Solid biofuels - Fuel specifications and classes - Part 8: Graded thermally treated and densified biomass fuels for commercial and industrial use (ISO/FDIS 17225-8:2022)

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/FDIS 17225-8:2022)

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/FDIS 17225-8:2022)

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/FDIS 17225-8:2022)

General Information

Status
Not Published
Publication Date
04-Apr-2023
Technical Committee
Drafting Committee
Current Stage
6055 - CEN Ratification completed (DOR) - Publishing
Start Date
27-Feb-2023
Due Date
15-Jun-2024
Completion Date
27-Feb-2023

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Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN ISO 17225-8:2022
01-julij-2022
Trdna biogoriva - Specifikacije goriv in razredi - 8. del: Sortirana termično
obdelana in zgoščena goriva iz biomase za komercialno in industrijsko uporabo
(ISO/DIS 17225-8:2022)

Solid biofuels - Fuel specifications and classes - Part 8: Graded thermally treated and

densified biomass fuels for commercial and industrial use (ISO/DIS 17225-8:2022)

Biogene Festbrennstoffe - Brennstoffspezifikationen und -klassen - Teil 8: Klassifizierung

von thermisch behandelten und gepressten Brennstoffen aus Biomasse für gewerbliche

und industrielle Verwendung (ISO/DIS 17225-8:2022)
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/DIS 17225-8:2022)
Ta slovenski standard je istoveten z: prEN ISO 17225-8
ICS:
75.160.40 Biogoriva Biofuels
oSIST prEN ISO 17225-8:2022 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 17225-8:2022
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oSIST prEN ISO 17225-8:2022
DRAFT INTERNATIONAL STANDARD
ISO/DIS 17225-8
ISO/TC 238 Secretariat: SIS
Voting begins on: Voting terminates on:
2022-04-21 2022-07-14
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
ICS: 75.160.40; 27.190
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
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 17225-8:2022(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 2022
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oSIST prEN ISO 17225-8:2022
ISO/DIS 17225-8:2022(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
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Phone: +41 22 749 01 11
Email: copyright@iso.org
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Published in Switzerland
© ISO 2022 – All rights reserved
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oSIST prEN ISO 17225-8:2022
ISO/DIS 17225-8:2022(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 classification of densified and non-densified biomass

fuels produced by thermal processing ......................................................................................................................................15

Annex B (informative) Reference values for the calculation of the limit values on energy

basis ................................................................................................................................................................................................................................17

Bibliography .............................................................................................................................................................................................................................19

iii
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oSIST prEN ISO 17225-8:2022
ISO/DIS 17225-8:2022(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 238, Solid biofuels.
This document replaces ISO/TS 17225-8:2016, which has been technically revised.
The main changes compared to the previous edition are as follows:
— Raw material basis was enlarged;

— Tables 1, 2, 3, 4, 5 and 6 were merged to Table 1, 2 and 3 to be used for pellets and briquettes;

— Table for thermally treated woody biomass was divided in two tables (Table 1 and Table 2);

— Threshold values for Tables 1, 2 and 3 were changed to energy basis;
— Additional normative Annex A was introduced to support product classification.

— Additional informative Annex B was introduced to support the calculation of the limit values on

energy basis
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.
© ISO 2022 – All rights reserved
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oSIST prEN ISO 17225-8:2022
ISO/DIS 17225-8:2022(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 authority 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 to obtain and use ISO 17225-1 in conjunction

with this document.
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oSIST prEN ISO 17225-8:2022
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oSIST prEN ISO 17225-8:2022
DRAFT INTERNATIONAL STANDARD ISO/DIS 17225-8:2022(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 and industrial use. This document covers

pellets and briquettes produced from the following raw materials (see ISO 17225-1:2021, Table 1):

— 1. Woody biomass;
— 2. Herbaceous biomass;
— 3. Fruit biomass;
— 4. Aquatic biomass;
— 5. Blends and mixtures.
Subcategories of the above stated raw materials are included.

This document does not consider products, which are marketed as charcoal or as charcoal products.

For these products, ISO 17225-1:2021, Table 14 shall apply.

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 17831-1, Solid biofuels — Determination of mechanical durability of pellets and briquettes — Part 1:

Pellets
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oSIST prEN ISO 17225-8:2022
ISO/DIS 17225-8:2022(E)
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 — Oven dry method — Part 1: Total

moisture — 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
pellets 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 thermal treatment in this definition.

Note 2 to entry: Fuel pellets which are produced by applying the thermal treatment after compaction are also

included in this definition.
3.2
briquettes 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 thermal treatment in this definition.

