ISO 13317-2:2001

Overview

ISO 13317-2:2001 - "Determination of particle size distribution by gravitational liquid sedimentation methods - Part 2: Fixed pipette method" specifies the Andreasen (fixed-position) pipette method for measuring particle size distribution by gravitational sedimentation in a liquid. The method typically covers the size range 1 µm to 100 µm and is applicable to powders that can be dispersed as stable suspensions (particles denser than the suspending liquid and chemically/physically stable in it). The standard describes apparatus, calibration, sample preparation, measurement procedure, calculation and reporting.

Key topics and technical requirements

• Principle: Incremental sampling with a fixed-depth pipette; cumulative undersize-by-mass is obtained by extracting timed aliquots as particles settle (Stokes law relates withdrawal time to particle Stokes diameter).
• Apparatus and dimensions: Typical sedimentation vessel ~500 ml with a graduated scale (0–20 cm); pipette capacity to the mark 10 ml; pipette capillary bore 1.0–1.3 mm, stem bore about 3.5 mm. A vented dome and two-way tap are described.
• Calibration: Determine vessel volume (V) to 0.3% and calibrate pipette internal volume (Vp) by weighing. Pipette and vessel volumes are used to calculate concentrations.
• Sample preparation: Representative sampling (ISO 8213) and dispersion (ISO 14887) to a test concentration of about 0.2% by volume; note use of ultrasonics or mechanical stirring where appropriate.
• Measurement controls: Temperature control (constant-temperature bath for analyses >1 h), vibration-free environment, and accurate timing (timer resolution 1 s). Balance accuracy recommended 0.1 mg or better. Drying oven temperatures for water given (about 378.15 K to 383.15 K).
• Procedure essentials: Initial duplicate 10 ml extracts to establish the 100% mass, timed extractions with pipette filled ~20 s (start 10 s before, end 10 s after target time), removal and drying of residues, and duplicate/validation checks (e.g., duplicate initial samples within 2%).
• Variations and notes: Leschonski modification and considerations when material sizes exceed the coarse end for a given suspending liquid (use higher-viscosity liquid or overlap distributions).

Applications and users

ISO 13317-2:2001 is used where accurate mass-based particle size distributions in the 1–100 µm range are required:

• Quality control and R&D laboratories
• Materials science (ceramics, minerals)
• Pigments, fillers and powder manufacturers
• Pharmaceutical and chemical testing labs
• Environmental and geological sample analysis

The method is valuable for powders that must be dispersed reliably in liquid and where mass-based undersize curves (via gravitational sedimentation) are required.

Related standards

• ISO 13317-1: General principles and guidelines for gravitational liquid sedimentation methods
• ISO 8213: Sampling techniques for solid chemical products
• ISO 9276-1: Graphical representation of particle size analysis results
• ISO 14887: Sample preparation - dispersing procedures for powders in liquids

Keywords: ISO 13317-2:2001, fixed pipette method, Andreasen pipette, particle size distribution, gravitational liquid sedimentation, Stokes diameter, sedimentation vessel, calibration, sample dispersion.