What is a Life Cycle Assessment?

A Life Cycle Assessment is defined as the systematic analysis of the environmental impact of products during their entire life cycle.

During a Life Cycle Assessment environmental impacts are evaluated throughout the entire life cycle of a product (production, use and disposal phases). This also includes the upstream and downstream processes associated with the production (e.g. production of raw, auxiliary and operating materials) and with the disposal (e.g. waste treatment).

Environmental impacts refer to all relevant extractions from the environment (e.g. ores and crude oil), as well as emissions into the same (e.g. wastes and carbon dioxide). The International Organization for Standardization provides guidelines for conducting a Life Cycle Asssessment according to ISO 14040 and 14044.

→ 7 Tips for Responsible Life Cycle Assessment Practice

The Main Phases of Life Cycle Assessment

Goal & Scope definition

The product or service to be assessed is defined, a functional basis for comparison is chosen and the required level of detail is defined.

Inventory analysis

An inventory analysis of extractions and emissions is performed. An inventory list of all the inputs and ouputs of a product or service.

Impact assessment

The effects of the resource use and emissions generated are grouped and quantified into a limited number of impact categories which may then be weighted for importance.


The results are reported in the most informative way possible and the need and opportunities to reduce the impact of the product(s) or service(s) on the environment are systematically evaluated.

What is the Most Critical Phase in Product Life Cycle​ Assessment?

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The Special Terms of Life Cycle Assessment

System boundaries (Goal & Scope)
Description of the product’s life cycle phases and the cut-off criteria delimiting the system under investigation.

Functional Unit (FU)
Reference unit of the system; environ-mental impacts are evaluated based on this unit. E.g. 1 kg product, annual output, 1kg*km, etc.

Life Cycle Inventory Analysis (LCIA)
Assembly and quanti-fication of inputs (resource and energy flows) and outputs (emissions and wastes) into and out of the system.

Impact Assessment
Evaluation of environmental impacts based on LCIA, and displaying the results in impact categories.

Interpretation and reporting
Displaying the environmental impacts of a report according to ISO 14040/44 standards.

Critical Review
Critical assessment by an independent expert to verify the data and to increase credibility of results.

Impact categories

Global Warming Potential (GWP), expressed as CO2-equivalents [kg];
→ Global warming

Acidification Potential, expressed as SO2 equivalents [kg];
→ Acid rain / forest decline;

Eutrophication Potential, expressed as PO4 equivalents [kg];
→ Over-fertilization of the soil or water;

Ozone Depletion Potential, expressed as R11 equivalents [kg];
→ Thinning of the ozone layer in the upper atmosphere;

Photochemical Ozone Creation Potential (“Summer Smog”), expressed as ethene equiva-lents [kg];
→ Ozone formation in the lower atmosphere;

Primary energy [MJ], renewable and fossil energy sources (on the input side)

How Is Data Collected for Life Cycle Assessment?

What is the chain of events leading up to a complete LCA study?

Flow chart
The flow chart of the system to be analysed is provided by the client.

On the basis of the flow chart, a questionaire is worked out for analysing the material and energy flows of the process cycle.

Data collection
The client collects data (with external support if necessary).

A model resulting from the collected data is created (e.g. with GaBi Software).

Evaluation and Interpretation
The developed model is evaluated regarding its potential environmental impact.

Critical Review (optional)
A critical review is possible in order to examine the ISO conformity and to increase the reliability of the study.

What are the requisites for data quality?

•   Correct units and their reference values (base year, production units etc.)
•   Reference to a single, well-defined functional unit
•   Adequate precision
•   System-relevant material and energy flows

    What are the options for collecting data?

    •   Data collection based on a “Black Box“ process, summarizing the entire process chain
    •   Data collection for each individual process in the chain separately

    What is an Example of Life Cycle Assessment?

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