ISO 26824:2022

Overview - ISO 26824:2022 (Particle characterization vocabulary)

ISO 26824:2022 is the international vocabulary for particle characterization of particulate systems. It defines standard terminology used to describe particle size, shape, morphology, porosity, specific surface area, sample preparation and measurement outcomes across a wide size range (nanometre to millimetre). This second edition (2022) reorganizes terms under Clause 3, harmonizes definitions with related ISO work, and updates entries to reflect modern measurement methods and interdisciplinary applications.

Key topics and technical scope

The standard provides clear, unambiguous definitions for terms related to:

• Particle classification and size representation (e.g., particle size, equivalent diameter, particle size distribution, cumulative and density distributions).
• Particle structure (primary particle, constituent particle, agglomerate, aggregate).
• Size scales and nano‑terminology (nanoscale, nano‑object, nanomaterial).
• Surface and pore properties (specific surface area, pore size distribution, porosity).
• Measurement methods and descriptors - vocabulary for widely used techniques, including:
  • sedimentation and centrifugal methods
  • sieving and classification
  • laser diffraction and dynamic light scattering
  • single particle light interaction methods and image analysis
  • differential electrical mobility and electrical mobility/number concentration for aerosols
  • acoustic methods and small-angle X‑ray scattering
  • electrical sensing zone methods and focused beam methods
• Sample preparation, reference materials, charge conditioning, zeta potential and data uncertainty terminology.

The document standardizes symbols and type‑of‑quantity conventions (number, length, area, volume/mass) for reporting particle distributions.

Practical applications and users

ISO 26824:2022 is essential for ensuring consistent communication and comparability of particle data across industries and disciplines, including:

• mining, construction, cement and aggregates
• pharmaceuticals and food production (particle size control, dissolution)
• chemical and materials processing (powders, suspensions)
• nanotechnology, microelectronics and advanced materials development
• environmental and aerosol monitoring, air quality measurement
• laboratories, instrument manufacturers, and regulators who need uniform particle characterization vocabulary for specifications, calibration, reporting and conformity assessment

Using this vocabulary helps improve data interoperability between instruments (laser diffraction, DLS, image analysis, electrical mobility analyzers), methods and international laboratories.

Related standards

ISO 26824:2022 aligns with and references related ISO documents such as ISO 9276 (presentation of particle size analysis results) and the ISO/TS 80004 family (nanotechnology terminology). It was prepared by ISO/TC 24/SC 4 (Particle characterization).

For implementation and exact definitions, consult the full ISO 26824:2022 text through your national standards body or ISO.