INDUSTRY NEWS
Module D is a key element to deliver truly sustainable construction
Improved standards and guidance for constructors calculating embodied carbon are helping to deliver truly sustainable construction projects , however practitioners in the industry and any new legislation must also fully consider the circular economy alongside embodied carbon to avoid any unintended consequences . It is not logical to equate a material that is landfilled following demolition with one that is reused or recycled .
Lifecycle assessments ( LCAs ) are commonplace and are an essential part of delivering sustainable construction . LCAs assess and measure the sustainability credentials of building projects from extraction and manufacture of raw materials to use and maintenance of a building and , later , materials ’ end-of-life .
By understanding where energy is required and environmental harm is caused during the construction process , the industry can reduce negative impact and work towards global net zero carbon emissions targets .
Previously LCAs often took a ‘ cradle to gate ’ view , considering the environmental impact of sourcing and manufacturing materials only . This was then broadened to ‘ cradle to cradle ’, reviewing the whole-life of a building , including operational impact .
And now the current version of BS EN 15804 ( BS 15804:2012 + A2:2019 ) mandates in most cases the reporting of Module D alongside A and C .
Completing a whole-life LCA delivers a comprehensive embodied carbon calculation for a project , by reviewing :
• Module A – the sourcing of materials or products and delivery of the construction process ; from extracting and manufacturing raw materials ( A1-3 ) to transporting and constructing or erecting products or materials ( A4-5 ).
• Module B – the operational use of a building ; from operational energy usage to maintenance and repair , to replacement or refurbishment of materials ( B1-5 ).
• Module C – the end-of-life process of a building ; covering the expected or advisable deconstruction process , including transport , disposal and processing of waste ( C1-4 ).
• Module D – reviewing the ongoing benefits of materials beyond a building ’ s primary use ; covering the recovery , reuse or recycling potential of components and materials .
By calculating the additional benefits of reusing or recycling materials , Module D not only improves the embodied carbon calculations of an existing project but also
reduces the requirements for Module A primary production for future projects .
The CAB has published a position paper with a formula to calculate Module D assuming closed loop recycling of materials ( typically seen for metals such as aluminium ). We will progress this work further in the future , highlighting practical considerations when using Module D , such as how it avoids any double-counting .
It is essential aluminium ’ s sustainability credentials after a building ’ s end-of-life are considered , as they mitigate any concerns about the high energy input required for initial aluminium production and benchmarking its benefits against alternative materials . Since aluminium can be infinitely recycled without losing its properties in a closed loop , the ability to measure its ongoing benefits in Module D further demonstrates its value and versatility as a construction material .
Including Module D in LCAs is regarded as the final piece of the puzzle for the construction sector to deliver on global net zero targets and create a futureproof circular economy . Without it , analysis cannot be truly comprehensive and any embodied carbon calculations or conclusions risk being reductionist with possible unintended consequences in the future .
www . c-a-b . org . uk
24 JANUARY 2023 CLEARVIEW-UK . COM