Relative and absolute character of the assessment Sample Clauses

Relative and absolute character of the assessment. Use of the functional unit as a basis for the modeling also determines another key characteristic of LCIA, that is, the relative character compared with the absolute character of XXXX. As indicated in the introduction, Xxxxxxxxxx et al. (1997) were the first to put this sharply. A functional unit usually is arbitrary in size; we could as well take 100 square meters to be painted, or 10,000 liters of milk to be packed, as long as it is the same size for all products to be compared. Instead, in HERA a fixed flow is taken as a starting point, usually the production volume of the chemi- cal. This is transformed into environmental flows and concentrations, usually compared with given acceptable threshold flows or levels. XXXX is therefore described as an absolute, ‘only-above-threshold’ approach. In contrast, LCA is in this context described as relative, ‘less-is-better,’ indicating the desirability of any decrease of hazardous substances, rather linking with prevention than with con- trol. We conclude that the latter two points, the use of the functional unit in contrast to actual flows, linked with the distinction between a relative versus an absolute mod- eling structure, fundamentally distinguish between LCIA and HERA. The other eight points are seen as secondary differences that in practice may occur to a greater or lesser degree. Besides these ten points, the literature mentioned earlier identifies a number of procedural differences as well. Among these are reporting formats, reviewing requirements, and the role in legislation. These type of differ- ences have nothing to do with the model structure itself, and are therefore not discussed in this chapter.