In today’s world, there is a lot of focus & emphasis on reducing a building’s energy consumption & its carbon footprint. However, reducing a building’s carbon footprint isn’t limited to its equipment & energy use. Throughout the service life of a building, the different materials used to construct the building can have a significant impact on the environment by way of global warming potential, acidification, eutrophication etc.
Typically, the environmental impact of different materials & products is assessed from raw material extraction and processing, through the product's manufacture, distribution, and use, to the recycling or final disposal of the materials composing it.
However, there has been a lack of clarity & emphasis on a standard methodology for assessing the environmental impacts associated with all the stages of the life cycle of building construction materials.
Life Cycle Assessment (LCA)
LCA has become a recognized instrument to assess the ecological burdens and impacts throughout the consecutive and interlinked stages of a product system, from the raw material acquisition or generation from natural resources, through production and use to the final disposal. This is also referred to as a ‘Cradle-To-Grave' assessment.
With construction contributing to around 39% of global carbon dioxide emissions, there is an urgent need for the sector to decarbonize.
It is therefore important to measure the amount of carbon emissions involved in the extraction process right through the service life of construction materials. Carbon dioxide equivalent (CO2-eq) is a measure for describing the climate-forcing strength of a quantity of greenhouse gases using the functionally equivalent amount of carbon dioxide as the reference.
Types of Carbon
While the amount of carbon associated with a building can be reduced by optimizing its energy use; a building’s carbon footprint can be reduced significantly by using the right construction materials. For this, it is crucial to understand the different measures of carbon.
Embodied carbon refers to the emissions arising from the extraction, manufacture, transportation, installation, maintenance, and disposal of building materials. It contributes to approximately 11% of global CO2 emissions.
Operational carbon refers to the emissions from the use of the building: for example, the energy needed to heat, cool, and maintain it. Efforts to reduce the impact of the construction sector have long focused on operational carbon.
Global Focus on Embodied Carbon
Due to the rapid decarbonization of the energy sector, embodied carbon is becoming recognized as a dominant climate impact driver. In response, many countries are setting limits for embodied carbon reduction.
Building LCA is a mandatory part of planning regulations in many countries, including Sweden, the Netherlands, France, and parts of the UK. It is incorporated in several green building certifications such as BREEAM, LEED, DGNB, and Energie Carbone.
With the growing focus on embodied carbon and achieving net zero carbon targets, investors, end-users, and tenants are increasingly looking for ways to assess and reduce the lifetime environmental impact of their projects. Conducting a building LCA demonstrates a commitment to measuring and reducing the environmental impact of construction projects. It also provides sound market advantages for actors across the supply chain.
Governments are increasingly recognizing the need to legislate and reduce whole-life carbon in construction. As a result, building LCAs are now a mandatory part of several existing and future regulations.
LCA Tools & EPD
LCA tools, such as "One Click LCA", can simplify the inventory collection process by importing materials, providing ready-to-use scenarios and a database. One Click LCA can support integration with design data from software such as BIM, Design Builder, IES-VE, Excel, and more.
Conducting an LCA through tools such as One Click LCA allows building materials & products to acquire an EPD. An Environmental Product Declaration (EPD) provides an independently verified summary of the environmental impact of a product throughout its life cycle, calculated via a life-cycle assessment (LCA). Such certifications can go a long way in convincing building owners to use materials that are environment friendly. Additionally, this can also act as a great marketing tool to attract tenants who are becoming increasingly environment conscious.
LCA & Dynamic Energy Simulation
Today, LCA and dynamic energy simulations are integrated to accurately assess the life cycle environmental burdens and benefits of eco-innovation measures at the building level. This allows quantitatively assessing the effectiveness of these measures to lower the energy use and environmental impact of buildings.
Research related to the sustainable refurbishment of buildings often focuses on improving the energy performance of buildings and transforming existing buildings into nearly zero energy buildings. These studies have a limited scope regarding sustainability as operational energy is the only focus.
Hence, building owners can now leverage the holistic benefits of using energy simulations & LCA tools to construct buildings that leave a minimal impact on the environment. Such an approach can act as a great driver for change in the construction industry.
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