Cost indices Engineering News-Record

Table 9E-9 lists unit operations in the polystyrene plant. The highest temperature is 400°F, in the extruder. From this and Figure 9-5, a temperature factor of 0.04 is obtained. There are no high pressures except in the extruder, and its value is unknown. The pressure factor will be assumed to be zero. Stainless steel is used, so the material factor is 0.2. From Equation 2 a complexity factor of 3.48 can be calculated. A direct process investment cost of 350,000 per functional unit is obtained from Figure 9-7. This means that the cost of constructing the plant when the Engineering News Record Construction Index (ENRCI) is 300 would be 3,150,000. This will be updated to 1960 when the ENRCI was 350, and then the CEPI will be used to obtain the cost in 1974. The resultant cost in 1974 is... 

Many different types of cost indexes are published regularly. Some of these can be used for estimating equipment costs others apply specifically to labor, construction, materials, or other specialized fields. The most common of these indexes are the Marshall and Swift all-industry and process-industry equipment indexes, the Engineering News-Record construction index, the Nelsotl-Fatrar refinery construction index, and the Chemical Engineering plant cost index. Table 3 presents a list of values for various types of indexes over the past 15 years. 

Relative construction costs at various dates can be estimated by the use of the Engineering News-Record construction index. This index shows the variation in... 

Table 9-42 presents information on some cost indices for the United States. Engineering News-Record updates its construction-cost index in March, June, September, and December. The Oil and Gas Journal gives the Nelson-Farrar refinery indices in the first issue of each quarter. The Chemical Engineering plant-cost index and Marshall and Swift equipment-cost index are given in each issue of the pubhcation Chemical Engineering. Derivation of the base values is referred to in the respective publications. 

The cost of a unit is then obtained from Figure 9-4. To obtain the cost of the plant this figure needs to be multiplied by the number of units, a factor (1.33) to account for utilities and general facilities, and the current or projected value of the Engineering News Record Chemical Cost Index. The accuracy of this method is unknown but should be better than the Lang factor and not as good as Miller s. 

The Engineering Netvs-Record construction cost index appears weekly in the Engineering News-Record. For a complete description of this index and the revised basis, see Eng. News-Record, 143(9) 398 (1949) 178(10 87 (1967). History is in March issue each year, for example, see Eng. News-Record, 22000 54 (March 15, 1988). 

For use with process-equipment estimates and chemical-plant investment estimates, the Marshall and Swift equipment cost indexes and the Chemical Engineering plant cost indexes are recommended. These two cost indexes give very similar results, while the Engineering News-Record construction cost index, relative with time, has increased much more rapidly than the other two because it does not include a productivity improvement factor. Similarly, the Nelson-Farrar refinery construction index has shown a very large increase with time and should be used with caution and only for refinery construction. 

The journal Engineering News Record publishes a monthly construction cost index. This is based on civil engineering projects and is sometimes used for updating offsite costs. This index has been published since 1904 and is the oldest of all the indices. 

Sources. U. S. Department of Labor and Engineering News Record "Construction Cost Index"... 

ENR Building Construction Cost Index Histories, Engineering News Record, Mar. 22, 1973,p. 79 (history in March issue each year). 

Here, I ew and Iref are the valnes of the cost index today arrd in the reference year, respectively. Cost indices for special types of eqrripmerrt arrd processes are published frequerrtly in several journals (e.g.. Chemical Engineering, The Oil and Gas Journal, arrd Engineering News Record ). 

The Engineering News-Record (ENR) Construction Cost Index... 

Complete costs can seldom be assembled at a particular date, and hence cost indexes such as those of Table 23-1 must be. employed. Indexes are especially useful if they are kept up to date in readily available publications. The ENR (Engineering News Record) index of constrq6tion costs has been used since 1913 and it is published each month. Likewise the Nelson Refinery Construction Cost Index is published in the first issue each month of The Oil and Gas Journal. Refinery wages and the productivity of refinery labor can be obtained (or computed) from informa -tion in the monthly magazine entitled Survey of Current Business (U.S. Department of Commerce) or from quarterly issues (January, April, July, and October) of The Oil and Gas Jouranl (Itemized Cost Indexes). There is no truly satisfactory way to state an operating cost index because the value of fuel varies widely from plant to plant, and the fuel cost Nelson, W. L.,. . . How it is Computed, Oil Gas J., Oct. 1, 1956, p. 110. 

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