TECHNICAL STANDARD
ISO 12944-4
Paints and varnishes — Corrosion protection of steel structures by protective paint systems — Part 4: Types of surface and surface preparation
ISO
2017 (ISO confirms published; revision in development)
Current
WHAT DOES THIS STANDARD COVER?
Covers types of steel surfaces and their preparation before protective painting, including uncoated, previously coated, galvanized and thermally sprayed surfaces.
WHY IS IT RELEVANT?
Helps inspectors and specifiers match the preparation approach to the actual substrate and coating history. A visual preparation grade alone does not settle contamination, profile or product-specific requirements.
KEY INSPECTION CONSIDERATIONS
Identify the existing substrate and coating condition before selecting or checking the specified preparation method.
WHAT THE STANDARD SHOULD NOT BE USED TO ASSUME
Do not assume every surface in the ISO 12944-4 scope is treated the same way, or that preparation grades establish the starting condition of the substrate.
PRACTICAL INSPECTION APPLICATION
Use to frame specification review and inspection planning for new and maintenance painting on steel.
RELATED TECHNICAL STANDARDS
RELATED TECHNICAL TOPICS
steel surface preparation; galvanized steel; existing coatings; protective paint systems
RELATED PIL GUIDANCE
Practical guidance on assessing abrasive blast-cleaned steel surface profile before protective coating application.
RELATED EXPERTISE
Coating Inspection; Condition Surveys; 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.
PIL TECHNICAL ASSISTANT
Ask the PIL Technical Assistant about this standard and related coating inspection topics.
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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
Verified 4 November 2026 against ISO publisher record: ISO 12944-4:2017, Edition 2, published and confirmed in 2023; a revision is in development. https://www.iso.org/standard/64836.html