Characterization of bulk materials - Determination of a size-weighted fine fraction and crystalline silica content - Part 1: General information and choice of test methods

This document specifies the requirements and choice of test method for the determination of the size-weighted fine fraction (SWFF) and the size-weighted fine fraction of crystalline silica (SWFFCS) in bulk materials.
This document gives also guidance on the preparation of the sample and determination of crystalline silica by X-ray Powder Diffractometry (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR).
NOTE    EN 17289-2 specifies a method to calculate the size-weighted fine fraction from a measured particle size distribution and assumes that the particle size distribution of the crystalline silica particles is the same as the other particles present in the bulk material. EN 17289-3 specifies a method using a liquid sedimentation technique to determine the size-weighted fine fraction of crystalline silica. Both methods are based upon a number of limitations and assumptions, which are listed in EN 17289-2 and EN 17289-3, respectively. The method in EN 17289-3 can also be used for other constituents than CS, if investigated and validated.
This document is applicable for crystalline silica containing bulk materials which have been fully investigated and validated for the evaluation of the size-weighted fine fraction and crystalline silica.

Charakterisierung von Schüttgütern - Bestimmung einer größengewichteten Feinfraktion und des Anteils an kristallinem Quarz - Teil 1: Allgemeine Information und Auswahl der Prüfverfahren

Dieses Dokument legt die Anforderungen und die Auswahl des Prüfverfahrens für die Bestimmung der größengewichteten Feinfraktion (SWFF) und der größengewichteten Feinfraktion von kristallinem Quarz (SWFFCS) in Schüttgütern fest.
Dieses Dokument gibt auch Hinweise zur Vorbereitung der Probe und zur Bestimmung von kristallinem Quarz durch Röntgenpulverdiffraktometrie (XRD) und Fourier-Transformations-Infrarotspektrometrie (FT IR).
ANMERKUNG   EN 17289-2 legt ein Verfahren zur Berechnung der größengewichteten Feinfraktion aus einer gemessenen Partikelgrößenverteilung fest und geht davon aus, dass die Partikelgrößenverteilung der kristallinen Quarzpartikel die Gleiche ist wie die der anderen Partikel im Schüttgut. EN 17289-3 legt ein Verfahren fest, bei dem eine Sedimentationstechnik in Flüssigkeit zur Bestimmung der größengewichteten Feinfraktion von kristallinem Quarz verwendet wird. Beide Verfahren basieren auf einer Reihe von Einschränkungen und Annahmen, die in EN 17289- bzw. EN 17289-3 angegeben sind. Das Verfahren nach EN 17289-3 kann auch für andere Bestandteile als CS verwendet werden, wenn diese untersucht und validiert werden.
Dieses Dokument ist für kristallinen Quarz enthaltende Schüttgüter anwendbar, die zur Bewertung der größengewichteten Feinfraktion und des kristallinen Quarzes untersucht und validiert wurden.

Caractérisation des matériaux en vrac - Détermination de la fraction fine pondérée par taille et de la teneur en silice cristalline - Partie 1 : Informations générales et choix des méthodes d’essai

Le présent document spécifie les exigences et le choix d’une méthode d’essai pour la détermination de la fraction fine pondérée par taille (SWFF) et de la fraction fine de silice cristalline pondérée par taille (SWFFCS) dans des matériaux en vrac.
Le présent document donne également des recommandations relatives à la préparation de l’échantillon et au dosage de la silice cristalline par analyse de poudre par diffraction de rayons X (XRD) et par spectroscopie infrarouge à transformée de Fourier (FT-IR).
NOTE    L’EN 17289-2 spécifie une méthode permettant de calculer la fraction fine pondérée par taille à partir d’une distribution granulométrique mesurée et part de l’hypothèse que la distribution granulométrique des particules de silice cristalline est identique à celle des autres particules présentes dans le matériau en vrac. L’EN 17289-3 spécifie une méthode utilisant une technique de sédimentation dans un liquide pour déterminer la fraction fine de silice cristalline pondérée par taille. Les deux méthodes sont fondées sur un certain nombre de limites et d’hypothèses, qui sont respectivement énumérées dans l’EN 17289-2 et l’EN 17289-3. La méthode décrite dans l’EN 17289-3 peut également être utilisée pour d’autres constituants que la silice cristalline, s’ils sont étudiés et validés.
Le présent document s’applique aux matériaux en vrac contenant de la silice cristalline, qui ont été entièrement étudiés et validés pour l’évaluation de la fraction fine pondérée par taille et de la silice cristalline.

