Overview
ISO 8130-5:2021 - "Coating powders - Part 5: Determination of flow properties of a powder/air mixture" specifies a laboratory method to estimate the flow and transport behaviour of a coating powder when fluidized with air. The standard defines the test apparatus, environmental conditions, sampling, procedure and calculation of key metrics used to characterise powder fluidization and spray-transfer performance.
Key topics and requirements
- Scope and influences: Results are affected by powder composition, density, particle size distribution, particle shape, agglomeration tendency and electrostatic charging.
- Apparatus essentials:
- Fluidization vessel (≈100 mm ID, ≥200 mm height) with porous bottom (max pore ~40 µm) and a 4 mm circular orifice.
- Air regulation and flowmeter (calibrated to ~200 l/h nominal).
- Clean dry compressed air, timer (1 s accuracy), analytical balance (500 g capacity, 0.1 g readability), ruler and spatula.
- Test conditions:
- Standard laboratory conditions: (23 ± 2) °C and (50 ± 5) % relative humidity; atmospheric pressure recorded.
- Sample charged: (250 ± 10) g for each run (NOTE: 1 kg sample recommended for overall sampling).
- Air flow: typically (200 ± 10) l/h; if optimum fluidization is outside this range, that value may be used (but direct comparison across different flows is not valid).
- Procedure highlights:
- Calibrate apparatus to the required air flow.
- Measure bed height at rest (h1) and fluidized height (h2) to ±2 mm.
- Fluidize and collect powder discharged through the 4 mm orifice for (30 ± 1) s, weigh collected mass (m) to 0.1 g.
- Perform tests in duplicate; if results differ by >5 %, perform a third run.
- Calculations:
- Fluidization factor φ = h1 / h2
- Powder flow rate R (g·s−1) = (m · φ) / t
- Reporting: test identification, reference to ISO 8130-5:2021, environmental conditions, air flow rate, observations (channelling/bubbling), results (φ and R), deviations and anomalies, and test date. Note: precision data currently not available.
Applications
ISO 8130-5 is used by:
- Powder coating manufacturers and formulators for quality control and R&D.
- QC laboratories assessing batch-to-batch consistency and sprayability.
- Equipment and spray-booth designers validating fluidization and feed behaviour.
- Suppliers and purchasers specifying performance requirements for transfer and application of coating powders.
Practical benefits include standardized assessment of powder transportability, easier troubleshooting of application problems (poor spray or clogging), and objective data for product specifications and supplier comparisons.
Related standards
- ISO 8130-14 (Vocabulary for coating powders)
- ISO 15528 (Sampling of paints, varnishes and raw materials)
- Other parts of the ISO 8130 series covering additional powder-coating test methods and properties
Keywords: ISO 8130-5, coating powders, powder/air mixture, fluidization factor, powder flow rate, flow properties test, powder coating testing, powder sprayability.
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