Introduction
Building Life Cycle Assessment (LCA) evaluates the environmental impacts of a building throughout its lifespan, from the extraction of raw materials for its construction, to its eventual demolition and waste disposal. This has a significant impact on both the environment and long-term costs. Would you like to know more about how this methodology can drive sustainability and reduce the costs of your project? In this article, we'll explain it to you!
1. Life cycle
The life cycle of a product or building refers to the set of stages it goes through from its conception, design, manufacture or construction, use, maintenance, renovation, to the end of its useful life and final disposal.
The life cycle of a product or building can vary depending on its duration and complexity, meaning it depends on several factors, such as the type of material used, the technology involved, and the conditions of use and maintenance, among others. Effective management of this cycle is crucial for optimising efficiency, reducing environmental impact, and promoting long-term sustainability.
2. What is Life Cycle Assessment (LCA)?
The Life Cycle Analysis (ACV) is a methodology, based on standards, which allows for the identification of the environmental impacts of the life cycle of a product, material or building. In the case of LCA in construction, it allows for the assessment environmental impacts generated by the building and its embedded carbon.
The embedded carbon, commonly known as the carbon footprint, this is generated during the creation of a material and throughout its lifecycle. Calculating embodied carbon is fundamental to understanding the total environmental impact of a product or project. By knowing the amount of emissions associated with its lifecycle, informed decisions can be made to reduce these emissions and lessen the contribution to climate change.
Life Cycle Assessment (LCA). Source: Evaluate (own analysis))
Would you like to carry out a Life Cycle Assessment (LCA) on your building to boost its sustainability?
3. Stages of the Life Cycle according to EN standard
The life cycle stages of a construction product and a building, according to the EN standard applicable to the European Union, are defined in the standards: EN 15804 and EN 15978.
Within Life Cycle Assessment (LCA) for buildings, we categorise emissions into full life cycle stages, designated with letters from “A” to “D”, covering everything from raw material extraction to end-of-life disposal of the building. These stages are divided into:
- Product stage (A1-A3)The phases of material extraction, transport to product manufacturing, are termed “From the cradle to the door”.
- Construction phase (A4-A5)It covers the transport of the construction product from the manufacturer (factory gate) to the site, the installation of the product in the building, installation waste, and includes the necessary labour and equipment.
- Usage stage (B1-B5)During this phase, the construction product is used in the building or project, and its operations and performance are evaluated throughout its lifespan. It encompasses all maintenance and refurbishment activities that may be undertaken during the building or project's useful life.
- Operational stages (B6-B7)This encompasses energy consumption (B6) and water consumption (B7). In some projects, this stage is excluded depending on the objective of the analysis. The project scope may not include a detailed analysis of the operational stages, particularly if the main objective of the LCA is to assess the environmental impact of the building's construction and demolition stages.
- End-of-life stage (C1-C4): It covers the impacts associated with the demolition, transport, treatment, and final disposal of building materials once their useful life is over.
- Profitability stage (D): Consider the avoided impacts from the reuse, recycling, or recovery of materials at the end of their useful life, accounting for environmental benefits beyond the building system.
The cradle-to-grave emissions are stages A, B and C together; the whole cycle including stage D, is known as cradle-to-cradle emissions.
By following these steps, the environmental and economic impact of a construction or building product can be calculated from extraction to disposal, allowing for informed decisions in the selection of more sustainable materials and construction methods.
Source: One Click. Image edited by Evaluate
4. Stages of a stroke
The lifecycle assessment of buildings consists of several interrelated phases that evaluate the environmental impact of all stages of the building's lifecycle, from raw material extraction to construction, use, maintenance, and eventual demolition or recycling. These phases generally include:
- Objective and scopeconsists of defining the specific objectives and life cycle stages considered.
- Inventory analysisIn this phase, data about the building should be collected, such as its design, construction materials and measurements, energy consumption, water use, and waste management.
- Environmental Impact Assessmentis based on the analysis of preliminary results.
- InterpretationThis is the final phase, where improvement opportunities are identified.
LCA phases. Source: ISO 14040.
The phases of an LCA are carried out iteratively and can vary in detail depending on the specific context of the life cycle assessment and the project objectives. The ultimate goal of an LCA for a building is to identify opportunities to reduce environmental impact throughout its life cycle and to promote the construction of more sustainable and environmentally friendly buildings.
5. Environmental impact categories assessed by LCA
The environmental impact categories assessed by Life Cycle Assessment (LCA) are specific aspects of the environment that can be affected by a product, process, or service throughout its life cycle. LCA uses indicators and models to quantify and compare these impacts, providing a comprehensive understanding of the environmental effects associated with a specific activity and enabling informed decisions to improve sustainability. Some of these are as follows:
- Global warming potential Greenhouse gases, kg CO2e: describes how much a product contributes to climate change.
- Acidification of terrestrial and aquatic sources (kg SO2): describes how much a product acidifies the environment (acid rain).
- Eutrophication (kg N or kg PO4e): describes the exaggerated flow of nutrients between ecosystems (algal growth).
- Ozone depletion (kg CFK-11): describes the damage caused to the ozone layer in the stratosphere.
- Tropospheric ozone (kg NOx, kg O3 eq o kg eteno): describes the amount of smog caused by the emitted gases.
