Overview
ISO 28763:2019 specifies minimum requirements and functional characteristics for vitreous and porcelain enamel coatings applied to profiled steel panels used in regenerative air‑gas and gas‑gas heat exchangers. It covers enamel application methods (wet dipping, flow‑coating, spraying, electrodeposition, dry‑powder electrostatic spraying), testing before and after packing in baskets, and allows for stricter, customer‑supplier agreements for severe service conditions.
Key topics and technical requirements
- Scope of coatings: Applies to enamelled, regenerative and packed panels for air‑gas and gas‑gas heaters, including DeNOx/stack applications.
- Steel substrate controls: Steel must meet EN 10209 delivery and chemical composition requirements and be supplied with EN 10204:2004 certificates.
- Hydrogen permeability / fish‑scaling: Minimum hydrogen permeation TH1 = 120 (or ≥8 min per EN 10209). Where not certified, the fish‑scaling test is required; certain grades require the fish‑scaling method.
- Enamel frit and testing: Requirements for delivery certificates, fusion flow, coefficient of thermal expansion, boiling‑water (vapour‑phase) resistance and acid resistance (boiling sulfuric acid per ISO 28706‑2:2017).
- Thermal‑shock resistance: When required, measured per Annex A at 350 °C on ≥3 specimens; specimens must show no damage after five cycles.
- Adherence and defects: Adherence tests per EN 10209 Annex C - enamel adherence shall be at least level 2. Coating thickness measurement per ISO 2178. Visual examination, open/fundamental defect limits and edge covering for gas‑gas heaters are defined.
- Post‑packing characteristics: Packing pressure, visual inspection after packing and documentation requirements are specified.
Practical applications
- Ensures reliable enamelled panels for regenerative heat exchangers in power plants, desulfurization (scrubber) systems and industrial boilers.
- Helps manufacturers, enamellers and specifiers verify coating durability against thermal shock, acid corrosion, hydrogen embrittlement and mechanical handling during packing.
- Useful for procurement teams setting acceptance criteria, QA/QC engineers performing testing, and designers specifying long‑life heat‑exchanger panels.
Who should use this standard
- Enamel manufacturers and frit producers
- Heat‑exchanger fabricators and panel suppliers
- Plant engineers (power, waste‑to‑energy, chemical) and maintenance teams
- Quality assurance, inspection bodies and procurement specialists
Related standards
Key normative references include ISO 2178 (coating thickness), ISO 4534 (fusion flow), ISO 7991 (thermal expansion), ISO 28706‑2:2017 (chemical resistance), ISO 28723/28764 and EN 10209:2013 (steel delivery/inspection).
Keywords: ISO 28763:2019, vitreous enamel, porcelain enamel, regenerative panels, heat exchangers, enamel coatings, thermal‑shock resistance, hydrogen permeability, fish‑scaling, coating thickness.
Open preview (PDF)Vitreous and porcelain enamels — Regenerative, enamelled and packed panels for air-gas and gas-gas heat exchangers — Specifications