Note 2 to entry: Fuel briquettes which are produced by applying the thermal treatment after compaction 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.
[SOURCE: ISO 17225-1:2021, 3.2]
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oSIST prEN ISO 17225-8:2022
ISO/DIS 17225-8:2022(E)
3.4
post-immersion durability reduction
DUR

measure of the drop in the durability of thermally treated biomass fuel pellets after immersion in water

according to ISO 23343-1.

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 indicate that the durability dropped by three percentage points as a result of wetting.

[SOURCE: ISO 23343-1:2021, modified]
3.5
thermally treated biomass

biomass whose chemical composition has been changed by heat (usually by temperatures of 200 to

300 °C and above)
[SOURCE: ISO 16559:2022, 3.200]
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 21596:2021]
3.7
water sorption

gain or loss of water/moisture by solid biofuels through absorption or adsorption, when exposed to

water or varying levels of humidity.
[SOURCE: ISO 23343-1:2021]
4 Symbols and abbreviated terms
A Designation for ash content on dry basis [g/MJ dry]
ar as received
BD Designation for bulk density as received [kg/m , (loose volume)]
C Fixed carbon, C [% in mass dry]
f 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]
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]
FT Designation for flow temperature of the fuel ash [°C]
© ISO 2022 – All rights reserved
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oSIST prEN ISO 17225-8:2022
ISO/DIS 17225-8:2022(E)
HT Designation for hemisphere temperature of the fuel ash [°C]
L Designation for length as received, [mm]
M Designation for moisture as received on wet basis, M [% in mass]
Q Designation for net calorific value as received, q [MJ/kg or GJ/t or kWh/kg or
p,net,ar
MWh/t] at constant pressure

Q Designation for net calorific value on 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]
S Water sorption [% in mass]

TA1, TA2 Property classes for graded densified fuels produced from non-woody biomass

TOW1, TOW2 Property classes for graded densified fuels produced from chemically untreated or

chemically treated woody biomass
TTBGI Thermally treated biomass grindability index [% in mass]

TW1, TW2 Property classes for graded densified fuels produced from chemically untreated woody

biomass
VM Volatile matter on dry basis [% in mass dry]

NOTE 1 1 MJ/kg equals 0,2 778 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 Table 1, 2, 3 and Annex A.

For designation of chemical properties, chemical symbols like S (sulfur), Cl (chlorine), N (nitrogen), 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 stated in unit g/MJ or mg/MJ both on dry basis with the index MJ

(example: S ).
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, of chemically untreated and/or chemically treated woody biomass, and

non-woody biomass are listed in Table 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 normative Annex A.

The specification of thermally treated pellets is stated in accordance with Table 1, 2 and 3, and Figure 1

while thermally treated briquettes are specified in accordance with Table 1, 2 and 3, and Figure 2. If

other traded forms are used, main dimensions (e.g. height, width, length) shall be stated.

© ISO 2022 – All rights reserved
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oSIST prEN ISO 17225-8:2022
ISO/DIS 17225-8:2022(E)
Key
D diameter
L length
Figure 1 — Dimension of pellets
Key
D diameter
L length
L width
L height or diameter for cylinder briquettes
Figure 2 — Shapes and dimensions of briquettes

Sampling (ISO 18135 or ISO 21945), sample preparation (ISO 14780) and analysis of the properties shall

be carried out in accordance with the methods listed in the normative references in Clause 2.

If data for chemical or physical properties are available, further analysis may not be required.

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oSIST prEN ISO 17225-8:2022
ISO/DIS 17225-8:2022(E)

To ensure resources are used appropriately and the declaration is accurate, use the most appropriate

measure as follows:

a) using previous measured values or obtained by experience of same raw material;

b) calculation of properties, e.g. by using typical values and considering generally accepted and

documented specific values;
c) carrying out of 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.

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 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 Table A1 shall be given in the product declaration.

Ash content as well as concentration of chemical compounds N, S, Cl, As, Cd, Cr, Cu, Pb, Hg, Ni and Zn

are influenced by thermal processing and shall be stated on energy basis with the unit g/MJ or mg/MJ

(dry), respectively. To calculate the unit mg/MJ from mg/kg, the chemical compound (mg/kg on dry

basis) shall be divided by the net calorific value (Q , MJ/kg on dry basis). Values on % in mass (dry)

basis 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 on energy basis are listed in informative Annex B. In any

analytical report or product declaration, values shall be stated additionally on mass basis (in mg/kg

dry or % in mass dry).

