Chart Pdf Updated | Iso 85023 Dust Level

The average size of the dust particles is assigned a class from 0 to 5 based on visibility and diameter: Particle Description Typical Diameter No particles visible under 10x magnification 1 Visible under 10x magnification (not to naked eye) 2 Just visible with normal vision 50 μm – 100 μm 3 Clearly visible with normal vision Up to 0.5 mm 4 Clearly visible 0.5 mm – 2.5 mm 5 Clearly visible 2. Dust Quantity Ratings

| Dust Class | Maximum Particle Size (µm) | Typical Quantity (particles/cm²) | Visual / Tape Appearance | Typical Coating Suitability | |------------|----------------------------|----------------------------------|--------------------------|-----------------------------| | | < 50 | 1–5 | Almost invisible, very few tiny specks | High-performance systems (epoxy, polyurethane, marine) | | 2 | 50 – 100 | 6–20 | Scattered small dots, clearly visible on tape | Industrial coatings (alkyd, epoxy mastic) | | 3 | 100 – 200 | 21–50 | Many medium-size particles, no clustering | Low-risk environments only (non-immersion) | | 4 | 200 – 300 | 51–100 | Dense particles, some clusters visible | Not acceptable for critical coatings | | 5 | > 300 | > 100 | Heavy dust layer, clumps | Rejection – requires re-blasting or cleaning | iso 85023 dust level chart pdf updated

Dust on blast-cleaned steel surfaces reduces coating adhesion, causes osmotic blistering, and creates premature failure points. ISO 8502-3:2017 specifies a method for assessing the quantity and size of dust particles remaining after surface preparation. This paper provides the and interpretation guidelines. The average size of the dust particles is