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STEPS TOWARDS
DECARBONISATION NEEDED IN BUILT ENVIRONMENT
As a significant contributor to global carbon emissions , the built sector is being compelled to adopt more sustainable practices , especially if it is to meet climate change mitigation targets by 2050 .
Processing of raw materials for buildings and infrastructure developments and the actual construction processes are the two largest contributors to greenhouse gas emissions . RIB CCS vice-president , Peter Damhuis , identifies three important aspects that construction firms need to consider in pursuit of a greener construction process and more sustainable industry .
IT STARTS WITH DESIGN Damhuis says design is the most critical element in establishing the greenhouse gas ( GHG ) emissions for the lifetime ( cradle to grave ) of a construction project . “ The design of a project affects the materials used as each material has a different carbon footprint that will affect the initial carbon calculations .
“ In addition , the design can affect the lifecycle costing of a development , for example , what glass is used and how does it affect the heat absorption or retention of the building ; should the structure be based on concrete or steel ; and how would this impact heating in winter and cooling in summer ? The efficiency of the design can materially impact the energy consumption during the lifetime of the project . So , does the ratio of glass to concrete affect the heating and cooling requirements ; does the design include natural ventilation or evaporative cooling systems , which could result in lower energy requirements in the cooling system ; does the glass or the roof design include solar generating capabilities ; or does the water system allow for grey water consumption for toilets ?”
Importantly , decisions made during the design phase do not merely affect the construction process but the entire life cycle of the building or infrastructure project and can have a significant impact on emissions for decades to come .
“ the design can affect the lifecycle costing of a development ”
SUPPLY CHAIN CONSIDERATION Damhuis notes that design is closely followed by supply chain as the second largest contributor to the carbon calculation . “ Let ’ s consider concrete as an example : if the design calls for a concrete structure , then the project team needs to establish where it is sourcing its aggregates , what the haulage distance is – and determine how these two factors contribute to the carbon calculation . More importantly , project teams need to establish how to maximise efficiency in the mix design . There are many young technologists designing “ cement free ” concrete , which is set to make a vast difference to the carbon footprint of buildings and other infrastructure .”
He continues saying that a carbon analysis is applicable to most material , for example , recycled wood or glass . “ Using recycled aggregates as part of your concrete or scraping roads to remove and recycle top layers for inclusion into a new asphalt layer are important supply chain considerations .”
Another aspect to consider is where the company sources its labour and how far its employees have to travel to get to site , as well as what vehicles they are using to get to site - busses , trains or individual cars – as these all have implications for a project ’ s carbon footprint .
DECARBONISING THE CONSTRUCTION PROCESS According to Damhuis , efficiency in construction to improve decarbonisation can be divided into three main areas of control : wastage , plant utilisation and planning .
“ Once the supply chain has been maximised , wastage can be reduced by ensuring that no materials are procured beyond what is required and where waste is generated , it should be split and recycled . Plant utilisation considerations include factors such as using electric versus fuels . Notably , the efficiency of the activity must be suited to the plant , and plant management must also be as efficient as possible ,” adds Damhuis . RACA
www . refrigerationandaircon . co . za RACA Journal I February 2023 11