Investment calculation for chemical plants, waste water technology and food industry technology means:
This diagram shows the
known state only:
fastest: the estimate of coarse expenditures (ca. +- 40%)
mostly sufficient: calculation by comparison and/or calculation by the method of factor-addition (ca. +-10%)
most exact: the detailed calculation (ca. +-5%)
Estimate of coarse expenditure:
This method of calculation is fast and easy: (Costs of machinery, apparatus and vessels) x (factor depending on type of plant) = investment costs. The costs of the complete equipment will be estimated or investigated by inquiries at the manufactures. The type-factor usually goes from 2 to 5 and depends on the type of plant.i.e. plants for solid handling, liquid handling or ex-plants with intensive process instrumentation. The method does not give very accurate results; but usually one can anwser questions like 'Does this process/plant have any chance to be realised'.
|one compares an already realised plant A with the plant B (same type of plant) to be realised :
The uncertainity of the calculation is overcome by addition of 10% to the total.
Method of factor-addition
All costs of the equipment (at ground moving work by appropiate calculations) and all specific work are calulated by inquiry. Additional costs (i.g. for authorities, legal permits, etc.) are listed separately and added. Expenses for this method of calculation is relatively high and it typically also needs considerable time. The accuracy normaly is about +-5%.