NOTE 1 For a sample of thermally treated pellets with a lead content of 12 mg/kg dry and a calorific value of

19 MJ/kg dry the resulting value for Pb is 0,63 mg/MJ dry and exceeds the limit value of 0,53 mg/MJ dry for

TW1. A sample with the same lead content of 12 mg/kg dry and a calorific value of 24,5 MJ/kg dry results in a

value of 0,49 mg/MJ dry and fulfils the requirement of class TW1.

NOTE 2 According to ISO 177225-1:2021, Annex D, the net calorific value (at constant pressure) on dry basis

can be calculated according to Formula (1).
100
 
qq=+0,02443×M × (1)
pn,,et dp,,netarar
 
100−M
where

q is the net calorific value (at constant pressure) as received in megajoules per kilogram

p,net,ar
(MJ/kg);

q is the net calorific value (at constant pressure) in dry matter in megajoules per kilogram

p,net,d
(MJ/kg);
M is the moisture content as received [% in mass].

0,024 43 is the correction factor of the enthalpy of vaporization (constant pressure) for water

(moisture) at 25 °C (in megajoules per kilogram (MJ/kg) per 1 % in mass of moisture).

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oSIST prEN ISO 17225-8:2022
ISO/DIS 17225-8:2022(E)

Table 1 — Specification of graded densified biomass fuels produced by thermal processing

of chemically untreated woody biomass
Master table
Property
Unit TW1 TW2
(analysis method)
Normative Origin and source 1.1 Forest, plantation and other virgin wood
(ISO 17225-1:2021, 1.2.1 Chemically untreated wood by-products and
Table 1) residues
Traded form (see
ISO 17225-1:2021, Pellets or briquettes
Table 2)
Dimensions (mm) ISO 17829
Diameter (D) and D06, 6 ± 1; D06, 6 ± 1;
Length (L) of pellets in mm D08, 8 ± 1; D08, 8 ± 1;
accordance with Figure 1 3,15 ≤ L ≤ 40 3,15 ≤ L ≤ 40
Diameter (D), Length (L)
and
mm Values to be stated
Shape of briquettes in
accordance with Figure 2
Moisture, M , % in mass as
ISO 18134-1, ISO 18134-2 received, on M08 ≤ 8 M08 ≤ 8
wet basis
Ash, A , ISO 18122 g/MJ dry A0.6 ≤ 0,6 A1.6 ≤ 1,6
Mechanical durability
to be stated for pellets
% in mass as
and for briquettes with DU97.5 ≥ 97,5 DU97.5 ≥ 97,5
received
shape 9 (Figure 2), DU,
ISO 17831-1, ISO 17831-2
Amount of fines to be
F2.0 ≤ 2,0 F4.0 ≤ 4,0
stated for pellets and for % in mass as
briquettes with shape 9 received
(value to be stated) (value to be stated)
(Figure 2), F , ISO 5370
Amount of fines below
0,5 mm to be stated for
% in mass as
pellets and for briquettes Value to be stated Value to be stated
received
with shape 9 (Figure 2),
F0.5 , ISO 5370
Additives ≤ 4 ≤ 5
% in mass as
received
(value to be stated) (value to be stated)

Negligible levels of glue, grease and other timber production additives (< 1 % in mass) used in sawmills during

production of timber and timber product from virgin wood are acceptable if all chemical parameters of the pellets are

clearly within the limits and/or concentrations are too small to be concerned with.

Selected size class D06 or D08 to be stated.

For D06 and D08, the amount of pellets longer than 40 mm may be 1 % in mass. Maximum length shall be ≤ 45 mm.

At the final point of delivery.

Type and amount of additive(s) to aid production, delivery or combustion (e.g. pressing aids, slagging inhibitors or any

other additives like starch, corn flour, potato flour, vegetable oil, lignin …)."

Fixed carbon (% in mass dry) is calculated by the following equation: 100 – (ash [% in mass dry] + volatile matter [% in

mass dry]).

