Significant Cost Items

Piping This cost includes the cost of the pipe, installation labor, valves, fittings, supports, and miscellaneous items necessary for complete installation of all pipes in the process. The accuracy of the estimates can be seriously in error by the improper application of estimating techniques to this component. Many pipe estimating methods are extant in the literature. 

Two general methods have been used to estimate piping costs when detailed flow sheets are not available. One method is to use a percentage of the FOB equipment costs or a percentage of the fixed capital investment. Typical figures are 80 to 100 percent of the FOB equipment costs or 20 to 30 percent of the fixed capital investment. This method is used 

Category number Direct capital cost account titles 

Electrical This item consists of transformers, wiring, switching gear, as well as instrumentation and control wiring. The installed costs of the electrical items may be estimated as 20 to 40 percent of the delivered equipment costs or 5 to 10 percent of the fixed capital investment for preliminary estimates. As with piping estimation, the process design must be well along toward completion before detailed electrical takeoffs can be made. 

Buildings and Structures The cost of the erection of buildings and structures in a chemical process plant as well as the plumbing, heating and ventilation, and miscellaneous building service items may be estimated as 20 to 50 percent of dehvered equipment costs or as 10 to 20 percent of the fixed capital investment for a preliminary estimate. 

---

Energy needed for pumping can be a significant cost item for the inexpensive basic chemicals therefore, pressure drop must be known more accurately than calculation methods can provide. The needed accuracy can be achieved only by measuring pressure drop versus flow for every new catalyst. This measurement can now be done much better and more easily than before. Even so, for a basic understanding of correlation between pressure drop and flow, some published work must be consulted. (See Figure 1.4.1 on the next page.)... 

It is claimed that side reactions, such as the formation of thiosulfate and sulfate ions from hydrosulfide ions, are minimized because the rapid reaction between H2S and iron ferrate prevents the buildup of hydrosulfide ions in the solution. This is a distinct advantage over processes where the purging and disposal of thiosulfate salts and the requirements for chemical makeup can represent significant cost items. 

The purpose and type of analysis undertaken will determine the categories for which cost data will need to be collected. For example, hospital costs may involve identifying costs of services, facihties and overheads, while community costs may involve costs associated with visits to GPs, nurses or other health professionals. From a third party perspective one may want to consider actual charges rather than costs because often third parties do not cover total health care costs. As regards patients it is important to place a value both on their time and that of their family, as well as to take into account any out-of-pocket expenses incurred. In such matters, however, it can be important to assess the relative importance of a cost item to the overall outcome since the cost of including some minor costs may not be justified by their significance in the total picture. 

Second problem is the classification aircraft items into Significant Structural Item (SSI) influenced safety when damaged and have to be prevent and other which may be servicing to failure and then replace as correction maintenance or could be replace according to assessed life-time. This is very important classification and generate the maintenance costs and influence on safety. Mentioned above problems of the activities before or after failure based on statistical assessments of the accelerated tests data. 

By this I mean that if somebody has a small power plant, a distributed power plant for say a mall, there are two possibilities. In the first, they rely entirely on their own power plant for their needs and do not require a utility to provide a backup in the event that their own unit goes down. In the second, which is much more common, they require the utility to put a line in and be available to them as a backup. The overall costs of the two are very different. The installation of the line is a cost item, of course, but the most significant item is the reserves that the utility has to maintain— unused mostly— to be able to... 

Raw material costs are probably the single most important cost item for smelters. They normally account for as much as 30-40 per cent of total operating costs at both primary and secondary lead plants, but are likely to be proportionately more significant at the latter. Plant location is a crucial influence, as is the particular range of feed that can be processed by each smelter. Raw material costs are also closely linked to the price of refined metal. 

The nondepreciable investments, ie, land and working capital, are often assumed to be constant preoperational costs that are fully recoverable at cost when the project terminates. Equipment salvage is another end-of-life item that can represent a significant fraction of the original fixed capital investment. However, salvage occurs at the end of life, can be difficult to forecast, and is partially offset by dismantling costs. Eor these reasons, a zero salvage assumption is a reasonable approximation ia preliminary analysis. 

---