm . 1 mg/kg equals 0,000 1 %.
NOTE 2 Designation symbols are used with a number to specify property levels in Tables 1 to 3 and Annex A.
For designation of chemical properties, chemical symbols such as S (sulfur), Cl (chlorine), N (nitrogen) and C
(carbon) are used and the property class is added at the end of the symbol. Values of ash content and chemical
properties (N, S, Cl, As, Cd, Cr, Cu, Pb, Hg, Ni and Zn) are given in g/MJ or mg/MJ, both on a dry basis, with the
index MJ (e.g. S ).
MJ
5 Specification of graded pellets and briquettes produced by thermal processing
Property classes of graded densified biomass fuels produced by thermal processing of chemically
untreated woody biomass, chemically untreated and/or chemically treated woody biomass and non-
woody biomass are listed in Tables 1, 2 and 3, respectively. If a densified biomass fuel produced by
thermal processing cannot be classified according to Table 1, 2 or 3, a specification shall be done
according to Annex A.
The specification of pellets made from thermally treated biomass is stated in accordance with Tables 1
to 3 and Figure 1, while briquettes made from thermally treated biomass are specified in accordance
with Tables 1 to 3 and Figure 2. If other traded forms are used, the main dimensions (e.g. height, width,
length) shall be stated.
Key
D diameter
L length
Figure 1 — Dimensions of pellets
ISO 17225-8:2023(E)
Key
D diameter
L length
L width
L height
Figure 2 — Shapes and dimensions of briquettes
Sampling and sample preparation shall be done according to ISO 18135 or ISO 21945 and ISO 14780,
respectively. Analyses of the properties shall be carried out in accordance with the appropriate
standard, i.e. ISO 5370, ISO 16948, ISO 16968, ISO 16994, ISO 17828, ISO 17829, ISO 17831-1,
ISO 17831-2, ISO 18122, ISO 18125, ISO 18134-1, and ISO 18134-2. For specification of the origin and
source, ISO 17225-1 shall be applied.
If data for chemical or physical properties are available, further analysis may not be required.
To ensure resources are used appropriately and the declaration is accurate, use the most appropriate
measure as follows:
a) using previous measured values or experience of the same raw material;
b) calculation of properties, for example using typical values and considering generally accepted and
documented specific values;
c) carrying out analysis:
1) with simplified methods, if available;
2) with reference methods.
The responsibility of the producer or supplier to provide correct and accurate information is exactly
the same whether laboratory analysis is performed or not. Typical values do not release the producer or
supplier from providing accurate and reliable information.
ISO 17225-8:2023(E)
To assign a fuel to a property class, all properties listed as normative in Table 1, 2 and 3 as well as
Table A.1 shall be determined. The determination of properties listed as informative is recommended.
The classes of mechanical, physical and chemical properties shall be stated when leaving the final point
of loading for delivery to the end user. Between the factory gates and the end user, distributors shall
take appropriate measures to maintain the stated level of fines. The quality class according to Table 1,
Table 2, Table 3 or the specification according to Table A.1 shall be given in the product declaration.
Ash content and concentration of chemical elements N, S, Cl, As, Cd, Cr, Cu, Pb, Hg, Ni and Zn are
influenced by thermal processing and shall be stated in terms of energy with the units g/MJ or mg/MJ
(dry), respectively. To calculate the unit mg/MJ from mg/kg, the concentration of chemical elements
(mg/kg on a dry basis) shall be divided by the net calorific value (Q , MJ/kg on a dry basis). Values in
d
percentage mass (dry) shall be additionally multiplied by 10 to obtain values in g/MJ (dry). The reference
values used for the calculation of the normative limit values in terms of energy are listed in Annex B.
In any analytical report or product declaration, values shall be stated additionally in terms of mass (in
mg/kg d
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