Life-Cycle Issues Environment: Life-Cycle Analysis (LCA)

Global environmental questions have increased in significance during the last few years. A life-cycle analysis (LCA) analyzes the environmental ef­fect with reference to ecological effects, health effects, and consumption of resources.

Life-cycle analysis of a filter shows that operation often corresponds to 70% to 80% of the filter’s total environmental load and is absolutely decisive as regards environmental effect.7 Raw material, refining, manufacturing, and transports correspond to about 20% to 30%, while the used filter contrib­utes at most 1%. Filters of plastic or other inflammable material can render

10 kWh to 30 kWh energy when burned, which correspondingly reduces the total environmental load from 0.5% to 1%. On the other hand, if the pres­sure loss in the filter is reduced by 10 Pa, the environmental load is reduced by 125 kW h per year, or approximately 5% decrease in total environmental load. Filters in industrial applications can have quite different figures.

TABLE 9.3 Example of Life-Cycle Cost Distribution of an Air Filter

Type of cost

Relative cost (%)







T fT’

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LCC, llta|

100 Life-Cycle Cost (LCC)

Life-cycle analysis (LCA) does not account for economic aspects, and such analysis should therefore be considered together with a life-cycle cost analysis (LCC),8 which takes into account the costs of investment, energy, maintenance, and dumping the final waste product throughout the lifetime of a plant.

Future costs of replacement filters and energy are calculated according to the current value method. The final result for a 1 m3/s filter with average pres­sure loss of 200 Pa may be as shown in Table 9.3, if the calculation is based on a 10-year period.

The table shows that energy costs account for 80% of the total cost dur­ing the plant’s period of operation. The actual costs of the filter, investment, and maintenance correspond to about 20%, while the costs of dumping amount to only 0.5%. The calculation is based on filtering outdoor air, and filters in industrial applications can have quite different figures.

LCC analyses provide an excellent tool for minimizing the filter costs of a plant. As in the case of LCA, the operation and low pressure loss are abso­lutely decisive as regards the costs of the filter function.