Solid biofuels - Determination of fines content in pellets (ISO 5370:2023)

This document specifies a method for determining the amount of material passing through a sieve with 3,15-mm-diameter round holes. It is intended for use in all applications (e.g. laboratories, production sites, field locations) where the measurement of fines is required.

Biogene Festbrennstoffe - Bestimmung des Gehaltes an Feingut in Pellets (ISO 5370:2023)

Dieses Dokument legt ein Verfahren zur Bestimmung der Materialmenge fest, die ein Rundlochsieb mit einer Lochweite von 3,15 mm Durchmesser passiert. Es ist für alle Einsatzbereiche (z. B. Laboratorien, Produktionsstätten, Feldstandorte) vorgesehen, bei denen die Messung des Feinanteils erforderlich ist.

Biocombustibles solides - Détermination de la teneur en fines des granulés (ISO 5370:2023)

Le présent document spécifie une méthode pour la détermination de la quantité de matériau passant à travers un tamis à trous ronds de 3,15 mm de diamètre. Il est destiné à être utilisé dans toutes les applications (par exemple: laboratoires, sites de production, emplacements sur le terrain) où la mesure des fines est requise.

Trdna biogoriva - Določanje vsebnosti drobnih snovi v peletih (ISO 5370:2023)

General Information

Status
Published
Publication Date
30-May-2023
Technical Committee
Drafting Committee
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Start Date
15-Feb-2023
Due Date
15-Apr-2023
Completion Date
15-Feb-2023

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Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 5370:2023
01-april-2023
Trdna biogoriva - Določanje vsebnosti drobnih snovi v peletih (ISO 5370:2023)
Solid biofuels - Determination of fines content in pellets (ISO 5370:2023)
Biogene Festbrennstoffe - Bestimmung des Gehaltes an Feingut in Pellets (ISO
5370:2023)
Biocombustibles solides - Détermination de la teneur en fines des granulés (ISO
5370:2023)
Ta slovenski standard je istoveten z: EN ISO 5370:2023
ICS:
75.160.40 Biogoriva Biofuels
SIST EN ISO 5370:2023 en,fr,de

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

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SIST EN ISO 5370:2023
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SIST EN ISO 5370:2023
EN ISO 5370
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2023
EUROPÄISCHE NORM
ICS 27.190; 75.160.40
English Version
Solid biofuels - Determination of fines content in pellets
(ISO 5370:2023)

Biocombustibles solides - Détermination de la teneur Biogene Festbrennstoffe - Bestimmung des Gehaltes an

en fines des granulés (ISO 5370:2023) Feingut in Pellets (ISO 5370:2023)
This European Standard was approved by CEN on 17 December 2022.

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 5370:2023 E

worldwide for CEN national Members.
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SIST EN ISO 5370:2023
EN ISO 5370:2023 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 5370:2023
EN ISO 5370:2023 (E)
European foreword

This document (EN ISO 5370:2023) 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 August 2023, and conflicting national standards shall

be withdrawn at the latest by August 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 5370:2023 has been approved by CEN as EN ISO 5370:2023 without any modification.

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SIST EN ISO 5370:2023
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SIST EN ISO 5370:2023
INTERNATIONAL ISO
STANDARD 5370
First edition
2023-01
Solid biofuels — Determination of
fines content in pellets
Biocombustibles solides — Détermination de la teneur en fines des
granulés
Reference number
ISO 5370:2023(E)
© ISO 2023
---------------------- Page: 7 ----------------------
SIST EN ISO 5370:2023
ISO 5370:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© 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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2023 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 5370:2023
ISO 5370:2023(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction .................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 1

5 Apparatus .................................................................................................................................................................................................................... 2

6 Sample preparation ..........................................................................................................................................................................................3

6.1 Sample size reduction ...................................................................................................................................................................... 3

6.2 Size of the test portion ..................................................................................................................................................................... 3

7 Procedure ....................................................................................................................................................................................................................4

7.1 Preparing of the sieving equipment .................................................................................................................................... 4

7.2 Sieving ............................................................................................................................................................................................................ 4

8 Calculations ............................................................................................................................................................................................................... 5

8.1 Proportion of fines .............................................................................................................................................................................. 5

8.2 Quality control ........................................................................................................................................................................................ 5

9 Performance characteristics .................................................................................................................................................................. 5

10 Test report .................................................................................................................................................................................................................. 5

Annex A (informative) Determination of coarse pellet fines (CPF) .................................................................................... 6

Annex B (informative) Determination of fractions of fines smaller than 3,15 mm ........................................11

Annex C (informative) Performance data ...................................................................................................................................................13

Annex D (informative) Research study data ............................................................................................................................................15

Bibliography .............................................................................................................................................................................................................................18

iii
© ISO 2023 – All rights reserved
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SIST EN ISO 5370:2023
ISO 5370:2023(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).

