Enamelled steel tanks, in combination with sacrificial magnesium anodes, represent the most effective solution for domestic hot water storage. Over the years, numerous standards have been developed to assess the performance and durability of enamel coatings in such applications. Among these, two critical parameters are the total weight loss and the watertightness of the enamel layer. The former, evaluated in boiling demineralised water or boiling sodium bicarbonate solution, serves as an indicator of the coating’s corrosion resistance. The latter is assessed via electrical current leakage testing across the entire enamelled surface, providing insight into the coating’s integrity.
Beyond durability, the physiological safety of enamelled tanks is paramount. Elemental leaching from enamel into drinking water must be minimized. The European Drinking Water Directive 98/83/EC, updated by Directive (EU) 2020/2184, has introduced stricter quality requirements. In 2021, Germany implemented a positive list for enamel compositions and specified permissible leaching thresholds for various elements. From 2027, new EU-wide regulations will enforce leaching limits at elevated temperatures (60?°C and 85?°C).
This presentation will review current and forthcoming standards and legislation, and examine how composition and temperature influence leaching behavior