ISO TS 5973-2024 PDF

Full title and description

St ISO TS 5973-2024 — Laser diffraction measurements — Good practice. This technical specification provides practical guidance to obtain high-quality particle size results by laser diffraction, covering method selection, sample preparation, instrument checks, data interpretation and quality assessment for solids (wet and dry), emulsions and bubbles.

Abstract

This Technical Specification gives guidance on when laser diffraction is the most appropriate method for particle size analysis, recommended sample preparation and sampling, verification and correct functioning of instruments, interpretation of measured scattering data, and assessment of data quality. It focuses on practical steps to obtain reliable results for a range of sample types (solid particles in wet and dry modes, emulsions and bubbles) and addresses expected result variation for real samples.

General information

• Status: Published
• Publication date: July 2024
• Publisher: International Organization for Standardization (ISO)
• ICS / categories: 19.120 (Particle size analysis; sieving)
• Edition / version: Edition 1 (Technical Specification)
• Number of pages: 23.

Scope

ISO/TS 5973:2024 provides practical best-practice guidance for laser-diffraction particle size measurements, including criteria for choosing the technique, recommended sampling and sample preparation methods, instrument verification and routine checks, data collection settings, optical-property considerations (e.g., refractive index, colour, porosity), identification of sample types unsuitable for the technique, and approaches to evaluate repeatability, intermediate precision and reproducibility of results. The document is intended to help users obtain meaningful and comparable particle size distributions across common sample matrices.

Key topics and requirements

• Criteria to determine when laser diffraction is appropriate versus alternative sizing methods.
• Recommended sampling strategies and sample preparation for powders, suspensions, emulsions, sprays and aerosols.
• Instrument verification, basic calibration checks and routine performance tests to confirm correct functioning.
• Guidance on optical assumptions (use of Mie vs Fraunhofer approximations, selecting refractive index and absorption values).
• Measurement configurations: wet and dry dispersion modes and recommendations to minimise agglomeration and multiple scattering.
• Data interpretation: converting scattering patterns to particle size distributions and limitations for non-spherical or porous particles.
• Assessment of data quality: expected repeatability, intermediate precision and reproducibility studies and recommended experiments.
• Reporting recommendations and required metadata to support result traceability and comparability.

Typical use and users

Laboratories performing routine particle size analysis, research and development teams, quality control departments in pharmaceuticals, chemicals, minerals and consumer products, instrument manufacturers and service providers, and regulatory bodies seeking harmonised good-practice guidance for laser-diffraction measurements.

Related standards

ISO/TS 5973:2024 is intended to be used alongside ISO 13320:2020 (Particle size analysis — Laser diffraction methods) which defines core measurement principles and instrument requirements; and with parts of the ISO 9276 series on representation and calculation of particle size distribution results. Users commonly apply these documents together to cover both measurement practice and reporting/representation of results.

Keywords

laser diffraction, particle size analysis, particle size distribution (PSD), Mie scattering, Fraunhofer approximation, sample preparation, wet dispersion, dry dispersion, instrument verification, repeatability, reproducibility, reporting

FAQ

Q: What is this standard?

A: ISO/TS 5973:2024 is a Technical Specification titled "Laser diffraction measurements — Good practice" that provides practical guidance for conducting and interpreting laser-diffraction particle size measurements.

Q: What does it cover?

A: It covers selection criteria for laser-diffraction, recommended sampling and sample-preparation methods, instrument checks and verification, optical-property considerations, measurement configurations (wet/dry), data interpretation and assessment of data quality including repeatability and reproducibility expectations.

Q: Who typically uses it?

A: Analytical laboratories, QC and R&D teams in industries (pharma, chemicals, minerals, food, consumer products), instrument manufacturers, testing service providers and regulators who require harmonised good-practice procedures for particle size measurement.

Q: Is it current or superseded?

A: It is current: ISO/TS 5973 was published in July 2024 as Edition 1 (Technical Specification) and is the active guidance document on good-practice for laser-diffraction measurements.

Q: Is it part of a series?

A: It is a standalone Technical Specification but is intended to be used with related ISO documents for particle-sizing, most notably ISO 13320:2020 (laser-diffraction methods) and the ISO 9276 series (representation and calculation of particle size distribution results).

Q: What are the key keywords?

A: Laser diffraction, particle size distribution, PSD, Mie, Fraunhofer, sample preparation, instrument verification, wet dispersion, dry dispersion, repeatability, reproducibility.