SIST EN 17289-1:2021

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

General Information

• Status: Published
• Public Enquiry End Date: 04-Mar-2019
• Publication Date: 11-Jan-2021
• ICS: 13.040.30 - Workplace atmospheres
• Technical Committee: KAZ - Air quality
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 05-Jan-2021
• Due Date: 12-Mar-2021
• Completion Date: 12-Jan-2021
• Ref Project: EN 17289-1:2020 - Characterization of bulk materials - Determination of a size-weighted fine fraction and crystalline silica content - Part 1: General information and choice of test methods

Overview

EN 17289-1:2020 (CEN) - Characterization of bulk materials - Determination of a size-weighted fine fraction and crystalline silica content - Part 1: General information and choice of test methods - provides the framework for assessing the size-weighted fine fraction (SWFF) and the size-weighted fine fraction of crystalline silica (SWFFCS) in bulk materials. It specifies requirements and guidance for selecting appropriate analytical approaches and gives practical advice on sample preparation and determination of crystalline silica using X‑ray Powder Diffractometry (XRD) and Fourier Transform Infrared Spectroscopy (FT‑IR).

Key topics and requirements

• Scope and applicability: Applicable to crystalline-silica-containing bulk materials that have been fully investigated and validated for SWFF/SWFFCS evaluation.
• Definitions and symbols: Clear terminology (e.g., SWFF, SWFFCS, d10/d50/d90, particle density) aligned with EN 1540 and EN 481 conventions.
• Choice of test method: Guidance for selecting calculation-based (EN 17289-2) or experimental sedimentation-based (EN 17289-3) approaches, with descriptions of underlying assumptions and limitations.
• Sample preparation: Procedures and recommendations for preparing bulk samples for XRD and FT‑IR analysis to quantify crystalline silica content in the fine fraction.
• Analytical techniques: Guidance on using XRD and FT‑IR for crystalline silica determination (reference to ISO 16258-2 where applicable).
• Quality and uncertainty: Informative annexes on bias, uncertainty estimation, round-robin testing to establish reference samples, and reproducibility considerations.
• Reporting: Required content for test reports to ensure traceability and comparability of SWFF/SWFFCS results.

Practical applications and users

• Who uses it: Laboratory analysts, occupational hygiene labs, mineral processors, construction material manufacturers, raw-material suppliers, and regulatory bodies. The standard is intended for laboratory experts familiar with PSD measurements, XRD and FT‑IR techniques.
• Use cases:
  • Compare bulk materials (e.g., sands vs. fine powders) by quantifying potential respirable-related fine mass fractions.
  • Support material selection and risk communication by providing mass-based estimates of fine crystalline-silica fractions (SWFFCS).
  • Complement dustiness testing (EN 15051‑1) and workplace monitoring, but not as a substitute for direct workplace exposure measurements or exposure risk assessments.
  • Provide validated laboratory data for product safety data sheets and supply-chain risk management.

Related standards

• EN 17289-2: Calculation method for SWFF
• EN 17289-3: Sedimentation method for SWFFCS
• EN 15051-1: Dustiness testing (complementary)
• EN 481: Conventions for particle fractions
• ISO 16258-2: XRD analysis of respirable crystalline silica

Keywords: EN 17289-1:2020, SWFF, SWFFCS, crystalline silica, bulk materials, XRD, FT‑IR, particle size distribution, sedimentation, occupational hygiene.

Standards Content (Sample)

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

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.

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
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.
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).
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.

