Introduction

The painting of hot dip galvanized steel is an orthodox and well-proven practice in outdoor environments, both in Australia (AS/NZS 2312.2) and internationally (ISO 12944.5). The practice is commonly called ‘duplex coating’.

However, there are examples of early failures of duplex coatings due to incorrect specifications and poor practice. This Guide aims to avoid such failures by directing specifiers and applicators to the paint systems, surface preparation and application practices that will provide a durable duplex coating in a broad range of service conditions.

While good painting practices and generic products for the various exposure conditions have been nominated, this does not preclude the possibility of other paints and methodologies also performing satisfactorily. However, in selecting alternative products, specifiers are urged to select products only from those with verified records of satisfactory long-term performance in equivalent or more severe service conditions.

This is a general guide only and requires strict compliance with the individual paint manufacturer’s detailed application instructions for each proprietary product.