What does it mean to be ‘sustainable’?
Construction professionals are responding to the climate and biodiversity emergencies, and now routinely factor the environmental impact of their choices into building designs and specifications.
Reduced environmental impact often means aiming for lower carbon emissions from the operation of the building. With lifespans typically assumed to be 60 years, and many buildings standing for longer than that, tackling operational emissions is undoubtedly important.
Now there is also a focus on reducing emissions associated with the sourcing of materials, the manufacturing of construction products, and their installation on site. It is necessary to sound a note of caution, however.
If, in the quest for better sustainability, we focus too narrowly, then there is a risk that any carbon savings we make now will lead to the unintended consequence of an overall increase in carbon emissions at the end of the building’s life. Taking a broader, long-term view is what we mean by ‘act today to protect tomorrow’, and it is what underpins Tata Steel’s commitment to being a responsible steel supplier.
Defining ‘upfront’ and ‘whole life’ carbon
The carbon cost of construction projects is assessed by dividing the life cycle of the building into stages.
‘Upfront carbon’ refers to the carbon emissions from the manufacturing and installation phases - known as cradle to practical completion. ‘Embodied carbon’ goes further, looking at the use of the material or product in service, and how it is dealt with at the end of the building’s life (‘cradle to grave’).
A true ‘whole life’ view also factors in ‘the four Rs’ of reducing, reusing, remanufacturing and recycling. Taking into account these benefits as part of a ‘cradle to cradle’ approach is the only way to assess the long-term impact of design and specification decisions.
To understand how construction products fit into a whole life view and deliver long-term benefits, designers, specifiers and installers need the right level of information to help them make informed decisions. Attempts to create a sustainable future risk being undone without looking at whole life carbon.
With that in mind, Tata Steel operates its own EPD scheme, allowing the whole life impact of steel components to be analysed. Material specification decisions can be made with confidence, in the knowledge that long-term impacts have been taken into account.
The burden of unintended consequences
Given the length of time over which buildings can be used, it’s important to be mindful that the people using a building now might not be the ones who have to deal with it at the end of its life.
Decisions we make today will influence the impact a building has on the climate in 60, 80 or even 100 years’ time, when we know that the environmental impact will need to be much lower than we might be used to now.
Design and specification choices are made with the aim of reducing carbon emissions. However, focusing on one area of the life cycle only can actually lead to an increase in whole life carbon. This type of long-term impact, born out of a desire to do ‘the right thing’, is known as an unintended consequence. Other people, and eventually the planet, will be left to deal with the unintended consequences of our material choices.
Steelmaking is a good example of how myths and misunderstandings about a material lead to assumptions being made about how to specify and use it in a ‘sustainable’ way. For example, misapprehensions associated with steelmaking can lead to the unintended consequence of increased carbon emissions in the future.
Many of those myths can be addressed through better understanding of the steel supply chain. Engaging with a product manufacturer, both inside and outside of projects, can increase that understanding and reduce the potential for unintended consequences to occur.
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