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
d
particle diameter corresponding to 10 % of the cumulative undersize distribution (by volume or by
mass)
3.2
90th–percentile particle diameter
d
particle diameter corresponding to 90 % of the cumulative undersize distribution (by volume or by
mass)
3.3
between-samples standard deviation
S
s
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
CV
R
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
n
p
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
i
is the square root of −1;
is the positive imaginary (absorption) part of the refractive index of a particle;
k
p
is the positive real part of the refractive index of a particle
n
p
[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.
=
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
w
CS
mass fraction of crystalline silica in the bulk sample, in percent (%)
3.10
median particle diameter
d
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
w
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
w
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
σ
measure of dispersion used in the assessment of proficiency, based on the available information
[SOURCE: ISO 13528:2015, 3.4 [4]]
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
z
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.
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
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:
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 (%).
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 ).
ae
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, neither when dispersed in air
nor when dispersed in the test liquid.
SWFF 2: same as SWFF 1 except for:
— all particles have two mineral phases, one of them being quartz. All particles have the same
mass fraction of quartz to total mass of the particle (independently of particle size).
— all particles have an identical and known density (density based on the densities of the two mineral
phases and their mass ratio);
If the density of phase 2 for SWFF 2 is smaller (e.g. sepiolite 2 000 kg/m ,) than the quartz density,
the calculated bias of SWFF 1 (defaulting density to quartz) compared to SWFF 2 (taking into account
the real density of the two mineral phases) is positive. This was calculated for quartz mass fraction
of 25 %, 50 % and 75 %.
3 3
If the density of phase 2 for SWFF 2 is larger (e.g. rutile 4 200 kg/m , or magnetite 5 200 kg/m )
than the quartz density, the calculated bias of SWFF 1 (defaulting density to quartz) compared to
SWFF 2 (taking into account the real density of the two mineral phases) is positive for quartz mass
fraction of 50 % and 75 %. For quartz mass fraction of 25 %, the bias is negative and ranged from 0 %
to −5 %.
For very large mass median aerodynamic diameter (MMAD), the bias can reach very high negative
values for very narrow size distributions, i.e. with GSD = 1,25. Even though the bias is large it is not
relevant for SWFF measurements since SWFF is very low for samples with very large MMAD.
Large positive bias (root-mean-square bias > 0,10) occurs when the true particle density
is overestimated, especially for the high quartz mass fraction (0,75).
A.2.3 Internal SWFF sedimentation bias
A.2.3.1 General
This subclause specifies the bias between SWFF 1 sedimentation (spherical non-agglomerated particles,
one mineral phase, density of quartz mixture) and SWFF 3 sedimentation (spherical non-agglomerated
particles, two mineral phases one of them being quartz, non-identical mass fraction of quartz to total
mass of the particle for all particles (e.g. dependent of particle volume equivalent diameter)).
A.2.3.2 Powder, two mineral phases of density varying with particle volume-equivalent
diameter and ideal SWFF sedimentation measurement
The SWFF 1 and SWFF 3 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 3: same as SWFF 1 except for:
— all particles have two mineral phases, one of them being quartz. The particles do not all have the
same mass fraction of quartz to total mass of the particle; this is dependent of particle volume-
equivalent diameter;
— the density of the particles varies with particle size.
In many cases, when the quartz mass fraction is dependent on the particle volume equivalent size,
the bias of SWFF 1 to SWFF 3 is less than ± 0,05. In other cases, it can be large and highly dependent
on the particle size distribution. It was not possible to identify any specific trend for the dependence
of the size and/or sign of the bias on the type of functional dependence of the quartz mass fraction
on the particle volume-equivalent size.
The bias is difficult to predict for particles having multiple phases of random variable quartz mass
ratios and random variable mineral phase ratios. In these situations, this document uses the value that
limits underestimation as specified in EN 17289-3:2020, 6.5.
A.2.3.3 Internal method bias and bias between EN 481 and sedimentation SWFF probability
curve for non-ideal powders
When the particles of the powder are not ideal (as discussed above), the internal method bias
for the calculation and sedimentation methods due to assumptions and the bias between the calculation
and sedimentation methods will increase in a complicated way that does not seem to be possible
to express using easily determined external parameters. This is especially true when particles have one
or more of these characteristics:
a) non-spherical particles (possibly, in addition, with a particle dynamic shape factor that can vary
with particle size), for both the SWFF and the SWFFCS;
b) crystalline silica-containing particles where the (mass) fraction of crystalline silica is a function
of particle size;
c) particles made of several mineral phases including multiphase crystalline silica with varying shape
and density with respect to particle size;
d) particle size-dependent density.
NOTE The liquid sedimentation method (automatically) takes the dynamic shape factor into account without
the analyst needing to know its value. The same is true for sampling airborne particles with the penetration curve
being a function of aerodynamic size.
A.3 Uncertainty
A.3.1 Uncertainty due to assumptions
List of assumptions that are made in EN 17289-2 and EN 17289-3 and which can be included
in the uncertainty assessment:
For the SWFF calculation method:
