This article provides the breakdown of the ISO 85023 dust level chart PDF , including how to download the latest version, interpret the classes (1, 2, 3), and apply it correctly on-site.
: Particles visible with normal vision but less than 0.5 mm in diameter.
"Q3, M100, Mx300" translates to: Quantity Class 3 dust, median particle size 100 micrometers, maximum particle size 300 micrometers.
“The particle density,” Jan said. “The old chart showed Size 3 as scattered particles under 10x magnification. The new update—ISO 85023-3:2025—has revised the micrograph. Size 3 now shows clusters . Which means our current ‘acceptable’ threshold for turbine tower internals is now a ‘reject’.”
A: The board is usually part of a dust tape test kit, available through manufacturers like Elcometer or Industrial Physics. iso 85023 dust level chart pdf updated
Always perform a high-pressure air blow-down after blasting. Ensure the compressed air used for blowing down is strictly oil-free and dry (compliant with ASTM D4285).
Understanding the dust quantity ratings and size classes is essential for inspectors to ensure paint adhesion and prevent premature corrosion. ISO 8502-3 Dust Level Ratings
Surface preparation is the most critical factor in determining the lifespan of a protective coating system. Among various surface contaminants, dust particles deposited on blast-cleaned steel surfaces can severely degrade coating adhesion, leading to premature blistering, peeling, and failure.
The updated ISO 8502-3 PDF reflects the latest research and developments in the field of coating applications. The revised standard includes: This article provides the breakdown of the ISO
The complete, authoritative standard can be purchased via ISO or ANSI.
Very high density. The tape is almost entirely covered by a dense layer of dust particles. 2. Dust Size Classes (0 to 5)
No dust present (Background contrast equal to reference). Class 1: Very low dust (Slightly detectable). Class 2: Low dust (Clearly visible but small amount). Class 3: Moderate dust (Moderate amount). Class 4: High dust (Large amount). Class 5: Very high dust (Extremely large amount). Particle Size Assessment
If a tape sample exhibits an overall reddish-brown or black discoloration, the rule requires inspectors to record a Quantity Rating 5 and Size Class 1 . This indicates a massive concentration of microscopic abrasive breakdown dust that can severely interfere with coating adhesion. Standard Step-by-Step Testing Procedure “The particle density,” Jan said
The standard was majorly updated in , which replaced the older 1992 version. The updated standard clarifies testing procedures, establishes rigorous parameters for the pressure-sensitive tape, and standardizes visual assessment templates to reduce human subjectivity. 2. The Core Metric: Dust Quantity Ratings (0–5)
The ISO 85023 dust level chart is a visual and descriptive reference table that classifies the amount of dust remaining on a blasted steel surface. It works in conjunction with the (also known as the "tape test").
Use tape that meets ISO 8502-3 specifications.
A specialized adhesive tape is applied to the surface, pressed down, and then removed to collect dust particles.
: Peel back and discard the first three full turns of the pressure-sensitive tape roll to avoid using contaminated adhesive.
The assessment is based on two factors: