There are many questions that arise when discussing issues concerning sustainability. Here is a summary of answers to the most frequent questions that we get asked.
1 Is galvanizing sustainable?
Galvanizing, the coating of iron on steel with zinc, is probably the most environmentally friendly process available to prevent corrosion. It is estimated that corrosion costs around 4% of GDP. Effective corrosion protection is a vital means of reducing the embodied carbon of buildings and structures.
2 Can galvanized steel be reused?
Many galvanized steel products can be removed, re-galvanized and returned to use. For example, highway guard rails are often removed and replaced during routine highway maintenance and resurfacing. The redundant barriers are returned to the galvanizing plant for re-galvanizing and are then used again in similar applications.
3 Can galvanized steel be recycled?
Galvanized steel can be recycled easily with other steel scrap in the electric arc furnace (EAF) steel production process. Zinc volatillises early in the process and is collected in the EAF dust that is then recycled in specilalist facilities and often returns to refined zinc production.
4 How much zinc is recycled from galvanized products?
In 2006, the European steel industry (EU27) produced 1,290,750 tonnes of EAF dust, which contained 296,872 tonnnes of zinc (i.e. 23%). 93% of this zinc (276,920 tonnes) was recycled. (source: Gesellschaft fur Bergbau, Metallurgie, Rohstaff - und Umwelttechnik, Germany).
5 What is the embodied carbon of galvanized steel?
A review of available life cycle studies by Life Cycle Engineering (Torino, Italy) has indicated the typical metrics for galvanizing one kilogramme of steel to EN ISO 1461 will produce 0.1 - 0.33 kg CO2 equivalent. The range represents variations in type of steel components, geographical factors and study methodology.
Galvanizers Association has been a major contributor to the European Initiative for Galvanizing in Sustainable Construction. Many independent experts have contributed to this initiative including Prof. Tom Woolley, a well-known advocate of green and natural building. The aims of the initiative were to help architects, specifiers, engineers, developers and their clients consider how to use galvanized steel in the context of sustainable construction.
7 What is cradle to cradle?
A phrase invented by Walter R. Stahel in the 1960s and popularized by William McDonough and Michael Braungart. The framework seeks to create production techniques that are not just efficient but are essentially waste-free. In cradle to cradle production all material inputs and outputs are seen either as technical or biological nutrients. Technical nutrients can be recycled or reused with no loss of quality and biological nutrients composted or consumed.
Holistic design is an approach to design which considers the system as an interconnected whole which is also part ofa larger framework . Design considerations will not only incorporate how design and material use will impact the environment in the short termbut also consider the long term impacts.
9 What is LCA?
A "Life Cycle Assessment" (LCA also known as "Life Cycle Analysis") is the investigation and evaluation of the environmental impacts of a green product or service caused or necessitated by its existence.
10 Can you recycle zinc?
Zinc is inherently recyclable non-ferrous metal and can be recycled indefinitely without any loss of physical or chemical properties. At present, approximately 70% of zinc comes from primary refining of zinc ores (including 10-15% from recycled sources) and about 30% comes directly from recycled zinc (representing 80% of the zinc available for recycling). The recycling level continues to increase as technology improves.
11 Are we running out of zinc?
Zinc is the 27th most common element in the earth's crust. The world is naturally abundant in zinc. Reserves of zinc - like those of any natural resource - are not a fixed amount stored in nature. Reserves are determined by geology and the interaction of economics, technology and politics. Proven reserves of zinc have increased significantly since the 1950s, as large new ore bodies have been discovered in many areas of the world. The sustainability of zinc supplies cannot therefore be judged simply by extrapolating the combined mine life of today's zinc mines. Despite increasing consumption of zinc from 1995 - 2005, the world's zinc reserves substantially increased over that same period.
The carbon profile per zinc is 3124 kgCO2 equivalent. (Inventory results per metric tonne of special high grade zinc).
13 What is "Zinc Saves Kids" all about?
"Zinc Saves Kids" is an initiative to improve the survival, growth and development of undernourished children by funding UNICEF-supported zinc programs around the world. 450,000 children are at risk of dying every year due to the impact of zinc deficiency on diarrhea, pneumonia and malaria. A few extra milligrams of zinc every day can make a huge difference. Zinc-containing supplements are a quick and easy, effective and inexpensive remedy. "Zinc Saves Kids" suppport undernourished children in develeoping countries who suffer most from zinc-deficiency related health problems.
14 What is the embodied carbon of steel?
The CO2 emitted during the production of one tonne of structural sections is 0.76 tonnes CO2 equivalent. This value is higher than some other structural materials on a tonne by tonne basis, but a tonne of steel goes a great deal further than other materials, so the actual carbon footprint of the structure is lower.
Over 500 million tonnes of steel are multicycled worldwide each year - equivalent to 180 Eiffel Towers every day. The recovery rates are high. Research shows that 99% of structural steel arising from demolition sites in the UK is recycled or re-used. There is a conservative estimate that over 80% of all steel scrap that becomes available each year is captured and recycled. This figure increases in poorer economies where the relative value of steel is higher.
The British Constructional Steelwork Association (BCSA) has developed a common methodology for calculating the carbon footprint of the steel fabrication process. Initial evidence from a selection of carbon footprinting assessments indicates that the answer will generally be of the order of 0.3 tonnes of CO2 per tonne of fabricated steelwork.