the first priority as recommended
by ISO 14044 [8] is to avoid allocation whenever possible by dividing
the unit process to be allocated into sub-processes, or expanding
the product system to include the additional functions of the
co-products. Otherwise, allocation for the system can be done in
such a way that it reflects the physical properties or the relative
economic values of co-products. There is a relationship between
the choice of method, allocation or system expansion, and the
choice of LCA approach, attributional or consequential