Particle Size Analysis
Particle Size Analysis is at the core of much of particle analysis as a whole. These standards apply broadly, providing some of the basic measuring practices and methods that underly the more niche topics presented below. Appropriately, a wide range of techniques are covered here, providing not just a detailed foundation, but a broad one.
SAE J 391-2011 (SAE J391-2011)
Definition for Particle Size ( Stabilized: Jun 2011 )
'Effective particle or domain size' is a phrase used in X-ray diffraction literature to describe the size of the coherent regions within a material which are diffracting. Coherency in this sense means diffracting as a unit. Small particle size causes X-ray line broadening and as such can be measured. It has been shown related to substructure as observed in transmission electron microscopy. Particle size is affected by hardening, cold working, and fatigue; conversely, there is increasing evidence that particle size, per se, affects both static and dynamic strength.
ISO 27891:2015
Aerosol particle number concentration - Calibration of condensation particle counters
ISO 27891:2015 describes methods to determine the detection efficiency of condensation particle counters (CPCs) at particle number concentrations ranging between 1 cm -3 and 10 5 cm -3 , together with the associated measurement uncertainty. In general, the detection efficiency will depend on the particle number concentration, the particle size, and the particle composition. The particle sizes covered by the methods described in this International Standard range from approximately 5 nm to 1 000 nm. The methods can therefore be used both to determine a CPC calibration factor to be applied across the range of larger particle sizes where the detection efficiency is relatively constant (the plateau efficiency), and to characterize the drop in CPC detection efficiency at small particle sizes, near the lower detection limit. These parameters are described in more detail in Annex A. The methods are suitable for CPCs whose inlet flows are between approximately 0,1 l/min and 5 l/min. This International Standard describes a method for estimating the uncertainty of a CPC calibration performed according to this International Standard.
ISO 13322-1:2014
Particle size analysis - Image analysis methods - Part 1: Static image analysis methods
ISO 13322-1:2014 is applicable to the analysis of images for the purpose of determining particle size distributions where the velocity of the particles against the axis of the optical system of the imaging device is zero. The particles are appropriately dispersed and fixed in the object plane of the instrument. The field of view may sample the object plane dynamically either by moving the sample support or the camera provided this can be accomplished without any motion effects on the image. Captured images can be analysed subsequently. ISO 13322-1:2014 concentrates upon the analysis of digital images created from either light or electron detection systems. It considers only image evaluation methods using complete pixel counts.
ISO 13322-2:2021
Particle size analysis - Image analysis methods - Part 2: Dynamic image analysis methods
This document describes a method to transfer the images from particles having relative motion to binary images within practical systems, in which the particles in the images are individually separated. Images of moving particles are created by an optical image capture device. Effects of particle movement on the images are either minimized by the instrumentation or corrected by software procedures. This method is applicable to the particle images that are clearly distinguishable from static background. Further processing of the binary image, which is then considered as static, is described in ISO 13322-1. A dynamic image analysis system is capable of measuring a higher number of particles compared to static image analysis systems. This document provides guidance on instrument qualification for particle size distribution measurements by using particulate reference materials. This document addresses the relative movement of the particles with respect to each other, the effect of particle movement on the image (motion blur), the movement and position along the optical axis (depth of field), and the orientation of the particles with respect to the camera.
ISO 22412:2017
Particle size analysis - Dynamic light scattering (DLS)
ISO 22412:2017 specifies the application of dynamic light scattering (DLS) to the measurement of average hydrodynamic particle size and the measurement of the size distribution of mainly submicrometre-sized particles, emulsions or fine bubbles dispersed in liquids. DLS is also referred to as quasi-elastic light scattering (QELS) and photon correlation spectroscopy (PCS), although PCS actually is one of the measurement techniques. ISO 22412:2017 is applicable to the measurement of a broad range of dilute and concentrated suspensions. The principle of dynamic light scattering for a concentrated suspension is the same as for a dilute suspension. However, specific requirements for the instrument setup and specification of test sample preparation are required for concentrated suspensions. At high concentrations, particle-particle interactions and multiple light scattering can become dominant and can result in apparent particle sizes that differ between concentrated and dilute suspensions.
