ISO 28722:2008

Overview

ISO 28722:2008 - "Vitreous and porcelain enamels - Characteristics of enamel coatings applied to steel panels intended for architecture" defines requirements for enamel-coated, plane, cold-rolled heavy- and light-gauge steel panels for interior and exterior architectural use. The standard covers functional and aesthetic characteristics of vitreous/porcelain enamel coatings and specifies resistance to graffiti, providing test-based limits and acceptance criteria for enamelled architectural panels.

Key topics and technical requirements

• Scope: Applies to enamel-coated steel panels intended for architectural cladding, facades and interior elements.
• Substrate and coating layers: Steel shall conform to EN 10209; a minimum of two enamel layers on external faces and one on internal faces is required.
• Final enamel thickness (measured per ISO 2178):
  • Heavy-gauge external: 180–500 µm; internal: 100 µm
  • Light-gauge external: 75–275 µm; internal: 60 µm
• Adherence: Minimum Class 3 adherence (EN 10209 Annex D) after final firing.
• Porosity: Open-pore limits defined by test (EN 14430 or ISO 8289 methods): e.g., max 10 pores/m2 (EN 14430).
• Abrasion resistance: Taber test (ASTM C501) - maximum mass loss 0.1 g after 1,000 revolutions (S33, 1 kg).
• Impact resistance: ISO 4532 pistol test - no damage greater than 2 mm diameter when activated at 20 N after 24 h.
• Surface hardness & scratch: Mohs hardness ≥ 5 (EN 101); scratch resistance ≥ 7 N (ISO 15695). Metallic and silk-screened finishes: ≥ 4 N.
• Flatness: Maximum deflection limits for finished panels (heavy gauge convex 0.5%, concave