Page 186 - Plant design and economics for chemical engineers

160 PLANT DESIGN AND ECONOMICS FOR CHEMICAL ENGINEERS
TABLE 1
Breakdown of fixed-capital investment items for a chemical process (Continued)
Direct Costs
9. Land
Surveys and fees
Property cost
Indirect costs
1. Engineering and supervision
Engineering costs-administrative, process, design and general engineering, drafting, cost
engineering, procuring, expediting, reproduction, communications, scale models, consultant
fees, travel
Engineering supervision and inspection
2. Construction expenses
Construction, operation and maintenance of temporary facilities, offices, roads, parking lots,
railroads, electrical, piping, communications, fencing
Construction tools and equipment
Construction supervision, accounting, timekeeping, purchasing, expediting
Warehouse personnel and expense, guards
Safety, medical, fringe benefits
Permits, field tests, special licenses
Taxes, insurance, interest
3. Contractor’s fee
4. Contingency

Types of Capital Cost Estimates
An estimate of the capital investment for a process may vary from a predesign
estimate based on little information except the size of the proposed project to a
detailed estimate prepared from complete drawings and specifications. Between
these two extremes of capital-investment estimates, there can be numerous
other estimates which vary in accuracy depending upon the stage of develop-
ment of the project. These estimates are called by a variety of names, but the
following five categories represent the accuracy range and designation normally
used for design purposes:

1. Order-of-magnitude estimate (ratio estimate) based on similar previous cost
data; probable accuracy of estimate over + 30 percent.
2. Study estimate (factored estimate) based on knowledge of major items of
equipment; probable accuracy of estimate up to f30 percent.
3. Preliminary estimate (budget authorization estimate; scope estimate) based
on sufficient data to permit the estimate to be budgeted; probable accuracy
of estimate within +20 percent.