ISO 4628-2-2016 PDF

Full title and description

Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity and size of defects, and of intensity of uniform changes in appearance — Part 2: Assessment of degree of blistering (ISO 4628-2:2016). This part specifies a visual method for assessing the degree of blistering in coatings by comparison with pictorial reference standards illustrating a range of blister sizes and densities.

Abstract

ISO 4628-2:2016 specifies a method for assessing the degree of blistering of coatings by comparison with pictorial standards. The pictorial standards in this part illustrate blisters in sizes 2, 3, 4 and 5, each shown at densities (quantities) 2, 3, 4 and 5. The method uses the designation system defined in ISO 4628-1 and is intended primarily for defects caused by ageing and weathering and for uniform appearance changes (e.g., yellowing).

General information

• Status: Published (confirmed by ISO review).
• Publication date: January 2016.
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 87.040 (Paints and varnishes).
• Edition / version: Edition 3 (2016).
• Number of pages: 13.

Scope

This part of ISO 4628 provides a standardized visual assessment procedure to rate blistering on coated surfaces by matching observed blister size and density to pictorial comparators. It is intended for use on coatings subject to ageing and weathering and for informing test reports, quality control, specification compliance and comparative evaluations between coatings or exposure conditions.

Key topics and requirements

• Use of pictorial reference standards showing blister sizes (2–5) and densities (2–5) for direct visual comparison.
• Designation and reporting conventions aligned with ISO 4628-1 (system for quantity/size/intensity designations).
• Guidance for selecting test areas and matching observed defects to the closest pictorial grade.
• Application primarily to defects from ageing, weathering and uniform appearance changes (e.g., yellowing, loss of gloss associated with blistering).
• Intended for visual assessment (qualified operator/judgement required) and for inclusion in test/inspection reports and specifications.

Typical use and users

Used by paint and coating manufacturers, independent test laboratories, quality-control and inspection personnel, coating specifiers, corrosion engineers and asset owners for product development, acceptance testing, condition surveys and failure analysis.

Related standards

ISO 4628-2 is part of the ISO 4628 series. Related parts include ISO 4628-1 (general introduction and designation system), ISO 4628-3 (assessment of degree of rusting), ISO 4628-4 (cracking), ISO 4628-5 (flaking), ISO 4628-6/7 (chalking methods) and ISO 4628-8 (delamination and corrosion around a scribe). Users typically refer to the relevant part(s) of ISO 4628 together when evaluating overall coating degradation.

Keywords

blistering; coatings; paints and varnishes; degradation; pictorial standards; visual assessment; defects; ISO 4628; inspection; quality control.

FAQ

Q: What is this standard?

A: ISO 4628-2:2016 is an international standard that defines a visual method for assessing the degree of blistering on paint and varnish coatings using pictorial reference standards.

Q: What does it cover?

A: It covers the visual comparison procedure and pictorial comparators for blister size (sizes 2–5) and blister density (quantities 2–5), and the way results are designated and reported in accordance with the ISO 4628 system.

Q: Who typically uses it?

A: Paint and coating manufacturers, testing laboratories, QC/inspection teams, specifiers and corrosion/asset managers use it for product testing, acceptance, condition surveys and comparative evaluations.

Q: Is it current or superseded?

A: ISO 4628-2:2016 is the current published edition (Edition 3, published January 2016) and was subject to ISO’s periodic review (confirmed in the ISO publication record). Users should check ISO or their national standards body for any later revisions or national adoptions before relying on the standard for compliance purposes.

Q: Is it part of a series?

A: Yes — it is Part 2 of the ISO 4628 series; ISO 4628-1 establishes the designation system and the other parts provide pictorial or procedural methods for specific defect types (rusting, cracking, flaking, chalking, delamination, filiform corrosion, etc.).

Q: What are the key keywords?

A: Key keywords include blistering, pictorial standards, visual assessment, coatings degradation, ISO 4628, defects, paints, varnishes, inspection and quality control.