ISO 14411-2:2020
(Main)Preparation of particulate reference materials — Part 2: Polydisperse spherical particles
Preparation of particulate reference materials — Part 2: Polydisperse spherical particles
This document describes the specifications for spherical polydisperse particulate reference materials with acceptable uncertainty in particle size distribution and describes protocols for their characterization. One potential use of these reference materials is the reliability test of the laser-diffraction instruments and other particle sizing methods. This document expresses polydispersity and the related uncertainties in size. Small variations in size can imply large variations in cumulative distribution. This document describes the requirements of particulate reference materials, which are intended to be used to test the reliability of various types of particle size measurement apparatus. The requirements for processing, homogeneity and stability assessment as well as for the preparation of certificates, which are not addressed in this document are described in ISO 17034.
Préparation des matériaux de référence à l'état particulaire — Partie 2: Particules sphériques polydispersées
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 14411-2
First edition
2020-09
Preparation of particulate reference
materials —
Part 2:
Polydisperse spherical particles
Préparation des matériaux de référence à l'état particulaire —
Partie 2: Particules sphériques polydispersées
Reference number
©
ISO 2020
© ISO 2020
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ii © ISO 2020 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 1
3.1 Terms and definitions . 1
3.2 Symbols . 2
4 Requirements for preparing polydisperse particles . 3
4.1 General description of a project for the production of a reference material . 3
4.2 Requirements on the general properties of the material for polydisperse particles . 4
4.3 Size distribution for polydisperse particles . 4
5 Characterization of polydisperse particles . 5
5.1 Particle size distribution . 5
5.2 Aspect ratio . 5
5.3 Apparent particle density . 5
5.4 Refractive index . 5
6 Estimation of size measurement uncertainties. 5
6.1 Uncertainty from sampling . 5
6.1.1 Uncertainty of the average value N replicate measurement . 5
6.1.2 Uncertainty of a single measurement . 6
6.2 Other uncertainty factors. 7
6.3 Expanded uncertainty of size distribution . 7
Annex A (informative) Example calculation of the uncertainty estimation of particle size
distribution determined by N replicate measurement . 8
Annex B (informative) Example calculation of the uncertainty estimation of number-based
particle size distribution determined by a single measurement .11
Annex C (informative) Example calculation of the uncertainty estimation for a volume-
based cumulative size distribution transformed from the number-based size
distribution having a log-normal size distribution .14
Bibliography .16
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
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committee has been established has the right to be represented on that committee. International
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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
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iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 24, Particle characterization including
sieving, Subcommittee SC 4, Particle characterization.
A list of all parts in the ISO 14411 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
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iv © ISO 2020 – All rights reserved
Introduction
The measurement of particle size distribution can be accomplished by a number of techniques
which measure some characteristics of the particle and usually equate this to a circular or spherical
equivalent. Each of these techniques measures different properties of an irregular particle and thus has
particular requirements for reference materials and method standardization. Often, the methods that
are employed for particle size distribution are indirect in nature which rely on measuring some other
property and converting this to a particle size distribution by means of equations based on ideal shapes
(usually spherical) and sizes to that of the equivalent particle size distribution. Thus, these techniques
usually require or assume knowledge of some other constant in order to calculate the particle size
distribution.
Even methods that do not require size calibration require reference materials for quality control and
operation qualification. Such a reference material should be certified for its particle size distribution
and the values should be traceable to the SI unit metre. This material allows instrument manufacturers
to demonstrate proper calibration of all input factors and hence demonstrate that their instrument
results are traceable to the SI unit metre. To achieve this, the reference material should be polydisperse
and consist of spherical particles.
The heterogeneity of a particle size distribution poses statistical challenges for particle size analysis
and therefore also for the production of reference materials for particle size analysis. This document
therefore describes the production of particulate reference materials consisting of spherical particles.
INTERNATIONAL STANDARD ISO 14411-2:2020(E)
Preparation of particulate reference materials —
Part 2:
Polydisperse spherical particles
1 Scope
This document describes the specifications for spherical polydisperse particulate reference
materials with acceptable uncertainty in particle size distribution and describes protocols for their
characterization. One potential use of these reference materials is the reliability test of the laser-
diffraction instruments and other particle sizing methods.
This document expresses polydispersity and the related uncertainties in size. Small variations in size
can imply large variations in cumulative distribution.
This document describes the requirements of particulate reference materials, which are intended to be
used to test the reliability of various types of particle size measurement apparatus. The requirements
for processing, homogeneity and stability assessment as well as for the preparation of certificates,
which are not addressed in this document are described in ISO 17034.
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 17034, General requirements for the competence of reference material producers
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions 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 http:// www .electropedia .org/
3.1.1
aspect ratio
ratio of minimum Feret diameter to the maximum Feret diameter of a particle
[SOURCE: ISO 26824:2013, 4.5, modified.]
3.1.2
apparent density
mass per unit volume of the material
Note 1 to entry: It is expressed in g/cm .
[SOURCE: ISO 5755:2012, 3.10]
3.1.3
reference material
RM
material, sufficiently homogeneous and stable with respect to one or more specified properties, which
has been established to be fit for its intended use in a measurement process
[SOURCE: ISO 17034:2016, 3.3, modified — Notes to entry have been deleted.]
3.1.4
certified reference material
reference material characterized by a metrological valid procedure for one or more specified
properties, accompanied by a certificate that provides the value of the specified property, its associated
uncertainty, and a statement of metrological traceability
[SOURCE: ISO 17034:2016, 3.2, modified — Notes to entry have been deleted.]
3.2 Symbols
Symbol Description Unit Derived unit
coverage factor; numerical factor used as a multiplier of the combined
k - -
standard uncertainty in order to obtain an expanded uncertainty
m total number of uncertainty contributions - -
N total number of size measurements - -
n number of particles counted - -
t
−1 −1
q (x) density distribution by number m μm
−1 −1
q (x) density distribution by volume m μm
Q (x) cumulative distribution by number - -
Q (x) cumulative distribution by volume - -
r type of quantity of distribution, r = 0: number, r = 3: volume - -
s standard deviation of Q (x) m μm
r r
s geometric standard deviation - -
g
U expanded uncertainty m μm
f
expanded uncertainty of p percentile of the cumulative distribution
U m μm
f, p, r
of r type quantity
uncertainty at p percentile of cumulative number-based size dis-
u - −
Q
tribution
p,0
u uncertainty of the between-unit homogeneity m μm
hom
u uncertainty of particle size x m μm
p, r p, r
u uncertainty of mean value due to N times of size measurement m μm
rep
u uncertainty of stability of materials m μm
stab
x minimum particle size in size range j m μm
min, j
2 © ISO 2020 – All rights reserved
x maximum particle size in size range j m μm
max, j
particle size at p percentile of cumulative distribution of r type
quantity, e.g. x = particle size at 90 percentile of cumulative
90,0
x m μm
p, r
number-based size distribution, x = median particle size of
50,3
cumulative volume-based
...
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