ISO 13318-1:2024

International
Standard
ISO 13318-1
Second edition
Determination of particle size
2024-10
distribution by centrifugal liquid
sedimentation methods —
Part 1:
General principles, requirements
and guidance
Détermination de la distribution granulométrique par les
méthodes de sédimentation centrifuge dans un liquide —
Partie 1: Principes généraux, exigences et orientation
Reference number
© ISO 2024
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Published in Switzerland
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Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms. 7
5 Measurement principle and technical realisations . 10
5.1 General measurement principle .10
5.2 Technical realisation of sedimentation-based centrifugal measurement techniques . 13
6 Measurement data and basic rules of data evaluation.15
6.1 Primary and derived measurands in centrifugal liquid sedimentation . 15
6.2 Spatial distribution of particles in centrifugal fields .17
6.3 Determination of distribution functions .18
6.3.1 General remarks .18
6.3.2 Distribution analysis for incremental techniques —homogeneous-start method
(HSM) .19
6.3.3 Distribution analysis for incremental techniques — line-start method (LSM) . 20
6.3.4 Distribution analysis for integral techniques .21
6.3.5 Conversion with respect to the type of quantity .21
6.3.6 Total quantity of dispersed phase and non-normalised particle size distributions . 22
6.3.7 Measurement analysis with respect to sedimentation and diffusion . 23
6.4 Deviations from Stokes-based analysis . 25
6.4.1 General . 25
6.4.2 Upper limit for sedimentation velocity and particle size . 25
6.4.3 Lower limits for particle size . 26
6.4.4 Limits for particle concentration .27
6.4.5 Handling of porous and heterogeneous particles .27
6.4.6 Handling of non-spherical particles and particle agglomerates .27
7 Performing size analyses .28
7.1 General . 28
7.2 Sampling . 28
7.3 Continuous phase and primary sample preparation . 28
7.4 Secondary sample preparation (sample conditioning) . 29
7.5 Instrument preparation . 30
7.6 Measurement . 30
7.6.1 General procedures for CLS . 30
7.6.2 Procedures for homogeneous-start method (HSM) .31
7.6.3 Procedures for line-start method (LSM) .31
7.6.4 Criteria for adjusting the rotational speed .32
7.7 Data analysis .32
7.8 Reporting . 33
8 System qualification and quality control .34
8.1 General remarks . 34
8.2 Reference materials . 35
8.3 Installation, operational and performance qualifications . 36
8.4 Sources of measurement uncertainty . 36
8.5 Accuracy and measurement of uncertainty of particle velocity and particle size . 38
8.6 Combined and expanded uncertainty of particle velocity and particle size measurement
(Stokes diameter) . 38
Annex A (informative) Particle sizing techniques based on centrifugal liquid sedimentation
(CLS) . 41

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Annex B (informative) Remarks on particle density .44
Annex C (informative) Sedimentation beyond the validity of Stokes’ law .50
Annex D (informative) Trueness, reproducibility and uncertainty determination for velocity
and particle size .57
Annex E (informative) Multiwavelength approach .62
Annex F (informative) Spatial distribution of particles in centrifugal fields .64
Annex G (informative) Additional particle and dispersion characteristics based on centrifugal
sedimentation velocity and sedimentation coefficient .73
Bibliography . 74

iv
Foreword
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This document was prepared by Technical Committee ISO/TC 24, Particle characterization including sieving,
Subcommittee SC 4, Particle characterization.
This second edition cancels and replaces the first edition (ISO 13318-1:2001), which has been technically
revised.
The main changes are as follows:
— revision of core terms (3.3, 3.5, 3.10, 3.11, 3.16, 3.14) and inclusion of further terms;
— revised and expanded explanation of measurement principle and techniques (Clauses 5 and 6);
— inclusion of the terminal sedimentation velocity as a measurand;
— introduction of informative annexes that provide:
— an overview of particle sizing techniques based on centrifugal liquid sedimentation (Annex A);
— remarks on particle density (Annex B);
— information regarding sedimentation beyond the validity of Stokes' law (Annex C);
— trueness, reproducibility and uncertainty determination for velocity and particle size (Annex D);
— an explanation on the mul
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