- Depletion of non-renewable energy resources (expressed in megajoules MJ): measures the amount of non-renewable energy consumed during all stages of the life cycle of a product, process or service, including fossil fuels such as oil, natural gas and coal.
Categories of environmental impact in LCA. Source: Evalore
En las edificaciones, la mayor parte de los impactos medioambientales provienen de la cadena de suministro de materiales, la construcción, la operación y el mantenimiento de los edificios, así como de su demolición. Product stage (A1-A3), which is to say, from the embedded carbon in construction materials. The amount of these impacts is declared in a standardised document called Environmental Product Declaration (DAP), this includes the results of a product's lifecycle analysis.
6. Tools and Methods
Life Cycle Analysis is carried out through various tools and methods, including Life Cycle Assessment (LCA) and Life Cycle Costing (LCC). The former focuses on environmental impact, while the latter analyses the economic costs of the project.
At Evalore, we recommend the use of specific Life Cycle Assessment (LCA) software, as it allows for precise comparisons between different designs or materials, automates calculations, and provides results consistent with the main standards (EN 15804 and EN 15978). These tools also facilitate integration with BIM models and the generation of reports compatible with building environmental certifications such as LEED and BREEAM, as well as for the Level(s) assessment framework. Nevertheless, the analysis can be performed manually using environmental impact factors per material type obtained from recognised databases or verified EPDs, thereby ensuring the traceability and consistency of the results.
It is important to highlight that the choice of software for LCA must be based on the specific needs of the project, compatibility, and the requirements of sustainability certifications. One of the platforms specialised in LCA is One Click LCA, it provides a comprehensive view of the environmental impact of projects, offers access to an extensive Life Cycle Inventory database that includes information on construction materials, energy, transport, maintenance and end-of-life. Furthermore, it provides calculation tools for the LCA of internationally recognised environmental certifications such as LEED y BREEAM, and for the Level(s) assessment framework, helping to meet the requirements of sustainable building certifications and standards.
The following graph reflects the results, in numerical values (kg), of a Life Cycle Assessment (LCA) of a building project with an area of 2929.45 m2. Environmental impacts are quantified according to the materials used in the construction.
Source: One Click. Image edited by Evalore
Using the One Click tool, graphs with percentages of embedded carbon in materials can be visualised and downloaded according to their classification and the life cycle stage they belong to, for example: foundations, structures and facades, beams, floor slabs and roofs.
Source: One Click. Image edited by Evalore
7. Sustainability certifications and LCA
The main building sustainability certifications, such as LEED, BREEAM, and others, consider LCA as a tool in their assessment requirements. Likewise, the Level(s) assessment framework incorporates life cycle analysis as one of its main tools for evaluating the environmental impact of buildings. However, the scope of the life cycle and the types of environmental impacts to be analysed vary between the certifications and the assessment framework.
According to the specifications of LEED v4, the following items are excluded from the analysis: electrical and mechanical equipment and controls, plumbing fixtures, fire alarm and detection system fittings, elevators and transportation systems, excavations and other site developments, and car parks. Adding them will not provide any additional credit.
Whereas for BREEAM, the scope of the LCA must obligatorily include the following elements: facades, external windows and rooflights, internal floor finishes, upper floor slabs, ground floor slab, vertical internal partitions and party walls, and roofs. Unlike LEED, the more construction elements that are included in the assessment, the higher the percentage of points achieved.
In the case of Level(s), the minimum scope of building elements must include: foundations, load-bearing structural frame, floor slab, internal walls, partitions, stairs, façades, roof, and car park.
If we analyse the environmental impact categories evaluated by these two certifications, LEED and BREEAM, we observe that the Level(s) framework covers more categories compared to the LEED and BREEAM certifications, including the abiotic depletion potential of both fossil and non-fossil resources.
Environmental impact categories analysed. Source: Evalore
8. Advantages of Life Cycle Analysis
The ACV provides the necessary foundation for taking Informed materials selection decisions, contributing significantly to the reduction of environmental impacts such as greenhouse gas emissions, resource consumption, and waste generation. It also analyses economic aspects, including operational costs, maintenance, renovation, and demolition, through Life Cycle Cost Analysis (LCCA).
Extension of building lifespan, by employing adaptable and durable materials, as well as considering maintenance.
Optimization of the project design and reduction of resource consumption, the LCA allows us to identify the life cycle stages that have the greatest environmental impact and to provide solutions to reduce them; to make comparisons between designs, for example, by using optimal thermal insulation for a building, energy consumption can be reduced. Or comparisons between structural systems, which allow for a reduction in the volume of materials.
Would you like to carry out a Life Cycle Assessment (LCA) on your building to boost its sustainability?
When assessing the environmental impact of a project from its conception to demolition, LCA allows us to make informed decisions that minimise our impact on the environment and promote a more sustainable future.
Implementing LCA not only benefits the environment, but can also lead to increased energy efficiency, long-term cost savings, and improved occupant well-being.
Discover how this Building Life Cycle Assessment methodology can take your construction projects to the next level in sustainability and efficiency. Contact us to find out more!
Laura Barrios Mogollón
Architect and Sustainability Consultant, IsPatio Evalore SLP
