Just visible with normal or corrected vision (50 μm to 100 μm). Naked Eye / Corrected Vision Clearly visible with normal vision (up to 0.5 mm). Naked Eye / Corrected Vision Class 4 Large particles clearly visible (0.5 mm to 2.5 mm). Naked Eye / Ruler Class 5 Macro-particles clearly visible (larger than 2.5 mm). Naked Eye / Ruler 2. Dust Quantity Ratings
A: The board is usually part of a dust tape test kit, available through manufacturers like Elcometer or Industrial Physics.
Small, scattered groupings of dust; standard pass threshold. Medium density; clear, widespread particle clusters. Rating 4 Heavy accumulation; large portions of the tape are covered. Rating 5 Severe / Discolored Total coverage or uniform tape discoloration. 2. Dust Particle Size Classes (0 to 5)
In addition to the quantity (Classes 0-5), the standard allows for the classification of particle size, typically described as: Not visible without magnification. Medium Particles: Visible to the eye, but small. Large Particles: Clearly visible. How to Perform the ISO 8502-3 Dust Test iso 85023 dust level chart pdf updated
To obtain the official PDF of , you must purchase it from an authorized standards distributor. This is a copyrighted document that cannot be legally obtained for free. Official PDFs are available for purchase from sources like normadoc.com , shop.standards.ie , and intertekinform.com , with prices generally ranging between $80 and $100 USD.
What or paint manufacturer guidelines are you trying to meet?
The updated standard emphasizes that any visible dust of size >500 µm is an automatic failure , regardless of quantity class. Just visible with normal or corrected vision (50
To future-proof your coating inspections, do this today:
Heavy dust level; particles cover a significant portion of the surface.
In the world of industrial coating, abrasive blasting, and protective painting, surface cleanliness is not negotiable. Before applying any high-performance coating—whether for a bridge, a pipeline, a ship, or an oil rig—you must ensure the surface is free from soluble salts, oil, grease, and . Naked Eye / Ruler Class 5 Macro-particles clearly
ISO 8502-3 specifies a simple, field-friendly method using (commonly a transparent Scotch tape of defined tackiness) to lift dust from a prepared steel surface. The tape is then applied to a contrasting background (typically a white or black card), and the extracted dust is compared against a standardized reference scale.
The standard classifies the size of the dust particles using letters:
| Error | Consequence | Correction | |-------|-------------|-------------| | Using non-approved tape | Underestimates dust | Use ISO-specified tape | | Pressing too lightly | Misses embedded dust | Apply ≥ 5 N/cm² pressure | | Viewing without magnification | Misses fine dust (Class 1–2) | Always use ×10 minimum | | Only checking one location | Non-representative result | Take 5 samples per 10 m² |