With infrastructure demands rising across Africa, selecting the right materials for structural and roofing applications has become a critical decision for engineers, architects, and developers. The International Zinc Association (IZA) Africa Desk highlights the enduring performance and versatility of hot dip galvanized structural steel and continuously galvanized roof sheeting, particularly in the face of tough environmental conditions.
“Whether you are designing for deep South African underground mines or the corrosive local coastline, galvanizing provides a proven and cost-effective corrosion protection system that extends the life of steel by decades,” says Simon Norton, Director of IZA Africa.
Hot dip galvanized steel, coated with a layer of zinc plus an organic coating, is especially valued in structural and roofing applications for its durability, low maintenance requirements, and lifecycle cost benefits. When exposed to the atmosphere, zinc forms a protective patina of complex zinc carbonate that shields steel from corrosion, even in aggressive environments. Zinc offers cathodic protection to the underlying steel as well. “It is a double whammy of benefits!” comments Norton.
Inland vs. Coastal Applications
Norton advises that while standard hot dip galvanized steel performs well in inland areas with low to moderate corrosion exposure, additional considerations are necessary for coastal or industrial zones. Inland in South Africa, the extensive deep underground mining industry will benefit substantially from the use of galvanized steel for mine shaft steel and buntons, as these are exposed to very corrosive mine waters and conditions underground.
“In sea salt sprayed coastal areas, it is essential to use thicker zinc coatings on steel sheet or duplex systems, namely galvanizing followed by paint, to withstand the increased corrosive impact,” explains Norton. A site-specific corrosion risk assessment (using ISO 9223) should guide the choice of coating type and thickness for continuous galvanized roof sheeting, with SANS 121 (ISO 1461) as a benchmark for hot dip galvanizing standards in South Africa.
For roof sheeting, continuous galvanized (zinc coated) steel is widely used due to its formability and corrosion protection. However, it cannot be used without a primer and organic overcoat, what is known as a duplex system. Hence products such as Chromadek are specified. Zinc-aluminium coated products such as Bluescope Colourbond and Safal Colourplus can also be specified, particularly in coastal zones (the ultra-version).
This is due to enhanced corrosion resistance in marine atmospheres resulting from the zinc-aluminium coating layer on the steel. However, again bear in mind that all these roof and cladding products have an organic coating on top of the zinc or aluzinc layer to provide that extra duplex system and protection from the external environment, notes Norton.
Sustainability and Circular Economy
Galvanized steel contributes to sustainability goals, aligning with global green building practices. Zinc is a natural, recyclable metal, and galvanized steel can be reused or recycled without loss of physical properties of the basic contents namely steel and zinc.
“Galvanizing supports Africa’s infrastructure development not only by increasing material lifespan, saving valuable capital and by lowering total environmental impact,” says Norton. “IZA Africa is committed to providing expert knowledge about appropriate zinc applications to ensure safe, economical, and long-lasting infrastructure across the continent.”
Ends
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Notes to the Editor
To download hi-res images for this news article, please visit http://media.ngage.co.za and click the International Zinc Association link to view the company’s press office.
About the International Zinc Association (IZA)
The IZA is the only global industry association dedicated exclusively to the interests of zinc and its users. Operating internationally and locally in Africa through the IZA Africa Desk, the IZA helps sustain the long-term global demand for zinc and its markets by promoting such key end uses as corrosion protection for steel and zinc as essential in human health and crop nutrition. IZA’s main programmes are Zinc Use Research, Sustainability & Environment, Technology & Market Development and technical Communications.
In South Africa, the IZA plays a vital role in establishing the basis for the successful growth of the zinc industry by increasing awareness of zinc and its applications and benefits in key sectors and markets.
International Zinc Association Contact
Simon Norton
Director
IZA Africa
Phone: (021) 788 9980
Cell: 082 831 2924
Email: zinc@iafrica.com
Web: www.zinc.org
Media Contact
Andile Mbethe
Account Executive
NGAGE Public Relations
Phone: (011) 867-7763
Cell: 073 565 6536
Email: andile@ngage.co.za
Web: www.ngage.co.za
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Continuously galvanized roof sheet.
Galvanized Rebar.
Galvanizing provides a proven and cost effective corrosion protection system that extends the life of steel by decades.
Hot dip galvanizing steel in a molten zinc kettle.
Zinc forms a protective patina of complex zinc carbonate that shields steel from corrosion. - Galvanized steel is the smart choice for infrastructure in coastal and inland environments_approved
Galvanized steel is the smart choice for infrastructure in coastal and inland environments_approved