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 2023 – All rights reserved
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SIST EN ISO 5370:2023
ISO 5370:2023(E)
Introduction

This document specifies a method for manual determination of the fines content in pellets. The fines

content is defined as the percentage in mass of material below 3,15 mm in size (measured with a round

hole perforated metal plate sieve according to ISO 3310-2). The fines content is an important parameter

since excessive amounts of fines in consignments of pellets can cause problems either in transportation

systems or during combustion, or both. It also can cause health problems if the dust is inhaled and

it increases the risk of dust explosions. Many of these problems are connected to the tendency of

stratification of fines caused by any movement of the pellets.
Annex A describes a procedure for determining the amount of coarse pellet fines

(3,15 mm ≤ CPF < 5,6 mm). The determination of the amounts of smaller fines particles, for example the

fractions < 1 mm and < 0,5 mm, is given in Annex B.

NOTE 1 The upper limit of 5,6 mm for CPF was chosen because a sieve with an aperture diameter of 5,6 mm is

the standard commercial sieve with the next-smallest aperture diameter after 6 mm, which corresponds to the

diameter of the standard pellet size. When conducting the procedure for CPF as outlined in Annex A, additional

CPF are created as a result of the sieving procedure. Test results are therefore indicative and best used for

comparative purposes rather than treated as CPF originally present in the sample.

NOTE 2 This document will replace ISO 18846.
© ISO 2023 – All rights reserved
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SIST EN ISO 5370:2023
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SIST EN ISO 5370:2023
INTERNATIONAL STANDARD ISO 5370:2023(E)
Solid biofuels — Determination of fines content in pellets
1 Scope

This document specifies a method for determining the amount of material passing through a sieve with

3,15-mm-diameter round holes. It is intended for use in all applications (e.g. laboratories, production

sites, field locations) where the measurement of fines is required.
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 3310-1, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth

ISO 3310-2, Test sieves — Technical requirements and testing — Part 2: Test sieves of perforated metal

plate
ISO 16559, Solid biofuels — Vocabulary
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
coarse pellet fines
CPF

particles with a size ranging from ≥ 3,15 mm to < 5,6 mm resulting from breakage of pellets during

production or handling

Note 1 to entry: The fraction of CPF contains all particles which pass through a sieve with 5,6-mm-diameter

round holes and which are retained on a sieve with 3,15-mm-diameter round holes (see ISO 3310-2).

4 Principle

A test portion is subjected to manual screening by means of a sieve with 3,15-mm-diameter round

holes while utilizing specific test conditions (e.g. a template is used to guide the movement of the sieve,

rotational speed is specified, the number of rotations is dependent on the nature of the material being

tested) and the mass of the material passing through the sieve is determined as a mass percentage of

the total mass of the test portion.
© ISO 2023 – All rights reserved
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SIST EN ISO 5370:2023
ISO 5370:2023(E)
5 Apparatus

5.1 Sieve template, as illustrated in Figure 1, consisting of a (14 ± 2) mm-thick wooden board with a

hole cut in the centre to receive the sieve with collecting pan, all mounted on a base panel with the same

size dimensions. The sieve template is for guiding the sieve during the screening process to ensure

consistent motion of the sieve. The inner circle should have a smooth surface to enable smooth circular

movements of the sieve with the collecting pan within the template. The template diameter is based on

a factor of 1,4 multiplied by the sieve diameter.

The diameter of the sieve and the template, the target size of the sub-portion used for a single screening

operation and the rotational speed are given in Table 1.

Table 1 — Diameter of sieve and the template, size of the sub-portion and rotational speed

Mass of sub-portion for a single
Inner diame- Approximate rota-
sieving procedure
Sieve diameter
ter of template tional speed
Recommended Range
mm r/min
g g
400 Recommended 560 500 300 to 600 80
sieve diameter
300 Alternative sieve 420 280 170 to 340 95
diameters
450 630 630 380 to 760 77
The template shall be secured to the workplace (table) by, for example, clamps.
a) Top view b) Cross-section
Key
A template, with a wooden base
B sieve
C collecting pan
D workplace, table
Figure 1 — Sieving apparatus with template

To facilitate operation, a lubricant may be used to improve the sliding properties of the collection pan in

the template, such as graphite powder or silicon lubricant. Additionally, roller tables may be used.

