Six-tenths factor

Chilton, C. H., Six Tenths Factor, Applies to Complete Plant Costs. Chem. Eng, reprinted in Cost Engineering in the Process Industries Estimation, McGraw-Hill Book Co., 1960. 

Six-tenths factor, 47 Yearly cost indices, 47 Critical flow, safety-relief, 438 Back pressure, 440 Sonic flow, 438 Critical flow, see Sonic Cyclone separators, 259-269 Design, 260-265 Efficiency chart, 263 Hydroclones, 265-267 Pressure drop, 263, 264 Scrubber, 269 Webre design, 265 Deflagration venting nomographs,... 

An analysis of equipment costs and capital investment for chemical plants (Wilson, 1947 Chilton, 1950 Vilbrandt and Dryden, 1959 Guthrie, 1970) showed that the six-tenths factor can be applied for a rough evaluation of the influence of equipment size on its cost. The six-tenths rule can be described as a power law expression ... 

Application of six-tenth-factor rule to costs for shell-and-tube heat exchangers. 

It is often necessary to estimate the cost of a piece of equipment when no cost data are available for the particular size of operational capacity involved. Good results can be obtained by using the logarithmic relationship known as the six-tenths-factor rule, if the new piece of equipment is similar to one of another capacity for which cost data are available. According to this rule, if the cost of a given unit at one capacity is known, the cost of a similar unit with X times the capacity of the first is approximately (X)0 6 times the cost of the initial unit. 

If no cost data are available for the specific dryer selected, a good estimate can be obtained by using the logarithmic relationship known as the six-tenths-factors rule. A price for a similar one, but having different capacity, is the sole requirement. 

Equipment Cost Comparisons, Several methods have been proposed for approximating costs of equipment of different size or capacity when the cost of a given unit is known. Williams offers the general "six-tenths factor. If the cost of a given unit is known at one capacity and 1 R. Williams, Jr., Chem. Eng., 64(12) 124 (1947). 

The latter equation becomes the six-tenths factor expressed in mathemati-... 

Use the EMD to compare the amount of duty in each stream. Match streams initially with the largest heat duty, Q, to take advantage of the economy of scale, a concept commonly referred to in chemical equipment design economics as the six-tenths factor rule. 

As discussed below in Section 16.7, the Aspen Engineering Suite provides methods more accurate than the six-tenths factor method of Equation (16.3) for determining the effect of scale on capital cost. The Aspen methods apply engineering-based scale-up rules to each piece of process equipment and to buildings, site development, and other items of capital cost. 

Williams, R., Six-Tenths Factor Aids in Approximating Costs, Chem. Eng., 54(12), 124-125, December (1947b). 

Williams, Rodger, Jr., Six-tenths Factor Aids in Approximating Gmts, Chem. Eng., 54, Decembtn- (1947), p. 124. 

The six-tenth factor is another handy method to determine the cost of an equipment of a given capacity (A), if the cost and the capacity of a similar one (B) are known ... 

---