Special attention should be paid to the ash melting behaviour for some thermally treated biomass fuels, e.g. produced

from eucalyptus, poplar, and short rotation coppice. It is recommended to state all characteristic temperatures (shrinkage

starting temperature (SST), deformation temperature (DT), hemisphere temperature (HT) and flow temperature (FT))

in oxidizing conditions. The default ashing according to ISO 21404 is 550 °C ± 10 °C. If alternative ashing temperature is

applied, it shall be specified.
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oSIST prEN ISO 17225-8:2022
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Table 1 (continued)
Master table
Property
Unit TW1 TW2
(analysis method)
Bulk density, BD, to be
stated for pellets and for kg/m as re-
BD650 ≥ 650 BD600 ≥ 600
briquettes with shape 9 ceived
(Figure 2), ISO 17828
Net calorific value, Q , Q20 ≥ 20
MJ/kg as re- Q19 ≥ 19
ISO 18125
ceived (value to be stated)
(value to be stated)
Nitrogen, N , ISO 16948 g/MJ dry N0.26 ≤ 0,26 N0.53 ≤ 0,53
Sulfur, S , ISO 16994 g/MJ dry S0.03 ≤ 0,03 S0.05 ≤ 0,05
Chlorine, Cl , ISO 16994 g/MJ dry Cl0.03 ≤ 0,03 Cl0.05 ≤ 0,05
Arsenic, As , ISO 16968 mg/MJ dry As0.05 ≤ 0,05 As0.11 ≤ 0,11
Cadmium, Cd ,
mg/MJ dry Cd0.03 ≤ 0,03 Cd0.05 ≤ 0,05
ISO 16968
Chromium, Cr ,
mg/MJ dry Cr0.53 ≤ 0,53 Cr0.79 ≤ 0,79
ISO 16968
Copper, Cu , ISO 16968 mg/MJ dry Cu0.53 ≤ 0,53 Cu1.05 ≤ 1,05
Lead, Pb , ISO 16968 mg/MJ dry Pb0.53 ≤ 0,53 Pb1.05 ≤ 1,05
Mercury, Hg ,
mg/MJ dry Hg0.005 ≤ 0,005 Hg0.005 ≤ 0,005
ISO 16968
Nickel, Ni , ISO 16968 mg/MJ dry Ni0.53 ≤ 0,53 Ni0.53 ≤ 0,53
Zinc, Zn , ISO 16968 mg/MJ dry Zn5.26 ≤ 5,26 Zn5.26 ≤ 5,26
Fixed carbon, C % in mass dry Value to be stated Value to be stated
Informative Total carbon, C,
% in mass dry Value should be stated Value should be stated
ISO 16948
Volatile matter, VM,
% in mass dry Value should be stated Value should be stated
ISO 18123
Ash melting behaviour SST, DT, HT and FT SST, DT, HT and FT should
, ISO 21404 should be stated be stated
Grindability index
% in mass Value should be stated Value should be stated
(TTBGI), ISO 21596
Water sorption and (S )
and post-immersion
% in mass Values should be stated Values should be stated
durability reduction
(DUR ), ISO 23343-1

Negligible levels of glue, grease and other timber production additives (< 1 % in mass) used in sawmills during

production of timber and timber product from virgin wood are acceptable if all chemical parameters of the pellets are

clearly within the limits and/or concentrations are too small to be concerned with.

Selected size class D06 or D08 to be stated.

For D06 and D08, the amount of pellets longer than 40 mm may be 1 % in mass. Maximum length shall be ≤ 45 mm.

At the final point of delivery.

Type and amount of additive(s) to aid production, delivery or combustion (e.g. pressing aids, slagging inhibitors or any

other additives like starch, corn flour, potato flour, vegetable oil, lignin …)."

Fixed carbon (% in mass dry) is calculated by the following equation: 100 – (ash [% in mass dry] + volatile matter [% in

mass dry]).

Special attention should be paid to the ash melting behaviour for some thermally treated biomass fuels, e.g. produced

from eucalyptus, poplar, and short rotation coppice. It is recommended to state all characteristic temperatures (shrinkage

starting temperature (SST), deformation temperature (DT), hemisphere temperature (HT) and flow temperature (FT))

in oxidizing conditions. The default ashing according to ISO 21404 is 550 °C ± 10 °C. If alternative ashing temperature is

applied, it shall be specified.
© ISO 2022 – All rights reserved
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oSIST prEN ISO 17225-8:2022
ISO/DIS 17225-8:2022(E)

Table 2 — Specification of graded densified biomass fuels produced by thermal processing

of chemically untreated and/or chemically treated woody biomass
Master table
Property
Unit TOW1 TOW2
(analysis method)
Normative Origin and source 1.1 Forest, plantation and other virgin wood
(ISO 17225-1:2021, 1.2 By-products and residues from wood process-
Table 1) ing industry
a, b
1.3 Used wood
Traded form (see
ISO 17225-1:2021, Pellets or briquettes
Table 2)
Dimensions (mm) ISO 17829
Diameter (D) and D06, 6 ± 1; D06, 6 ± 1;
Length (L) of pellets in D08, 8 ± 1; D08, 8 ± 1;
...

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