COST ACCOUNTING AND ESTIMATING. 249 



eluding bedplates, bearings, columns, guides, all items of the reciprocating group, the valve 

 gear, etc., so that it is possible without detailed calculations to obtain the weights which 

 meet tlie required engineering conditions. This saine procedure can be adopted for all por- 

 tions of the machinery estimates, including condensers, boilers, stacks and uptakes, shafting, 

 bearings, etc. 



One of the largest and the most difficult item in steain engineering is the steam engi- 

 neering piping. The best procedure for calculating steam piping is to make a quick layout of 

 the machinery with a single line sketch plan of the various piping systems, including main 

 and auxiliary steam, main and auxiliary exhaust, suction and discharge piping, and to cal- 

 culate from this layout all the valves, flanges, pipe and fittings in the same manner as for 

 hull piping. Where the time limit will not permit of such detailed layout, piping is estimated 

 in separate groups, as described above, by comparison with the nearest similar job; but 

 here again great care must be exercised, since the several owners' requirements vary to such 

 extent. One company might require copper pipe and composition valves for the system, 

 whereas ordinary good practice would consist of wrought-iron pipe with cast-iron valves; 

 and realizing that the former would cost several times as much as the latter it will be at 

 once seen that the greatest care must be exercised in making assumptions in this group. The 

 deck steam pipes, smothering pipes and heater coils for oil steamers sometimes consist of 

 very large quantities, and, being comparatively simple, they are calculated separately. 



The specifications cannot specify all sizes, dimensions and character of material, and 

 therefore the estimator must have a complete knowledge of the character of the material and 

 the size required for any portion of the machinery; for instance, in piping, it will be necessary 

 for the estimator to know what connections are made to the various pumps, their size and 

 character of piping. If the sizes of the condenser, air pump, and circulating pump are not 

 specified, it will be necessary for him to know the best practice to determine these sizes. 

 In reciprocating pumps he is required to know not only the size of the pumps, but whether 

 they would be composition end, composition fitted, or with cast-iron cylinders — whether or 

 not soft packing or metallic packing is required. The same detailed knowledge is required 

 for determining all sizes and dimensions w^here not definitely specified. Having determined 

 the net quantities, they are transferred to the cost sheet ; due allowance for wastage, current 

 unit rates are applied, obtaining the estimated cost of the material. 



The labor, as with the hull, is estimated in hours, and in most of the groups is based 

 upon the weight, though in some cases better results are obtained by applying unit rates, 

 following the method of manufacture. Thus it has been found that in a condenser it 

 is better to base the hours upon the number of tubes. 



A summary of the hull and machinery is prepared from these detailed figures, and on 

 this sheet is applied the current rate of expense. This is not constant for hull and ma- 

 chinery nor even for the separate jobs, since the expense rates of the various departments 

 differ greatly, as described above. 



The sum, then, of the material, labor and expense for the hull and machinery gives 

 the estimated cost of the vessel. Throughout the process of estimating, check methods 

 are continually applied, so that there is little possibility of a large error appearing in the 

 process. 



STANDARDIZATION. 



To avoid repeat operations and to obtain uniform results, the various groups should 

 be standardized. The general method of standardizing a group is, first, to ascertain the 



