Sustainabilty FAQs

Steel is arguably the most sustainable of the major structural materials.  It has numerous sustainability benefits, which are guaranteed to be realised whenever steel is used.  They include: low waste, flexibility, offsite manufacture, speed, resource efficiency, adaptability, demountability, long lasting appeal, safety, reusability and recyclability.  These inherent characteristics result in many social, environmental and economic benefits to satisfy sustainability’s ‘triple bottom line’.

Steel is a fast, safe construction material. Reduced time on site means lower costs, quicker returns and less disruption to the local community. Steel is manufactured offsite in a safe, factory environment and arrives on site when needed, making it predictable with no unpleasant surprises. There is no site waste and any waste that is generated earlier in the process is easily returned to the steel supply chain.  Steel treads lightly on the ground.  It has high strength to weight ratio and is resource efficient.  Fewer deliveries mean reduced emissions.

People like a steel built environment, which is light, open, airy and adaptable.  Steel structures mature with age, rather than deteriorate and decay.  Steel’s long clear spans mean that interiors can be changed with ease.  Steel frames can readily be adapted and reconfigured to give old buildings a new lease of life.  The longevity of a building is fundamental to its overall sustainability.

Steel structures are inherently reusable in full or part.  Whole buildings can be taken down and rebuilt elsewhere or individual elements can be reused.  An increasing number of buildings are being designed with this in mind, but reuse is an option for steel structures without any special provision.  Any steel which is not reused is captured and recycled for further use in construction or elsewhere.

Most other materials are recycled once to a lesser use.  This is referred to as downcycling.  Steel can be recycled indefinitely without loss of property or performance.  This is referred to as multicycling.  It means steel always has a value, which guarantees that virtually none is ever disposed of to landfill.  The multicycling of steel is a self-sustaining system that predates modern appreciation of environmental issues and would continue in the unlikely event that they should ever lessen in importance.

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.

Recycled content is a driver to encourage recycling of materials which would otherwise be disposed of.  However, it is not a suitable driver for metals that are already recovered and recycled close to their maximum.  Specifying recycled content for steel does not have any beneficial environmental effect, but can distort the market and result in unnecessary transport costs and emissions.  All steel is recyclable and will be multicycled many times without any artificial stimulus.

Recycled content varies by process route.  Most large scale modern steelmaking processes produce steel with a significant recycled content, as scrap steel is a standard input.  When a figure is needed to calculate overall recycled content of a building, the Waste Resource Action Programme (WRAP) recommends applying a value of 60% recycled content for structural steel sourced in the UK.

On rare occasions it is possible to manufacture steel without recyclate. For example, direct reduced iron can be charged to an Electric Arc Furnace or a Basic Oxygen Steelmaking plant using plated iron. This is, however, extremely rare.

It is accepted that, to be sustainable, a solution needs a sound economic basis.  Steel is fast, efficient, predictable and safe.  Production is highly automated and site operations are not labour intensive.  Steel is the cost effective solution and delivers long term value through flexibility, adaptability and lasting appeal.

Steel construction is fast, clean and relatively quiet, so disruption of the community is kept to a minimum.  Steel construction is carried out by small teams of skilled workers in a consistent manner which is predictable and safe.  Steel is manufactured and fabricated offsite, so workers are stably employed in good conditions.  All steel works and major fabrication premises are integrated into their local communities and in the case of the bigger sites are the reason that the community exists.  The steel built environment is light, airy, pleasant and popular with people.

Corus and the BCSA have recently embarked on a major new initiative to help make zero carbon buildings a reality. The ‘Target Zero’ project will provide the construction industry with the guidance it needs to meet the emissions reduction targets towards the aspiration of zero carbon by 2019.  The £1m Target Zero project will look at five major building types (school, warehouse, office, supermarket and mixed-use development) and will generate fully-costed solutions demonstrating how to achieve the three highest BREEAM ratings and meet the changes to Part L of the Building Regulations. For more information, please visit www.targetzero.info

Corus and our customers are addressing climate change on a local scale by continually making our processes more and more efficient.  Since 2000, there has been an 11% reduction in the energy required to produce steel which has contributed to an overall reduction of 50% over the last 40 years. Through optimising the use of process gases arising at our plants, Corus has achieved very high levels of on-site generation of electricity. In 2007, on-site generation produced almost 1,600 GWh of electrical energy. The effect of these efforts is a reduction of approximately 700,000 tonnes of CO₂ emissions from the electricity generation sector.  Corus is a partner in the Ultra-low CO₂ Steelmaking (ULCOS) programme, a €360m pan-European initiative to achieve a step change reduction in emissions.

As for our own emissions, our long-term climate change goal is to reduce CO ₂ emissions to less than 1.5 tonnes for every tonne of liquid steel produced by 2020

The thermal mass of a building can be used to reduce the requirement for active heating and cooling.  People instinctively associate the cool inside churches with their mass, but it has far more to do with the lack of windows and low solar gain along with an absence of heat generating electrical equipment and lighting.  Optimum thermal mass is mobilised from the first 100mm thickness of concrete floor slab, which is available in standard steel-framed construction.  The extra mass associated with heavier weight structures is a waste, which is compounded by the larger foundations required.

The CO₂ emitted during the production of one tonne of structural sections is 0.76 tonnes^*.  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. 

The values for all structural steel products are shown below and the calculation method is given at ' the embodied carbon content of steel'

  ^* The data provided has been generated based on worldsteel data collection and methodology for calculating the LCI for steel products. It is based  on the worldsteel Life Cycle Inventory Methodology Report 1999/2000, and data collected and published in 2002.

The World Steel Association collects a lot of data, which has been used to calculate the value of 0.76 t/tonne^* using the System Expansion methodology, which is the highest ranked method in the ISO 14040 series of standards.  There are other values in circulation, some are higher and some are lower than 0.76 t/tonne^*.  Most are derived by less rigorous methods than System Expansion in an attempt to have a common method for all materials.  They are intended to provide a fair comparison, but do not take account of steel’s unique environmental qualities.

The calculation method is given in  ' the embodied carbon content of steel'

^* The data provided has been generated based on worldsteel data collection and methodology for calculating the LCI for steel products. It is based  on the worldsteel Life Cycle Inventory Methodology Report 1999/2000, and data collected and published in 2002.

This is something that each fabricator must determine for their operations. 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 CO₂ per tonne of fabricated steelwork.

Corus’ processes have been refined over many years to ensure that the consumption of materials within them is optimised. Although a high level of conversion efficiency is achieved, a small amount of waste will inevitably be generated. The vast majority of ferrous waste is re-incorporated immediately back into the steel production chain.  Uses have been found for many of the other wastes and by-products in other sectors of industry. For example about 3 million tonnes of ground granulated blast furnace slag (GGBS) is used annually as a cement replacement, which helps to reduce the high carbon footprint of concrete.

Almost no steel or indeed any metal is ever intentionally wasted. It is too valuable. Throwing away metal is like throwing away money. A recent survey indicated that no more than 1% of structural steel ever goes to landfill.  The rest is multicycled indefinitely.

A full listing of end-of-life parameters can be found at 'end of life parameters'.