To ensure accurate results, the following procedure, which aligns with industrial practices, should be followed:

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 Using an outdated chart can lead to failed audits or incorrect acceptance of dirty steel.

If your ISO 8502-3 test reveals a dust level higher than the project specification allows, you must remediate the surface before painting can commence.

(using a reference scale of particles/mm²):

Direct you to suppliers for the Elcometer 142 Dust Assessment Plate.