Karakterizacija razsutih materialov - Določanje velikostno utežene fine frakcije in deleža kristaliničnega kremena - 1. del: Splošne informacije in izbira preskusnih metod

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SLOVENSKI STANDARD
SIST EN 17289-1:2021
01-februar-2021

Karakterizacija razsutih materialov - Določanje velikostno utežene fine frakcije in

deleža kristaliničnega kremena - 1. del: Splošne informacije in izbira preskusnih

metod

Characterization of bulk materials - Determination of a size-weighted fine fraction and

crystalline silica content - Part 1: General information and choice of test methods

Charakterisierung von Schüttgütern - Bestimmung einer größengewichteten Feinfraktion

und des Anteils an kristallinem Quarz - Teil 1: Allgemeine Information und Auswahl der

Prüfverfahren

Caractérisation des matériaux en vrac - Détermination de la fraction fine pondérée par

taille et de la teneur en silice cristalline - Partie 1 : Informations générales et choix des

méthodes d’essai
Ta slovenski standard je istoveten z: EN 17289-1:2020
ICS:
13.040.30 Kakovost zraka na delovnem Workplace atmospheres
mestu
SIST EN 17289-1:2021 en,fr,de

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

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SIST EN 17289-1:2021
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SIST EN 17289-1:2021
EN 17289-1
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2020
EUROPÄISCHE NORM
ICS 13.040.30
English Version
Characterization of bulk materials - Determination of a
size-weighted fine fraction and crystalline silica content -
Part 1: General information and choice of test methods

Caractérisation des matériaux en vrac - Détermination Charakterisierung von Schüttgütern - Bestimmung

de la fraction fine pondérée par taille et de la teneur en einer größengewichteten Feinfraktion und des Anteils

silice cristalline - Partie 1 : Informations générales et an kristallinem Quarz - Teil 1: Allgemeine Information

choix des méthodes d'essai und Auswahl der Prüfverfahren
This European Standard was approved by CEN on 4 October 2020.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 17289-1:2020 E

worldwide for CEN national Members.
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SIST EN 17289-1:2021
EN 17289-1:2020 (E)
Contents Page

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

Introduction .................................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 6

2 Normative references .................................................................................................................................... 6

3 Terms and definitions ................................................................................................................................... 6

4 Symbols and abbreviations ......................................................................................................................... 9

5 Test methods .................................................................................................................................................... 9

6 Guidelines for the determination of crystalline silica .................................................................... 11

6.1 Preparation of sample to be analysed .................................................................................................. 11

6.2 Sample preparation for further analysis by XRD and FT-IR ......................................................... 11

7 Test report ...................................................................................................................................................... 11

Annex A (informative) Bias and uncertainties ................................................................................................. 13

A.1 General ............................................................................................................................................................. 13

A.2 Bias between EN 481 and sedimentation SWFF probability function and influence of

density and mineral phase mass fraction ........................................................................................... 13

A.3 Uncertainty ..................................................................................................................................................... 16

Annex B (informative) Round robin test to establish a SWFF reference sample ................................. 18

B.1 General ............................................................................................................................................................. 18

B.2 Test material .................................................................................................................................................. 18

B.3 Evaluation and appraisal method .......................................................................................................... 19

B.4 Results .............................................................................................................................................................. 20

Annex C (informative) Determination of crystalline silica in bulk samples using X-Ray

diffraction (XRD) or FT-IR spectroscopy ............................................................................................. 23

C.1 General ............................................................................................................................................................. 23

C.2 Preparation of bulk samples for determination of CS using XRD ............................................... 23

C.3 Preparation of bulk samples for determination of CS using FT-IR ............................................ 26

Annex D (informative) Calculating SWFF and SWFFCS from a given particle size distribution

using a spreadsheet ..................................................................................................................................... 29

D.1 Spreadsheet setup ........................................................................................................................................ 29

D.2 Example ........................................................................................................................................................... 30

Bibliography ................................................................................................................................................................. 33

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SIST EN 17289-1:2021
EN 17289-1:2020 (E)
European foreword

This document (EN 17289-1:2020) has been prepared by Technical Committee CEN/TC 137

“Assessment of workplace exposure to chemical and biological agents”, the secretariat of which is held

by DIN.

