In sustainable design, material selection is becoming more and more critical, not only for its performance characteristics but for its carbon emissions and environmental impact. These days, specifiers are taking on a more responsible role for the “cradle to gate” or production to delivery cycle than ever before, focusing on the environmental impact and energy consumption of selected materials.
One material in particular that is having ever increasing focus placed on it is Steel. More and more attention is being placed on the Carbon Footprint of Steel products in Construction, locality to Site, Transport methods and finishes and coatings. “Green” energy efficient buildings have enjoyed the inclusion of Stainless Steel as the steel of choice for its Green credentials.
When considering Galvanised Steel over Stainless Steel, the energy consumption per Kilogram of Steel produced is arguably almost the same. Stainless Steel however, has an advantage when it comes to the Galvanising process or painting application. Stainless Steels when correctly selected to suit their operating environment, require no special treatment to the surface, coatings or protective layers.
Galvanised Steel on the other hand is a chemical process of Degreasing, Rinsing, Pickling and Rinsing, dipping in a Flux Solution and finally Zinc Coating. All processes which consume a lot of Primary Energy as well as chemicals potentially hazardous to humans and the environment; Chemicals, which require processing as hazardous waste.
Galvanising campaigners speak of the advantages of loss of Zinc to the natural washing by rain over time into natural waterways and as Zinc being the 27th most abundant element in the Earth’s Crust and an Element critical in day-to-day life. The down side however as mentioned, is the extra processes the raw steel has to go through during the Galvanising process. This is not the case with Stainless Steel. Stainless Steel is manufactured using a minimum of 60% recycled material. The surface of the steel is a Chromium rich (Passive Layer) layer, which is self-repairing.
When correctly selected, the surface finish, be it mill finish, bead blasted, pattern rolled, brushed or polished will remain intact for life with a basic maintenance regimen. Even severe surface scratches will not cause material failure, unlike Galvanised Steel, which will leave the area exposed to environmental attacks and corrosion.
Galvanised material can also only be patched on the Site with Zinc- rich coatings or be returned to the Production Plant for stripping and coating from scratch. Stainless Steels can be cut, bent and welded on site and either chemically or mechanically cleaned. The Passive Layer of Stainless Steel will restore itself on exposure to Oxygen!
Often, Galvanised products are painted as an additional corrosion protection. This in itself causes environmental damage with peeling and flaking paint polluting our waterways and environment. These coatings are often also harmful in their production, consuming Energy with a large Carbon footprint. Painting is also not a permanent finish with sanding and recoating required fairly regularly making it a costly exercise when Life Cycle Costing is taken into account, versus the life of Stainless Steel in the same application.
Lately, design trends have moved towards the “look and feel” of Galvanised Steel as an “upcycled” product as opposed to new shiny metals. Please feel free to chat with one of our Technical Sales Consultants about designs and the available finishes in Stainless Steel.