Life cycle inventory

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An LCI is after the target definition, the second stage of a life cycle assessment before the impact assessment in accordance with DIN EN ISO 14044: 2006 . It includes the compilation and quantification of environmental aspects as inputs and outputs of a selected object in the course of its life. The material mass and energy flows are balanced on the input side as well as desired ( products ) and undesired output (conducts) on the output side . The latter is recorded in the form of emissions into air, soil and water.

introduction

After the goal and the scope of the study have been set and defined in the initial phase of the life cycle assessment, the next step is to make quantitative statements on material and energy consumption and emissions. These input and output flows of the entire product life cycle are described in the life cycle inventory analysis, the results of which in turn form the basis for the subsequent life cycle assessment phase of the impact assessment.

To make the life cycle inventory analysis easier, the product system is divided into individual modules and these modules in turn into sub-modules. Each module represents a clearly delimited system for which a partial balance sheet is drawn up. The total of the partial balance sheets results in the life cycle inventory analysis. In the literature, the life cycle inventory is also referred to as the life cycle inventory.

Data collection

When collecting data, all relevant inputs and outputs of the process are recorded by measurement, estimation or calculation. A reference is necessary if data from existing literature are used. In order to keep the risk of misunderstandings low and to achieve a uniform and coherent understanding of the product module to be modeled, measures are specified in DIN EN ISO 14044: 2006:

  • Representation of the special system flow diagram with all process modules
  • Indication of the factors of each process module that influence the inputs and outputs;
  • Information about rivers and relevant data for the operating conditions
  • List in which the units used are recorded;
  • Presentation of the data collection and calculation methods and
  • Instructions for the clear documentation of every special case, every irregularity or other occurrence

In addition, the main groups are named under which the data may be categorized:

  • Energy inputs, raw material inputs, operating material inputs, other physical inputs;
  • Products, by-products and waste;
  • Emissions to air, water and soil and
  • further environmental aspects.

Data calculation

In general, when calculating the data, it is important to always use the same calculation methods within a life cycle assessment and to clearly document and explain these and the assumptions made. When recording the elementary flows, all types of resources consumed should be taken into account; d. This means that the actual production mix (e.g. composition of the electricity) must be taken into account and combustible material is included in the input or output as a value multiplied by the calorific value. The following work steps are finally necessary for the data calculation:

First of all, proof of the required data quality must be provided by means of data validation . This check can be carried out on the basis of the creation of independent mass and energy balances, etc., since the substances follow the laws of conservation of mass and energy and therefore the input and output sum must be identical. Any data errors must be corrected using valid alternatives.

The reference of the data to a process module and a functional unit is the next step in data calculation. For each production step or each process module, a material and energy flow must be determined for which the quantitative input and output data are to be calculated. The flows of all process modules are finally related to the reference flow - the amount of all products necessary to fulfill the function. It should then be possible to relate the complete input and output data to the functional unit through calculation. When aggregating input and output in a production system, however, it should be noted that data are only summarized if they actually relate to substances of equal value and similar environmental effects. Specifically made assumptions should be explained at the beginning of the inventory process or in the later impact assessment.

Since the entire life cycle assessment or its data have to be iteratively checked and adjusted again and again, a new adjustment of the system boundary must be checked by means of a sensitivity analysis. This can result in the fact that individual inputs and outputs or entire process sections are negligible in the life cycle inventory analysis or life cycle assessment due to a lack of significance. But new process modules, inputs and outputs can also prove to be essential for the goal of the study and must therefore be included in the balance sheet. All results of the sensitivity analysis and the adjustment process must be documented.

Allocation

During the allocation , the inputs and outputs are assigned to the products according to defined procedures. The sum of the inputs and outputs of a process module assigned by the allocation must correspond to those before the allocation.

The procedure is carried out according to DIN EN ISO 14044: 2006 in the following steps:

Step 1: Avoid allocation if possible by:
  1. Division of the affected process modules into sub-processes with specification of the input and output data or
  2. Inclusion of additional functions relating to by-products
Step 2: If step 1 is not possible, the inputs and outputs should be assigned to the various products or systems that have a physical relationship
Step 3: If step 2 cannot be fully implemented, the inputs should be assigned according to a relationship to the products and functions.

There are a few things to consider when allocating reuse and recycling. The changes in the inherent properties of the materials and the system boundaries must be observed and identified.

literature

  • Edeltraut Günther: Ecology-oriented management . Thinking about (world-oriented) in business administration. UTB, Stuttgart 2008, ISBN 978-3-8252-8383-4 .
  • Silvio Dall'Acqua, Matthias Fawer, Renato Fritschi, Caroline Allenspach: Eco-inventories for the production of detergent ingredients (=  EMPA report . No. 244 ). EMPA , Dübendorf 1999, ISBN 3-905594-08-0 .
  • Kurt Habersatter: Eco-inventories for packaging . Ed .: Switzerland Federal Office for the Environment, Forests and Landscape (=  Environmental Series . No. 250 / I ). Documentation Service, SAEFL , Bern 1996.
  • DIN German Institute for Standardization e. V. (Ed.): Environmental Management - Life Cycle Assessment - Requirements and Instructions . DIN EN ISO 14044. Beuth, Berlin October 2006 ( content [accessed on June 5, 2012]).

Individual evidence

  1. ^ A b Edeltraut Günther: Ecology-oriented management . 2008, p. 290 .
  2. ↑ Silvio Dall'Acqua, u. a .: eco-inventories for the production of detergent ingredients . 1999, p. 7 .
  3. ↑ Kurt Habersatter: Eco inventories for packaging . tape I , 1996, p. 3 .
  4. ↑ DIN EN ISO 14044: 2006, p. 24.
  5. ↑ DIN EN ISO 14044: 2006, p. 24.
  6. ↑ DIN EN ISO 14044: 2006, p. 26.
  7. ↑ DIN EN ISO 14044: 2006, p. 27.
  8. ↑ DIN EN ISO 14044: 2006, p. 27.
  9. ↑ DIN EN ISO 14044: 2006, p. 28.
  10. ↑ DIN EN ISO 14044: 2006, p. 28.
  11. ↑ DIN EN ISO 14044: 2006, p. 29.
  12. ↑ DIN EN ISO 14044: 2006, p. 30.