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 June 2021, and conflicting national standards shall be

withdrawn at the latest by June 2021.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

According to the CEN-CENELEC Internal Regulations, the national standards organisations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
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SIST EN 17289-1:2021
EN 17289-1:2020 (E)
Introduction

A method was developed in the industrial minerals industry for the purpose of determining the “size-

weighted relevant fine fraction” within the bulk material. This document sets out the methods

which can be used to measure and calculate the fine fraction of the bulk material and the fine fraction

of the crystalline silica, in several types of bulk materials. This information provides additional

information to users for their risk assessment and to compare bulk materials. It has been used

in the industry and by institutes previously under the acronym SWeRF. EN 17289 (all parts) is based

on that industrial method and specifies the analytical methods to determine the difference between

materials with coarse quartz and fine quartz, for example, sands versus flour.

As further activities with the material (intentional or otherwise) can change the particle size

distribution, the size-weighted fine fraction can also change. Therefore, the method reports (in terms of

the mass fraction in the bulk material in percent) both, the total crystalline silica (CS) and the estimated

size-weighted fine fraction of CS.

Conventions as specified in EN 481 [1] can be used as input for this document. However, the output

of this document is not related to the respirable fraction and cannot be used to replace workplace

exposure measurements.

EN 17289 (all parts) specifies two procedures that can be used to estimate the size-weighted fine

fraction (SWFF) in bulk materials. It also specifies how the SWFF, once separated, can be further

analysed to measure the content of crystalline silica (SWFFCS). The method can be used for comparing

the fine fraction in different bulk samples. EN 17289 (all parts) uses the term fine fraction to indicate

that it does not analyse airborne particles, but it evaluates the proportion of particles in a bulk material

that, based on their particle size, have a potential to be respirable if they were to become airborne.

EN 17289 (all parts) also allows for the size-weighted fine fraction of crystalline silica (SWFFCS)

particles in bulk materials to be evaluated in terms of mass fraction in percent, if the fraction separated

is subsequently analysed by a suitable method.

In a comparison of similar bulk materials, in which the particle size distribution is the only variable,

the SWFF can provide useful information to guide material selection. For example, leaving all other

factors aside, a bulk material with a lower SWFF value can pose less of a risk in terms of potential

occupational exposure. For the actual exposure at the workplace, the handling etc. of the material,

will play a major role.

Concentrations of respirable dust, or respirable crystalline silica (RCS), in the workplace air, resulting

from processing and handling of bulk materials, will depend on a wide variety of factors and these

concentrations cannot be estimated using SWFF or SWFFCS values. SWFF and SWFFCS values are not

intended for workplace exposure assessments as they have no direct relationship with occupational

exposure.

The evaluation of bulk materials using SWFF is complementary to determining the dustiness according

to EN 15051-1 [2].

The difference between EN 17289 (all parts) and EN 15051-1 is that SWFF quantifies the fine fraction in

a bulk material while dustiness quantifies the respirable, thoracic and inhalable dust made airborne

from the bulk material after a specific activity (dustiness characterizes the material with relation to the

workplace atmosphere when working with the bulk material).
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SIST EN 17289-1:2021
EN 17289-1:2020 (E)

EN 17289 Characterization of bulk materials — Determination of a size-weighted fine fraction

and crystalline silica content consists of the following parts:
— Part 1: General information and choice of test methods;
— Part 2: Calculation method;
— Part 3: Sedimentation method.

NOTE This document is intended for use by laboratory experts who are familiar with FT-IR, XRD methods,

PSD measurements and other analytical procedures. It is not the intention of this document to provide instruction

in the fundamental analytical techniques.
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SIST EN 17289-1:2021
EN 17289-1:2020 (E)
1 Scope

This document specifies the requirements and choice of test method for the determination of the size-

weighted fine fraction (SWFF) and the size-weighted fine fraction of crystalline silica (SWFFCS) in bulk

materials.

This document gives also guidance on the preparation of the sample and the determination of

crystalline silica by X-ray Powder Diffractometry (XRD) and Fourier Transform Infrared Spectroscopy

(FT-IR).

