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 <0.25%; light gauge ±0.15%).
• Acid resistance: Minimum Class A (ISO 28706-1); exterior environments maximum mass loss 18.5 g/m2 (ISO 28706-2).
• Aesthetics: Surface appearance, gloss (ISO 2813), and colour tolerance determined by agreement; visual inspection in D65 or natural light.
• Graffiti resistance: After eight days’ ageing, inks/paints shall be removable with suitable solvents without visible change to gloss or colour.

Applications and users

ISO 28722:2008 is used by:

• Architects and facade engineers specifying durable, aesthetic enamelled cladding
• Manufacturers of vitreous and porcelain enamelled steel panels for quality control and production acceptance
• Specifiers and procurement teams writing performance-based contracts
• Testing laboratories and QA inspectors performing adherence, porosity, abrasion, impact, hardness, and graffiti-resistance tests
• Installers and fabricators concerned with edge protection, flatness and on-site assembly

Related standards

Normative references include ISO 2178, ISO 2813, ISO 4532, ISO 15695, ISO 28706-1/-2, EN 10209 and EN 14430 - all relevant when applying ISO 28722:2008 to architectural enamelled panel specification and testing.