5.2 Circular sieve with 3,15-mm-diameter round holes, and aperture geometry in accordance

with ISO 3310-2. A sieve with a diameter of 400 mm is recommended. Other sieve diameters within

the range of 300 mm to 450 mm may be used, but it is important to make sure the sieving criteria is

adjusted for the specific sieve to be used (see Table 1). The frame of the sieve shall have a height which

allows for free movement of the sample without losing material during the sieving process.

© ISO 2023 – All rights reserved
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SIST EN ISO 5370:2023
ISO 5370:2023(E)

5.3 Sieve with 5,6-mm-diameter round holes. If coarse pellet fines (3,15 mm ≤ CPF < 5,6 mm) are

determined in accordance with Annex A, the circular sieve shall have round holes with a diameter of

5,6 mm and aperture geometry in accordance with ISO 3310-2. All other requirements are given in 5.2.

5.4 Sieves, with metal wire cloth having aperture sizes smaller than 3,15 mm. If fines fractions

smaller than 3,15 mm, for example < 1 mm or < 0,5 mm, are determined in accordance with Annex B,

the circular or rectangle sieves shall have an aperture geometry in accordance with ISO 3310-1 and

shall have a minimum effective sieve area of 250 cm .

5.5 Collecting pan, for collection of material passing through the sieve, with the same diameter as

the sieve.

5.6 Weighing container(s), of adequate size for weighing of the fractions. The collecting pan may

also be used as a weighing container.

5.7 Balance, with suitable capacity to weigh the total mass of the sample plus any container used to

hold the sample, capable of reading to the nearest 0,1 g.

5.8 Metronome or stopwatch, for confirmation of the rotational speed when performing the sieving

procedure.

NOTE Use of a simple metronome, such as a mobile phone app, has been shown to be a convenient method for

speed control.
6 Sample preparation
6.1 Sample size reduction

The laboratory sample used for the determination of the fines content shall be obtained in accordance

with ISO 18135 or ISO 21945. The sampling strategy shall be such that special provisions are taken

regarding the tendency for stratification of the fines in a consignment of pellets. For example, the

entire quantity of pellets in a bag shall be taken as the laboratory sample. Due to the special provisions

necessary regarding sampling for fines determination, the combined (raw) sample can end up being very

large. The combined sample may be divided into one or more smaller test portions using appropriate

methods of subdivision as outlined in ISO 14780 (e.g. a riffle box). For the test portion used for the

determination of fines content, the minimum mass given in 6.2 shall be considered.

NOTE In bulk handling of large volumes of pellets there is often a risk of stratification of materials in storage

bins. There is also the risk of incremental variations of fines in volumes of pellets due to batch-wise operation

during transportation by rail carriages, trucks and ocean-going vessels.
6.2 Size of the test portion

The size of the test portion shall be selected in relation to pellet diameter as given in Table 2.

Table 2 — Minimum mass of test portion depending on the pellet diameter
Minimum size of a test
Pellet diameter
portion
6 to 8 3
> 8 (up to 25) 5
© ISO 2023 – All rights reserved
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SIST EN ISO 5370:2023
ISO 5370:2023(E)
7 Procedure
7.1 Preparing of the sieving equipment

The template shall be placed on a table or work bench as shown in Figure 1. It shall be fixed, for example

with clamps, to ensure regular circular movements of the combination of sieve and collecting pan.

The sieve is placed on top of the collecting pan and together they are placed inside the template against

the edge.

This sieving procedure is based on the use of a 400-mm-diameter sieve and a template of 560 mm inner

diameter. When using a sieve with another size, the appropriate template shall be used.

7.2 Sieving
Weigh the test portion to the nearest 0,1 g and record the mass.

Place a first sub-portion on the sieve. The target mass of the sub-portion is 500 g but it is also permitted

to use a mass within the range given in Table 1. If a sieve with another diameter is being used, see

Table 1 for the size of sub-portions.

Sieve the sub-portion using circular rotations within the template at a rate of approximately 80 rotations

per minute (r/min). At this speed (10 ± ¼) rotations will take approximately 7,5 s and (20 ± ¼) rotations

will take approximately 15 s. Technicians performing the test procedure the first time should adjust

their rotational speed in pre-tests using a stopwatch or a metronome. Rotational speed can also be

checked from time to time using the stopwatch or the metronome. For other sieve sizes, an appropriate

rotational speed shall be used; values for sieves with a diameter of 300 mm and of 450 mm are given in

Table 1. In all cases, the rotational speed should be sufficient to maintain most of the pellets in motion.

