1. Define the Goal and Scope

The initial stage of conducting an LCA requires a precise definition of the assessment’s objectives and scope, a crucial step that lays the foundation for the entire analysis. This phase involves:

• Clarifying the LCA’s Purpose: Are you aiming to improve a product’s environmental performance, compare alternatives, or inform policy or strategy? The goals can vary widely, influencing the depth and focus of the study.
• Identifying the Intended Audience: The results could be intended for internal stakeholders, regulatory bodies, customers, or the public. This determines the level of detail and how the findings will be communicated.
• Selecting the Product or Process: Clearly specify what is being assessed. For products, this could range from a single component to a complex assembly. For processes, it may involve a particular manufacturing process or the entire operational methodology.
• Defining System Boundaries: Decide which stages of the product’s life cycle will be included (e.g., cradle-to-grave, cradle-to-gate, or gate-to-gate). This decision affects the comprehensiveness of the study and the data collection efforts required.
• Setting Functional Unit: Establish a functional unit to which all data will be normalized, enabling meaningful comparisons. This could be a specific measure of the product’s performance, output, or use.

2. Conduct the Inventory Analysis (LCI)

The Life Cycle Inventory (LCI) phase is a critical and often the most time-consuming part of an LCA, involving:

• Data Collection: Compile detailed data on all inputs such as raw materials, energy usage, and water, and outputs including emissions to air, water, and soil, as well as waste generation, for each stage of the product’s life cycle. This data should be as specific and representative as possible.
• Data Sources: Utilize a mix of primary data from direct measurements or company records and secondary data from databases and literature, especially for background processes or when primary data is not available.
• Chemical Industry Specifics: For the chemical industry, this might involve gathering data on the extraction and processing of raw materials, specific chemical reactions, energy consumption at various stages of production, and the treatment of by-products and emissions.

3. Perform the Impact Assessment (LCIA)

The Life Cycle Impact Assessment (LCIA) translates the inventory data into potential environmental impacts through:

• Selection of Impact Categories: Choose relevant impact categories such as global warming potential (GWP), acidification, and eutrophication. The selection should align with the study’s goals and the environmental concerns most relevant to the product or industry.
• Characterization: Apply characterization factors to convert LCI results into common units for each impact category, facilitating comparison. This involves using models that estimate the potential impacts of the inventoried inputs and outputs.
• Normalization and Weighting (optional): These steps may be included to further interpret the results, providing a comparative understanding of the significance of different impact categories based on a reference system.

4. Interpret the Results

The final phase of the LCA, interpretation, involves analyzing the findings from the LCI and LCIA phases to:

• Assess Completeness, Sensitivity, and Consistency: Verify that the LCA is comprehensive and the results are robust. Sensitivity analysis can help understand how changes in data or assumptions affect the outcomes.
• Identify Significant Issues: Determine which life cycle stages, processes, or materials contribute most significantly to the overall environmental impact.
• Recommendations and Reporting: Based on the analysis, develop recommendations for reducing environmental impacts. Prepare a report that communicates the findings, methodology, assumptions, and limitations in a clear and transparent manner.