TECHNICAL STANDARD
ISO 8502-3
Preparation of steel substrates before application of paints and related products — Tests for the assessment of surface cleanliness — Part 3: Assessment of dust on steel surfaces prepared for painting (pressure-sensitive tape method)
ISO
Edition 2 / 2017
Current
WHAT DOES THIS STANDARD COVER?
Describes assessment of dust remaining on cleaned steel surfaces using pressure-sensitive tape, including assessment of dust quantity and particle size.
WHY IS IT RELEVANT?
Used during surface-preparation inspection to identify residual dust before coating. Project specifications should define required acceptance criteria.
KEY INSPECTION CONSIDERATIONS
ISO 8502-3 provides a pressure-sensitive tape method for assessing dust remaining on cleaned steel surfaces prepared for painting. The assessment considers both the quantity of dust present and the size of the dust particles. Residual dust can interfere with coating application and may affect adhesion or the integrity of the applied coating system. The test provides a practical means of assessing surface dust before coating and can also provide a retained record of the condition observed at the test location.
WHAT THE STANDARD SHOULD NOT BE USED TO ASSUME
The dust test should not be treated as an assessment of soluble salt contamination, surface profile or visual preparation grade. A surface can satisfy a visual preparation requirement while still carrying dust or other contamination requiring separate assessment. ISO 8502-3 does not establish one universal dust acceptance criterion for every coating system. The acceptable dust quantity and particle-size classification should be established from the project specification, coating manufacturer requirements or other controlling documentation.
PRACTICAL INSPECTION APPLICATION
ISO 8502-3 is commonly used after surface preparation and before coating application where dust contamination is controlled by the project. Representative areas of the prepared steel should be selected and tested using the specified procedure. The inspector should record the test location and resulting dust quantity and particle-size classifications where required. The result should then be compared with the project-specific acceptance requirement before coating application proceeds.
RELATED TECHNICAL STANDARDS
RELATED TECHNICAL TOPICS
dust; surface cleanliness; surface preparation
RELATED EXPERTISE
Coating Inspection; Testing & Analysis; Technical Consultancy
ABOUT THIS TECHNICAL SUMMARY
Paint Inspection Ltd provides this information to help inspectors, engineers, asset owners and contractors understand the practical relevance of commonly referenced protective coatings standards. This page is PIL technical guidance and does not reproduce or replace the published standard. Users should refer to the current published standard, project specification, coating manufacturer requirements and other applicable contract documents when establishing project requirements or acceptance criteria.
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OFFICIAL STANDARD
PIL technical summaries are intended to explain the inspection relevance of industry standards and do not replace the published document.
STATUS AND SOURCE VERIFICATION
Edition and status checked against the official ISO catalogue in September 2026.