Sieve rotations can be either clockwise or anticlockwise.

Empirical data for the sieving speed using sieves with a diameter of 400 mm and of 300 mm are given

in Annex D.

The total number of rotations will depend on the nature of the material being sieved and is given in

Table 3. The number of rotations will remain the same regardless of the sieve diameter being used.

Table 3 — Number of rotations for sieving procedure
Pellets to be sieved Number of rotations
Pellets made for residential or commercial use where
compliance limits for fines content is 1,0 % in mass 10 ± ¼
or less
Pellets made for commercial or industrial use where
20 ± ¼
compliance limits for fines content is > 1 % in mass

After completing the sieving of the sub-portion, transfer the coarse material retained on the sieve

to another container. The fines fraction can be left inside the collecting pan or, if desired, can be

transferred to a weighing container. Place the sieve back on the collecting pan, place both the collecting

pan and the sieve back into the template against the edge and place the next sub-portion on the sieve.

Repeat this sieving process until all sub-portions have been screened for fines.

Once the whole test-portion has been sieved, weigh the cumulated fines fraction (either in the tared

weighed collecting pan or in a separate weighing container) to the nearest 0,1 g. For quality control,

also weigh the cumulated coarse material that was retained on the sieve.

NOTE 1 The maximum mass of 600 g of a sub-portion allows the subsequent use of the sub-portion for the

determination of durability according to ISO 17831-1.
© ISO 2023 – All rights reserved
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SIST EN ISO 5370:2023
ISO 5370:2023(E)

NOTE 2 Sieving of pellets with low durability leads to formation of fines due to abrasion during sieving. The

tendency of an over-estimation of the fines content increases with decreasing mechanical durability of the

pellets.
8 Calculations
8.1 Proportion of fines

Calculate the percentage in mass of fines by dividing the mass of the cumulated fines fraction by the

mass of the test portion used for the sieving procedure and multiply by 100.
The result shall be given to the nearest 0,1 % in mass for reporting.
8.2 Quality control

Calculate the difference between the mass of the test portion and the total mass of the cumulated fines

fraction and the cumulated coarse material that was retained on the sieve and express the difference

in per cent of the mass of the test portion. If the difference is larger than 2 % in mass, the causes for the

deviation shall be investigated and the determination shall be repeated with a new test portion. If the

difference after repeated determination still exceeds 2 % of the mass of the test portion, the size of the

test portion and the difference in percentage mass shall be reported together with the fines content as

per 8.1.

If the amount of CPF is determined according to Annex A from the sample used in 7.2, then the mass of

cumulated CPF and the mass of cumulated coarse material that was retained on the sieve with 5,6-mm-

diameter round holes can be calculated as a sum and used instead of cumulated coarse material

retained on the sieve during the initial screening.
9 Performance characteristics

The achievable performance of the method is given in Annex C, showing the results obtained by an

international laboratory comparison study carried out on two industrial samples of 6-mm-diameter

pellets with different amounts of added fines and different mechanical durability.

Additional information about the recovery of fines, CPF and fines smaller than 3,15 mm depending on

the number of rotational movements are given in Annex D.
10 Test report
The test report shall include at least the following information:

a) the identification of the laboratory performing the test and the date of the test;

b) the identification of product (or sample) tested;
c) a reference to this document, i.e. ISO 5370:2023;
d) the mass of the test portion (as per 7.2);
e) the result of the test on an as-received basis as indicated in 8.1;

f) the difference between the mass of the test portion and the total mass of all fractions, in per cent of

the mass of the test portion if the difference exceeds a mass fraction of 2 %;

g) any unusual features noted during the determination, which can affect the result;

h) any deviation from this document, or operations regarded as optional.
© ISO 2023 – All rights reserved
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SIST EN ISO 5370:2023
ISO 5370:2023(E)
Annex A
(informative)
Determination of coarse pellet fines (CPF)
A.1 Procedure for the determination of CPF

When the analysis of coarse pellet fines (3,15 mm ≤ CPF < 5,6 mm) is desired the pellets are screened

using the principles outlined in this document with a sieve with 5,6-mm-diameter round holes having

an aperture geometry in accordance with ISO 3310-2. A 400-mm-diameter test sieve is recommended.

