Sustainability megatrends are shaping our world.  In particular climate change, scarcity of resources, and demographic shifts.  This is feeding into societal expectations which in turn drives policy frameworks and legislation. 

What does this mean for the construction industry? 

Well, as an industry it is responsible for a significant amount of resource use (both materials and energy consumption) and waste.  The pressure on the industry to become more sustainable is considerable and, in fairness, the desire of much of the industry to reduce resource use, decrease waste and become more sustainable, is apparent.

Building materials, and how such materials perform in use, has an important role to play in achieving a more sustainable construction environment.  Steel, as a building material, has many attributes that are very well suited to achieving this ambition and here are just some of the reasons why...

1) Steel can reduce resource use for a given building design

Improvements in the understanding of the use of steel, combined with improvements in steel processing (including micro casting – producing just 20 kilograms of steel) has meant the ability to very efficiently develop higher strength and higher performing steels. The development of higher strength steels means that we can build with less steel therefore reducing the transport weight, construction and, foundation weight and resulting construction time.  The use of a steel framed building for example utilises less space and less foundations when compared with an equivalent concrete design.   The development of higher performing steels, such as wear resistant steels, has increased the durability of steel which brings us to that very subject.

2) Steel is extremely durable and long lasting – maximising its use as a resource

An important but often underestimated attribute - but building with a material that requires little or zero maintenance, and can meet design life requirements into three figures, equates to a resource that is being maximised. If we take weathering steel for example we have a material that can last 120 years or more with little or no maintenance. Combining this capability with the flexibility of steel and you have a material that will last a very long time and then, at the end of its life, can be put to another use (which we discuss further below).

3) Steel is well suited to the circular economy

The durability and flexibility of steel makes it very well suited to the circular economy. If we define the circular economy as ‘reducing resource use and reducing the waste associated with that resource use’ then we have already demonstrated above that we can do more, with less steel, than ever before, but this durability and flexibility also allows us to;

• Modify and adapt existing buildings as steel buildings provide this flexibility.
• Reuse steel at the end of its first use; the inherent ability of steel to be demounted, though simple product design, makes the deconstruction and reuse of steel in the build environment a potentially extremely efficient process. The construction industry is not yet ready, at scale, for this, but with coordination on standardisation of products, consistent and fully adopted data protocols and construction techniques, then steel reuse can become a key driver of improved build environment sustainable performance.
• Steel can be deconstructed and ‘remanufactured’ for another purpose, unleashing a further life for the resource.

Finally when steel cannot be reused or repurposed then it has a real trick up its sleeve – it can be (and is 99% likely to be) recycled to become another steel product. A key to driving the circular economy is to retain value in resources for as long as possible.  The steel scrap market is one such mechanism for steel that almost guarantees that if steel can be recycled it will be.

4) Steel manufacturing is continuously improving

The energy used, and the CO₂ intensity in the manufacture of steel in Europe, has reduced on average around 1%[¹] per year from the turn of this century, and the energy required to produce a tonne of steel in the UK has reduced by some 40%[²]  since the mid 1970’s. And we are now approaching theoretical limits on steel making meaning that breakthrough technology will be essential to maintain these trends, which leads us to….

5) Steel is well suited to break through sustainable technologies

Tata Steel are the owners of HIsarna a break though technology which has the capability to lower future steel making CO₂ intensity by up to 50%. Combined with carbon capture and storage this may increase to 80%.  Work to further develop HIsarna continues and this work is in the context of Tata Steel’s confirmed ambition to be carbon neutral steel making in 2050.

6) Steel in construction minimises waste

Whilst steel manufacturing is extremely circular, with many of the by-products of the steel making process being utilised in other processes or industries, steel as a construction material also contributes to reduced waste. Steel is extremely well suited to offsite construction and modular methods of construction by its very nature.  Both its formability and processing characteristics mean that what waste is generated becomes the input to further steel making (recycling).  Such characteristics contribute to reduced construction time and increased construction efficiency. 

7) Steel’s contribution to the built environment

Probably the most important of our magnificent 7 reasons; it is not only steel as a material that can contribute to a more sustainable construction industry but the products that are produced from steel, during their lifetime, can make our building assets more efficient, more effective (as ideal living and working spaces) and more sustainable. From the insulated and air-tight panels that Tata Steel produce (reducing energy consumption) to the integrated renewable energy generators that will deliver energy positive buildings  steel has an important role to play in our ambition for a more sustainable built environment.

References:

[¹] Derived from World Steel data.

[²] Derived from UK Steel data