Applying the allocation rules

The Active single processes resulting from the allocation process should add up to the original multiple process if their respective inputs and outputs are added together. Some examples of multiple processes are  

Combined waste processing are processes such as mixed waste incineration and landfill, where outputs in terms of emissions to air, water and soil should be allocated to each of a multitude of materials being fed to the process. 

What rule of allocation should be used The SETAC methodology maintains that the choice of allocation basis should be related directly to the chemistry and physics of the process . This is one type of causal allocation. The analysis itself may consequently be partly chemical-analytical and partly physical. As a principle, this type of allocation should be used wherever possible. In cases where this is not possible overall apportioned allocation must be used, based on the functional unit. This means that allocation is made, for example by weight in automotive applications, while for surface treatment it would be by covered surface. 

Allocation has been thoroughly discussed in the 1994 SETAC European Workshop on Allocation in LCA [9], 

Fictional HDPE automotive part Allocation assumptions. 

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