Overview
ISO 13317-1:2024 - Determination of particle size distribution by gravitational liquid sedimentation methods (Part 1) defines the general principles, requirements and guidance for particle size analysis based on gravitational sedimentation in liquids. The standard establishes how to measure and report sedimentation velocity distributions and convert them into particle size distributions (Stokes diameter) using sedimentation theory. It updates the 2001 edition and adds guidance on measurands, method validation and the determination of measurement uncertainty.
Key points:
- Primary measurand: sedimentation velocity, converted to particle size via Stokes’ law where applicable.
- Typical measurable size range (aqueous samples): roughly 200 nm to 100 µm; velocity range ~0.6 µm/s to 10 mm/s.
- Intended for low particle concentrations (volume fractions well below 1%).
- Safety note: hazardous liquids may require explosion-proof analysers.
Key Topics and Requirements
- Measurement principle and techniques: description of gravitational sedimentation-based instruments and technical realisations for monitoring phase separation (deposition or depletion).
- Data evaluation: defining sedimentation velocity distributions, Stokes-based analysis, and rules for quantifying size fractions.
- Limits and deviations: guidance on where Stokes’ law fails (porous, non‑spherical particles, agglomerates), and limits for upper/lower particle size, velocity and concentration.
- Sampling and sample preparation: requirements for primary dispersion, secondary conditioning, and representative sampling.
- Instrument preparation and measurement procedure: operational guidance for reproducible analyses.
- Method validation and quality control: system qualification, use of reference materials and performance checks.
- Uncertainty budget: stepwise approach to determine combined and expanded uncertainty for velocity and derived Stokes diameter.
- Informative annexes on technique lists, particle density considerations, and sedimentation beyond Stokes’ law.
Applications and Who Uses It
ISO 13317-1:2024 is relevant to laboratories and organizations performing particle characterization using gravitational sedimentation, including:
- Analytical and quality-control laboratories in pharmaceuticals, coatings, ceramics, chemicals, food and environmental sectors.
- Instrument manufacturers and method developers for sedimentation-based analyzers.
- R&D teams evaluating particle size distributions where high resolution in size fractions is required.
- Regulatory and conformity assessment bodies that require standardized reporting and uncertainty estimation.
Practical benefits: consistent, traceable particle size and velocity measurements; improved method validation; clear reporting formats for comparability across labs.
Related standards
- ISO 13317 series (other parts covering specific techniques)
- ISO 9276-1 (Representation of results of particle size analysis - graphical representation)
Keywords: ISO 13317-1:2024, gravitational liquid sedimentation, particle size distribution, sedimentation velocity, Stokes diameter, measurement uncertainty, method validation, particle characterization.