— for the laser diffraction methods, particle shape is not taken into account in the measurement
and thus the measured particle diameter is assumed to be equal to the particle volume diameter.
Neither is the particle dynamic shape factor included in the conversion of the particle volume
equivalent diameter into the aerodynamic diameter;
— when SWFFCS is calculated by multiplying SWFF sample with the fraction of crystalline silica
in the sample, it is assumed that the particle size distribution of particles containing crystalline
silica is the same as the particle size distribution of all particles present in the sample.
NOTE This document does not provide guidance on how this can be checked.
— for non-spherical particles such as needles and platelets, the laser diffraction methods should not be
used but instead the gravitational liquid sedimentation should be used to determine the particle
size distribution;
— the subsample for analysis is representative of the bulk material.
For the SWFF sedimentation method:
— all liquid extracted from the sedimentation vessel should come from the space above the extraction
nozzle, and not from the space below. If this is not the case it will result in a higher SWFF value;
— the particle size distribution is constant over the particle size range of interest, i.e. from 0 μm to
12 μm (aerodynamic);
— the particle size distribution of the sample does neither have a d in the range from 6 μm to
12 μm, nor a too narrow distribution. The distribution is considered too narrow when the relative
span of the distribution is less than 1,5. Relative span is calculated as (( d - d )/ d ). In cases
90 10 50
where the sample has a narrow size distribution, the SWFF and SWFFCS should be calculated
from the particle size distribution;
— Stokes law is only valid for particles settling in a medium at low Reynolds number. The velocity
of a particle settling in a medium is limited by the drag force and this depends on the Reynolds
number for that particle. Although the density of liquids are much higher than air, so is their
viscosity so that in the end the difference between the Reynolds number of a particle in air and in
e.g. water is only a factor of 5. And although the constants for calculating the drag coefficient of
particles depend on the Reynolds number, the variation with Reynolds number within this range is
very small and can be neglected. Therefore, the dynamic form factor is assumed to be equal in both
air and liquid;
— in the material of interest all particles have the same and known density;
— the sub sample is representative of the bulk material.
In addition:
— for the laser diffraction Mie Theory the real Refractive Index (RI), imaginary RI, and absorption
coefficient of medium / water need to be known. The Mie theory assumes that particles are
homogeneous, isotropic and their optical properties are known (according to ISO 13320). This
document provides no guidance on whether or not the parameters RI and coefficient of medium /
water should be measured and how they should be accounted for during the measurement of SWFF
for minerals;
— for SWFF calculation and sedimentation, the particle density is an average density of the densities of
all particles being present in the sample measured by helium or liquid pycnometer.
A.3.2 Uncertainties due to measurements
A.3.2.1 Calculation method
Uncertainty of the methods:
— laser diffraction Fraunhofer theory;
— laser diffraction Mie Theory: the real RI, imaginary RI and absorption coefficient of medium / water
known. The Mie theory provides that particles are homogeneous, isotropic and their optical
properties are known;
— sedimentation X-ray Technique;
— XRD and FT-IR measurement for SWFFCS on bulk sample;
— uncertainty due to assumptions: size distribution same as size distribution of sample analysed;
— conversion from particle volume equivalent diameter to aerodynamic diameter (shape factor
defaulted to 1 and using density of particles);
— density used to convert particle number distribution into mass distribution and used for conversion
of particle volume equivalent diameter to aerodynamic diameter. As measured by helium or liquid
pycnometer;
— uncertainty numbers added to measurement and assumptions. When uncertainty of a specific
measurement is unknown or a judgement on the uncertainty cannot reasonably be made, it is
defaulted to 10 %.
A.3.2.2 Sedimentation method
Uncertainty of the methods:
— density measurement for time calculation;
— sample weighing (total mass dispersed);
— height measurements;
— weighing of mass residue in the extracted supernatant;
— XRD and FT-IR measurement for SWFFCS;
— uncertainties due to concentrations, level of dispersion, liquid viscosity (change due to dissolution
of some particles).
Annex B
(informative)
Round robin test to establish a SWFF reference sample
B.1 General
The IMA-Europe Metrology Working Group has arranged a round robin test in order to make a SWFF
reference sample available. In this Annex, the most relevant results are summarized.
NOTE A full report (Examination Report No. 20100437, not published) on this work is available from the IMA
Metrology WG.
B.2 Test material
Typical quartz flour from a German quartz production company was used as the test material. It was
produced from processed silica sand of Frechen deposit by iron-free grinding with subsequent air
separation.
Essentially the mass fraction of quartz was 100 %, therefore in this case SWFF is equal to SWFFCS.
Further, because the test material consists only of quartz, hence the particle density is constant
and in case of this round robin the mass fraction (w/w-%) is equal to the volume fraction (v/v-%).
A 75 kg sample was homogenized and divided by coning and quartering to give a number
of representative portions, in accordance with ISO 14488. Reference samples of fully characterized
quartz flour are available upon request via IMA-Europe.
For further material data of the flour sample, see B.1, Note. Sample homogeneity was checked by laser
diffraction at the central laboratory of the German quartz production company. A random sample
from each of the 50 subsamples was measured and evaluated (Fraunhofer approximation).
In accordance with ISO 13528 samples can be considered as homogenous, if they fulfil Formula (B.1):
s ≤×0,3 δ (B.1)
s
where
s is the between-samples standard deviation;
s
δ
is the standard deviation for proficiency assessment.

