It is primarily suited for assessing rust grades A, B, and C as defined in ISO 8501-1. The ISO 8502-3 Dust Level Chart (Updated Guide)
An earlier document, but useful for understanding the foundational process.
Disclaimer: Always refer to the latest official publication of the ISO 8502-3 standard for precise, legal compliance in surface inspection.
Determined by comparing the tape sample to pictorial references that show the density of dust coverage. Common Acceptance Criteria: Many painting specifications require a maximum Quantity Rating 2 Size Class 2 for high-performance coatings. Rösler Group The Critical Role of ISO 8502-3 in Surface Preparation Introduction iso 85023 dust level chart pdf updated
Very low density; a few scattered particles are visible.
This class defines the physical size of the dominant dust particles on the tape.
A 7x or 10x magnifier (with a graticule) to evaluate particle sizes. It is primarily suited for assessing rust grades
ISO 8502-3 is a global standard developed by the International Organization for Standardization. It outlines the specific method for assessing dust remaining on cleaned steel surfaces before painting.
: Significant to heavy dust (typically requiring re-cleaning).
| Coating Environment | Acceptable Dust Quantity | Max Particle Size | Recommended Action | | :--- | :--- | :--- | :--- | | | Class 1 or 2 | <100 µm | High-pressure fresh water rinse before coating. | | Chemical Storage Tank Lining | Class 1 | <50 µm | Vacuum cleaning + tack rag immediately before coating. | | Bridge Structural Steel (Atmospheric) | Class 3 | <200 µm | Compressed air blow-down acceptable. | | Pipes buried in soil | Class 3 | <300 µm | Minor dust acceptable if primer is high-build. | | Recreational equipment / handrails | Class 4 | <400 µm | Cosmetic only – structural risk low. | Determined by comparing the tape sample to pictorial
Ranging from very fine particles to large, coarse particles clearly visible without magnification. How to Perform an ISO 8502-3 Dust Test
What or paint manufacturer guidelines are you trying to meet?
Dense dust layer; the surface is completely covered. Particle Size Classes
: Heavy dust accumulation. High particle density covering major sections of the tape area.
ISO 8502-3 Dust Tape Test — Dust Test After Blast Cleaning IOGS Official Video