ISO 13320:2020
Particle size analysis - Laser diffraction methods
This document provides guidance on instrument qualification and size distribution measurement of particles in many two-phase systems (e.g. powders, sprays, aerosols, suspensions, emulsions and gas bubbles in liquids) through the analysis of their light-scattering properties. It does not address the specific requirements of particle size measurement of specific materials. This document is applicable to particle sizes ranging from approximately 0,1 µm to 3 mm. With special instrumentation and conditions, the applicable size range can be extended above 3 mm and below 0,1 µm. For spherical and non-spherical particles, a size distribution is reported, where the predicted scattering pattern for the volumetric sum of spherical particles matches the measured scattering pattern. This is because the technique assumes a spherical particle shape in its optical model. For non-spherical particles the resulting particle size distribution is different from that obtained by methods based on other physical principles (e.g. sedimentation, sieving).
ISO 20998-1:2006
Measurement and characterization of particles by acoustic methods - Part 1: Concepts and procedures in ultrasonic attenuation spectroscopy
ISO 20998-1:2006 describes ultrasonic methods for determining the size distributions of one or more material phases dispersed in a liquid. Colloids, dispersions, slurries and emulsions are within the scope of ISO 20998-1:2006. The typical particle size for such analysis ranges from 10 nm to 3 mm, although particles outside this range have also been successfully measured. Measurements can be made for concentrations of the dispersed phase ranging from 0,1 % by volume up to 50 % or more by volume, depending on the density contrast between the continuous and the dispersed phases. These methods can be used to monitor dynamic changes in the size distribution, including agglomeration or flocculation in concentrated systems.
ISO 20998-2:2013
Measurement and characterization of particles by acoustic methods - Part 2: Guidelines for linear theory
ISO 20998-2:2013 describes ultrasonic attenuation spectroscopy methods for determining the size distributions of a particulate phase dispersed in a liquid at dilute concentrations, where the ultrasonic attenuation spectrum is a linear function of the particle volume fraction. In this regime, particle?particle interactions are negligible. Colloids, dilute dispersions, and emulsions are within the scope of ISO 20998-2:2013. The typical particle size for such analysis ranges from 10 nm to 3 mm, although particles outside this range have also been successfully measured. For solid particles in suspension, size measurements can be made at concentrations typically ranging from 0,1 % volume fraction up to 5 % volume fraction, depending on the density contrast between the solid and liquid phases, the particle size, and the frequency range. For emulsions, measurements may be made at much higher concentrations. These ultrasonic methods can be used to monitor dynamic changes in the size distribution. While it is possible to determine the particle size distribution from either the attenuation spectrum or the phase velocity spectrum, the use of attenuation data alone is recommended. The relative variation in phase velocity due to changing particle size is small compared to the mean velocity, so it is often difficult to determine the phase velocity with a high degree of accuracy, particularly at ambient temperature. Likewise, the combined use of attenuation and velocity spectra to determine the particle size is not recommended. The presence of measurement errors (i.e. noise ) in the magnitude and phase spectra can increase the ill-posed nature of the problem and reduce the stability of the inversion.
ISO 21501-1:2009
Determination of particle size distribution - Single particle light interaction methods - Part 1: Light scattering aerosol spectrometer
ISO 21501-1:2009 specifies characteristics of a light scattering aerosol spectrometer (LSAS) which is used for measuring the size, number concentration and number/size distribution of particles suspended in a gas. The light scattering technique described in this document is based upon single particle measurements. The size range of particles measured by this method is between approximately 0,06 ¦m to 45 ¦m in diameter. Instruments that conform to ISO 21501-1:2009 are used for the determination of the particle size distribution and particle number concentration at relatively high concentrations of up to 10 11 particles/m 3 . Application fields include: characterization of metered dose inhalers (MDI), dry powder inhalers (DPI) and nebulizers in pharmacy; production control of active agents; cut-off determination: impactors, cyclones and impingers; atmospheric aerosols: bio-aerosols, stables/composting facilities, nebulized droplets, measurements in street tunnels; fractional separation efficiency determination of filters. For the above-mentioned applications, aerosol spectrometers should determine the particle size distribution, particle number concentration, size resolution and sizing accuracy as accurately as possible. These aerosol spectrometers are not suitable for the classification of clean rooms.
