How is PCF calculated?
In order to make the PCF of different products comparable, a reference value, the so-called "functional unit", must be defined before balancing, according to which all subsequent quantifications are aligned.
In addition, the so-called reference flow must be defined. This is the quantity of a material or product that is required to provide the benefit defined by the functional unit.
With the help of a so-called system flow diagram, the product system to be balanced, including the associated influences, can be represented graphically. All process modules that belong to the life cycle of the respective product are represented by boxes. Arrows connect the individual modules according to their input and output flows.
The system boundaries are used to define which product life cycle phases are taken into account in the life cycle assessment. The main question here is whether the distribution, use and disposal of a product should be included or neglected. If all life cycle phases including distribution, use and disposal are accounted for, the so-called "cradle-to-grave" approach is used. This approach is typically used for end consumer products. In contrast, industrial products are often only accounted for using the cradle-to-gate approach, i.e. only up to the boundary of their own value chain. The reason for this approach is that it is often not possible to determine exactly which further processes the respective product will subsequently undergo.