NOTE EN 17289-2 specifies a method to calculate the size-weighted fine fraction from a measured particle

size distribution and assumes that the particle size distribution of the crystalline silica particles is the same as the

other particles present in the bulk material. EN 17289-3 specifies a method using a liquid sedimentation

technique to determine the size-weighted fine fraction of crystalline silica. Both methods are based upon a

number of limitations and assumptions, which are listed in EN 17289-2 and EN 17289-3, respectively. The method

in EN 17289-3 can also be used for other constituents than CS, if investigated and validated.

This document is applicable for crystalline silica containing bulk materials which have been fully

investigated and validated for the evaluation of the size-weighted fine fraction and crystalline silica.

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.

EN 1540, Workplace exposure — Terminology

EN 17289-2, Characterization of bulk materials — Determination of a size-weighted fine fraction and

crystalline silica content — Part 2: Calculation method

EN 17289-3:2020, Characterization of bulk materials — Determination of a size-weighted fine fraction

and crystalline silica content — Part 3: Sedimentation method

ISO 16258-2:2015, Workplace air — Analysis of respirable crystalline silica by X-ray diffraction — Part 2:

Method by indirect analysis
3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN 1540 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
10th–percentile particle diameter

particle diameter corresponding to 10 % of the cumulative undersize distribution (by volume or by

mass)
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SIST EN 17289-1:2021
EN 17289-1:2020 (E)
3.2
90th–percentile particle diameter

particle diameter corresponding to 90 % of the cumulative undersize distribution (by volume or by

mass)
3.3
between-samples standard deviation
standard deviation between the random samples used for homogeneity check
3.4
bulk sample
portion that is representative of the bulk material
3.5
coefficient of variation of the reproducibility

ratio of standard deviation to the mean of test results produced under reproducibility conditions,

i.e. conditions where test results are obtained with the same method on identical test items in different

laboratories with different operators using different equipment
3.6
complex refractive index

refractive index of a particle, consisting of a real and an imaginary (absorption) part

Note 1 to entry: The complex refractive index of a particle can be expressed mathematically as

nn−×i k
pp p
where
is the square root of −1;

is the positive imaginary (absorption) part of the refractive index of a particle;

is the positive real part of the refractive index of a particle
[SOURCE: ISO 13320:2020, 3.1.5, [3] modified – Note 2 to entry deleted]
3.7
crystalline silica
SiO

silicon dioxide with Si and O orientated in a fixed pattern as opposed to a nonperiodic, random

molecular arrangement defined as amorphous

Note 1 to entry: The three most common crystalline forms of silica are quartz, tridymite, and cristobalite.

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SIST EN 17289-1:2021
EN 17289-1:2020 (E)
3.8
equivalent Stokes diameter
equivalent spherical diameter

diameter of a sphere having the same rate of sedimentation and density as the particle for laminar flow

in a liquid
3.9
mass fraction of crystalline silica
mass fraction of crystalline silica in the bulk sample, in percent (%)
3.10
median particle diameter

particle diameter, where 50 % of the particles, by volume or by mass, are smaller than this diameter

and 50 % are larger
3.11
mineral phase

homogeneous substance with a well-defined set of physical and chemical properties; it defines a

uniquely identifiable mineral
3.12
particle density

ratio of the mass of particles to the volume of the particles, in which closed pores are included

in the volume while open pores and volume between particles are excluded

Note 1 to entry: Particle density is typically determined using a pycnometer and has the dimension kg/m .

3.13
size-weighted fine fraction
SWFF
SWFF

fraction of the mass of a bulk material as determined by the size and density of the particles and a well-

defined probability function, in percent (%)
3.14
size-weighted fine fraction of crystalline silica
SWFFCS
SWFFCS
fraction of the mass of crystalline silica particles in the SWFF, in percent (%)
3.15
skeletal density

mass of a unit volume of the diatomaceous earth (DE) skeleton, inaccessible to Helium

3.16
standard deviation for proficiency assessment

measure of dispersion used in the assessment of proficiency, based on the available information

