Overview
ISO 28340:2013 - Combined coatings on aluminium - specifies general requirements and test methods for combined coatings made of electrophoretic organic coatings (e-coat) applied over anodic oxidation (anodizing) on aluminium used in architecture. The standard defines characteristic properties, classification by performance, and the test procedures and acceptance criteria for appearance, corrosion resistance, weathering, adhesion, hardness and related properties.
Key topics and requirements
- Scope & classification
- Coatings are classified (Classes 1–4) by corrosion resistance, resistance to accelerated weathering, and resistance to cyclic corrosion/UV light. Test durations and acceptance criteria are given in Table 1.
- Test methods
- Corrosion: AASS (acetic acid salt spray) or CASS (copper-accelerated acetic acid salt spray).
- Accelerated weathering: xenon‑arc or open‑flame carbon‑arc exposure.
- Cyclic corrosion/UV: UV lamp exposure followed by AASS/CASS as applicable.
- Other referenced methods: gloss, thickness, cross‑cut adhesion, pencil hardness, solvent and chemical resistance tests.
- Performance metrics
- Appearance: visual defects (scratches, peeling) not acceptable on significant surfaces.
- Anodic layer thickness: average > 5 μm; local minimum ≥ 80% of average (i.e., ≥ 4 μm at sampled points).
- Hardness: electrophoretic organic coating ≥ 3H (pencil test).
- Adhesion: cross‑cut test (25/25) before and after immersion in boiling water without wrinkles, cracks or notable colour change.
- Solvent resistance: hardness change ≤ Δ1H with no swelling, cracking or peeling.
- Reporting
- Test specimens, sampling, expression of results and test report content are specified to ensure repeatability and traceability.
Applications and who uses it
ISO 28340:2013 is intended for professionals involved in architectural aluminium finishes:
- Architects, facade designers and specifiers selecting durable coated aluminium for building envelopes.
- Surface processors, anodizers and e‑coating manufacturers establishing process control and product specifications.
- Quality and compliance engineers defining acceptance criteria for supplied components.
- Independent testing laboratories performing AASS/CASS, weathering and adhesion tests to verify performance.
- Manufacturers of windows, curtain walls and outdoor aluminium components requiring durable combined coatings.
Related standards
Normative and related references include (examples): ISO 7599, ISO 9227, ISO 11341, ISO 2813, ISO 2810, ISO 2409, ISO 1463, ISO 2360, ISO 8251, ISO 15184, and industry documents such as AAMA 612-02.
Keywords: ISO 28340:2013, combined coatings on aluminium, electrophoretic organic coatings, anodic oxidation coatings, corrosion resistance, AASS, CASS, xenon‑arc, carbon‑arc, architectural aluminium.
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