Other sieve sizes with a minimum diameter of 300 mm may be use but it is important to make sure the

sieving criteria is adjusted for the specific sieve size used as referenced in this document. For example,

template size and rotational speed need to be adjusted as well as the maximum amount of material

that can be placed on the sieve. It should be noted that sieving pellets in this fashion causes significant

amounts of new fines and CPF to be created. It is therefore important to note that the determination

of CPF needs to be conducted after the fines content has been determined and that test results are

considered indicative and best used for comparative purposes rather than treated as CPF originally

present in the sample. The determination of the amount of CPF should be conducted in conjunction with

the fines determination using the following procedure (see also Figure A.1).
Key
1 3,15 mm sieve
2 collecting pan; fines
...

SLOVENSKI STANDARD
oSIST prEN ISO 5370:2022
01-april-2022

Trdna biogoriva - Določanje vsebnosti drobnih snovi v peletih (ISO/DIS 5370:2022)

Solid biofuels - Determination of fines content in pellets (ISO/DIS 5370:2022)

Biogene Festbrennstoffe - Bestimmung des Gehaltes von Feingut in Pellets (ISO/DIS

5370:2022)
Ta slovenski standard je istoveten z: prEN ISO 5370
ICS:
75.160.40 Biogoriva Biofuels
oSIST prEN ISO 5370:2022 en,fr,de

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

---------------------- Page: 1 ----------------------
oSIST prEN ISO 5370:2022
---------------------- Page: 2 ----------------------
oSIST prEN ISO 5370:2022
DRAFT INTERNATIONAL STANDARD
ISO/DIS 5370
ISO/TC 238 Secretariat: SIS
Voting begins on: Voting terminates on:
2022-02-01 2022-04-26
Solid biofuels — Determination of fines content in pellets.
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 5370:2022(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
---------------------- Page: 3 ----------------------
oSIST prEN ISO 5370:2022
ISO/DIS 5370:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on

the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2022 – All rights reserved
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oSIST prEN ISO 5370:2022
ISO/DIS 5370:2022(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction .................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 1

5 Apparatus .................................................................................................................................................................................................................... 2

5.1 Sieve Template ........................................................................................................................................................................................ 2

5.2 Sieves ............................................................................................................................................................................................................... 3

5.2.1 Sieve with 3,15 mm diameter round holes. ................................................................................................ 3

5.2.2 Sieve with 5,6 mm diameter round holes ..................................................................................................... 3

5.2.3 Sieves with metal wire cloth having aperture sizes smaller than 3,15 mm ................. 3

5.3 Collecting pan .......................................................................................................................................................................................... 3

5.4 Weighing container(s) ...................................................................................................................................................................... 3

5.5 Balance .......................................................................................................................................................................................................... 3

5.6 Metronome or stopwatch .............................................................................................................................................................. 3

6 Sample preparation ..........................................................................................................................................................................................3

6.1 Sample size reduction ...................................................................................................................................................................... 3

6.2 Size of the test portion ..................................................................................................................................................................... 4

7 Procedure ....................................................................................................................................................................................................................4

7.1 Preparing of the sieving equipment .................................................................................................................................... 4

7.2 Sieving ............................................................................................................................................................................................................ 4

8 Calculations ............................................................................................................................................................................................................... 5

8.1 Proportion of fines .............................................................................................................................................................................. 5

8.2 Quality control ........................................................................................................................................................................................ 5

9 Performance characteristics .................................................................................................................................................................. 5

10 Test report .................................................................................................................................................................................................................. 6

Annex A (informative) Determination of coarse pellets fines ................................................................................................. 7

Annex B (informative) Determination of fractions of fines smaller than 3,15 mm ........................................12

Annex C (informative) Performance data ...................................................................................................................................................13

Annex D (informative) Research study data ............................................................................................................................................15

Bibliography .............................................................................................................................................................................................................................18

iii
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oSIST prEN ISO 5370:2022
ISO/DIS 5370:2022(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 238, Solid biofuels.

This second edition cancels and replaces the first edition (ISO 18846:2016), which has been technically

revised.
The main changes are as follows:

— Changes in the analytical procedure to assure a more complete removal of fines (e.g. if fines are

expected to exceed 1% than additional sieving is required). It is expected that testing per ISO 5370

will result in a larger amount of fines reported than would have been reported using ISO 18846 in

certain circumstances.
— An Annex with performance data was inserted.

— An Annex with a procedure for the determination of coarse pellet fines was inserted.

— An Annex with a procedure for the determination of additional fines fractions was inserted.

— An Annex on data from a research study has been included.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
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oSIST prEN ISO 5370:2022
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Introduction

This document describes a method for manual determination of the fines content in pellets. The fines

content is defined as the percentage in mass of material below 3,15 mm in size (round hole perforated

metal plate sieve per ISO 3310-2). The fines content is an important parameter since excessive amounts

of fines in consignments of pellets can cause problems either in transportation systems or during

combustion, or both, can cause health problems if the dust is inhaled and also increases the risk for

dust explosions. Many of these problems are connected to the tendency of stratification of fines by any

movement of the pellets.

