ISO 4628-3-2024 PDF

Full title and description

St ISO 4628-3-2024 — Paints and varnishes — Evaluation of quantity and size of defects, and of intensity of uniform changes in appearance — Part 3: Assessment of degree of rusting. This part provides pictorial standards and a visual assessment method for rating the degree of rusting on coated surfaces (including duplex metallic + organic systems) by comparison with reference images and percentage-area estimations.

Abstract

ISO 4628-3:2024 specifies a visual method for assessing the degree of rusting on surfaces coated with organic coatings, and metallic coating plus organic coating (duplex systems), by comparison with pictorial standards that show different degrees of rust penetration and under-rusting. The method gives an estimation of affected area (edges excluded) and is intended for evaluation of deterioration caused by ageing and weathering. The document is available in English and French.

General information

• Status: Published.
• Publication date: 13 November 2024 (ISO edition released November 2024).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 87.040 — Paints and varnishes.
• Edition / version: Edition 4 (2024).
• Number of pages: 22.

Scope

Provides pictorial reference standards and a visual assessment procedure to estimate the degree of rusting on coated metal surfaces. Applicable to organic coatings and duplex systems, the procedure is intended primarily for defects resulting from ageing and outdoor exposure and for uniform changes in appearance related to rusting; it defines how to compare specimens with reference images and how to express the affected area as an approximate percentage (edges are excluded from the assessment).

Key topics and requirements

• Provision of pictorial standards illustrating increasing degrees of rusting and under-rusting.
• Visual comparison method for assigning a rusting degree based on percentage-area estimation.
• Guidance on inspection conditions and how to treat edges (edges excluded from area estimation).
• Application to organic coatings and metallic + organic (duplex) coating systems.
• Intended use for evaluations caused by ageing, weathering and other environmental exposure.

Typical use and users

Used by corrosion engineers, coating and paint manufacturers, quality-control and test laboratories, inspection bodies, asset owners (e.g., infrastructure and marine operators), specification writers, and research organisations for routine inspections, comparative assessments, specification compliance and failure analysis.

Related standards

Part of the ISO 4628 series (general system defined in ISO 4628-1 and pictorial/assessment parts for specific defect types such as blistering, cracking, flaking, rusting, etc.). ISO 4628-3:2024 supersedes ISO 4628-3:2016 (previous edition). Other relevant parts include ISO 4628-1 (general introduction and designation system), ISO 4628-2 (blistering), ISO 4628-4 (cracking), ISO 4628-5 (flaking), ISO 4628-6 (chalkability/abrasion of surface film), ISO 4628-7 and ISO 4628-8 where applicable. Users often reference related corrosion and coating standards (for example standards on accelerated corrosion testing and exposure) when setting up inspection and test programs.

Keywords

rusting; corrosion assessment; pictorial standards; coatings evaluation; paints and varnishes; duplex systems; visual inspection; ISO 4628; degree of rusting; area estimation.

FAQ

Q: What is this standard?

A: ISO 4628-3:2024 is the ISO international standard that defines pictorial reference standards and a visual assessment method for determining the degree of rusting on coated metal surfaces.

Q: What does it cover?

A: It covers visual comparison with pictorial standards to estimate the percentage area affected by rust (including under-rusting and rust broken through the coating), guidance on exclusion of edges, and applicability to organic coatings and metallic + organic (duplex) systems. It is intended mainly for deterioration from ageing and weathering.

Q: Who typically uses it?

A: Coating manufacturers, quality and test laboratories, corrosion/inspection engineers, asset owners, specification writers and independent inspection bodies use this standard for routine inspections, acceptance testing and failure analysis.

Q: Is it current or superseded?

A: Current — ISO 4628-3:2024 (Edition 4) was published in November 2024 and replaces the previous 2016 edition (ISO 4628-3:2016).

Q: Is it part of a series?

A: Yes — it is part of the ISO 4628 series that provides a general designation system (ISO 4628-1) plus parts addressing specific defect types (blistering, cracking, flaking, rusting, etc.). See ISO 4628-1 for the series framework.

Q: What are the key keywords?

A: Rusting, corrosion assessment, pictorial standards, coatings inspection, ISO 4628, visual rating, duplex coating systems.