The positive and negative impact of construction
In The Real Face of Construction 2020, a report analysing the “true value of the built environment”, The Chartered Institute of Building (CIOB) determined that construction in the UK contributes up to 15% of our nation’s GDP and directly supports 2.3 million jobs.
With such a profound impact on the economy it should be no surprise, then, that construction is also responsible for a large proportion of global carbon emissions. Reducing that negative environmental impact through better practices in construction materials and manufacturing is key to sustainability.
The manufacture, use, and end-of-life of construction materials cause 11% of all global carbon emissions.
The World Green Building Council in their Bringing Embodied Carbon Upfront report identified a carbon lifecycle for construction materials, broken down into stages representing the journey for materials from production through to construction, use, and end-of-life.
The sum of all of these carbon stages is referred to as embodied carbon, and is defined as follows;
Carbon emissions associated with materials and construction processes throughout the whole lifecycle of a building or infrastructure. Embodied carbon therefore includes: material extraction, transport to manufacturer, manufacturing, transport to site, construction, use phase, maintenance, repair, replacement, refurbishment, deconstruction, transport to end of life facilities, processing, disposal.
In the report, the World Green Building Council called for a 40% reduction in embodied carbon by 2030 for new buildings, infrastructure, and renovations, and net zero embodied carbon by 2050.
Within these goals an emphasis was made that significant upfront carbon reduction must be achieved, firmly putting the onus on construction materials manufacturers and constructors.
Aluminium, the “green” metal
Aluminium is a metal with unique properties; light weight, naturally available in abundance, extremely durable, resistant to corrosion, and much more.
Most importantly in terms of sustainable construction, however, is that aluminium is infinitely recyclable. This means that a vast amount of upfront carbon can be saved by using recycled aluminium rather than freshly mined and produced aluminium. This is referred to as “pre-consumer aluminium vs post-consumer aluminium”.
Using post-consumer aluminium recycled from end-of-life materials to produce new construction materials is one of the key ways that manufacturers can reduce their contribution to upfront carbon.
Upfront carbon is the emissions caused in the materials production and construction phases (see diagram above) of the carbon lifecycle. By avoiding this through the use of post-consumer aluminium, a vast amount of emissions are simply not released to produce the materials. Additionally, aluminium is considered an “energy bank”, which means that each time it is recycled that most of the original energy input involved in originally producing the material can be recovered.