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.
A background board (typically contrasting black and white) to mount the tape for inspection.
Inspectors must also classify the physical size of the dust particles using an illuminated hand lens with 10x magnification. Description Particle Size Dimension Particles not visible Under 50 µm in diameter Class 1 Small particles Visible only under 10x magnification (50 µm to 100 µm) Class 2 Medium particles iso 85023 dust level chart pdf updated
To future-proof your coating inspections, do this today:
CLASS 2 – ACCEPTABLE (with approval)
Compare the dust density on the tape with the pictorial classes in the standard to determine the rating. Download Updated ISO 8502-3 Dust Level Chart PDF (2026)
The current version of the standard is ISO 8502-3:2017 , which replaced previous editions like the 1992 version. This standard provides a qualitative, pressure-sensitive tape method to assess the quantity and size of dust remaining on blast-cleaned steel surfaces before painting. iTeh Standards ISO 8502-3 Dust Level Classifications The assessment is divided into two primary metrics: Quantity Rating Size Class iTeh Standards Particle Size Description Particle Diameter No particles visible under 10x magnification Visible under 10x magnification, not by naked eye Just visible with normal/corrected vision Clearly visible with normal/corrected vision Large particles clearly visible Very large particles clearly visible Quantity Rating (1–5): If your ISO 8502-3 test reveals a dust
It offers a permanent record of the dust present at the time of inspection.
: A scale of 0 to 5 based on measured particle diameters. The ISO 8502-3 Dust Level Chart Breakdown iTeh Standards ISO 8502-3 Dust Level Classifications The
Always ensure you are using the revision, obtain the official PDF for legal traceability, and carry a laminated reference card for daily field use.
What is the of the asset (e.g., marine immersion, bridge structural steel, or internal tank lining)?