THE SUSTAINABILITY OF GALVANIZED STEEL Galvanized steel is all around us. But how does its prevalence today affect the environment of the future? How sustainable is it for architectural projects? What role does it play in the circular economy? And is the galvanizing process itself environmentally friendly? Everywhere you look, you’ll see galvanized steel: frames for our buildings, safety on our roads, and support for the bridges we cross. Hence, we must never waste it, or waste the resources used to produce it, by throwing it away when its original function is no longer valid. We must repurpose galvanized steel, especially if the world wants to move away from traditional business models of ‘use-throw-
away-remake’ to a more environmentally friendly, sustainable circular economy which aims to eliminate waste and repurpose resources. What is a circular economy and how can galvanizing play a part? A circular economy encourages materials to be made, used, reused, remade and recycled. Hot dip galvanizing fits perfectly into a circular economy because it optimises the durability of steel (enabling it to be used again), facilitates the ease of reuse, and if there’s no immediate need to repurpose, it can be recycled:
• Optimising durability When steel is galvanized it is immersed into a bath of molten zinc where it alloys with the iron in the steel to form zinc/iron alloy layers. These layers form the basis of the coating, which is then overlain with free zinc, as it is withdrawn from the galvanizing bath. The result is a robust, durable and corrosion protective finish that will last between 34 and 170 years before the base steel is exposed. This means that steel can be used for the original purpose for which it was fabricated, and – once the project is dismantled – the steel is still good enough to be used elsewhere. • Facilitating ease of reuse Once a structure reaches its end of life, the steel can easily be repurposed if it has been hot dip galvanized as the coating protects it from impact and abrasion when it is disassembled and reassembled. • Recycling Finally, galvanized steel can be melted and used again and again with no loss of quality if there is no immediate need for repurposing.
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The zinc coating can also be reused. How else does the galvanizing process enhance sustainability? A hot dip galvanized finish not only gives steel a long life and durability, but it also creates a maintenance free finish, which lessens the
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