The long-term durability provided by galvanizing is achieved at relatively low environmental burden in terms of energy and other globally relevant impacts, especially when compared to the energy value of the steel it is protecting.
Attention to durability of steel structures and components has important environmental, economic and social consequences. Some of these are less obvious than others.
The overall economic cost of corrosion has been studied in several countries. It is commonly estimated at up to 4% of gross domestic product.
Several studies have demonstrated the high economic and environmental costs associated with the repeated maintenance painting of steel structures. These burdens can be significantly reduced by an initial investment in long-term protection.
Lack of attention to optimal corrosion protection can leave a damaging economic legacy of repeated maintenance costs. In social housing projects, future maintenance costs will be borne by the local authorities. In public infrastructure projects, use of galvanized steel leads to lower maintenance budgets, releasing public funds for other purposes.
In 2005, EGGA contracted Life Cycle Engineering (LCE), Torino, Italy to perform a pan-European life cycle inventory (LCI) study of hot dip galvanized products. The study considered an average result for typical general galvanized products.
The objective of the work was to deliver life cycle inventory data sets for the galvanizing process, sometimes known as ‘the service’, using data submitted by members of EGGA National Associations from their members’ operations. This involved quantifying the average energy, resource consumption and emission of substances to the environment, resulting in an LCI of a sample of processes operating in several plants in Europe, according to the defined system boundaries. The sample covered about 937,000 tonnes of steel galvanized by 46 plants.
The systems under consideration have the purpose of processing steel pieces and steel products to protect the surface of the steel from the environment. The functional unit was thus expressed in terms of 1 tonne of averaged zinc coated steel product.
Energy and environmental results are expressed by reference to the functional unit, but an extension of the analysis provides data about the system, independently of the steel product, in order to focus attention on ‘the service’.
Such results were expressed in terms of ‘1kg of zinc alloy ready for coating purposes’. This represents a useful measure of the energy and environmental costs of ‘the service’. This LCI data is available, on request from EGGA, to LCA professionals and customers who wish to generate an environmental product declaration for a galvanized steel construction product.
EGGA has published an Environmental Product Declaration based on this European LCI study.