[SOURCE: ISO 13528:2015, 3.4 [4]]
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SIST EN 17289-1:2021
EN 17289-1:2020 (E)
3.17
supernatant

column of liquid that is separated from the total sedimentation liquid column which contains the solid

particles of interest
Note 1 to entry: See EN 17289-3:2020, Figure A.2.
3.18
z-score

standardized measure of laboratory bias, calculated using the assigned value and the standard

deviation for proficiency assessment
[SOURCE: ISO 13528:2015, 3.7]
4 Symbols and abbreviations
CS crystalline silica
DE diatomaceous earth
LD laser diffraction
PSD particle size distribution
FT-IR Fourier transform infrared spectroscopy
MMAD mass median aerodynamic diameter
RCS respirable crystalline silica
RI refractive index
SWFF size-weighted fine fraction
SWFFCS size-weighted fine fraction of crystalline silica
XRD X-ray powder diffractometry
5 Test methods
There are two ways to determine the SWFF and SWFFCS:
a) by calculation, as specified in EN 17289-2;
b) by sedimentation in a liquid, as specified in EN 17289-3.

The calculation method requires that the aerodynamic particle size distribution of the bulk material

is known. When SWFFCS needs to be determined this is often not possible since the PSD of the CS

in the sample cannot be determined separately from the rest of the sample. The CS can be finer

or coarser than the bulk of the sample. Instead, in this case the sedimentation method shall be used

to determine the SWFFCS.

The calculation method is easier and faster to perform. This can be a reason to choose the calculation

method over the sedimentation method; the assumption is then made that the size distributions

are the same so that SWFFCS can be calculated from the PSD of the whole sample. However, this can

only be done after experiments have shown that the results are accurate and consistently equal

or higher than the results from sedimentation for that particular bulk material.
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SIST EN 17289-1:2021
EN 17289-1:2020 (E)

The sedimentation method is a good approximation for the determination of SWFF and SWFFCS.

However, when samples have a narrow size distribution and a median diameter ( d ) in the range

from 6 µm to 12 µm (aerodynamic) the method shall not be used since results will be too low.

Instead the calculation method shall be applied. This is possible because of the narrow size distribution.

In this case the difference in PSD between CS and bulk of the sample is small.

The analytical approach specified in these methods fulfils the expanded uncertainty requirements

of EN 482 [5]. Guidance on bias and uncertainties is given in Annex A.

Figure 1 gives a flowchart to assist the user in selecting the appropriate test method for the

determination of SWFF and SWFFCS. Both calculation and sedimentation methods are based

upon a number of assumptions, which are listed in EN 17289-2 and EN 17289-3, respectively.

Figure 1 — Selection of test method for SWFF and SWFFCS
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SIST EN 17289-1:2021
EN 17289-1:2020 (E)

NOTE Experiments were performed on a series of minerals in order to make recommendations on the use

of the different methods (see Annex B).
6 Guidelines for the determination of crystalline silica
6.1 Preparation of sample to be analysed

Samples shall be extracted from the bulk material using a method, which will result in a representative

sample (for example, ISO 14488 [7], BS 3406-1 [6]), respecting the limitations of the analytical methods.

6.2 Sample preparation for further analysis by XRD and FT-IR
Sample preparation is specified in Annex C using XRD and FT-IR.

The content of crystalline silica of the sample shall be determined using techniques such as X-ray

Powder Diffractometry (XRD) as specified, for example, in EN 13925-1, EN 13925-2 and EN 13925-3

[8], [9], [10] and ISO 16258-2 or Fourier Transform Infrared Spectroscopy (FT-IR) as specified in

ISO 19087 [11].

NOTE 1 The sample preparation step in EN 13925-2 is applicable for both analytical methods.

NOTE 2 All paragraphs related to sampling in ISO 16258-2 and ISO 19087 are not applicable to this document.

NOTE 3 Omotoso et al. [12] and Chipera and Bish [13] specify quantitative mineral analysis.

7 Test report
The test report shall contain at least the following information:
a) reference to this document (“EN 17289-1”);
b) date of testing;
c) identification of test facility;
d) identification of contractor or subcontractor, if applicable;
e) identification of the test method used – calculation or sedimentation method;
f) identification of the method of sampling and sample preparation used;
g) identification of samples of test materials;
h) particle density of the sample, in kilograms per cubic metre (kg/m );

i) density of the substance of interest (for example, quartz, cristobalite), in kilograms per cubic metre

(kg/m );

j) the mass fraction of the substance of interest (for example, quartz, cristobalite) in the bulk sample,

in percent (%);
k) the mass fraction of SWFF and/or SWFFCS in the bulk sample, in percent (%).

