Page 200 - Plant design and economics for chemical engineers

174 PLANT DESIGN AND ECONOMICS FOR CHEMICAL ENGINEERS

TABLE 9
Component electrical costs as percent of total
electrical cost

Typical
Component Range, % value, %

Power wiring 25-50 40
Lighting I-25 1 2
Transformation and service 9-65 40
Instrument control wiring 3-8 5
The lower range is generally applicable to grass-roots single-product plants;
the higher percentages apply to complex chemical plants and expansions
to major chemical plants.

piping costs is presented in Chap. 14. Labor for installation is es ‘mated as
approximately 40 to 50 percent of the total installed cost of piping. Mat ial and
\
labor for pipe insulation is estimated to vary from 15 to 25 percent of the total
installed cost of the piping and is influenced greatly by the extremes in
temperature which are encountered in the process streams.

Electrical Installations
The cost for electrical installations consists primarily of installation labor and
materials for power and lighting, with building-service lighting usually included
under the heading of building-and-services costs. In ordinary chemical plants,
electrical-installations cost amounts to 10 to 15 percent of the value of all
purchased equipment. However, this may range to as high as 40 percent of
purchased-equipment cost for a specific process plant. There appears to be little
relationship between percent of total cost and percent of equipment cost, but
there is a better relationship to fixed-capital investment. Thus, the electrical
installation cost is generally estimated between 3 and 10 percent of the fixed-
capital investment.
The electrical installation consists of four major components, namely,
power wiring, lighting, transformation and service, and instrument and control
wiring. Table 9 shows these component costs as ratios of the total electrical cost.

Buildings Including Services
The cost for buildings including services consists of expenses for labor, materi-
als, and supplies involved in the erection of all buildings connected with the
plant. Costs for plumbing, heating, lighting, ventilation, and similar building
services are included. The cost of buildings, including services for different types
of process plants, is shown in Tables 10 and 11 as a percentage of purchased-
equipment cost and tied-capital investment.