This paper provides a measure of South Australian atmospheric corrosion rates as measured over 24 months at 20 sites. The methods include the use of internationally recognized galvanized steel corrosion coupons (1 and 2 years exposure) and monthly quantified directional pollution deposition gauges. MATENV has extensive experience over the past 30 years in using these techniques to quantify atmospheric corrosion rates in Australia, New Zealand, South Africa, and other locations.
The 20 sites carefully chosen throughout South Australia were selected with reference to the range of terrains and coastlines present in South Australia, from Mt Gambier, Port Augusta, Iron Knob, to Port Lincoln. At the request of project sponsor ElectraNet (South Australian high voltage Electricity Transmission Company), the program investigated not only the validity of the very limited historical data including AS2312 / AS4312 but expanded the knowledge base to assist in the selection of materials for power transmission assets. This project was commissioned by ElectraNet to quantify the relevant pollution and corrosion rates which affect asset degradation. The objective was to better predict end-of-life in order to augment asset management strategies. The atmospheric corrosivity study was a part of a larger investigation into durability of power transmission assets.
The assessment concluded in 2017 and was conducted during the 6 years drought, and subsequently the results for corrosion rates were lower than expected. These results provide an opportunity to discuss the relevance of the SOI (Southern Oscillations Index) measurements El Nino / La Nina conditions, climate change, and terrain.