The program shows the results by sections as well as for the whole plant. The package consists of some 100 program units and requires about 200,000 bytes of computer memory to load and execute. Average execution time for a run on a minicomputer, such as VAX 780, is about 10 seconds. This method rests on a statistical correlation of cost data for 42 separate refining, petrochemical, and synthetic fuel plants. These costs, as proportions of total equipment f.o.b. costs, are correlated in terms of ratios of costs of various classes of equipment to total equipment cost.
Correlations are in terms of costs as if all equipment wre made of carbon steel.
The calculated costs are applicable only for the categories of equipment whose f.o.b. costs are used in the computations. Hirsch and Glazier assume the costs of other types of equipment to be estimated on an erected basis. SRI modified piping material costs to account for alloy piping. SRI has used this method for plants processing predominantly fluids. This method is based on the premise that various direct installation cost elements, as percentages of total process equipment cost, are related to the average cost of an equipment item in the plant.