Formula (B.1) compares s , which is the standard deviation between the random samples
s
δ
of the 50 subsamples, with . According to ISO 13528, the standard deviation for proficiency
assessment was derived from the requirements for repeatability of laser diffraction devices given in
ISO 13320. This document claims for samples with particles smaller than 10 μm that the coefficient of
d d d
variation for should be smaller than 6 % and for and smaller than 10 %.
50 10 90
The subsamples comply with this requirement of ISO 13528, see Table B.1. Therefore, they are
adequately homogeneous.
Table B.1 — Homogeneity check (according to ISO 13528) by laser diffraction (Fraunhofer)
with 50 subsamples of the SWFF reference sample
Passing Passing Passing
Parameter
d d d
10 50 90
Mean (µm) 0,83 3,18 9,70
abs
Between-samples standard deviation ( s ), absolute (µm) 0,01 0,02 0,04
s
rel
1,2 0,6 0,4
Between-samples standard deviation ( s ), relative (%)
s
δ
Standard deviation for proficiency assessment ( ) (%) 10 6 10
δ
3 1,8 3
0,3 x (%)
rel
δ
Fulfil requirement: s ≤ 0,3 x (%) yes yes Yes
s
B.3 Evaluation and appraisal method
The main focus of the round robin test is the estimation of SWFF by laser diffraction and gravitational
liquid sedimentation method analysis. For the gravitational liquid sedimentation method analyses,
automated X-ray sedimentation was used according to ISO 13317-3 [15].
For laser diffraction, results based on the Fraunhofer theory were requested in a first run. The Mie
theory provides that particles “are homogeneous, isotropic and their optical properties are known”
(according to ISO 13320). Because these data, especially effects depending on shape and kind of surface
(e.g. rough or smooth, transparent or opaque) of the used quartz flour were not known, the Fraunhofer
theory was in principle preferred. Nevertheless, some laboratories sent in results using the Mie theory.
The initial laser diffraction data using the Mie theory showed large differences between the data
of the different laboratories. When the results were evaluated it became clear that the participants used
different optical data. Therefore, it was decided that analyses with harmonized Mie parameters from
literature (e.g. ISO 13320) were carried out in a second run. The following parameters were defined:
— positive real part of the refractive index of quartz ( n ): 1,54;
p
— positive imaginary (absorption) part of the refractive index of quartz ( k ): 0,10;
p
— refractive index of medium/water ( n ): 1,33.
m
The mean values of each participating laboratory were used as the basis of the evaluation. The results
were first checked for outliers after Dixon (according to DIN 53804-1 [16]) with significance of
α
= 0,05.
The statistical model is based on the means and standard deviations obtained from all laboratories.
For the evaluation of the performance of the round robin test two different criteria were
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