ISO 28706-1:2008

Overview

ISO 28706-1:2008 - Vitreous and porcelain enamels - Part 1 defines a standardized laboratory method to determine the resistance of vitreous and porcelain enamelled articles to chemical corrosion by acids at room temperature. The standard sets out test principles, required reagents and apparatus, specimen preparation references, procedures for exposure and assessment, and a method for classifying results.

Key Topics

• Scope and principle: exposes a defined area of enamel to an acidic test solution at ambient temperature and assesses resistance primarily by appearance and cleanability of the enamel surface.
• Reagents and quality requirements: uses analytical-grade reagents and high-purity laboratory water (see ISO 3696). Examples in the standard include citric acid (monohydrate) and sulfuric acid (0.5 mol/l) as test solutions.
• Apparatus and specimens: specifies common laboratory glassware (100 ml graduated cylinder and 100 ml volumetric flask per ISO 4788 / ISO 1042), pipettes, cleaning cloths and filter papers, and refers to ISO 28764 for specimen production from enamelled steel, aluminium and cast iron.
• Procedure and classification: defines exposure procedure, inspection and cleaning methods, and a classification scheme based on visual change and the enamel’s ability to be cleaned after attack.
• Limitations: notes that enamels fired below 700 °C may require different conditions; Part 1 is intended for room-temperature acid testing only.

Applications

ISO 28706-1:2008 is used for:

• Quality control of enamel coatings in manufacturing (sanitaryware, cookware, appliances, chemical equipment).
• Comparative testing during product development and material selection to ensure acid resistance in service environments.
• Third‑party testing and specification compliance for purchasers and regulators.
• Failure analysis of enamelled articles exposed to acidic environments at ambient temperature.

Typical users:

• Enamel manufacturers and coating formulators
• Materials and corrosion testing laboratories
• Product engineers, quality managers and procurement teams
• Regulatory bodies and standards organizations

Related Standards

• ISO 28706 series (Part 2 - boiling acids/vapours; Part 3/4 - alkaline liquids; Part 5 - closed systems)
• ISO 28764 - specimen production for enamel tests
• ISO 3696 - laboratory water quality
• ISO 1042, ISO 4788 - laboratory glassware specifications

Keywords: ISO 28706-1:2008, vitreous and porcelain enamels, resistance to chemical corrosion, acid corrosion test, room temperature, enamel testing, test method, classification.