ISO 21501-2:2019
Determination of particle size distribution - Single particle light interaction methods - Part 2: Light scattering liquid-borne particle counter
This document describes a calibration and verification method for a light scattering liquid-borne particle counter (LSLPC), which is used to measure the size and particle number concentration of particles suspended in liquid. The light scattering method described in this document is based on single particle measurements. The typical size range of particles measured by this method is between 0,1 µm and 10 µm in particle size. The method is applicable to instruments used for the evaluation of the cleanliness of pure water and chemicals, as well as the measurement of number and size distribution of particles in various liquids. The measured particle size using the LSLPC depends on the refractive index of particles and medium; therefore, the measured particle size is equivalent to the calibration particles in pure water. The following are within the scope of this document: size setting error; counting efficiency; size resolution; false count; maximum particle number concentration; sampling flow rate error; sampling time error; sampling volume error; calibration interval; reporting results from test and calibration.
ISO 21501-3:2019
Determination of particle size distribution - Single particle light interaction methods - Part 3: Light extinction liquid-borne particle counter
This document describes a calibration and verification method for a light extinction liquid-borne particle counter (LELPC), which is used to measure the size and particle number concentration of particles suspended in liquid. The light extinction method described in this document is based on single particle measurements. The typical size range of particles measured by this method is between 1 µm and 100 µm in particle size. The method is applicable to instruments used for the evaluation of the cleanliness of pharmaceutical products (e.g. injections, water for injections, infusions), as well as the measurement of number and size distribution of particles in various liquids. The following are within the scope of this document: size setting error; counting efficiency; size resolution; maximum particle number concentration; sampling flow rate error; sampling time error; sampling volume error; calibration interval; reporting results from test and calibration.
ISO 15900:2020
Determination of particle size distribution - Differential electrical mobility analysis for aerosol particles
This document provides guidelines and requirements for the determination of aerosol particle number size distribution by means of the analysis of electrical mobility of aerosol particles. This measurement is usually called differential electrical mobility analysis for aerosol particles . This analytical method is applicable to particle size measurements ranging from approximately 1 nm to 1 µm. This document does not address the specific instrument design or the specific requirements of particle size distribution measurements for different applications but includes the calculation method of uncertainty. In this document, the complete system for carrying out differential electrical mobility analysis is referred to as DMAS (differential mobility analysing system), while the element within this system that classifies the particles according to their electrical mobility is referred to as DEMC (differential electrical mobility classifier). NOTE This document does not include technical requirements and specifications for the application of DMAS, which are defined in application specific standards or guidelines, e.g. for road vehicle applications (ISO/TC 22), environmental measurements (ISO/TC 146) or nanotechnologies (ISO/TC 229).
ISO 13319-1:2021
Determination of particle size distribution - Electrical sensing zone method - Part 1: Aperture/orifice tube method
This document specifies the measurement of the size distribution of particles dispersed in an electrolyte solution using the electrical sensing zone method. This can include biologics such as cells, but also industrial particles such as carbon, cement, ceramic powders, metal powders, pigments and polymer powders. The method measures pulse heights and their relationship to particle volumes or diameters, and is applicable over the range (implementation dependant) from approximately 0,5 m t above 1 mm. This document does not address the specific requirements of the measurement of specific materials.
