“Did you see the email?” Jan’s voice was tight. “The new charts are live. They’ve changed Size 3.”

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

Many free charts online are from obsolete versions (pre-2010). Using an outdated chart can lead to failed audits or incorrect acceptance of dirty steel.

The chart rates dust from Class 0 (cleanest) to Class 5 (dirtiest) based on a visual comparison: No dust visible under 10x magnification.

Always discard the first three turns of a new tape roll to ensure no environmental contamination affects the test.

The ISO 8502-3 dust level chart is a visual guide used to classify the dust levels on steel surfaces. The chart provides a reference for assessing the cleanliness of surfaces, which is crucial in ensuring the adhesion and performance of coatings.

The heart of the standard is a reference chart that provides both pictorial references and descriptive classes for two key parameters: the (density) of dust and the size of the dust particles. This dual assessment is crucial, as both factors independently affect coating performance.