The informative Annex A describes a procedure for determining the amount of coarse pellet fines

(3,15 mm ≤ CPF < 5,6 mm). The determination of the amounts of smaller fines particles, e.g. the fractions

< 1 mm and < 0,5 mm is given in the informative Annex B.

NOTE 1 The upper limit of 5,6 mm for coarse pellet fines was chosen because the sieve with an aperture size

of 5,6 mm is the standard commercial sieve with the next smaller aperture size than 6 mm, which corresponds

to the diameter of the standard pellet size. When conducting the procedure for coarse pellet fines as outlined

in Annex A, additional coarse pellet fines are created as a result of the sieving procedure. Test results should

therefore be considered indicative and best used for comparative purposes rather than treated as empirical

values.
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oSIST prEN ISO 5370:2022
DRAFT INTERNATIONAL STANDARD ISO/DIS 5370:2022(E)
Solid biofuels — Determination of fines content in pellets.
1 Scope

This document specifies a method for determining the amount of material passing through a sieve with

3,15 mm diameter round holes. It is intended for use in all applications (e.g. laboratories, production

sites, field locations) where the measurement of fines is required.
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 3310-2, Test sieves — Technical requirements and testing — Part 2: Test sieves of perforated metal

plate
ISO 14780, Solid biofuels — Sample preparation
ISO 16559, Solid biofuels — Terminology, definitions and descriptions
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 terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
coarse pellet fines

particles with a size ranging from ≥ 3,15 mm to < 5,6 mm resulting from breakage of pellets during

production or handling

Note 1 to entry: The fraction of coarse pellet fines contains all particles which pass through a sieve with an

aperture size of 5,6 mm round holes and which are retained on a sieve with an aperture size of 3,15 mm round

holes (ISO 3310-2).
4 Principle

A test portion is subjected to manual screening by means of a sieve with 3,15 mm diameter round holes

while utilizing specific test conditions (e.g. a template is used to guide the sieving process, rotational

speed is specified, number of rotations is dependent on the nature of the material being tested, etc.) and

the mass of the material passing through the sieve is determined as a weight percentage of the total

mass of the test portion.
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5 Apparatus
5.1 Sieve Template

Sieve Template, as illustrated in Figure 1, consisting of a (14 ± 2) mm thick wooden board with a hole

cut in the centre to receive the sieve with collecting pan, all mounted on a base panel with the same

size dimensions. The sieve template is for guiding the sieve during the screening process to assure

consistent motion of the sieve. The inner circle should have a smooth surface to enable smooth circular

movements of the sieve with collecting pan within the template. Template size (inner diameter) is based

on a factor of 1,4 multiplied by the sieve diameter.

The size of the sieve and the template, the target size of the sub-portion used for a single screening

operation and the rotational speed are given in Table 1.

Table 1 — Size of sieve and the template, size of the sub-portion and rotational speed

Mass of sub-portion
Inner diameter Approximate ro-
Sieve size
of template tational speed
Recommended Minimum/maximum
(mm)
(mm) (rpm)
(g) (g)
Recommended sieve size
400 560 500 300 -600 80
Alternative sieve sizes
300 420 280 170 - 340 95
450 630 630 380 - 760 77
The template shall be secured to the workplace (table), e.g. by clamps.
a) b)
Key
A Template, with a wooden base
B Sieve
C Collecting pan
D Workplace, Table
Figure 1 — Sieving apparatus with template: Top view (a) and front view (b)

NOTE For an easy operation a lubricant may be used to improve sliding properties of the collection pan in

the template e.g. graphite powder or silicon lubricant. Additionally, roller tables could be used.

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5.2 Sieves
5.2.1 Sieve with 3,15 mm diameter round holes.

A circular sieve which shall have round holes with a diameter of 3,15 mm and aperture geometry in

accordance with ISO 3310-2.

A sieve with a diameter of 400 mm is recommended. Other sieve diameters within the range from

300 mm to 450 mm may be used, but it is important to make sure the sieving criteria is adjusted for the

specific sieve to be used (see Table 1). The frame of the sieve shall have a height which allows for free

movement of the sample without losing material during the sieving process.
5.2.2 Sieve with 5,6 mm diameter round holes

If coarse pellet fines (3,15 mm ≤ CPF < 5,6 mm) are determined in accordance with informative

Annex A, the circular sieve shall have round holes with a diameter of 5,6 mm and aperture geometry in

accordance with ISO 3310-2. All other requirements are given in 5.1.1.
5.2.3 Sieves with metal wire cloth having aperture sizes smaller than 3,15 mm

If fines fractions smaller than 3,15 mm, e.g. < 1 mm or < 0,5 mm, are determined in accordance with

informative Annex B, the circular or rectangle sieves shall have an aperture geometry in accordance

with ISO 3310-1 and shall have a minimum effective sieve area of 250 cm .
5.3 Collecting pan

Collecting pan, for collection of material passing through the sieve, a collecting pan with the same

diameter as the sieve is required.
5.4 Weighing container(s)

Weighing container(s)of adequate size for weighing of the fractions. The collecting pan may also be

used as weighing container.
5.5 Balance

The balance shall have suitable capacity to weigh the total mass of the sample plus any container used

to hold the sample and shall be capable of reading to the nearest 0,1 g.
5.6 Metronome or stopwatch

Metronome or stopwatch, for confirmation of the rotational speed when performing the sieving

procedure.

NOTE Use of a simple metronome, e.g. mobile phone app, has shown to be a convenient method for speed

control.
6 Sample preparation
6.1 Sample size reduction

The laboratory sample used for the determination of the fines content shall be obtained in accordance

with ISO 18135 or ISO 21945. The sampling strategy shall be such that special provisions are taken

regarding the tendency for stratification of the fines in a consignment of pellets. For example, the

entire quantity of pellets in a bag shall be taken as the laboratory sample. Due to the special provisions

necessary regarding sampling for fines determination, the combined (raw) sample can end up being

very large. The combined sample may be divided into one or more smaller test portion using appropriate

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methods of sub-division as outlined in ISO 14780 (e.g. a riffle box). For the test portion used for the

determination of fines content the minimum mass given in 6.2 shall be considered.

NOTE In bulk handling of large volumes of pellets, there is often a risk for stratification of materials in

storage bins. There is also the risk of incremental variations of fines in volumes of pellets due to batch-wise

operation during transportation with rail cars, trucks and ocean-going vessels.
6.2 Size of the test portion

The size of the test portion shall be selected in relation to pellet diameter as given in Table 2.

Table 2 — Size of sieve and the template, size of the sub-portion and rotational speed

Minimum size of a test
Pellet diameter
portion
6 to 8 3
> 8 (up to 25) 5
7 Procedure
7.1 Preparing of the sieving equipment

The template must be placed on a table or work bench as shown in Figure 1. It shall be fixed, e.g. by

clamps, to ensure regular circular movements of the combination of sieve and collecting pan.

Place the sieve on top of the collecting pan and place both inside the template against the edge.

This sieving procedure is based on the use of a 400 mm diameter sieve and a template of 560 mm inner

diameter. When using a sieve with another size the appropriate template shall be used.

7.2 Sieving
Weigh the test portion to the nearest 0,1 g and record the weight.

Place a first sub-portion on the sieve. The target mass of the sub-portion is 500 g but it is also allowed to

use a mass within the range given in Table 1. If a sieve with another diameter is being used see Table 1

for the size of sub-portions.

Sieve the sub-portion using circular rotations within the template at a rate of approximately 80 rotations

per minute (rpm). At this speed (10 ± 1/4) rotations will take approximately 7,5 seconds and (20 ± 1/4)

rotations will take approximately 15 seconds. Technicians performing the test procedure the first time

should adjust their rotational speed in pre-tests using a stopwatch or a metronome. Rotational speed

can also be checked from time to time using the stopwatch or the metronome. For other sieve sizes, an

appropriate rotational speed shall be used, values for 300 mm and 450 mm-sieves are given in Table 1.

In all cases the rotational speed should be sufficient to maintain most of the pellets in motion. Sieve

rotations can be either clockwise or counter clockwise.

Empirical data for the sieving speed using a 400 mm sieve and a 300 mm sieve are given in the

informative Annex D.

The total number of rotations will depend on the nature of the material being sieved and is given in

Table 3. The number of rotations will remain the same regardless of the sieve diameter being used.

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Table 3 — Number of rotations for sieving procedure
Pellet to be sieved Number of rotations
Pellets made for residential/commercial markets
where compliance limits for fines content is 1.0 % in 10 ± ¼
mass or below
Pellets made for commercial or industrial markets
where compliance limits for fines content is >1 % in 20 ± ¼
mass.