ANSI/ASAE S424.1 MAR1992 (R2022)
Method of Determining and Expressing Particle Size of Chopped Forage Materials by Screening
The purpose of this Standard is to define a test procedure to determine the particle size distribution of chopped forage materials and to define a method of expressing the particle length of the material. The determined particle size distribution can be used to evaluate forage harvesting machine and handling equipment variables and to define forage physical length in animal feeding trials. This Standard shall be used to determine the particle size of chopped forage materials where the reduction process yields particles such as that material produced by shear-bar type forage harvesters. It is not intended for use on material produced by flail-type harvesters where substantial fractions of the material may be extremely long. This Standard is intended for use in the field as well as in the laboratory. It is intended to separate chopped forage samples without drying them first.
ASTM F660-83(2019)
Standard Practice for Comparing Particle Size in the Use of Alternative Types of Particle Counters
1.1 This practice provides a procedure for comparing the sizes of nonspherical particles in a test sample determined with different types of automatic particle counters, which operate on different measuring principles. 1.2 A scale factor is obtained by which, in the examination of a given powder, the size scale of one instrument may be multiplied to agree with the size scale of another. 1.3 The practice considers rigid particles, free of fibers, of the kind used in studies of filtration, such as: commercially available test standards of quartz or alumina, or fly ash, or some powdered chemical reagent, such as iron oxide or calcium sulfate. 1.4 Three kinds of automatic particle counters are considered: 1.4.1 Image analyzers, which view stationary particles under the microscope and, in this practice, measure the longest end-to-end distance of an individual particle. 1.4.2 Optical counters, which measure the area of a shadow cast by a particle as it passes by a window; and 1.4.3 Electrical resistance counters, which measure the volume of a particle as it passes through an orifice in an electrically conductive liquid. 1.5 This practice also considers the use of instruments that provide sedimentation analyses, which is to say provide measures of the particle mass distribution as a function of Stokes diameter. The practice provides a way to convert mass distribution into number distribution so that the meaning of Stokes diameter can be related to the diameter measured by the instruments in 1.4 . 1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
ASTM E2651-19
Standard Guide for Powder Particle Size Analysis
1.1 This guide covers the use of many available techniques for particle size measurement and particle size distribution analysis of solid particulate (powder) materials, off-line in a laboratory. It does not apply to in-line (on-line) analysis, nor to analysis of liquid droplets or liquid aerosols. The guide is intended to serve as a resource for powder/particle technologists in characterizing their materials. 1.2 This guide provides significant detail regarding the numerous particle size analysis methods available. Although this guide is extensive, it may not be all inclusive. 1.3 The principle of operation, range of applicability, specific requirements (if any), and limitations of each of the included particle size analysis techniques are listed and described, so that users of this guide may choose the most useful and most efficient technique for characterizing the particle size distribution of their particular material(s). 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
ASTM E1617-09(2019)
Standard Practice for Reporting Particle Size Characterization Data
1.1 This practice covers reporting particle size measurement data. 1.2 This practice applies to particle size measurement methods, devices, detail levels, and data formats for dry powders, and wet suspensions of solids, gels, or emulsion droplets. This practice does not pertain to liquid particles. Note 1: For information on reporting liquid particle measurement data, refer to Practice E799 . 1.3 This practice does not concern particle concentration information. 1.4 This practice uses SI (Syst me International) units as standard. State all numerical values in terms of SI units unless specific instrumentation software reports particle size information, including percentiles, indices, and distributions as tabulations and graphs using alternate units. In this case, present both reported and equivalent SI units in the final written report. Refer to Practice E380 for proper usage of SI units. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
ASTM E2578-07(2018)
Standard Practice for Calculation of Mean Sizes/Diameters and Standard Deviations of Particle Size Distributions
