TECHNICAL STANDARD
ISO 4628-1
Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity and size of defects, and of intensity of uniform changes in appearance — Part 1: General introduction and designation system
ISO
2016
Current
WHAT DOES THIS STANDARD COVER?
ISO 4628-1 establishes the general system used within the ISO 4628 series for designating the quantity and size of coating defects and the intensity of changes in coating appearance. It provides the framework used by the other parts of the series for more specific forms of deterioration.
WHY IS IT RELEVANT?
Provides coating inspectors with a recognised framework for recording and communicating coating deterioration consistently during condition surveys and failure investigations. It supports structured assessment rather than relying solely on subjective descriptions such as minor, moderate or severe.
KEY INSPECTION CONSIDERATIONS
The standard provides the general system for describing the quantity and size of coating defects and the intensity of uniform changes in appearance. It provides a consistent framework used with other parts of the ISO 4628 series addressing conditions such as blistering, rusting, cracking, flaking and chalking. Consistent assessment terminology is important when comparing coating condition across surveys or inspection periods.
WHAT THE STANDARD SHOULD NOT BE USED TO ASSUME
A coating condition rating describes the observed condition; it does not establish why the condition developed. Identification or classification of a defect should not be treated as a root-cause determination. Condition assessment alone does not establish remaining coating life or determine the appropriate maintenance action.
PRACTICAL INSPECTION APPLICATION
The standard can support coating condition surveys, maintenance assessments and failure investigations by providing a consistent method of recording observed deterioration. Inspectors should record defect type, location and extent and use photographs where appropriate. Additional evidence may be required where the cause of deterioration needs to be established.
RELATED TECHNICAL STANDARDS
RELATED TECHNICAL TOPICS
Condition Assessment Coating Condition Coating Degradation Defect Assessment Coating Inspection
RELATED PIL GUIDANCE
A pre-condition coating survey brings visual inspection, testing, sampling and access planning together to support evidence-based maintenance decisions.
A structured approach to investigating protective coating failure through evidence, testing, sampling and project-record review.
RELATED EXPERTISE
Condition Surveys 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
Standard number, edition, title and current publication status checked against the official ISO catalogue in September 2026.