Resource: Corrosion maps now available for macro-climate classification

We are pleased to announce the launch of our online corrosivity map to enable our members to search by address to quickly and precisely determine a recommended corrosion classification for their project.

Developed in collaboration with NIWA, these corrosion maps were first published in SNZ TS3404:2018 based on our past research projects. These paper-based maps providing guidance to designers on the macro-climate corrosion classification of any site in New Zealand.

Since then, we have worked to develop this into an interactive digital tool so our members who are designers and engineers are able to precisely and quickly determine the correct corrosivity zone for the structural steel in their project. This in turn, improving durability design and enhancing the steels long term sustainability.

Why did we turn this into a digital tool?

Moving this offering to a digital offering was part of our sustainability research fund projects – to increase the durability of steel structures to improve lifespan for more sustainable structures.

The maps provided in TS3404 did not provide corrosion classification within 500m of the coastlines. For any structures in this region, designers needed to use additional table data from TS3404 to determine macro-climate classification. While this was a relatively easy step to do, it did make the process laborious and time consuming for an engineer as it required them to determine relative distances to saltwater, whether the areas was considered calm or had breaking surf, along with coastal aspects and prevailing winds. This was also challenging to determine if the site in question was close to the intersection of two different corrosivity zones. Getting this right is crucial, as the durability of a steel structure has a direct link to the life span of the structure. If we are able to assist in increasing the lifespan of steel structures, it in turn, increases the sustainability of steel structures for future generations.

By going digital, it allows users to more easily identify how close a site is to the boundary of a corrosion classification by precisely and quickly assisting designers and engineers in finding the correct corrosivity zone for the structural steel they intend to use in their project.