The test report shall also include specific minimum requirements for the calculation and/or

sedimentation methods as follows:
1) For the calculation method:
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SIST EN 17289-1:2021
EN 17289-1:2020 (E)

a) method of determination of PSD (for example, by laser diffraction (LD) analysis (specify wet or

dry and Mie or Fraunhofer), gravitational sedimentation method, particle time-of-flight

(TOF) method)

b) an example of a calculation sheet for determining SWFF by calculation can be found in Annex D

and on the Safe Silica website (https://safesilica.eu/safety-and-measurement/).
2) For the sedimentation method:
a) total sample mass that was dispersed, in grams [g];
b) type and volume of sedimentation liquid, in millilitres (ml);
c) temperature, density and viscosity of the liquid;
d) type of dispersants (if used);
e) method of dispersion;
f) sedimentation time, in seconds (s);
g) depth of the separated liquid column, in metres (m);
h) supernatant residue, in grams (g);
i) method of determination of substance of interest e.g. Quartz XRD or FT-IR;
j) fine fraction of CS in the supernatant, in percent (%).
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SIST EN 17289-1:2021
EN 17289-1:2020 (E)
Annex A
(informative)
Bias and uncertainties
A.1 General

As with any method of analysis there are biases and uncertainties. These are investigated in this Annex.

A.2 looks at the biases arising from the size distribution measurement and in particular: the biases

arising from the different probability functions and the issues associated with the density of

multicomponent particles. The biases arising from three scenarios of increasing complexity are

compared with the ideal powder of a single mineral phase of crystalline silica. A.3 lists the uncertainties

associated with the calculation method (EN 17289-2) and sedimentation method (EN 17289-3).

With any method of analysis representative sampling is extremely important. A recognized method or

standard should be followed. The use of the methods specified in the sampling standards referenced in

ISO 14488 and BS 3406-1, will allow the sampling uncertainty to be calculated.
A.2 Bias between EN 481 and sedimentation SWFF probability function
and influence of density and mineral phase mass fraction
A.2.1 Bias between EN 481 and sedimentation SWFF probability curve
A.2.1.1 General

This subclause specifies the theoretical comparison between the respirable sampling convention

and the SWFF probability function.

A.2.1.2 Ideal powder, one mineral phase of known density and ideal SWFF measurement

The SWFF and respirable sampling conventions have been compared theoretically for an ideal

dispersed powder and ideal SWFF measurement (without bias or uncertainties) for which the particles

have the following characteristics:
— all particles are spherical;
— all particles have an identical and known density;

— all particles (independent of size) are completely dispersed in air and test liquid, respectively;

— no particle is attached to (agglomerated with) any other particle, neither when dispersed in air

nor when dispersed in the test liquid.

The comparison was carried out by calculating a bias map of the SWFF probability function / fraction

relative to the respirable fraction for the aerodynamic mass-weighted particle size distributions

specified in EN 13205-2 [14]. For such an ideal powder and an ideal measurement, it does not matter

whether the SWFF was determined using EN 17289-2 or EN 17289-3.

For this ideal situation, the bias between the two sampling conventions is small, generally within ± 5 %

except for particles greater than 6 μm where the bias is in the range from −5 % to −20 %. This is due

to the sedimentation method not sampling particles of more than 6 μm aerodynamic diameter ( d ).

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SIST EN 17289-1:2021
EN 17289-1:2020 (E)
A.2.2 Internal SWFF sedimentation bias
A.2.2.1 General

This subclause specifies the bias between SWFF 1 sedimentation (spherical non-agglomerated particles,

one mineral phase, density of quartz mixture) and SWFF 2 sedimentation (spherical non-agglomerated

particles, two mineral phases one of them being quartz, identical mass fraction of quartz to total mass

of the particle for all particles independently of particle size).

A.2.2.2 Ideal powder, two mineral phases of known density and ideal SWFF sedimentation

measurement

The SWFF 1 and SWFF 2 have been compared theoretically for ideal dispersed powders and ideal SWFF

measurement (without bias or uncertainties) for which the particles have the following characteristics:

SWFF 1:
— all particles are spherical;
— all particles have one mineral phase;
— all particles have an identical and known density (quartz density);

— all particles (independent of size) are completely dispersed in air and test liquid, respectively;

— no particle is attached to (agglomerated with) any other particle
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