Pipe insulation, cost

Pipe insulation, cost of, 513 Pipe painting, cost of, 514 Pipe roughness, equivalent, 480, 482 Piping standards, 492-494 Piping systems cost of, 173-174, 497-510 design of, 494-497 Plant ... 

A popular overall factor refinement, known as the Hand factor approach, uses a different factor to estimate overall costs for each class of equipment to cover all labor field materials, eg, piping, insulation, electrical, foundations, stmctures, and finishes and indirect costs, but not contingencies. Hand factors range from 4 for fractionating towers down to 2.5 for miscellaneous equipment. 

The premise upon which the Lang factors are based is that the equipment costs are a certain fraction of the total cost of the plant. Or conversely, it can be said that the costs of piping, insulation, wiring, site preparation, and so on are a function of the cost of the equipment. However, the cost of equipment is very dependent on the materials used to make it, while most of the other items listed in Table 9-6 are not dependent on materials. 

Objective functions that allow only discrete values of the independent variable ) occur frequently in process design because the process variables assume only specific values rather than continuous ones. Examples are the cost per unit diameter of pipe, the cost per unit area for heat exchanger surface, or the insulation cost considered in Example 1.1. For a pipe, we might represent the installed cost as a function of the pipe diameter as shown in Figure 4.2 [see also Noltie (1978)]. For... 

Costs can be lowered with the use of newer types of pipes, insulating materials and excavation techniques. Plastic piping in long rolls is laid in plastic insulation and placed in narrow trenches. Using these techniques, hundreds of feet of pipe can be laid quickly. Metal radiators can also be replaced by plastic units. 

The optimum thickness of insulation can be established by economic analysis when all of the cost data are available, but in practice a rather limited range of thicknesses is employed. Table 8.22 of piping insulation practice in one instance is an example. 

The second step is to estimate the direct installation costs by summing all the cost factors involved in the direct installation costs, which include piping, insulation, foundation and supports, and so on. The sum of these factors is designated as the DCF (direct installation cost factor). The direct installation costs are then the product of the DCF and X. The third step consists of estimating the indirect installation cost. Here all the cost factors for the indirect installation costs (engineering and supervision, startup, construction fees, and so on) are added the sum is designated by ICF (indirect installation cost factor). The indirect installation costs are then the product of ICF and X. Once the direct and indirect installation costs have been calculated, the total capital cost (TCC) may be evaluated as follows ... 

When very high or very low temperatures are involved, insulation factors can become important, and it may be necessary to estimate insulation costs with a great deal of care. Expenses for equipment insulation and piping insulation are often included under the respective headings of equipment-installation costs and piping costs. 

The sum of costs for piping, insulation, and instrumentation can be estimated to be 60 percent of the cost for the installed equipment. Annual fixed charges amount to 15 percent of the total cost for installed equipment, piping, instrumentation, and insulation. 

Cost of pipe insulation. Price includes cost of standard covering. 

The total-cost method does not in general provide a satisfactory means for making most insulation investment decisions, since an economic return on investment is required by investors and the method does not properly consider this factor. Return on investment is considered by Rubin ( Piping Insulation—Economics and Profits, in Practical Considerations in Piping Analysis, ASME Symposium, vol. 69,1982, pp. 27-A6). The incremental method used in this reference requires that each incremental in of insulation provide the predetermined return on investment. The minimum thickness of installed insulation is used as a base for calculations. The incremental installed capital cost for each additional V2 in of insulation is determined. The energy saved for each increment is then determined. The value of this energy varies directly with the temperature level [e.g., steam at 538°C (1000°E) has a greater value than condensate at 100°C (212°F)]. The final increment selected for use is required either to provide a satisfactory return on investment or to have a suitable payback period. 

The tables were based upon the cost of energy at the end of the first year, a 10 percent inflation rate on energy costs, a 15 percent interest cost, and a present-worth pretax profit of 40 percent per annum on the last increment of insulation thickness. Dual-layer insulation was used for 3Vh-in and greater thicknesses. The tables and a full explanation of their derivation appear in a paper by F. L. Rubin (op. cit.). Alternatively, the selected thicknesses have a payback period on the last nominal Vh-in increment of 1.44 years as presented in a later paper by Rubin [ Can You Justify More Piping Insulation Hydrocarbon Process., 152-155 (July 1982)]. 

Insulation - The take-offs for piping insulation are developed as part of the piping account estimate. The take-offs for equipment insulation are developed by identifying and estimating the outside area of those items requiring insulation. The unit prices in Section 19.5 are used to estimate cost. 

Incremental investments, 315-329 Index name, 893 subject, 897 Indexes, cosf 163-166 Indirect costs, 210 in capital investments, 160, 167 Inflation, 295 strategy for, 408-413 tax effects on, 410-413 Informal reports, definition of 453- 454 Infringements of patents, 102 Installation costs for equipmenf 171-172 Instrumentation cost of 172-173, 812-814 plant requirements for, 97 Insulation cost of 172 for pipe, 513 Insurance, 262-265 as a cost, 253, 262 cost of 205, 210 Intalox saddles, 688, 690, 694 cost of 710 Interest ... 

The cost of calcium silicate insulation is a function of the nominal diameter of the pipe and the insulation thickness. Costs for several pipe diameters and thicknesses (in half-inch increments) were obtained from quotations from a reputable insulation vendor. These estimates established the functional dependence, Zj(Dn,0), of insulation cost on thickness and pipe diameter. 

The Optimal Insulation Thickness and Pipe Diameter. The principal results are embodied in Figures 7 and 8. Figure 7 shows total cost curves as functions of nominal pipe diameter for three insulation thicknesses (0 = 1.0, 3.5, and 7.0 inches). Figure 8 illustrates the piping system costs (friction, heat-loss, pipe, insulation, and total) as functions of nominal pipe diameter when the insulation thickness is optimal for that pipe diameter. 

Figure 8. Piping system costs as functions of nominalpipe diameter for 6 — 3.5 in. (1 in. — 2.54 cm) (X)> total cost (%), pipe cost fl), friction cost (-)-), insulation cost and (A), heat loss cost.

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