1.1 The purpose of this practice is to present procedures for calculating mean sizes and standard deviations of size distributions given as histogram data (see Practice E1617 ). The particle size is assumed to be the diameter of an equivalent sphere, for example, equivalent (area/surface/volume/perimeter) diameter. 1.2 The mean sizes/diameters are defined according to the Moment-Ratio (M-R) definition system. 2 , 3 , 4 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
ASTM E1037-21
Standard Test Method for Measuring Particle Size Distribution of RDF-5
1.1 This test method is used to determine the size distribution of a RDF-5 sample. Size is defined as the maximum length of the particle, where length is determined by the RDF-5 manufacturing process. That is, a pellet, cubette, or briquette all have a recognizable length. Fig. 1 displays the sizes and shapes of some RDF-5 particles. FIG. 1 RDF-5 Sizes 1.2 An air-dried RDF-5 sample is separated into categories of differing particle sizes. The size distribution is measured as the weight percentage of each size category. A graph of a function of the cumulative fraction of material by weight finer than particle size versus particle size is plotted. From this plot are taken values which describe the size distribution - the uniformity constant and the characteristic particle size. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
ASTM D2862-16
Standard Test Method for Particle Size Distribution of Granular Activated Carbon
1.1 This test method covers the determination of the particle size distribution of granular activated carbon. For the purposes of this test, granular activated carbon is defined as a minimum of 90 % of the sample weight being retained on a 180- m Standard sieve. A U.S. mesh 80 sieve is equivalent to a 180 m Standard sieve. Note 1: For extruded carbons, as the length/diameter ratio of the particles increases, the validity of the test results might be affected. 1.2 The data obtained may also be used to calculate mean particle diameter (MPD), effective size, and uniformity coefficient. 1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.3.1 Exception All mass measurements are in SI units only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
BS 3625:1963
Specification for eyepiece and screen graticules for the determination of the particle size of powders (British Standard)
Design and construction of eyepiece and screen graticules for particle size analysis by the optical microscope method as described in BS 3406-4.
SAE AIR 4906-1995 (SAE AIR4906-1995)
Droplet Sizing Instrumentation Used in Icing Facilities ( Reaffirmed: Dec 2007 )
A review of droplet sizing instruments used for icing research is presented. These instruments include the Forward Scattering Spectrometer Probe, the Optical Array Probe, the Phase Doppler Particle Analyzer, the Malvern Particule Size Analyzer, the oil slid technique, and the rotating multicylinder. The report focuses on the theory of operation of these instruments and practical considerations when using them in icing facilities. The purpose of this SAE Aerospace Information Report (AIR) is to provide information that is useful for the selection, operation, and appreciation of the limitations of droplet sizing instruments when applied to aircraft icing research and development.
BS 3406-8:1997
Methods for determination of particle size distribution. Photon correlation spectroscopy (British Standard)
This International Standard describes the application of photon correlation spectroscopy (PCS) to the measurement of an average particle size and a measure of the broadness of the size distribution of particles dispersed in liquids. It is applicable to particle sizes ranging from a few nanometres to about 1 m, or to the onset of sedimentation. In the data analysis procedure (see annexes A and C) it is assumed that the particles are isotropic and spherically shaped.
BS 3406-4:1993
Methods for determination of particle size distribution. Guide to microscope and image analysis methods (British Standard)
Recommends methods for measuring particles in the range 2 nm to 1 mm using light, scanning electron and transmission electron microscopes. Calculation examples are included.
BS 3406-1:1986
Methods for determination of particle size distribution. Guide to powder sampling (British Standard)
Recommended methods for the subdivision of laboratory powder samples into test portions suitable for analysis by methods for the determination of the particle size distribution described in other Parts of this standard and for particle characterization analysis described in other British Standards.
ISO 9276-1:1998
Representation of results of particle size analysis -- Part 1: Graphical representation
This part of ISO 9276 specifies rules for the graphical representation of particle size analysis data in histograms, density distributions and cumulative distributions. It also establishes a standard nomenclature to be followed to obtain the distributions mentioned above from the measured data. This part of ISO 9276 applies to the graphical representation of distributions of solid particles, droplets or gas bubbles covering all size ranges.
