Nothing lasts forever – well, that’s not entirely true, some things can be made to last forever.
Things like steel which can be recycled infinitely without degrading its qualities: exceptional durability, the highest strength-to-weight ratio of any other commonly used material and formability among others.
The fact that steel lasts forever and can be reused, repurposed and recycled in a continuous cycle, makes it critical at a time when we’re trying to reduce our impact on the climate.
There are currently no other alternatives for most of steel’s critical uses in our buildings and infrastructure – whether it is providing a resilient structural steel core or frame, reinforcing concrete or providing a durable light-weight cladding system.
The challenge is that steelmaking is a carbon intensive industry and there’s currently no commercially viable carbon-free solution – though various technologies are being research that show it’s possible.
So, steel does contribute to the embodied greenhouse gas emissions of the buildings that use it along with other emissions generated across the supply chain including resource extraction, construction and waste management, the building’s energy use and what happens at end of life.
But we need to look at steel with a wider-angle lens and consider the significant benefits it delivers as strong and sustainable building material.
Steel enables healthy, allergy free homes. It won’t support mould growth and it won’t rot. Neither will borer and other insects touch it.
It doesn’t warp, twist, sag or shrink so framing and linings and cladding won’t crack ensuring it maintains structural integrity. It’s also non-combustible.
It has excellent seismic performance – less weight means less material to displace and cause damage. And steel has proven performance in events such as the Christchurch earthquakes.
Steel is also one of the most efficient and waste-free materials, pre-manufactured precisely to specification in quality-controlled factory environments. With its high strength to weight ratio, far less material is needed to get the same outcome.
Opportunities to reducing its initial emissions and environmental impact come down to efficiency in production, supply chain efficiencies and end of life uses. When a building is demolished, steel has significant value either for immediate re-use or repurposing and as scrap for recycling.
Steel can be designed for the purpose of the end-use application and the specific strength, durability and end-of-life recycling requirements. And almost every by-product from steelmaking can be used in new products.
This approach minimises the amount of waste sent to landfill, reduces emissions, and preserves raw materials.
Steel also enables CO2 mitigation in other sectors, as a key ingredient in geothermal, hydro, large-scale solar, and wind energy solutions. Without steel, none of these would be as efficient or sustainable.
For example, a typical wind turbine uses around 140 tonnes of steel, while an off-shore turbine can use over 1,000 tonnes. Even so, the embodied carbon emissions tied up in a wind turbine are paid back in only a few months.
Ultimately, we need steel and will continue to need steel in our buildings and infrastructure.
As the focus turns to reducing embodied emissions of buildings, it’s important to look for steel from reputable producers that provide environmental product declarations.
Buying New Zealand product guarantees the highest quality, conforming to standards and backed by Environmental Product Declarations.
New Zealand steel production contributes just to 2.2% of our total CO2 emissions, much lower than other industries.
It also generates around $630 million annually and provides around,4,000 full-time equivalent jobs.
Local jobs and proven technology for a structure that at the end of its life can be deconstructed and the material reused as steel portals elsewhere or recycled into another metal product.
Domestic steel making also provides greater flexibility for the local economy in responding to changes in global supply and demand, as well as local shocks (such as natural disasters) and the ability to maintain standards tailored to the local market.
Another approach to reducing CO2 is the efficient use of energy. This has always been one of the steel industry’s key priorities – Sustainable Steel Council member NZ Steel’s Glenbrook Mill in the Waikato generates 60% of its energy on site from off-gases of the smelting process.
Local products are also made for New Zealand conditions, such as the iconic COLORSTEEL® range which has been Kiwi’s cladding and roofing choice for decades and AXXIS® steel framing with its high strength to weight ratio. Both are completely recyclable and developed and tested by New Zealand Steel for New Zealand conditions. The metal coating substrate for COLORSTEEL® is an alloy consisting of 55% aluminium, 43.5% zinc, and 1.5% silicon. AXXIS® steel framing is protected by a hot-dipped 99% zinc coating.
We need steel now and we’ll continue to need it into the future. We’re working to continue to advance it’s sustainable production and role in building a low-emissions, climate-resilient and circular economy based future.