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FLEXO Magazine : Sustainable Spring 2009
Additionally, key raw materials consumed in a process are calculated in terms of kg/CB with a cut-off criterion being < 0.1 percent. These values are weighted with a factor that reflects the demand and exploitable reserves of the raw materials so that the lower the reserves of a raw material and the higher the rate of consumption, the scarcer that material is and therefore the higher the weighting factor it is assigned. The amount of air emissions were weighted with a factor reflecting their potency regarding the global warming, acidi- fication, smog creation, and ozone depletion potentials. The air emissions for each major greenhouse gas were adjusted for the 100-year GWP as defined by the Intergovernmental Panel on Climate Change (IPCC)2 . Water emissions are as- sessed through a critical volumes approach, which considers both the total amount of emissions to water, as well as the environmental toxicity of the chemicals being emitted. Critical volumes (CV) are calculated as the ratio of the amount of chemical emitted to the Maximum Emission Concentration threshold limits For example, an emission of 200 mg NH4-N with an MEC threshold value 10 mg/L results in a critical volume of 20 L (CV = 200 mg/10 mg/L). The individual critical volumes are then summed for each emission to water in order to obtain an overall impact (L/CB). The solid waste emissions account for all materials generated and disposed of in a land- fill, therefore materials that are recycled or reused are not counted as solid waste. Wastes are categorized as municipal, hazardous, construction, and mining, with a weighting factor applied to each type to account for impact. The impacts are then summed to obtain an overall impact amount in kg/CB. The weighting factors are 1, 5, 0.2, and 0.4 for each waste cat- egory, respectively, and are based on costs for landfill which reflect the degree of potential environmental impact for each. Furthermore, even though land is considered to be a finite FIGURE 1. System boundaries for the three alternatives. resource, most lifecycle analyses do not include an evaluation of land use patterns. The EEA, however, allows for the con- sideration of land use as an environmental impact category based on the degree of land development needed to fulfill the customer benefit. Land use has five categories according to the degree of development that is needed. These categories include: i) No Development – untouched ecosystems, for- ests, lakes, rivers, wetlands; ii) Partially Developed – organic agriculture, green land, fallow, heterogeneous agriculture; iii) Developed – conventional agriculture, modified areas; iv) Covered – long-term paved areas, industrial areas, landfills, areas with buildings on them; and v) Covered and Divided – long-term paved areas that divide ecosystem areas, transpor- tation areas such as streets, rail tracks, canals. The land use results are calculated based on the total amount of land used (m2 /CB) with weighting factors applied to categories iii – v to reflect the higher potential impact for these land uses. The toxicity potential was assessed not only for the compo- FIGURE 2. Relevance Factors. nents of the finished printing inks, but for the entire pre-chain of chemicals used to manufacture the components as well. The result is an assessment of lifecycle toxicity potential. The entire method for performing the analysis of toxicity potential is de- scribed in Saling et al. (2002)1 and is based upon the Hazard- ous Materials Regulations (R-phrases). A total score for toxicity potential is calculated and then weighted. From the standpoint of the final consumer the use phase is the most important so it is weighted at 70 percent of the total score while the production phase is weighted at 20 percent and disposal at 10 percent. www. f l e x oma g . c om S P R ING/SUMME R 20 0 9 Su s t a i n a b l e F LEXO 1 1