After completing the sieving of the sub-portion, transfer the coarse material retained on the sieve

to another container. The fines fraction can be left inside the collecting pan or if desired it can be

transferred to a weighing container. Place the sieve back on the collecting pan, place both the collecting

pan and sieve back into the template against the edge and place the next sub-portion on the sieve.

Repeat the sieving process described above until all sub-portions have been screened for fines.

Once the whole test-portion have been sieved weigh the cumulated fines fraction (either in the tared

weighed collecting pan or in a separate weighing container) to the nearest 0,1 g. For quality control also

weigh the cumulated coarse material that was retained on the sieve.

NOTE 1 The maximum weight of 600 g of a sub-portion allows the subsequent use of the sub-portion for the

determination of durability according to ISO 17831-1.

NOTE 2 Sieving of pellets with low durability lead to formation of fines due to abrasion during sieving. The

tendency of an over-estimation of the fines content increases with decreasing mechanical durability of the

pellets.
8 Calculations
8.1 Proportion of fines

Calculate the % in mass of fines by dividing the mass of the cumulated fines fraction by the mass of the

test portion used for sieving procedure and multiply by 100.
8.2 Quality control

Calculate the difference between the mass of the test portion and the total mass of the cumulated fines

fraction and the cumulated coarse material that was retained on the sieve and express the difference

in per cent of the mass of the test portion. If the difference is larger than 2 % in mass, the causes for the

deviation shall be investigated and the determination shall be repeated with a new test portion. If the

difference after repeated determination still exceeds 2 % of the mass of the test portion, the size of the

test portion and the difference in % mass shall be reported together with the fines content as per 8.1.

Note If the amount of coarse pellet fines is determined according to Annex A from the sample used in 7.2

then the weight of cumulated coarse pellet fines and the weight of cumulated coarse material that was retained

on the 5,6 mm sieve can be calculated as a sum and used instead of cumulated coarse material retained on the

sieve during the initial screening.
9 Performance characteristics

The achievable performance of the method is given in Annex C, showing the results obtained by an

international laboratory comparison study carried out on two industrial samples of 6-mm diameter

pellets with different amounts of added fines and different mechanical durability.

Additional information about the recovery of fines, coarse pellet fines and fines smaller than 3,15 mm

depending on the number of rotational movements are given in Annex D.
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10 Test report
The test report shall include at least the following information:

a) the identification of the laboratory performing the test and the date of the test;

b) the identification of product (or sample) tested;
c) a reference to this document, i.e. ISO 5370;
d) the mass of the test portion (as per 7.2);
e) the result of the test on an as received basis;
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Annex A
(informative)
Determination of coarse pellets fines
A.1 Procedure for the determination of coarse pellet fines

When the analysis of coarse pellet fines (3,15 mm ≤ CPF < 5,6 mm) is desired the pellets are screened

using the principles outlined in this document with a 5,6 mm round hole sieve having an aperture

geometry in accordance with ISO 3310-2. A 400 mm diameter test sieve is recommended. Other sieve

sizes with a minimum diameter of 300 mm may be use but it is important to make sure the sieving

criteria is adjusted for the specific sieve size used as referenced in this document. For example,

template size and rotational speed need to be adjusted as well as the maximum amount of material

that can be placed on the sieve. It should be noted that sieving pellets in this fashion causes significant

amounts of new fines and coarse pellet fines to be created. It is therefore important to note that the

determination of coarse pellet fines must be conducted after the fines content has been determined and

that test results are considered indicative and best used for comparative purposes rather than treated

as empirical values. The determination of the amount of coarse pellet fines should be conducted in

conjunction with the fines determination using the following procedure (see also Figure A.1).

Figure A.1 — Sieving scheme for the determination of coarse pellet fines

Upon completion of sieving the test portion for fines, the material retained on the 3,15 mm sieve can

be further screened using the 5,6 mm sieve. This can be done by sieving the cumulated coarse fraction

incrementally in the same fashion as when screening on the 3,15 mm sieve or by screening each of the

sub-portions immediately after it has been screened with the 3,15 mm sieve. Sieving the cumulated

coarse fraction will be necessary if only one collection pan is available. In such cases it should be noted

that every transfer of pellets should be done with great care. Unnecessary movement of the pellets can

lead to increased amounts of fines and coarse pellet fines.

For each screening mount the 5,6 mm sieve on a collecting pan. Place the sieve with the collecting pan

inside the template against the edge and then add a sub-portion to the sieve.

Screen the sub-portion using (10 ± ¼) circular rotations within the template at a rate of approximately

80 rotations per minute (rpm). At this rate screening should be complete within approximate

...

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