Operation and Maintenance Overview
Hot-dip galvanized items are subject to corrosion over time, with the rate depending on environmental and mechanical factors. The document outlines the expected lifespan of zinc coatings under various corrosivity categories (C1 to C5) based on the mean zinc layer thickness as per EN ISO 1461:2009. Regular inspections are recommended to assess the zinc layer's condition, especially in critical areas prone to wear or thermal bridges. Inspection intervals typically range from 1 to 5 years.

Corrosion Categories and Zinc Layer Thickness
The document provides a detailed table showing the life expectancy of zinc coatings across different corrosion categories (C1-C5) for various steel and cast iron thicknesses. Special requirements for thicker zinc layers are noted, particularly for steel with specific silicon content.

Repairing Damage to Galvanized Surfaces
If repairs are needed, the Nordic Galvanizers organization provides guidelines in line with DS/EN ISO 1461:2009. Repair methods include metal spraying with zinc, zinc-rich paint application, and low-melting soldering zinc. Specific requirements for repairs include limitations on bare spot size and ensuring the repaired coating provides cathodic protection.

Repair Methods
- Zinc Dust Paint: Suitable for areas smaller than 4 cm², involving grinding and applying multiple layers of zinc dust paint to a minimum thickness of 100 μm.
- Zinc Spray Metallizing: Used for areas larger than 4 cm², involving sandblasting and metallizing with zinc to a minimum thickness of 100 μm.

Non-Repairable Damage
Small zinc flaking areas up to 5 mm wide, typically on edges, do not require repair as they are protected cathodically by surrounding zinc.

Contact Information
For further inquiries, contact DOT A/S at their various locations in Denmark.