ISO 9276-1:2025
(Main)Representation of results of particle size analysis — Part 1: Graphical representation
Representation of results of particle size analysis — Part 1: Graphical representation
This document specifies guidelines and instructions for the graphical representation of particle size analysis data in histograms, distribution densities and cumulative distributions. It also establishes a standard nomenclature to obtain the histograms, distribution densities and cumulative distributions from measured particle size data. This document applies to the graphical representation of particle size distributions (PSDs) of solid particles, droplets or gas bubbles covering all size ranges.
Représentation de données obtenues par analyse granulométrique — Partie 1: Représentation graphique
General Information
Relations
Standards Content (Sample)
International
Standard
ISO 9276-1
Third edition
Representation of results of particle
2025-10
size analysis —
Part 1:
Graphical representation
Représentation de données obtenues par analyse
granulométrique —
Partie 1: Représentation graphique
Reference number
© ISO 2025
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 5
4.1 General .5
4.2 Symbols .5
5 Particle size, measures and types . 6
5.1 General .6
5.2 Particle size, x .6
5.3 Measures and types of quantity .7
6 Graphical representation of PSDs. 7
6.1 Cumulative distribution, Q (x) .7
r
6.2 Representation in discrete classes as histogram, q̅ .9
r,i
6.3 Distribution density, q (x) .10
r
7 Graphical representation of cumulative distribution and distribution density on a
logarithmic abscissa .11
7.1 Cumulative distribution on a logarithmic abscissa .11
7.2 Distribution density on a logarithmic abscissa . 12
8 Graphical representation of non-normalized distributions .12
8.1 Graphical representation of concentration distribution . 12
8.2 Graphical representation of separated particle distributions . 13
9 Graphical representation of two-dimensional distribution .13
9.1 Graphical representation of two-dimensional PSD . 13
9.2 Graphical representation of shape and size distribution data.16
Annex A (informative) Example of graphical representation of particle size analysis results of
sieving . 19
Annex B (informative) Example of number concentration size distribution as result of aerosol
measurement .22
Annex C (informative) Example of graphical representation of two-dimensional PSD .24
Bibliography .27
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
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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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
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This document was prepared by Technical Committee ISO/TC 24, Particle characterization including sieving,
Subcommittee SC 4, Particle characterization.
This third edition cancels and replaces the second edition (ISO 9276-1:1998), which has been technically
revised. It also incorporates the Technical Corrigendum ISO 9276-1:1998/Cor 1:2004.
The main changes are as follows:
— Clause 3 has been added;
— Formulae (9) and (10) have been added in 7.2;
— Clauses 8 and 9 have been added;
— Annex B and Annex C have been added.
A list of all parts in the ISO 9276 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
The characterization of a dispersed phase with respect to its particle size distribution (PSD) is a major
task, whenever the generation, emission, transport, application or consumption of particulate matter is
monitored or investigated. The spectrum of relevant materials is very broad and "particle" can refer to
grains, flakes, fibres, droplets, bubbles, micelles or pores. Within a particulate material, particles typically
vary with regard to their size. The distribution of this measurand is characterized by the relative quantity of
particles belonging to a specific size class.
There are a wide range of methods for the size analysis of particulate matter. For many reasons, the results
will, in general, not be the same. One of the main problems still encountered with most methods in use is
their unknown absolute accuracy. Apart from this, there are two principal origins of the differences among
measured PSDs.
Firstly, the measurand "particle size" is an ambiguous property being specified by the measurement
principle of the instrumentation and the way of signal analysis. Both specifications define the type of
particles which are intrinsically measured: agglomerates or their constituent particles; Pickering emulsion
droplets or the nanoparticles at their surface; complete core-shell particles or the core of the particles only.
Therefore, “size” can refer to a variety of physical and geometric properties.
Secondly, the distribution of size can be measured and expressed by different types (and measures) of
[1]
quantity.
A disperse system can be described by different types of PSD, which supplement each other in providing a
comprehensive view on the granulometric state of the particulate material. Moreover, each type of PSD can
be represented in various manners.
Beside numerical and mathematical representations, graphical ones are particularly popular and useful
because they allow for a quick comprehension of the main PSD features or a fast evaluation of differences
among product lots. There are various ways of plotting a PSD, which emphasize different details though
communicating the same information. This requires explanation, especially when a PSD is described by
discrete data.
A harmonized view on terms and a common understanding of how to graphically plot and interpret PSDs
support the communication between suppliers and clients and improve the comparability of measurement
data from different instruments.
v
International Standard ISO 9276-1:2025(en)
Representation of results of particle size analysis —
Part 1:
Graphical representation
1 Scope
This document specifies guidelines and instructions for the graphical representation of particle size analysis
data in histograms, distribution densities and cumulative distributions. It also establishes a standard
nomenclature to obtain the histograms, distribution densities and cumulative distributions from measured
particle size data.
This document applies to the graphical representation of particle size distributions (PSDs) of solid particles,
droplets or gas bubbles covering all size ranges.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
particle
minute piece of matter with defined physical boundaries
Note 1 to entry: A physical boundary can also be described as an interface.
Note 2 to entry: A particle can move as a unit.
Note 3 to entry: This general particle definition applies to nano-objects.
[SOURCE: ISO 26824:2022 3.1.1]
3.2
particle size
x
d
linear dimension of a particle (3.1) determined by a specified measurement method and under specified
measurement conditions
Note 1 to entry: Different methods of analysis are based on the measurement of different physical properties.
Independent of the particle property actually measured, the particle size is reported as a linear dimension, e.g. as the
equivalent diameter.
Note 2 to entry: Possible types of particle size values are equivalent diameters from physical measurement or
equivalent circular diameters from image analysis as well as linear
...
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