TECHNICAL STANDARD
ISO 4628-6
Paints and varnishes — Evaluation of quantity and size of defects, and of intensity of uniform changes in appearance — Part 6: Assessment of degree of chalking by tape method
ISO
Edition 4 / 2023
Current
WHAT DOES THIS STANDARD COVER?
Provides a method and pictorial references for assessing the degree of chalking of paint coatings using a tape method.
WHY IS IT RELEVANT?
Relevant during coating condition surveys and failure investigations when degradation includes chalking. Care is required to distinguish actual coating degradation products from surface dirt or other contamination.
KEY INSPECTION CONSIDERATIONS
The standard addresses assessment of the degree of chalking using a tape method. Chalking is associated with friable material developing at the coating surface. The method provides a consistent means of assessing surface chalking and should distinguish coating degradation from unrelated dirt or surface contamination.
WHAT THE STANDARD SHOULD NOT BE USED TO ASSUME
A chalking assessment does not establish remaining coating life and is not an adhesion test. It describes a surface condition rather than the overall integrity of the complete coating system. Where recoating is being considered, chalking should be assessed alongside wider coating condition, cleanliness, adhesion and suitability for maintenance coating.
PRACTICAL INSPECTION APPLICATION
Inspectors can use the method at representative areas during coating condition surveys and record the location and coating condition. Differences associated with exposure should be considered where relevant. Maintenance decisions should take account of the wider coating condition rather than the chalking assessment alone.
RELATED TECHNICAL STANDARDS
RELATED TECHNICAL TOPICS
chalking; condition assessment; coating failure; condition surveys
RELATED EXPERTISE
Condition Surveys; 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.