Page 124 - Materials Chemistry, Second Edition

108 3 Life Cycle Inventory Analysis

System boundary A System boundary B
A B

Raw material Raw material
extraction for A extraction for B
Collection
transport
Production of A processing Production of B

Use Use

Waste
Waste disposal of B
disposal of A

System boundary A + B

Figure 3.18 Simplified presentation of two product systems with recycling in open-loop
recycling – OLR.

The question concerning the ‘right’ allocation is: How are environmental advan-
tages and disadvantages to be ‘fairly’ or ‘suitably’ allocated to the subsystems A and
B (generally +C, D, … )? The following environmental advantages apparently occur
in this simple example:
1. Less waste accumulation in A (extreme case: no waste at all by use of product A).
2. Less primary raw material (resource) consumption in B (extreme case: no
material resource consumption for production of product B).

A scientifically strict solution to the problem (indicated by the dotted framework
in Figure 3.18) is system expansion, which within a simple A/B system still seems
possible with justifiable effort. This system expansion is also recommended by
ISO 14044. 103) It assumes however that system B is known in detail and data are
available for an analysis of B. This for OLR is often just not the case! Besides, the
benefit of the expanded system and thereby its fU must be newly defined. System
expansion avoids allocation, but the price is often too high.
Typical secondary raw materials for OLR are:
• Waste paper and carton,
• Waste glass,
• Metal scrap and
• Thermoplastic polymers.

103) International Standard Organization (ISO), 1998a; ISO, 2006b; Curran, 2007, 2008.