In this study, some allocation procedures were applied following ISO
recommendations (ISO, 1998). Allocation is needed in multi-functional processes,
such as multi-output and -input processes, and open-loop recycling, to allocate the
input or output flows to each product. Wherever possible, allocation was avoided by
unit process disaggregation or system boundaries expansion. Where allocation could
not be avoided, the outputs and inputs of the system were partitioned between its
different products or functions in a way that reflects physical relationships between
them. When physical relationships could not be established, the inputs and outputs
were allocated between the products and functions in a way that reflects other
relationships between them.