Page 207 - Plant design and economics for chemical engineers

COST ESTIMATION 181

TABLE 16
Correction factors for operating pressure,
operating temperature, and material of construction
to apply for fixed-capital investment of major plant
items?*

Operating pressure, psia (atm) Correction factor
0.08 (0.005) 1.3
0.2 (0.014) 1.2
0.7 (0.048) 1.1
8 (0.54) to 100 (6.8) 1.0 (base)
3z $i; 1.2 1.1
6000 (408) 1.3
Operating temperature, “C Correction factor

-80 1.3
0 1 .O (base)
100 1.05
600 1.1
5,000 1.2
10,000 1.4

Material of construction Correction factor
Carbon steel-mild 1 .O (base)
Bronze 1.05
Carbon/molybdenum steel 1.065
Aluminum 1.075
Cast steel 1.11
Stainless steel 1.28 to 1.5
Worthite alloy 1.41
Hastelloy C alloy 1.54
Monel alloy 1.65
Nickel/inconel alloy 1.71
Titanium 2.0

t Adapted from D. H. Allen and R. C. Page, Revised
Techniques for Predesign Cost Estimating, Chem. Eng., 82(5):
142 (March 3, 1975).
3 It should be noted that these factors are to be used
oni’y for complete, main-plant items and serve to correct from
the base case to the indicated conditions based on pressure or
temperature extremes that may be involved or special materials
of construction that may be required. For the case of small or
single pieces of equipment which are completely dedicated to
the extreme conditions, the factors given in this table may be
far too low and factors or methods given in other parts of this
book must be used.