Process - uo-lca/uo-lca.github.io GitHub Wiki

In life cycle assessment, a process is a set of interrelated or interacting activities that transforms inputs into outputs. Process attributes and LCIA results are displayed in both the Process LCIA and Process Instance views. LCIA in the Process Instance view applies the activity level from fragment navigation in the Fragment Flows view.

Process Instance

The Process Instance view is entered by clicking on a blue process node in the fragment Sankey view. Here you see details about the process, including its activity level, general comments, and a link to the ILCD reference. The ILCD Reference link opens the ILCD Process data set in a separate page.

Fragment Flows Table

Below the header block is a list of fragment flows, intermediate flows that form the process's inputs and outputs within the fragment. These flows do not have any environmental impacts and instead form the accounting mechanisms used to compute different process activity levels. The Fragment Flows may be parameterized if you have authorization to edit the current scenario.

Fragment flows are used to enforce property balance constraints, such as mass or energy balance. Processes which are marked during model construction as having conservation properties will always include one fragment flow marked "balance." The magnitude of this flow is computed from the other flows in order to enforce conservation. If other flows are parameterized, the magnitude of the balance flow is re-computed. Only flows having the same property as the balance flow's reference property are included in the balance computation.

Fragment flows for the Used Oil Management process, showing the results of the mass balance calculation.

Dissipation

Below the Fragment Flows table, any dissipation flows are listed. Dissipation flows are emissions into the environment whose magnitudes are computed based on flow properties of an input flow. If the current process instance has any dissipation quantities, they are shown in this table. The dissipation rate is the fraction of a given flow constituent that is dissipated into the environment by the process, with one minus the dissipation rate being retained within the process (i.e. not emitted). The quantity of the emission is computed as:

Emission quantity = Activity level x Composition value x Dissipation rate x Scale

where 'Scale' is the stoichiometric scaling factor between the constituent material and the emission.

The Dissipation rates may be parameterized if you have authorization to edit the current scenario.

Process LCIA Results

If the process has any elementary flows, the LCIA results from those flows are shown below in rainbow charts. Each band in the rainbow chart represents the impacts from a single emission. For details, see rainbow charts .

Private processes

Some processes are private because they originate in data sources that are proprietary, such as the GaBi professional database or Ecoinvent .

When private processes are viewed, the individual elementary flows are not revealed. Instead, only LCIA aggregate scores are visible. When the ILCD reference link is followed, individual flows are again not shown. Note that when private processes are used in fragments, the intermediate flows associated with those processes are shown because they are part of the inventory model.

Process LCIA

Process LCIA can also be performed using the LCIA comparison view. Here, individual processes can be added to a list and compared against one another or against other model components. From the LCIA Comparison view, clicking on a process name will navigate to a Process LCIA detail view.