Etc engineering practices classifying capital cost estimates

estimate

Classifying capital cost estimates 5.Order-of-magnitude estimate

 Data: This type of estimate utilizes a list of the major equipment found in the process. Generically, it includes all pumps, digesters, kilns, etc. Each piece of equipment is roughly sized and the approximate cost determined.

The total cost of equipment is then factored to give the estimated capital cost.

 Data: This type of estimate requires more accurate sizing of equipment than used in the study estimate. In addition, approximate layout of equipment is made along with estimates of digesters, kilns, instrumentation and electrical requirements. Utilities are estimated.

 Diagrams: Process flow diagrams, sketches for major equipment, preliminary sizing of the Bayer Process

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 Diagrams: Final process flow diagrams and smelter and subplants diagram, smelter sketches, utility balances. All diagrams are required to complete the construction of the plant if it is built.

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Example 2. Cost of the estimate

 Lowest expected cost-range (factor 10): - Highest expected value:
$5,000,000 x 0.003 x 10 = $150,000 - Lowest expected value:
$5,000,000 x 0.00015 x 10 = $7,500

 The more detailed the cost analysis, the closer we will be to the actual cost of building the plant.

 The reason for underestimating the actual cost lies predominantly in the failure to include all of the equipment needed in the process. As the planning goes into more detail, it may uncover additional equipment that needs to be included.