ISO 9276-2:2014
Representation of results of particle size analysis - Part 2: Calculation of average particle sizes/diameters and moments from particle size distributions
ISO 9276-2:2014 provides relevant equations and coherent nomenclatures for the calculation of moments, mean particle sizes and standard deviations from a given particle size distribution. Two notation systems in common use are described. One is the method of moments while the second describes the moment-ratio method. The size distribution may be available as a histogram or as an analytical function. The equivalent diameter of a particle of any shape is taken as the size of that particle. Particle shape factors are not taken into account. Samples of particles measured are intended to be representative of the population of particles. For both notation systems, numerical examples of the calculation of mean particle sizes and standard deviation from histogram data are presented in an annex.
ISO 9276-3:2008
Representation of results of particle size analysis - Part 3: Adjustment of an experimental curve to a reference model
ISO 9276-3:2008 specifies methods for the adjustment of an experimental curve to a reference model with respect to a statistical background. Furthermore, the evaluation of the residual deviations, after the adjustment, is also specified. The reference model can also serve as a target size distribution for maintaining product quality. ISO 9276-3:2008 specifies procedures that are applicable to the following reference models: a) normal distribution (Laplace-Gauss): powders obtained by precipitation, condensation or natural products (pollens); b) log-normal distribution (Galton MacAlister): powders obtained by grinding or crushing; c) Gates-Gaudin-Schuhmann distribution (bilogarithmic): analysis of the extreme values of the fine particle distributions; d) Rosin-Rammler distribution: analysis of the extreme values of the coarse particle distributions; e) any other model or combination of models, if a non-linear fit method is used. ISO 9276-3:2008 can substantially support product quality assurance or process optimization related to particle size distribution analysis.
ISO 9276-4:2001
Representation of results of particle size analysis -- Part 4: Characterization of a classification process
The main object of this part of ISO 9276 is to provide the mathematical background for the characterization of a classification process. This part of ISO 9276 is not limited to an application in particle size analysis, the same procedure may be used for the characterization of a technical classification process (e.g. air classification, centrifugal classification) or a separation process (e.g. gas or hydrocyclones). In clause 3 the characterization of a classification process is described under the presupposition that the density distribution curves describing the feed material and the fractions, as well as the overall mass balance, are free from errors. In clause 4 the influence of systematic errors on the efficiency of a classification process is described. The effect of stochastic errors in the characterization of a classification process is described in annex A.
ISO 9276-5:2005
Representation of results of particle size analysis - Part 5: Methods of calculation relating to particle size analyses using logarithmic normal probability distribution
The main objective of ISO 9276-5:2005 is to provide the background for the representation of a cumulative particle size distribution which follows a logarithmic normal probability distribution, as a means by which calculations performed using particle size distribution functions may be unequivocally checked. The design of logarithmic normal probability graph paper is explained, as well as the calculation of moments, median diameters, average diameters, and volume-specific surface area. Logarithmic normal probability distributions are often suitable for the representation of cumulative particle size distributions of any dimensionality. Their particular advantage lies in the fact that cumulative distributions, such as number-, length-, area-, volume- or mass-distributions, are represented by parallel lines, all of whose locations may be determined from a knowledge of the location of any one.
ISO 9276-6:2008
Representation of results of particle size analysis - Part 6: Descriptive and quantitative representation of particle shape and morphology
ISO 9276-6:2008 specifies rules and nomenclature for the description and quantitative representation of particle shape and morphology. To achieve a more comprehensive description of a particle or particle system, particle size information can be used together with other information but, in most cases, the particle size information cannot be replaced. The averaging of shape over all particles in a sample has been shown to be an ineffective approach. Distributions of other particle characteristics are required in addition to particle size distributions (see ISO 9276 1). The relevance, to technological applications, of any method of representing particle shape is the deciding factor in its use. Therefore this part of ISO 9276 is restricted to methods which can be correlated with physical properties in industrial applications. The aim of particle analysis is to determine the most appropriate characterization method for a particular application. This implies a profound understanding of the relationship between particle characteristics and macroscopic product and process properties (or at least a database of broad empirical data). Problems of shape and morphology would normally be three-dimensional problems, but most definitions in this part of ISO 9276 are in fact given for two dimensions because of the widespread use of image analysis methods.
