The topic of product life cycle assessment (LCA) is gaining increasing attention, particularly in the construction sector. This industry significantly contributes to the unsustainable depletion of natural resources and various forms of environmental pollution.
The construction industry, known for its long-lasting and complex product supply chains, should implement aspects of the circular economy and harness its potential to reduce both embedded and operational emissions. This can be achieved through the use of natural, recycled, and alternative materials, as well as renewable energy sources.
The goal of this article is to introduce the LCA method, its structure, and its significance in determining the environmental impacts of products.
Life cycle assessment (LCA) is an internationally recognized method for evaluating the environmental impacts and resource usage associated with products, services, or processes. It provides a comprehensive understanding of the entire lifecycle, from raw material acquisition through transport, production, use, to waste recovery and disposal.
A product life cycle is defined as the successive and interconnected stages of a product system, from the acquisition of raw materials or their creation from natural resources to final disposal (EN ISO 14040:2006/A1:2020). It begins with the acquisition of raw materials and energy sources from the environment. This phase also includes the transport of raw materials to the place of further processing. During the production stage, raw materials are transformed into usable materials through the use of fuels, electricity, and other resources. The product manufacturing stage involves transforming necessary materials into the final product, completing the product, and packaging it for distribution to the consumer. Each of these stages involves energy and material inputs and outputs, which consequently impact the environment. all life cycle phases.
In the usage phase, the product fulfills its intended function, requiring energy and raw materials for operation, maintenance, repair, or replacement. The end-of-life phase involves energy and material demands for disposal, reuse, recycling, or energy recovery. Recycling in the waste recovery stage can yield reusable materials or energy. Throughout its life cycle, a product interacts with the environment at various stages, each posing different potential environmental burdens. Comparing and evaluating the environmental impact of products is possible by considering all life cycle phases.
All processes involved in individual life cycle phases form a product system, which consists of processes and flows. Processes transform inputs into outputs, while flows connect these processes, with one flow's output serving as the next process's input. Material and energy flows must be described in terms of inputs, outputs, and their positions relative to other processes, ensuring continuity and consistency. The typical unit for material flows is mass (kilograms), while energy flows are measured in units like MJ or kWh.
Each phase of the product life cycle comprises various processes that convert material and energy inputs into outputs. Complex processes may include internal subprocesses. The product system interacts with the environment through pollutant emissions into air, water, and soil. These interactions, termed elementary flows, cross the product system's boundary, facilitating energy and matter exchange with the environment.
The LCA method, an essential environmental management tool, evaluates and compares the environmental impacts of products throughout their life cycle. It quantifies significant emissions, resource consumption, related environmental and health impacts, and resource depletion issues. The LCA approach assesses environmental impacts with respect to the entire product life cycle.
The main structure of LCA consists of four mutually dependent phases, each influencing the others:
This first step involves clarifying the intended use of the LCA study, its reasons, target audience, and whether the results will be used for comparative statements intended for publication. Precise goal definition eliminates misunderstandings in result interpretation. Key points to define include the product system functions, functional unit, system boundary, allocation procedures, types of evaluated impacts, evaluation methodology, data requirements, assumptions, limitations, data quality requirements, type of critical assessment, and the format of the LCA study report.
This most time-consuming part involves collecting and compiling data on elementary flows from all processes within the analyzed product system. The output is a comprehensive list of quantified elementary flows across all life stages, serving as input for the subsequent life cycle impact assessment (LCIA) phase.
This phase evaluates the significance of potential environmental impacts using LCI results. It includes classifying inventory data into impact categories, characterizing the rate of effects on specific areas, and calculating category indicator results. Normalization and weighting may be performed to express the relative importance and social significance of impacts.
This final phase involves analyzing results, drawing conclusions, identifying study boundaries and limitations, and providing recommendations based on previous phases' results. The outcome is a comprehensive report on the life cycle interpretation, offering insights for decision-making and recommendations to reduce environmental impacts.
The LCA method is not only useful for choosing environmentally suitable technologies but also for determining operational procedures with minimal life cycle impacts. Its holistic approach ensures complete monitoring of material and energy flows, identifying all negative impacts associated with different life cycle phases and preventing the shifting of problems between them.
The method's results help in making informed recommendations and measures to reduce environmental impacts directly or indirectly, influencing market behavior and promoting sustainability, circularity, and decarbonization in the construction industry. Disseminating LCA study results to stakeholders, including architects, builders, developers, and other experts, is crucial for supporting the production of sustainable building materials and environments.
Silvia Vilcekova Co-founder and LCA team lead Silvia has contributed to the field of Life Cycle Assessment (LCA) for over two decades, establishing herself as a renowned expert.
She also holds the position of Director at the Institute of Sustainable and Circular Construction at the Technical University of Kosice. Additionally, she serves as the chairman of the Technical Committee TK112 for Sustainable Construction.