A 7x or 10x magnifier (with a graticule) to evaluate particle sizes.

Typically a clear tape with a specific width (usually 25 mm) and adhesion strength.

The ISO 8502-3 standard defines the following dust levels:

The chart displays 5 levels of dust density.

The primary version in active use globally is , which was reviewed and reconfirmed as the current version. This standard is widely deployed across marine, oil and gas, infrastructure, and structural steel manufacturing fields where defensive industrial coatings are mandatory. The Core Classifications: Quantity and Size

Particles just visible with normal vision (50 µm to 100 µm). Class 3: Clearly visible particles (100 µm to 500 µm). Class 4: Large particles (0.5 mm to 2.5 mm). Class 5: Very large particles (greater than 2.5 mm). Why You Need an Updated PDF Chart

High density; particles cover a significant portion of the tape.

If the test results show a high dust quantity, the surface must be re-cleaned, often using clean and dry compressed air, and re-tested.